TW200539794A - Electromagnetic wave absorbing sheet material and electromagnetic wave absorbin body using it - Google Patents
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200539794 Η ι 九、發明說明： 【發明所屬之技術領域】 本發明係有關一種電波吸收片材及使用它之電波吸收 體。 【先前技術】 電波暗室係爲使用於天線各種特性之測定試驗或電子 裝置之電波測定試驗者。電波暗室之牆壁、天井、地面等中 組裝電波吸收體，以遮蔽來自外部的電波侵入，且自內部之 • 被測定裝置產生的電波不會放射至外部。 · 、 多數該目的所使用的電波吸收體，係使用含浸有導電性 材料之碳黑的發泡胺基甲酸酯或發泡苯乙烯等樹脂發泡體 所成形者。然而，以該樹脂發泡體成形的電波吸收體之體積 大，且硬脆於搬運時振動或與其他物體衝突致使成形體之前 端受損。因此，由於因保管空間變大使保管費變大，且由於 爲保護搬運時受到破損，於捆包時必須很大的容積，導致運 送費提高且形成成本提高的原因。 • 該問題之對策，揭示有作爲含碳黑之板材搬入施工現 β 場，且於施工現場中組裝成中空金字塔形等之電波吸收體 (參照專利文獻1、2)。然而，該含碳黑之板材之厚度過薄時， 由於剛性不充足，導致組裝後電波吸收體變形或形態不安 定，板材之厚度必須爲約5〜20mm。然而，使板材變厚的結 果，因板材之重量增大致使現場施工性惡化，且運送費亦相 當貴，碳黑之使用量亦增多等問題產生。 有鑑於該問題，本發明人等發明由積層經波狀加工的中 200539794 ^ 芯與平面狀襯墊的瓦楞紙構造所成電波吸收片材（參照作爲 先行申請案之專利文獻3)。該電波吸收片材由於以瓦楞紙構 造作爲基體，內包中空部分、爲輕量，可使搬運或現場組裝 情形佳。其中，爲保護具吸收特性之電損失材且得到長期安 定特性時，以使用在波狀中芯部含有電損失材之片更佳。 然而，包含該技術之電波吸收片材，具有該介電損失特 性之異方向性時，會產生電波吸收體於設計時極爲耗時，且 對片而言爲保持造型方向時處理性降低的問題，故以解決該 _ 異方向性爲課題。 _ 【專利文獻1】 日本特開平11-87978號公報 【專利文獻2】 日本特開2000-21 6584號公報 【專利文獻3】 日本特開2004-253760號公報 【發明內容】 本發明之課題係爲有關介電損失特性之等向性優異的 電波吸收片材及使用它之電波吸收體。 換言之，本發明係由下述構成所成。 • [1] 一種電波吸收片材，其特徵爲積層含有電損失材之 ® 含電損失材之片波形加工的中芯與平面狀襯墊的瓦愣紙構 造所成，該含電損失材之片於平面狀面內具有最大介電損失 的方向（Ρ)之介電損失（ε”ρ)與垂直該方向的方向（V)之介電損 失（ε”ν)的比例（ε”ρ/ ε”ν)爲1.2〜4的異方向性，且使該含電 損失材之片在具有最大介電損失之方向與波形頂部之稜線 大約垂直下波狀加工所成。 [2]如上述【1】記載之電波吸收片材，其中含電損失 200539794 ^ 材之片係爲含導電性纖維之混抄紙。 [3] 如上述【2】記載之電波吸收片材，其中導電性纖 維之纖維長度爲2mm〜20mm之範圍。 [4] 如上述【2】或【3】記載之電波吸收片材，其中導 電性纖維之含量爲0.1〜1 0質量％。 [5] 如上述【2】〜【4】中任一項記載之電波吸收片材， 其中含電損失材之片另含有難燃性纖維。 [6] 如上述【2】〜【5】中任一項記載之電波吸收片材， • 其中含電損失材之片另含有11〜63.9質量％纖維素纖維與 36〜88.9質量％含水無機化合物。 [7] 如上述【2】〜【6】中任一項記載之電波吸收片材， 其中混抄紙爲以水作爲介質藉由濕式抄紙法抄造者。 [8] 如上述【1】〜【7】中任一項記載之電波吸收片材， 其中含電損失材之片的坪量爲120〜200g/m2。 [9] 如上述【1】〜【8】中任一項記載之電波吸收片材， 其中使含電損失材之片波形加工的中芯之山高爲2〜5mm， _ 相鄰的頂部間之間隔爲4〜15mm。 [10] 如上述【9】記載之電波吸收片材，其中中芯之山 筒爲2.5〜5mm。 [1 1 ]如上述【1】〜【1 0】中任一項記載之電波吸收片 材，其中平面狀襯墊係含有12〜60質量％纖維素纖維與40 〜88質量％含水無機化合物。 [1 2]如上述【1】〜【1 1】中任一項記載之電波吸收片 材，其中平面狀襯墊之坪量爲12〇〜400g/m2。 200539794 ‘ [13]如上述【1】〜【12】中任一項記載之電波吸收片 材，其中瓦楞紙具有積層數張中芯所成的構造。 [14] 如上述【1 3】記載之電波吸收片材，其中積層的 數張中芯係由含電損失材之片所成的中芯與不含電損失材 之片所成的中芯構成。 [15] 如上述【1】〜【14】中任一項記載之電波吸收片 材，其中平面壓縮強度爲40〜250kPa。 [1 6 ]如上述【1】〜【1 5】中任一項記載之電波吸收片 φ 材，其中垂直壓縮強度爲I·5〜8kN/m。 [17] —種電波吸收體，其特徵爲由如上述【1】〜【16】 中任一項記載之電波吸收片所成。 [1 8]如上述【1 7】記載之電波吸收體，其中積層數張 電波吸收片材所成。 [1 9]如上述【1 7】記載之電波吸收體，其中電波吸收 片材係由選自於楔形、多角錐形及多角柱形之中空立體構造 體組裝所成。 • [20]如上述【19】記載之電波吸收體，其中使中空立 體構造體立設於燒結的純粒鐵板上所成。 [2 1 ]如上述【1 9】記載之電波吸收體，其中使中空立 體構造體立設於積層數張電波吸收片材所成的板狀體上形 成。 發明效果 藉由本發明可製得有關介電損失特性之等向性優異的 電波吸收片材。 200539794 因此，以短時間設計製得可吸收來自各方向之電波的電 波吸收片體。 【實施方式】 實施發明之最佳形態 本發明之電波吸收片材，係爲積層含有電損失材之含電 損失材之片波形加工的中芯與平面狀襯墊的瓦楞紙構造所 成。 電損失材係藉由使電波能量變換成微小電流且變換成 φ 熱能量，進行電波之銳變作用。該電損失材例如碳黑、碳微 線圈粉、石墨粉等之導電性粉末、或碳纖維、碳化矽纖維、 金屬纖維、金屬電鍍纖維等之導電性纖維。而且，對碳纖維 或碳化矽纖維之一般燒成溫度1000°C以上而言，亦可以藉由 使燒成溫度爲500〜700°C之低溫所得的半導體纖維。 含電損失材之片中電損失材之形態，特別以混抄紙之導 電性纖維較佳。於混抄紙中藉由使導電性纖維配向，可容易 控制含電損失材之片的介電損失特性之異方向性。換言之， • 若導電性纖維之配向程度愈低時含電損失材之片的介電損 失特性之異方向性愈低，若導電性纖維之配向程度愈高時含 電損失材之片的介電損失特性之異方向性愈高。就該觀點而 言，於導電性纖維中碳纖維以低比重容易混抄，且由於纖維 本身剛直容易使纖維配向，故較佳。 此外，導電性纖維之纖維長度以2〜20mm較佳。藉由 爲2mm以上時，可抑制纖維無規配向，容易控制配向，而 藉由爲20mm以下時，可防止纖維間纏繞，容易控制配向。 200539794 ^ 導電性纖維之配合量以0 · 1〜1 0質量％較佳。藉由爲ο · 1 質量％以上，可具有充分的電波吸收效果，而藉由爲1 0質量 %以下，由於沒有過剩的導電性纖維成分，可容易控制配向。 此外，混抄紙以另含有難燃性纖維較佳。如上所述，由 於電波吸收變換成電波能量之熱能量，就安全性而言作爲電 波吸收片以具備難燃性較佳。 該難燃性纖維例如有玻璃纖維、芳香族聚醯胺纖維、聚 醚醚酮纖維、聚對亞苯基苯并雙噁唑纖維、聚硫化亞苯基纖 Φ 維等。另外，可使用含浸在由非難燃性樹脂所成纖維中含有 難燃劑之樹脂混合物等所成的難燃性纖維者。該難燃劑以不 含對環境負荷大的鹵素元素者較佳，至少一種選自於縮合磷 酸酯、磷酸酯、芳香族二磷酸酯、氫氧化鎂、氫氧化鋁及紅 磷時，即使添加量少、仍可得提高爲高難燃性之效果，故爲 企求。 此外，含電損失材之片的混抄紙中，除導電性纖維外以 另含有11〜63.9質量％纖維素纖維與36〜88.9質量％含水無 # 機化合物較佳。纖維素纖維具有親水性，由於具有熱收縮之 性質，藉由瓦楞紙貼合時之熱與糊料中所含水分之作用，可 使片具有適當的剛性。惟纖維素纖維具有容易燃燒的弱點， 故藉由倂用含水無機化合物可賦予難燃性，爲所企求。該含 水無機化合物以使用氫氧化鋁等較佳。藉由使纖維素纖維爲 i i質量％以上，可賦予適當的剛性。而且，纖維素纖維之含 量的上限値，係視倂用的導電性纖維及含水無機化合物之含 量的下限値所決定。另外，藉由使含水無機化合物爲3 6質 200539794 * 量％以上，可賦予難燃性。此外，含水無機化合物之含量的 上限値，係視倂用的纖維素纖維含量之下限値所決定。 混抄紙之製法例如使纖維與水混合的漿料抄造之濕式 抄紙法，或使纖維在空氣中攪拌混合且使該物捕集成片狀之 乾式抄紙法。濕式抄紙法及乾式抄紙法中任一方法，皆可藉 由抄造方法中連續移動的網狀輸送帶之行走速度，控制混抄 紙中纖維之配向方向。換言之，若網狀輸送帶之行走速度愈 快時進行導電性纖維之配向，若行走速度愈慢時導電性纖維 • 之配向被控制的傾向。該傾向之原因係可能因網狀輸送帶之 行走方向，導電性纖維中水等之介質的電阻產生變化之故。 而且，濕式抄紙法與乾式抄紙法中，濕式抄紙法就不會 傷害導電性纖維、可保持原有性質下均勻抄造而言較佳。 於此等之抄紙法中，以添加無機結合材'或澱粉、聚乙 烯醇、聚乙烯、烯烴'丙烯酸纖維等之有機結合材較佳。藉 由添加結合材，可自抄紙網使抄紙完美地剝離。 另外，中芯所使用的含電損失材之片的坪量，以120〜 # 200g/m2較佳。藉由爲I20g/m2以上，於波形加工且黏合於 平面狀襯墊時可防止片產生破裂等情形。此外，藉由爲 200g/m2以下，可容易進行波形加工。 本發明之電波吸收片材所使用的含電損失材之片，於平 面狀之面內對具有最大介電損失的方向（p)之介電損失（ε”ρ) 與該方向垂直的方向（ν)的介電損失（ε”ν)之比例（ε”ρ/ 8%)爲 3〜18GHz的周波數範圍之電波而言以具有1.2〜4的異方向 性者極爲重要。3〜1 8 GHz之周波數範圍的電波，係波長以 200539794 、 數l〇cm〜數mm爲適當長度，較爲容易處理，測定時必要 的試樣尺寸大小以30cmx30cm較爲容易處理。因此，可較 爲精準地測定ε”。而且，在此等以外之周波數範圍下測定的 ε”ρ/ ε”ν，具有一定程度的關係，（惟以特定周波數引起特異 共鳴時除外），在此等以外之周波數範圍下可得具有吸收之 電波吸收片時，可以使具有典型的3〜18GHz測定的ε”ρ/ ε”ν 調整於上述範圍，遂而達成目的。此處，介電損失係藉由上 述能量變換表示銳變作用大小的指標之一，定義作爲下式之 鲁比介電率ε的虛數部ε”。 ❿ ε = ε，一 j ε” 對本發明所使用的含電損失材之片而言必要的異方向 性，係藉由使瓦楞紙之中芯波形加工產生，即使形狀引起的 介電損失之異方向性相抵之故。 另外，ε”ρ/ ε”ν小於1.2時無法完全吸收形狀引起的介 電損失之異方向性，大於4時無法完全吸收形狀引起的介電 損失之異方向性。ε”ρ/ ε”ν係如上所述可藉由控制抄紙中導 # 電性纖維之配向狀態予以調整。 籲 使含電損失材之片內部的介電損失之異方向性與形狀 引起的介電損失之異方向性相抵的方法，係於含電損失材之 片的平面狀面內具有最大介電損失之方向（Ρ)與波形頂部之 稜線大約垂直下波形加工極爲重要。 換言之，本發明人等發現波形引起的介電損失之異方向 性中，介電損失係在中芯波之波長方向小，垂直於該物之波 形頂部的稜線方向大，故藉由組合內在異方向性與形狀引起 -12- 200539794 • 的異方向性與各介電損失大的方向與小的方向，可使兩異方 向性相抵。 就內在異方向性與形狀引起的異方向性相抵的觀點而 言，於含電損失材之片的平面狀面內具有最大介電損失之方 向（P)與波形頂部之稜線，不須嚴密垂直，只要是可得如上 述之相抵效果程度的方向（大約垂直）下相交即可。 使含電損失材之片加工的中芯之波形形狀，本發明之電 波吸收材就形成作爲瓦楞紙之體而言山高（即振幅之2倍）爲 φ 1 mm以上，相鄰的頂部間之間隔爲1 mm以上較佳。另外， 就上述相抵的效果而言，山高以2〜5mm更佳，以2.5〜5mm 最佳。此外，相鄰的頂部間之間隔爲4 mm〜1 5 mm較佳。藉 由使山高爲2mm以上、相鄰的頂部間之間隔爲4mm以上， 可防止形狀引起的異方向性變得過大。而且，藉由使山高爲 5 mm以下，相鄰的頂部間之間隔爲1 5 mm以下，可容易得到 使上述含電損失材之片的內部異方向性相抵的效果。此外， 就作爲瓦愣紙之構件而言，就考慮貼合強度與貼合加工性兩 Φ 者時山高以上述範圍較佳，另外，就考慮貼合工程所需的工 數與強度兩者時相鄰的頂部間之間隔以上述範圍較佳。 本發明之電波吸收片材，係由使波形加工的中芯與平面 狀襯墊積層的瓦愣紙構造所成。就上述理由而言，於本發明 之電波吸收片材中至少部分波形加工的中芯使用含電損失 材之片極爲重要，使用含電損失材之片作爲中芯時，藉由平 面狀襯墊保護，可避免因外部之衝擊導致電損失材脫落或惡 化，經過長時間可保持安定的電波吸收性。而且，藉由瓦愣 -13- 200539794 w 紙構造，可內包中空部以形成輕量，且容易搬運。而且，由 於藉由內部存在中芯、具有適當剛性，可廣泛應用於各種電 波吸收體。 瓦楞紙之構造爲得到儘可能的薄片、輕量、強的片材 時，以選自於單面球段、兩面瓦楞紙、複兩面瓦楞紙或三重 壁較佳。此處，單面瓦愣紙係指在一張襯墊上張貼波形加工 的中芯之瓦楞紙構造，兩面瓦楞紙係指在2張襯墊間張貼波 形加工的中芯之瓦愣紙構造，複兩面瓦楞紙係指在兩面瓦楞 φ 紙之一面上張貼一面瓦愣紙之瓦楞紙構造，而三重壁係指在 複兩面瓦愣紙上另張貼一面瓦楞紙形成3段構造之瓦愣紙構 造。其中，爲同時具有薄度與適當剛性時，以兩面瓦愣紙更 佳。 此外，一張電波吸收片以由一張含電損失材之片所成的 中芯滿足企求的電波吸收特性時，使由含電損失材之片所成 的中芯與由不含電損失材之片所成的中芯混合積層，就不會 提高製造成本下可提高強度而言較佳。 # 平面狀襯墊之原料，亦以抄紙較佳，以含有1 2〜60質 量％纖維素纖維、與40〜88質量％含水無機化合物較佳。纖 維素纖維由於具有親水性、具有熱收縮的性質，可藉由瓦愣 紙貼合時之熱與糊料中所含水分之作用，賦予片具有適當剛 性。惟由於纖維素纖維具有容易燃燒的弱點，故以藉由倂用 含水無機化合物以賦予難燃性較佳。藉由使纖維素纖維爲1 2 質量％以上，可賦予作爲片之剛性。而且，纖維素纖維之含 量的上限値係視倂用的含水無機化合物之含量的下限値所 -14- 200539794 • 決定。此外，藉由使含水無機化合物爲40質量％以上，可賦 予難燃性。另外，含水無機化合物之含量的上限値係視倂用 的纖維素纖維之含量的下限値所決定。 而且，平面狀襯墊之坪量以120〜40 Og/m2較佳。藉由 爲120g/m2以上，與中芯黏合時可防止片產生破裂等情形。 另外，坪量過大時，導致成本提高，故以400g/m2即可。 本發明之電波吸收材中爲製得瓦楞紙構造之方法例，可 利用高速、且製造成本低之習知紙瓦楞紙的製法。具體而 φ 言，藉由使稱爲波形加工機之機械使中芯形成波形，可使表 或裏之襯墊附加糊料，製作單面瓦愣紙。另外，可利用以波 形加工機使單面瓦楞紙與襯墊密接且加熱，形成兩面或複兩 面瓦楞紙，且送入切斷機裁成所定尺寸的方法。 使中芯或平面狀襯墊等、構成瓦愣紙的構件間黏合的黏 合劑，可使用澱粉漿糊等之習知黏合劑。 本發明之電波吸收片材，係以平面壓縮強度爲40〜 2 5 0kPa較佳。藉由使平面壓縮強度爲40kPa以上，於輸送或 φ 組裝時即使受到衝擊，表面上仍不易留下擦傷情形，處理性 優異。就該觀點而言以平面壓縮強度大者較佳，惟由於過大 時會有增加重量的傾向，反而在處理性不會受損下以250kPa 爲宜。 另外，本發明之電波吸收片材以垂直壓縮強度爲1 .5〜 8kN/m較佳。藉由垂直壓縮強度爲1.5kN/m以上，即使爲大 型構造體時仍可得良好的尺寸安定性。就該觀點而言以垂直 壓縮強度大者較佳，惟過大時由於有重量增加的傾向，反而 -15- 200539794 • 在不會損害處理性下以8kN/m爲宜。 其次，本發明之電波吸收體係由本發明之電波吸收片材 所成。 本發明之電波吸收體的形態，例如以積層數張本發明之 電波吸收片材所成者較佳。藉由積層數張或調整中芯所含的 電損失材之量，可調整可吸收的電波之周波數。而且，於該 積層構成中混入不含有含電損失材之片的瓦愣紙時，就調整 可吸收的電波之周波數而言較佳。 φ 此外，其他形態以組裝楔形、多角錐形或多角柱形之中 空立體構造體所成者較佳。該中空構造體由於組裝前以裁斷 狀態、或摺疊狀態搬運，可在設置現場附近組裝，就節省輸 送W呆管費用而言較佳。另外，由於瓦愣紙具有適當的剛性， 於組裝後可具有良好的電波吸收體之形態保持性。 此外，以使上述中空立體構造體設置於燒結純粒鐵板上 所成者較佳。藉由組合燒結純粒體板，可吸收30MHz〜 300GHz之低周波電波。 • 而且’以使上述中空立體構造體設置於由積層數張本發 明電波吸收片材所成平板狀之本發明電波吸收體上較佳。藉 由組合平板狀本發明之電波吸收體，可吸收約1〜1〇〇GHz 之高周波電波。 如此本發明之電波吸收片材，可藉由作爲電波吸收體之 形態或組合使用的原料，可形成具有企求周波數之電波吸收 體。 本發明之電波吸收片材，可使用作爲構成電波暗室壁面 -16- 200539794 • 之電波吸收體的構成構件。另外’亦可使用作爲船舶或飛機 等之移動體、橋樑、鐵塔等之構造物、無線通信之裝置或設 備、大樓等之建築物、辦公室用品等之內裝材。而且，亦可 使用於簡單的密閉室中使用的電磁波密閉壁紙或電路週邊 所組裝的控制不需電波之片。如此可使用作爲吸收不需的反 射波、且爲防止電波障礙時各種形態之電磁環境對應材料。 實施例 於下述中藉由實施例更詳細地說明本發明。而且，實施 φ 例所示之性能値係以下述方法測定。 籲 [測定方法] (1)介電損失 在縱30cmx橫30cmx厚度lmm之鋁板前面經由發泡苯 乙烯製調距器配置試樣，使用弓型測定器裝置的雙富導向家 用天線與亞吉雷頓（譯音）科技公司製網路分析器以 3〜 1 8GHz之輸入阻抗。然後，取出試樣，以調距器單獨測定以 3〜18 GHz之輸入阻抗，自具有試樣時與不具試樣時之輸入 φ 阻抗差，藉由反算求取試樣之比介電率。 ® 具有試樣最大介電損失之方向（P)係決定試樣平面上之 直線軸，所決定的直線軸以10°之刻度回轉至90°，以設定 10個方向之直線軸。對各上述直線軸而言，30cmx3 0cm試 樣之一邊平行下採取1 〇張試樣。然後，對各方向軸而言， 以自雙富導向家用天線照射的電波在電介振動方向平行下 照射電波，測定輸入阻抗，且於1 0張試樣中設定比介電率 之最大試樣的直線軸方向爲（P)。 -17- 200539794 ^ (2)電波吸收性 使用上述網路分析器測定縱60cmx橫60cmx厚度1mm 之鋁板上垂直照射電波時之反射水準，且自在相同面積之電 波吸收體上照射相同的電波時下述所示反射水準之差値求 取。 (3)難燃性 以UL94 「機器零件用塑膠材料之燃燒性試驗」爲基準 測定。 φ (4)平面壓縮強度 以JIS Z 0403- 1 「瓦愣紙-第1部：平面壓縮強度試驗 方法」爲基準測定。 (5) 垂直壓縮強度 以JIS Z 0403-2 「瓦愣紙-第2部：垂直壓縮強度試驗 方法」爲基準測定。 [實施例1] (中芯用片） # 使下述纖維及含水無機化合物以各對應的記載比例與 作爲介質之水混合，以捲取速度l〇〇m/分鐘濕式抄紙，製得 厚度0.12mm、坪量100g/m2之含電損失材之片A。 平均纖維長度6mm、纖維直徑7μπι之PAN系碳纖維 :0.8質量％ 纖維長度6mm、纖維直徑7μιη之短玻璃纖維 :2 9.2質量％ 平均纖維長度1mm之芳族聚醯胺漿料 200539794 :1 0質量％ 氫氧化I呂 :6 0質量％ 於該片A之面內，具有最大介電損失之方向係爲抄紙流 動方向，具有最小介電損失之方向係爲抄紙寬度方向。該2 個方向之介電損失（ε”ρ，ε”ν)與其比例（ε”ρ/ ε”ν)如表1所示。 表1200539794 Η IX. Description of the invention: [Technical field to which the invention belongs] The present invention relates to a radio wave absorbing sheet and a radio wave absorber using the same. [Prior art] An anechoic chamber is a tester for measuring various characteristics of an antenna or a radio wave tester for an electronic device. A radio wave absorber is installed on the wall, patio, floor, etc. of the radio wave anechoic chamber to shield the radio wave from the outside from entering, and the radio wave generated from the device under test is not radiated to the outside. · Most of the radio wave absorbers used for this purpose are those formed by using resin foam such as foamed urethane or foamed styrene impregnated with carbon black impregnated with a conductive material. However, the radio wave absorber formed from the resin foam has a large volume and is brittle and vibrates during transportation or collides with other objects, causing damage to the front end of the molded body. Therefore, as the storage space becomes larger, the ambassador's storage fee becomes larger, and because of the need to protect it from damage during transportation, a large volume must be used during packing, which leads to increased transportation costs and increased costs. • The countermeasures to this problem have revealed that radio wave absorbers that have been moved into the construction site as a carbon black material and are assembled into a hollow pyramid shape at the construction site (see Patent Documents 1 and 2). However, when the thickness of the carbon black-containing sheet is too thin, the rigidity of the sheet will cause the radio wave absorber to deform or become unstable after assembly. The thickness of the sheet must be about 5 to 20 mm. However, as a result of the thickening of the plate, the site construction performance is deteriorated due to the increase in the weight of the plate, and the transportation costs are relatively expensive, and the use of carbon black is also increased. In view of this problem, the present inventors and others have invented an electromagnetic wave absorbing sheet made of a corrugated paper structure with a laminated corrugated medium 200539794 ^ core and a flat gasket (see Patent Document 3 as a prior application). Since the radio wave absorbing sheet is made of corrugated paper as a substrate, it contains a hollow portion and is lightweight, which makes it ideal for transportation or field assembly. Among them, in order to protect an electric loss material having absorption characteristics and obtain long-term stability characteristics, it is more preferable to use a sheet containing an electric loss material in a corrugated core. However, when the radio wave absorbing sheet including this technology has the different directivity of the dielectric loss characteristics, the problem that the radio wave absorber is extremely time-consuming in design and the handling property is reduced for the sheet to maintain the molding direction is caused. , So the problem is to solve this _ anisotropy. _ [Patent Document 1] Japanese Patent Application Laid-Open No. 11-87978 [Patent Document 2] Japanese Patent Application Laid-Open No. 2000-21 6584 [Patent Literature 3] Japanese Patent Application Laid-Open No. 2004-253760 [Content of the Invention] The subject matter of the present invention The invention relates to a radio wave absorbing sheet having excellent isotropic properties of dielectric loss characteristics and a radio wave absorber using the same. In other words, the present invention is constituted by the following constitution. • [1] An electric wave absorbing sheet characterized by a laminated core structure with a flat core and a corrugated paper made of a corrugated sheet containing an electric loss material® and an electric loss material. The ratio of the dielectric loss (ε "ρ) in the direction (P) with the largest dielectric loss in the plane to the dielectric loss (ε" ν) in the direction (V) perpendicular to the direction (ε "ρ / ε ”ν) is an anisotropy of 1.2 to 4, and is formed by wave-processing the sheet containing the electrical loss material in a direction having a maximum dielectric loss approximately perpendicular to a ridge line at the top of the waveform. [2] The radio wave absorbing sheet according to the above [1], wherein the sheet containing electric loss 200539794 ^ is a mixed paper containing conductive fibers. [3] The radio wave absorbing sheet according to the above [2], wherein the fiber length of the conductive fiber is in a range of 2 mm to 20 mm. [4] The radio wave absorbing sheet according to the above [2] or [3], wherein the content of the conductive fiber is 0.1 to 10% by mass. [5] The radio wave absorbing sheet according to any one of the above [2] to [4], wherein the sheet containing an electric loss material further contains a flame-resistant fiber. [6] The radio wave absorbing sheet according to any one of the above [2] to [5], wherein the sheet containing the electric loss material further contains 11 to 63.9% by mass of cellulose fibers and 36 to 88.9% by mass of water-containing inorganic compounds . [7] The radio wave absorbing sheet according to any one of the above [2] to [6], wherein the mixed paper is made by a wet papermaking method using water as a medium. [8] The radio wave absorbing sheet according to any one of the above [1] to [7], wherein the weight of the sheet containing the electric loss material is 120 to 200 g / m2. [9] The radio wave absorbing sheet according to any one of the above [1] to [8], in which the core height of the core of the wave processing of the sheet containing the electric loss material is 2 to 5 mm, _ between the adjacent tops The interval is 4 ~ 15mm. [10] The radio wave absorbing sheet according to the above [9], wherein the core tube is 2.5 to 5 mm. [1 1] The radio wave absorbing sheet according to any one of the above [1] to [10], wherein the planar gasket contains 12 to 60% by mass of cellulose fibers and 40 to 88% by mass of an aqueous inorganic compound. [1 2] The radio wave absorbing sheet according to any one of the above [1] to [1 1], wherein the flat pad has a floor mass of 120 to 400 g / m2. 200539794 ‘[13] The radio wave absorbing sheet according to any one of [1] to [12] above, wherein the corrugated paper has a structure formed by laminating a plurality of cores. [14] The radio wave absorbing sheet according to the above [13], wherein the laminated cores are composed of a core made of a sheet containing an electric loss material and a core made of a sheet without an electric loss material. [15] The radio wave absorbing sheet according to any one of the above [1] to [14], wherein the planar compressive strength is 40 to 250 kPa. [1 6] The radio wave absorbing sheet φ material described in any one of the above [1] to [1 5], wherein the vertical compressive strength is 1 · 5 to 8 kN / m. [17] A radio wave absorber comprising the radio wave absorber described in any one of [1] to [16] above. [18] The radio wave absorber according to the above [17], wherein a plurality of radio wave absorption sheets are laminated. [19] The radio wave absorber according to the above [17], wherein the radio wave absorption sheet is assembled from a hollow three-dimensional structure selected from a wedge shape, a polygonal cone shape, and a polygonal column shape. [20] The radio wave absorber according to the above [19], wherein the hollow solid structure is formed by standing upright on a sintered pure-grain iron plate. [2 1] The radio wave absorber according to the above [19], wherein the hollow solid structure is formed by standing on a plate-like body formed by laminating several radio wave absorption sheets. ADVANTAGEOUS EFFECTS OF THE INVENTION According to the present invention, a radio wave absorbing sheet having excellent isotropic properties regarding dielectric loss characteristics can be obtained. 200539794 Therefore, a short-time design has been made to obtain a radio wave absorbing sheet body that can absorb radio waves from all directions. [Embodiment] The best form for carrying out the invention The radio wave absorbing sheet of the present invention is a corrugated paper core structure with a corrugated core and a flat gasket formed by laminating a corrugated sheet of an electric loss material containing an electric loss material. The electric loss material performs a sharp change in radio waves by converting radio wave energy into minute currents and into φ thermal energy. Examples of the electrical loss material include conductive powders such as carbon black, carbon microcoil powder, and graphite powder, or conductive fibers such as carbon fiber, silicon carbide fiber, metal fiber, and metal plating fiber. In addition, for carbon fibers or silicon carbide fibers which are generally fired at a temperature of 1000 ° C or higher, semiconductor fibers obtained by lowering the firing temperature to a low temperature of 500 to 700 ° C can also be used. The form of the loss-of-electricity material in the sheet containing the loss-of-electricity material is particularly preferably a conductive fiber mixed with paper. By aligning the conductive fibers in the mixed paper, it is possible to easily control the anisotropy of the dielectric loss characteristics of the sheet containing the electric loss material. In other words, • the lower the orientation of the conductive fiber, the lower the directionality of the dielectric loss characteristics of the sheet containing the electric loss material, and the higher the orientation of the conductive fiber, the lower the dielectricity of the sheet containing the electric loss material. The higher the directivity of the loss characteristics. From this viewpoint, it is preferable that the carbon fibers are easily mixed with the low specific gravity among the conductive fibers, and the fibers are easy to align the fibers because they are straight. The fiber length of the conductive fiber is preferably 2 to 20 mm. When it is 2 mm or more, random alignment of the fibers can be suppressed, and the alignment can be easily controlled. When it is 20 mm or less, inter-fiber entanglement can be prevented, and the alignment can be easily controlled. 200539794 ^ The blending amount of the conductive fiber is preferably from 0.1 to 10% by mass. When it is ο · 1% by mass or more, a sufficient radio wave absorption effect can be obtained, and when it is 10% by mass or less, the alignment can be easily controlled because there is no excess conductive fiber component. In addition, it is preferable that the mixed paper contains flame retardant fibers separately. As described above, since the thermal energy converted into radio wave energy by radio wave absorption, it is preferable to have flame retardancy as a radio wave absorption sheet in terms of safety. Examples of the flame-retardant fibers include glass fibers, aromatic polyamide fibers, polyetheretherketone fibers, polyparaphenylenebenzobisoxazole fibers, and polysulfide fibers. In addition, a flame retardant fiber formed by impregnating a resin mixture containing a flame retardant in a fiber made of a non-flammable resin can be used. The flame retardant is preferably one that does not contain a halogen element that has a large environmental impact. At least one selected from the group consisting of condensed phosphates, phosphates, aromatic diphosphates, magnesium hydroxide, aluminum hydroxide, and red phosphorus. A small amount can still be improved to a high flame retardant effect, so it is an enterprise. In addition, the mixed paper containing the sheet of the loss-of-electricity material preferably contains 11 to 63.9% by mass of cellulose fibers and 36 to 88.9% by mass of water-containing inorganic compounds in addition to the conductive fibers. Cellulose fibers are hydrophilic. Due to their heat-shrinking properties, the heat of corrugated paper and moisture contained in the paste can be used to make the sheet rigid. However, cellulose fibers have the disadvantage of being easy to burn. Therefore, it is desirable to provide flame retardancy by using a water-containing inorganic compound. As the water-containing inorganic compound, aluminum hydroxide or the like is preferably used. By setting the cellulose fiber to a mass% or more, appropriate rigidity can be imparted. The upper limit of the content of the cellulose fiber is determined by the lower limit of the content of the conductive fiber and the water-containing inorganic compound for use. In addition, flame retardancy can be imparted by setting the amount of the water-containing inorganic compound to 3,600,2005,794,794% by weight or more. The upper limit of the content of the water-containing inorganic compound is determined by the lower limit of the content of the cellulose fibers used. The method for producing mixed paper is, for example, a wet papermaking method in which a slurry is prepared by mixing fibers with water, or a dry papermaking method in which fibers are mixed and stirred in the air and the material is collected into a sheet. Either the wet papermaking method or the dry papermaking method can control the alignment direction of the fibers in the mixed paper by the running speed of the mesh belt continuously moving in the papermaking method. In other words, if the running speed of the mesh conveyor is faster, the conductive fibers will be aligned, and if the running speed is slower, the conductive fibers' orientation will be controlled. The reason for this tendency is that the resistance of a medium such as water in conductive fibers may change due to the running direction of the mesh belt. Furthermore, among the wet papermaking method and the dry papermaking method, the wet papermaking method is preferable in that it does not damage the conductive fibers and can uniformly make the paper while maintaining the original properties. In these papermaking methods, inorganic binders or organic binders such as starch, polyvinyl alcohol, polyethylene, olefins, and acrylic fibers are preferably added. By adding a binding material, the paper can be perfectly peeled from the papermaking web. In addition, the weight of the sheet containing the lossy material used in the core is preferably 120 to 200 g / m2. When it is I20g / m2 or more, it is possible to prevent the sheet from cracking when the wave shape is processed and adhered to the flat gasket. In addition, if it is 200 g / m2 or less, waveform processing can be easily performed. The sheet containing the electric loss material used in the radio wave absorbing sheet of the present invention has a dielectric loss (ε "ρ) in a plane having a direction with the largest dielectric loss (p) in a direction perpendicular to the direction ( ν) The ratio of the dielectric loss (ε ”ν) (ε” ρ / 8%) is 3 to 18 GHz, and it is extremely important to use a wave with a frequency range of 1.2 to 4. 3 to 18 Radio waves in the GHz frequency range have a wavelength of 200539794 and a number of 10 cm to several mm as appropriate lengths, which are relatively easy to handle. The necessary sample size for measurement is easier to handle with 30 cm x 30 cm. Therefore, it can be more accurate. Ground ε ". In addition, ε ”ρ / ε” ν measured in a range of frequencies other than these has a certain degree of relationship (except when a specific resonance is caused by a specific resonance), and in other ranges of frequencies When an absorbing sheet having an electromagnetic wave is obtained, ε "ρ / ε" ν, which has a typical measurement of 3 to 18 GHz, can be adjusted to the above range, and the object can be achieved. Here, the dielectric loss is one of the indexes indicating the magnitude of the sharpening effect by the above-mentioned energy conversion, and is defined as the imaginary part ε of the Ruby dielectric constant ε of the following formula. ❿ ε = ε, a j ε "for the present invention The necessary anisotropy for the sheet containing the electrical loss material used is produced by corrugated core corrugation processing, even if the different anisotropy of the dielectric loss due to the shape is offset. In addition, when ε "ρ / ε" ν is less than 1.2, the different directionality of the dielectric loss caused by the shape cannot be completely absorbed, and when it is greater than 4, the directionality of the dielectric loss by the dielectric loss cannot be completely absorbed. ε ”ρ / ε” ν is adjusted as described above by controlling the orientation state of the conductive fibers in the papermaking paper. A method of calling for a method of offsetting the different directivity of the dielectric loss inside the sheet containing the electric loss material and the different directivity of the dielectric loss caused by the shape is to have the largest dielectric loss in the plane of the sheet containing the electric loss material. The direction (P) is approximately perpendicular to the ridge line at the top of the waveform. Wave processing is extremely important. In other words, the inventors found that in the different directivity of the dielectric loss caused by the waveform, the dielectric loss is small in the wavelength direction of the core wave and the direction of the ridge line perpendicular to the top of the waveform of the object is large. Directivity and shape caused by -12-200539794 • The different directivity and the direction of each dielectric loss are large and small, which can make the two different directivities offset. From the standpoint of the inherent heterogeneity and shape-induced heterogeneity, the direction (P) with the largest dielectric loss in the plane of the sheet containing the electrical loss material and the ridgeline at the top of the waveform need not be exactly perpendicular As long as they intersect in a direction (about vertical) where the degree of the opposite effect is obtained as described above. The corrugated shape of the core processed by the sheet containing the electric loss material. The radio wave absorbing material of the present invention is formed as a corrugated paper body with a mountain height (that is, twice the amplitude) of φ 1 mm or more, and the interval between adjacent tops. It is preferably 1 mm or more. In addition, in terms of the above-mentioned contradictory effects, Seco is more preferably 2 to 5 mm, and most preferably 2.5 to 5 mm. In addition, the interval between adjacent tops is preferably 4 mm to 15 mm. By making the height of the mountain 2 mm or more and the interval between adjacent tops 4 mm or more, it is possible to prevent the anisotropy caused by the shape from becoming too large. In addition, by setting the mountain height to 5 mm or less and the interval between adjacent tops to 15 mm or less, the effect of offsetting the internal heterogeneity of the sheet containing the electric loss material can be easily obtained. In addition, as a component of the corrugated paper, when considering both the bonding strength and the bonding processability Φ, Seco is preferably in the above range. In addition, when considering both the number of labor and strength required for the bonding process The interval between adjacent tops is preferably in the above range. The radio wave absorbing sheet of the present invention is made of a corrugated paper structure in which a corrugated core and a flat gasket are laminated. For the above reasons, it is extremely important to use a sheet containing an electric loss material in the core of at least a part of the wave processing of the radio wave absorbing sheet of the present invention. When using a sheet containing an electric loss material as the core, a flat gasket is used. Protection can avoid the loss or deterioration of electrical loss material due to external impact, and maintain stable radio wave absorptivity over a long time. In addition, with the tile structure of -13-200539794 w, the hollow part can be enclosed to form a lightweight and easy to carry. In addition, due to the presence of a core in the inner part and appropriate rigidity, it can be widely used in various radio wave absorbers. When the structure of the corrugated paper is to obtain as thin, light and strong sheets as possible, it is preferably selected from single-sided ball segments, double-sided corrugated paper, double-sided corrugated paper, or triple walls. Here, the single-sided corrugated paper refers to a corrugated corrugated paper structure with a corrugated core on one pad, and the double-sided corrugated paper refers to a corrugated corrugated paper structure with a corrugated core on two pads. Corrugated paper refers to the corrugated paper structure with corrugated paper on one side of the corrugated φ paper, and triple wall refers to the corrugated paper structure with three corrugated papers on the other side. Among them, when both thickness and appropriate rigidity are used, double-sided corrugated paper is more preferable. In addition, when a radio wave absorbing sheet uses a core made of a sheet containing a loss material to satisfy the desired radio wave absorption characteristics, the core made of a sheet containing loss of electricity material and the core without a loss material The core laminated layer formed by the sheet is better in terms of increasing strength without increasing manufacturing cost. # The material of the flat liner is also preferably papermaking, and it is preferable to contain 12 to 60% by mass of cellulose fibers and 40 to 88% by mass of water-containing inorganic compounds. Because cellulose fibers are hydrophilic and have heat shrinkage properties, they can impart proper rigidity to the sheet by the action of heat and moisture in the paste when the corrugated paper is bonded. However, since cellulose fibers have a weak point of being easily burned, it is better to impart flame resistance by using a water-containing inorganic compound. When the cellulose fiber is 12% by mass or more, rigidity as a sheet can be imparted. Moreover, the upper limit of the content of cellulose fibers is determined by the lower limit of the content of the water-containing inorganic compound for use. -14- 200539794 • Decided. Further, by setting the water-containing inorganic compound to 40% by mass or more, flame retardancy can be imparted. The upper limit of the content of the water-containing inorganic compound is determined by the lower limit of the content of the cellulose fibers for use. Moreover, it is preferable that the flat pad has a floor mass of 120 to 40 Og / m2. When it is 120 g / m2 or more, it is possible to prevent the sheet from cracking when it is bonded to the core. In addition, if the floor mass is too large, the cost will increase, so 400g / m2 is sufficient. The radio wave absorbing material of the present invention is an example of a method for producing a corrugated paper structure, and a conventional paper corrugated paper manufacturing method with high speed and low manufacturing cost can be used. Specifically, by making the core wave-shaped by a machine called a wave processing machine, it is possible to add paste to the surface or inside pads to make single-sided corrugated paper. In addition, a single-sided corrugated paper can be tightly contacted with a pad and heated by a corrugated processing machine to form double-sided or double-sided corrugated paper, and then fed to a cutting machine to cut into a predetermined size. Conventional adhesives such as a starch paste can be used as the adhesive for adhering the members constituting the corrugated paper, such as a core or a flat gasket. The radio wave absorbing sheet of the present invention preferably has a plane compressive strength of 40 to 250 kPa. By setting the plane compressive strength to be 40 kPa or more, even if it is impacted during transportation or φ assembly, scratches are not easily left on the surface, and the handleability is excellent. From this point of view, the larger the plane compressive strength is, the more the weight tends to increase when the plane compressive strength is too large, on the contrary, 250 kPa is preferable without impairing the handleability. The radio wave absorbing sheet of the present invention preferably has a vertical compressive strength of 1.5 to 8 kN / m. With a vertical compressive strength of 1.5 kN / m or more, good dimensional stability can be obtained even in a large structure. From this point of view, the larger the vertical compressive strength is, the larger it is, because it tends to increase weight, but -15-200539794 • 8kN / m is preferred without compromising handling. Next, the radio wave absorbing system of the present invention is made of the radio wave absorbing sheet of the present invention. The form of the radio wave absorber of the present invention is preferably formed by laminating a plurality of radio wave absorbent sheets of the present invention. The number of radio waves that can be absorbed can be adjusted by stacking several sheets or adjusting the amount of electrical loss material contained in the core. In addition, when the corrugated paper containing no sheet containing an electric loss material is mixed into the laminated structure, it is preferable to adjust the number of radio waves that can be absorbed. φ In addition, other forms are better made by assembling a wedge, polygonal cone, or polygonal cylindrical hollow solid structure. Since the hollow structure is transported in a cut or folded state before assembly, the hollow structure can be assembled near the installation site, which is preferable in terms of saving the cost of conveying a dead pipe. In addition, since the corrugated paper has appropriate rigidity, it can have good shape retention of the radio wave absorber after assembly. In addition, it is preferable that the hollow three-dimensional structure is provided on a sintered pure-grain iron plate. By combining sintered pure granular boards, it can absorb low frequency radio waves of 30MHz to 300GHz. • Furthermore, it is preferable that the above-mentioned hollow three-dimensional structure is provided on the radio wave absorber of the present invention formed by laminating a plurality of radio wave absorption sheets of the present invention in a flat plate shape. By combining the plate-shaped radio wave absorber of the present invention, high frequency radio waves of about 1 to 100 GHz can be absorbed. As described above, the radio wave absorbing sheet of the present invention can be formed into a radio wave absorber having a desired number of cycles by using the form or combination of raw materials used as the radio wave absorber. The radio wave absorbing sheet of the present invention can be used as a constituent member of a radio wave absorber constituting a wall surface of a radio wave anechoic chamber. In addition, it is also possible to use interior materials such as ships, airplanes, and other moving objects, structures such as bridges, towers, wireless communication devices or equipment, buildings, and office supplies. In addition, it can be used in a simple enclosed room for electromagnetic wave-sealed wallpapers or circuits. Controls that do not require radio waves are incorporated in the circuit. In this way, it can be used as an electromagnetic environment-compatible material that absorbs unwanted reflected waves and prevents various forms of radio wave disturbance. Examples The present invention will be described in more detail by the following examples. The performances shown in the examples of φ were measured by the following methods. [Measurement method] (1) Dielectric loss Samples are placed in front of an aluminum plate with a length of 30cmx 30cmx and a thickness of 1mm via a styrofoam distance adjuster. A dual-rich home antenna with a bow-type measuring device and Yagray The network analyzer made by Dunton Technology Co., Ltd. has an input impedance of 3 to 18 GHz. Then, take out the sample, and measure the input impedance at 3 ~ 18 GHz with a distance adjuster. The difference in input φ impedance between the sample with and without the sample, and the specific permittivity of the sample is calculated by inverse calculation. . ® The direction (P) with the maximum dielectric loss of the sample determines the linear axis on the plane of the sample. The determined linear axis is rotated to 90 ° at a 10 ° scale to set a linear axis in 10 directions. For each of the above-mentioned linear axes, 10 samples were taken with one side of the 30 cmx3 0 cm sample parallel. Then, for each direction axis, the radio waves radiated from the dual-fusible home antenna were irradiated with radio waves parallel to the direction of dielectric vibration, the input impedance was measured, and the maximum specific permittivity sample was set among 10 samples. The direction of the linear axis is (P). -17- 200539794 ^ (2) Radio wave absorptivity Use the above network analyzer to measure the reflection level when the radio wave is irradiated vertically on an aluminum plate with a length of 60 cmx 60 cm x a thickness of 1 mm. Determine the difference between the reflection levels shown above. (3) Flame resistance It is measured based on UL94 "flammability test of plastic materials for machine parts". φ (4) Planar compressive strength Measured based on JIS Z 0403-1 "Corrugated Paper-Part 1: Test Method for Planar Compressive Strength". (5) Vertical compressive strength is measured based on JIS Z 0403-2 "Corrugated Paper-Part 2: Test Method for Vertical Compressive Strength". [Example 1] (sheet for core) # The following fibers and water-containing inorganic compounds were mixed with water as a medium at respective corresponding ratios, and wet papermaking was performed at a winding speed of 100 m / min to obtain a thickness Sheet A of 0.12mm, loss-of-electricity material with a basis weight of 100g / m2. PAN-based carbon fibers with an average fiber length of 6 mm and a fiber diameter of 7 μm: 0.8% by mass Short glass fibers with a fiber length of 6 mm and a fiber diameter of 7 μm: 2 9.2% by mass Aramid pulp 200539794: 1 0% by mass Hydroxide I Lu: 60% by mass In the plane of the sheet A, the direction with the largest dielectric loss is the paper flow direction, and the direction with the smallest dielectric loss is the paper width direction. The dielectric loss (ε "ρ, ε" ν) and the ratio (ε "ρ / ε" ν) of the two directions are shown in Table 1. Table 1
周波數 (GHz) 中芯用片A 介電損失 比 ε”ρ ε”ν ε，，ρ/ε，，ν 3 346 189 1.8 4 300 164 1.8 5 271 148 1.8 6 277 145 1.9 7 249 130 1.9 8 214 114 1.9 9 169 94 1.8 10 149 83 1.8 11 132 80 1.7 12 120 79 1.5 13 119 78 1.5 14 118 70 1.7 15 117 64 1.8 16 103 58 1.8 17 100 56 1.8 18 90 50 1.8Frequency (GHz) Dielectric loss ratio ε ”ρ ε” ν ε ,, ρ / ε, ν 3 346 189 1.8 4 300 164 1.8 5 271 148 1.8 6 277 145 1.9 7 249 130 1.9 8 214 114 1.9 9 169 94 1.8 10 149 83 1.8 11 132 80 1.7 12 120 79 1.5 13 119 78 1.5 14 118 70 1.7 15 117 64 1.8 16 103 58 1.8 17 100 56 1.8 18 90 50 1.8
-19- 200539794 、 如表1所示，ε”Ρ/ε'對3〜18GHz之電波而言爲1.5〜1.9。 (平面狀襯墊用片） 使下述纖維及含水無機化合物以各對應的記載比例與 作爲介質之水混合’以捲取速度1 0 0 m /分鐘濕式抄紙，製得： 厚度0.12mm、坪量100g/m2、不含電氣損失材之片b。 纖維長度6mm、纖維直徑7μιη之短玻璃纖維 :3 0質量％ 平均纖維長度1mm之芳族聚醯胺漿料 _ : 10質量％ φ 氫氧化鋁 :6 0質量％ (電波吸收片材） 對上述中芯用片A而言，於片之面內具有最大介電損失 之方向與波形頂部之稜線垂直下，以波形機波形加工，製作 山高2 · 5 mm、相鄰頂部間之間隔爲5 mm之中芯。 然後，以相同的波形機以塗覆量5g/m2之澱粉系黏合劑 # 黏合上述中芯與上述平面狀襯墊用片B，製作具有兩面瓦楞 Φ 紙構造之電波吸收片材C。此時，製造瓦愣紙之輸送方向（長 度方向）與上述中芯頂部之棱線方向垂直 對該電波吸收片材C而言，使電場平行於瓦楞紙之長度 方向時與使電場平行於寬度方向時之介電損失如表2所示。 -20- 200539794-19- 200539794 As shown in Table 1, ε ″ P / ε ′ is 1.5 to 1.9 for radio waves of 3 to 18 GHz. (Plane-shaped gasket sheet) The following fibers and water-containing inorganic compounds are used in the corresponding manner. Mix the recorded ratio with water as the medium 'wet papermaking at a take-up speed of 100 m / min to obtain: a sheet with a thickness of 0.12mm, a mass of 100g / m2, and a sheet excluding an electrical loss material. Fiber length 6mm, fiber Short glass fiber with a diameter of 7 μm: 30% by mass Aramid pulp with an average fiber length of 1mm_: 10% by mass φ Aluminum hydroxide: 60% by mass (Radio-absorbing sheet) For the above-mentioned core sheet A In other words, the direction with the largest dielectric loss in the plane of the sheet is perpendicular to the ridge line at the top of the waveform, and the waveform is processed by a waveform machine to produce a core with a height of 2.5 mm and an interval between adjacent tops of 5 mm. Using the same waveform machine, a starch-based adhesive # with a coating amount of 5 g / m2 was used to bond the core and the flat sheet B described above to produce an electromagnetic wave absorbing sheet C having a double-sided corrugated Φ paper structure. At this time, Manufacture the conveying direction (length direction) of corrugated paper and the ridge line on the top of the core Direction perpendicular To this radio wave absorbing sheet C, the dielectric loss when the electric field is parallel to the length of the corrugated paper and when the electric field is parallel to the width is shown in Table 2. -20- 200539794
表2 周波數 (GHz) 電波吸收片材C 比例 長度方向 寬度方向 3 5.3 3.6 1.5 4 4.9 3.6 1.4 5 4.3 3.4 1.3 6 3.6 3.5 1.0 7 2.9 2.7 1.1 8 2.9 2.8 1.0 9 2.4 2.2 1.1 10 1.9 1.8 1.1 11 1.8 1.7 1.1 12 1.5 1.5 1.0 13 1.4 1.3 1.1 14 1.6 1.6 1.0 15 1.6 1.6 1.0 16 1.5 1.4 1.1 17 1.1 1.1 1.0 18 1 1 1.0Table 2 Frequency (GHz) Radio wave absorbing sheet C Proportional length direction Width direction 3 5.3 3.6 1.5 4 4.9 3.6 1.4 5 4.3 3.4 1.3 6 3.6 3.5 1.0 7 2.9 2.7 1.1 8 2.9 2.8 1.0 9 2.4 2.2 1.1 10 1.9 1.8 1.1 11 1.8 1.7 1.1 12 1.5 1.5 1.0 13 1.4 1.3 1.1 14 1.6 1.6 1.0 15 1.6 1.6 1.0 16 1.5 1.4 1.1 17 1.1 1.1 1.0 18 1 1 1.0
如表2所示，所得的電波吸收片材C係爲介電損失的異 方向性極小者。而且，該電波吸收片材C具有UL94 V_0之 難燃性，且平面壓縮強度爲65kPa，垂直壓縮強度爲2kN/m。 [實施例2] (電波吸收體） -21 - 200539794 使2張實施例1所得的電波吸收片材c，積層於中芯之 段目方向，以澱粉系黏合劑黏合層間，裁成60cmx60cm尺 寸，製作電波吸收體。 對該電波吸收體而言，使電場平行於瓦楞紙之長度方向 時與使電場平行於寬度方向時之電波吸收性如表3所示。As shown in Table 2, the obtained radio wave absorbing sheet C was one having extremely small anisotropy of dielectric loss. In addition, this radio wave absorbing sheet C has flame retardancy of UL94 V_0, and has a planar compressive strength of 65 kPa and a vertical compressive strength of 2 kN / m. [Example 2] (Radio wave absorber) -21-200539794 Two sheets of the radio wave absorption sheet c obtained in Example 1 were laminated in the direction of the core section, and the starch-based adhesive was used to bond between the layers, and cut into a size of 60 cmx60 cm. Manufacture of radio wave absorber. Table 3 shows the radio wave absorptivity of the radio wave absorber when the electric field is parallel to the longitudinal direction of the corrugated paper and when the electric field is parallel to the width direction.
表3 周波數 (GHz) 電波吸收體 電波吸收量（dB) 比例 長度方向 寬度方向 3 10 9 1.1 4 15 14 1.1 5 17 18 0.9 6 30 25 1.2 7 7 7 1.0 8 8 8 1.0 9 5 4 1.3 10 4 4 1.0 11 3 3 1.0 12 2 2 1.0 13 2 2 1.0 14 2 2 1.0 15 2 2 1.0 16 2 1 2.0 17 2 1 2.0 18 1 1 1.0Table 3 Frequency (GHz) Radio wave absorber radio wave absorption (dB) Proportional length direction Width direction 3 10 9 1.1 4 15 14 1.1 5 17 18 0.9 6 30 25 1.2 7 7 7 1.0 8 8 8 1.0 9 5 4 1.3 10 4 4 1.0 11 3 3 1.0 12 2 2 1.0 13 2 2 1.0 14 2 2 1.0 15 2 2 1.0 16 2 1 2.0 17 2 1 2.0 18 1 1 1.0
-22- 200539794 * 如表3所示，所得的電波吸收體係爲電波吸收性之異方 向性極小者。 [實施例3] (中芯用片） 使下述纖維及含水無機化合物以各對應的記載比例與 作爲介質之水混合，以捲取速度60m/分鐘濕式抄紙，製得 厚度0.15mm、坪量120g/m2之含電損失材之片D。 平均纖維長度12mm、纖維直徑7μιη之PAN系碳纖維 φ : 0 · 4質量％ 平均纖維長度2mm之纖維素纖維 :20質量％ 纖維長度6mm、纖維直徑20μπι之丙烯酸短纖維 :4.6質量％ 氫氧化鋁 :7 5質量％ 於該片D之面內，具有最大介電損失之方向係爲抄紙流 Φ 動方向，具有最小介電損失之方向係爲抄紙寬度方向。該2 個方向之介電損失（ε”Ρ，ε”ν)與其比例（ε”ρ/ ε”ν)如表4所示。 -23 - 200539794 表4 周波數 (GHz) 中芯用片D 介電損失 比例 ε，，Ρ ε55 ν ε”ρ/ε”ν 3 17 1 110 1.6 4 154 95 1.6 5 132 82 1.6 6 1 15 72 1.6 7 106 65 1.6 8 91 56 1.6 9 80 50 1.6 10 80 52 1.5 11 76 50 1.5 12 69 46 1.5 13 62 50 1.2 14 55 40 1.4 15 48 35 1.4 16 45 32 1.4 17 38 25 1 .5 18 35 25 1.4 如表4所示，ε”ρ/ε”ν對3〜18GHz之電波而言爲1.2 (平面狀襯墊用片） 使下述纖維及含水無機化合物以各對應的記載比例與 -24- 200539794 • 作爲介質値之水混合，以捲取速度100m/分濕式抄紙，製得 厚度0.18mm、坪量160g/m2、不含電氣損失材之片E。 平均纖維長度2mm之纖維素纖維 :2 0質量％ 纖維長度6mm、纖維直徑20μιη之丙烯酸短纖維 :5質量％ 氫氧化鋁 :7 5質量％ • · (電波吸收片材） 對上述中芯用片D而言，於片之面內具有最大介電損失 之方向與波形頂部之稜線垂直下，以波形機波形加工，製作 山高3 · 5 m m、相鄰頂部間之間隔爲8.8 m m之中芯。 然後，以相同的波形機以塗覆量5g/m2之澱粉系黏合劑 黏合上述中芯與上述平面狀襯墊用片E，製作具有兩面瓦楞 紙構造之電波吸收片材F。此時，製造瓦愣紙之輸送方向（長 • 度方向）與上述中芯頂部之稜線方向垂直。 Φ 對該電波吸收片材F而言，使電場平行於瓦楞紙之長度 方向時與使電場平行於寬度方向時之介電損失如表5所示。 -25- 200539794 表5-22- 200539794 * As shown in Table 3, the radio wave absorption system obtained is one with extremely small anisotropy of radio wave absorptivity. [Example 3] (sheet for core) The following fibers and water-containing inorganic compounds were mixed with water as a medium at respective corresponding ratios, and wet papermaking was performed at a winding speed of 60 m / min to obtain a thickness of 0.15 mm and a ping A piece D of a loss-making material containing 120 g / m2 of electricity. PAN-based carbon fibers with an average fiber length of 12 mm and a fiber diameter of 7 μm φ: 0.4% by mass Cellulose fibers with an average fiber length of 2 mm: 20% by mass Acrylic short fibers with a fiber length of 6 mm and a fiber diameter of 20 μm: 4.6% by mass Aluminum hydroxide: 75% by mass In the plane of the sheet D, the direction with the largest dielectric loss is the papermaking flow direction, and the direction with the smallest dielectric loss is the papermaking width direction. The dielectric loss (ε "P, ε" ν) and the ratio (ε "ρ / ε" ν) of the two directions are shown in Table 4. -23-200539794 Table 4 Peripheral wave number (GHz) Dielectric loss ratio of chip D for core ε ,, P ε55 ν ε ”ρ / ε” ν 3 17 1 110 1.6 4 154 95 1.6 5 132 82 1.6 6 1 15 72 1.6 7 106 65 1.6 8 91 56 1.6 9 80 50 1.6 10 80 52 1.5 11 76 50 1.5 12 69 46 1.5 13 62 50 1.2 14 55 40 1.4 15 48 35 1.4 16 45 32 1.4 17 38 25 1 .5 18 35 25 1.4 As shown in Table 4, ε ”ρ / ε” ν is 1.2 for radio waves of 3 to 18 GHz (sheets for flat gaskets). The following fibers and water-containing inorganic compounds are used at a ratio of -24- 200539794 • Mixed with water as a medium and wet papermaking at a take-up speed of 100m / min to produce a sheet E with a thickness of 0.18mm, a weight of 160g / m2 and no electrical loss material. Cellulose fibers with an average fiber length of 2mm: 20% by mass Acrylic staple fibers with a fiber length of 6mm and a fiber diameter of 20μm: 5% by mass Aluminum hydroxide: 75% by mass • • (Radio-absorbing sheet) For the above-mentioned core sheet In terms of D, the direction with the largest dielectric loss in the plane of the sheet is perpendicular to the ridge line at the top of the waveform, and is processed with a waveform machine waveform to produce a core with a height of 3.5 mm and an interval of 8.8 mm between adjacent tops. Then, the core and the sheet E for flat gaskets were bonded with a starch-based adhesive having a coating amount of 5 g / m2 by the same corrugating machine to produce an electromagnetic wave absorbing sheet F having a double-sided corrugated paper structure. At this time, the conveying direction (length direction) of the corrugated paper is perpendicular to the ridge line direction on the top of the core. Φ For the radio wave absorbing sheet F, the dielectric loss when the electric field is parallel to the length direction of the corrugated paper and when the electric field is parallel to the width direction is shown in Table 5. -25- 200539794 Table 5
周波數 (GHz) 電波吸收片材F 比例 長度方向 寬度方向 3 4.2 4.5 0.9 4 4 4 1.0 5 3.8 4 1.0 6 3.5 3.5 1.0 7 3.1 3 1.0 8 2.8 2.6 1.1 9 2.3 2.4 1.0 10 1.2 1.1 1.1 11 1.8 1.7 1.1 12 1.2 1.3 0.9 13 1.1 1.3 0.8 14 1.2 1.2 1.0 15 1.3 1.4 0.9 16 1.2 1.3 0.9 17 1.1 1.1 1.0 18 1 1 1.0Frequency (GHz) Radio wave absorbing sheet F Proportional length direction Width direction 3 4.2 4.5 0.9 4 4 4 1.0 5 3.8 4 1.0 6 3.5 3.5 1.0 7 3.1 3 1.0 8 2.8 2.6 1.1 9 2.3 2.4 1.0 10 1.2 1.1 1.1 11 1.8 1.7 1.1 12 1.2 1.3 0.9 13 1.1 1.3 0.8 14 1.2 1.2 1.0 15 1.3 1.4 0.9 16 1.2 1.3 0.9 17 1.1 1.1 1.0 18 1 1 1.0
如表5所示，所得的電波吸收片材F係爲介電損失的異 方向性極小者。而且，該電波吸收片材F具有UL94 VTM-1 之難燃性，且平面壓縮強度爲85kPa，垂直壓縮強度爲 25kN/m。 [實施例4] -26 - 200539794 ‘ （電波吸收體） 6 0cm、 之高度 作底面 之燒結 而言電 上之良 性，即 張底邊 邊3角 作底面 之燒結 而言電 由實施例3所得的電波吸收片材F切出4張底邊 高度150cm之2等邊3角形。此時，在2等邊3角形 方向與瓦愣紙之長度方向平行下裁斷。 該4張2等邊3角形之等邊間以膠帶貼合，製 60cmx60cm之中空金字塔形中空立體構造。 另外，使該電波吸收體組裝於尺寸60cmx60cm 純粒鐵磚。 φ 測定對該電波吸收體之30MHz〜18GHz之電波 波吸收特性的結果，在全部周波數範圍可得20dB以 好吸收特性。而且，該電波吸收體由於具有適當的剛 使場所移動，仍可保持良好構造體之尺寸大小。 [實施例5] (電波吸收體） 由實施例3所得的電波吸收片材材F切出4 60cm、高度150cm之2等邊3角形。此時，在2等 φ 形之高度方向與瓦楞紙之長度方向垂直下裁斷。 該4張2等邊3角形之等邊間以膠帶貼合，製 60cmx60cm之中空金字塔形中空立體構造。 另外，使該電波吸收體組裝於尺寸6 0 c m X 6 0 c m 純粒鐵磚。 測定對該電波吸收體之30MHz〜18GHz之電波 波吸收特性的結果，在全部周波數範圍可得20dB以上之良 好吸收特性。 200539794 * 實施例4及5中使用本發明之電波吸收片材時，即使裁 斷方向不同，仍可製作性能相等的電波吸收體。 [實施例6] (不含電損失材之瓦楞紙） 對實施例1之作爲平面狀襯墊用所得的相同片B而言， 以波形機波形加工，製作山高2.5mm、相鄰頂部間之間隔爲 5 mm之中芯。 然後，以相同的波形機以塗覆量5g/m2之澱粉系黏合劑 φ 黏合上述中芯與實,施例1所得相同的平面狀襯墊用片B，製 作單面的瓦愣紙構造。 (電波吸收體） 使實施例1所得的電波吸收片材C與上述單面瓦愣紙， 以單面瓦愣紙中芯側作爲黏合部，以塗覆量5g/m2之澱粉系 黏合劑貼合，製作電波吸收片材G。 對該電波吸收片材G而言，使電場平行於瓦愣紙之長度 方向時與使電場平行於寬度方向時之介電損失，與實施例1 # 所得的電波吸收片材C相等的測定結果，爲介電損失的異方 向性極小者。而且，該電波吸收片材G具有UL94 VTM-1之 難燃性，且垂直壓縮強度爲3.2kN/m。 [實施例7] (電波吸收片） 對實施例1之片A而言，在片之面內具有最大介電損失 之方向與波形頂部稜線垂直下，以波形機波形加工，製作山 高1mm、相鄰頂部間之間隔爲4mm之中芯。 -28 - 200539794 然後，使上述中芯與實施例i之平面狀襯墊B以塗覆量 5 g/m2之Μ粉系黏合劑黏合，製作具有兩面瓦愣紙構造之電 波吸收片材Η。此時’瓦楞紙製造之輸送方向（長度方向）， 與上述中芯頂部之稜線方向垂直。對該電波吸收片材Η而 言，使電場平行於瓦楞紙之長度方向時與使電場平行於寬度 方向時之介電損失如表6所示。 表6As shown in Table 5, the obtained radio wave absorbing sheet F was one having extremely small anisotropy of dielectric loss. In addition, this radio wave absorbing sheet F has flame retardancy of UL94 VTM-1, and has a planar compressive strength of 85 kPa and a vertical compressive strength of 25 kN / m. [Example 4] -26-200539794 '(Radio wave absorber) The height of 60cm, which is used as the bottom surface for sintering, is good for electricity, that is, 3 corners of the bottom edge of the sheet are used for sintering for the bottom surface. The radio wave absorbing sheet F was cut into 4 equilateral triangles with a bottom edge height of 150 cm. At this time, it is cut in a direction of 2 equilateral triangles parallel to the longitudinal direction of the corrugated paper. The 4 sheets of 2 equilateral and 3 angular shapes are bonded with an adhesive tape to form a hollow pyramid-shaped hollow three-dimensional structure of 60cmx60cm. In addition, the radio wave absorber was assembled on a 60 cmx60 cm pure iron brick. φ As a result of measuring the radio wave absorption characteristics of the radio wave absorber from 30 MHz to 18 GHz, 20 dB was obtained in the entire range of the cycle number to obtain good absorption characteristics. In addition, since the radio wave absorber has a proper rigidity for moving the place, the size of the good structure can be maintained. [Example 5] (Radio wave absorber) From the radio wave absorbing sheet F obtained in Example 3, 2 equilateral triangles of 4 60 cm and a height of 150 cm were cut out. At this time, cut in a height direction of 2 φ shape perpendicular to the length direction of the corrugated paper. The 4 sheets of 2 equilateral and 3 angular shapes are bonded with an adhesive tape to form a hollow pyramid-shaped hollow three-dimensional structure of 60cmx60cm. In addition, the radio wave absorber was assembled in a pure iron brick having a size of 60 cm x 60 cm. As a result of measuring the radio wave absorption characteristics of the radio wave absorber from 30 MHz to 18 GHz, a good absorption characteristic of 20 dB or more was obtained in the entire frequency range. 200539794 * When the radio wave absorbing sheet of the present invention was used in Examples 4 and 5, radio wave absorbers having the same performance were produced even when the cutting directions were different. [Example 6] (Corrugated paper without electrical loss material) For the same sheet B obtained as a flat gasket in Example 1, the same sheet B obtained by using a waveform machine was processed to produce a mountain height of 2.5 mm and an interval between adjacent tops. For 5 mm cores. Then, using the same corrugating machine at a coating amount of 5 g / m2, the starch-based adhesive φ was used to bond the core sheet and the same flat sheet B obtained in Example 1 to a single-faced corrugated paper structure. (Radio Wave Absorber) The radio wave absorbing sheet C obtained in Example 1 and the single-sided corrugated paper were used, and the core side of the single-sided corrugated paper was used as an adhesive part, and a starch-based adhesive was applied in a coating amount of 5 g / m2. Then, the radio wave absorbing sheet G was produced. For this radio wave absorbing sheet G, the dielectric loss when the electric field is parallel to the longitudinal direction of the corrugated paper and when the electric field is parallel to the width direction is the same measurement result as the radio wave absorbing sheet C obtained in Example 1 # , Is the one with the least directivity of the dielectric loss. In addition, the radio wave absorbing sheet G had flame retardancy of UL94 VTM-1 and a vertical compressive strength of 3.2 kN / m. [Example 7] (Radio Absorption Sheet) For the sheet A of Example 1, the direction with the largest dielectric loss in the plane of the sheet was perpendicular to the ridge line at the top of the waveform, and processed with a waveform machine waveform to produce a 1mm mountain height, phase The interval between adjacent tops is 4mm cores. -28-200539794 Then, the above-mentioned core and the flat gasket B of Example i were adhered with an M powder-based adhesive having a coating amount of 5 g / m2 to produce an electromagnetic wave absorbing sheet Η having a double-sided tile paper structure. At this time, the conveying direction (longitudinal direction) of corrugated paper manufacturing is perpendicular to the ridgeline direction of the top of the core. For this radio wave absorbing sheet, the dielectric loss is shown in Table 6 when the electric field is parallel to the longitudinal direction of the corrugated paper and when the electric field is parallel to the width direction. Table 6
周波數 (GHz) 電波吸收片材Η 比例 長度方向 寬度方向 3 4 8.5 0.5 4 3.7 8.8 0.4 5 3.9 8.6 0.5 6 2.4 8 0.3 7 4.8 10 0.5 8 5 10 0.5 9 4 8.2 0.5 10 3.7 8.1 0.5 11 3.5 7.1 0.5 12 3.2 7.2 0.4 13 3.3 7.2 0.5 14 3.4 6.9 0.5 15 3.6 6.8 0.5 16 3.8 6.6 0.6 17 3.6 6.5 0.6 18 3.7 6.4 0.6Frequency (GHz) Radio wave absorption sheet 片 Proportional length direction Width direction 3 4 8.5 0.5 4 3.7 8.8 0.4 5 3.9 8.6 0.5 6 2.4 8 0.3 7 4.8 10 0.5 8 5 10 0.5 9 4 8.2 0.5 10 3.7 8.1 0.5 11 3.5 7.1 0.5 12 3.2 7.2 0.4 13 3.3 7.2 0.5 14 3.4 6.9 0.5 15 3.6 6.8 0.5 16 3.8 6.6 0.6 17 3.6 6.5 0.6 18 3.7 6.4 0.6
-29- 200539794 ， 如表6所示，所得的電波吸收片材Η係爲介電損失的異 方向性極小者。而且，該電波吸收片材Η具有UL94 V-0之 難燃性，且平面壓縮強度爲 40kPa，垂直壓縮強度爲 1 ·5kN/m 〇 [比較例1 ] (中芯用片） 使用與實施例1所得相同的片A作爲中芯用片。 (平面狀襯墊用片） φ 使用與實施例1所得相同的片B作爲平面狀襯墊用片。 · (電波吸收片材） 對上述中芯用片A而言，於片之面內具有最大介電損失 之方向與波形頂部之稜線平行下，以波形機波形加工，製作 山高2.5mm、相鄰頂部間之間隔爲5mm之中芯。 然後，以相同的波形機以塗覆量5g/m2之澱粉系黏合劑 黏合上述中芯與上述平面狀襯墊用片B，製作具有兩面瓦愣 紙構造之電波吸收片材I。此時，製造瓦楞紙之輸送方向（長 # 度方向）與上述中芯頂部之稜線方向垂直。 Φ 對該電波吸收片材I而言，使電場平行於瓦愣紙之長度 方向時與使電場平行於寬度方向時之介電損失如表7所示。 -30- 200539794-29- 200539794, as shown in Table 6, the obtained radio wave absorbing sheet system is the one with extremely small dielectric anisotropy. In addition, this radio wave absorbing sheet Η has flame retardancy of UL94 V-0, and has a planar compressive strength of 40 kPa and a vertical compressive strength of 1.5 kN / m 〇 [Comparative Example 1] (sheet for core) Use and Examples The obtained same sheet A was used as a core sheet. (Plane-shaped gasket sheet) φ The same sheet B obtained in Example 1 was used as a plane-shaped gasket sheet. · (Radio wave absorbing sheet) For the above-mentioned core sheet A, the direction with the maximum dielectric loss in the plane of the sheet is parallel to the ridge line at the top of the waveform, and processed with a waveform machine waveform to produce a 2.5mm high mountain, adjacent The space between the tops is a 5mm core. Then, the above-mentioned core and the planar pad sheet B were bonded with a starch-based adhesive having a coating amount of 5 g / m2 by the same waveform machine to produce an electromagnetic wave absorbing sheet I having a double-faced corrugated paper structure. At this time, the conveying direction (length # degree direction) of manufacturing corrugated paper is perpendicular to the ridge line direction on the top of the core. Φ For this radio wave absorbing sheet I, the dielectric loss when the electric field is parallel to the longitudinal direction of the corrugated paper and when the electric field is parallel to the width direction is shown in Table 7. -30- 200539794
表7 周波數 (GHz) 電波吸收片材I 比例 長度方向 寬度方向 3 326 189 1.7 4 280 164 1.7 5 251 148 1.7 6 257 145 1.8 7 229 130 1.8 8 194 114 1.7 9 149 94 1.6 10 129 83 1.6 11 112 75 1.5 12 100 65 1.5 13 99 54 1.8 14 98 67 1.5 15 97 64 1.5 16 83 58 1.4 17 80 53 1.5 18 70 40 1.8Table 7 Frequency (GHz) Radio wave absorption sheet I Proportional length direction Width direction 3 326 189 1.7 4 280 164 1.7 5 251 148 1.7 6 257 145 1.8 7 229 130 1.8 8 194 114 1.7 9 149 94 1.6 10 129 83 1.6 11 112 75 1.5 12 100 65 1.5 13 99 54 1.8 14 98 67 1.5 15 97 64 1.5 16 83 58 1.4 17 80 53 1.5 18 70 40 1.8
兩方向之介電損失差爲30以上，係爲極大値，產生大 的異方向性。 -31-The difference in dielectric loss between the two directions is more than 30, which is extremely large and produces large anisotropy. -31-
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| TWI407117B (en) * | 2010-03-23 | 2013-09-01 |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2019186507A (en) * | 2018-03-30 | 2019-10-24 | デュポン帝人アドバンスドペーパー株式会社 | Electromagnetic wave absorbing sheet and manufacturing method of the same |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1187978A (en) | 1997-09-09 | 1999-03-30 | Nitto Boseki Co Ltd | Incombustible radio wave absorber |
| JP4377467B2 (en) | 1999-01-21 | 2009-12-02 | Ｔｄｋ株式会社 | Radio wave absorber assembly member and radio wave absorber using the same |
| JP4346360B2 (en) | 2002-12-25 | 2009-10-21 | 東レ株式会社 | Sheet material for radio wave absorber and radio wave absorber |
-
2005
- 2005-03-21 TW TW094108538A patent/TWI374007B/en active
- 2005-03-22 KR KR1020050023478A patent/KR101102643B1/en active IP Right Grant
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI407117B (en) * | 2010-03-23 | 2013-09-01 |
Also Published As
| Publication number | Publication date |
|---|---|
| KR101102643B1 (en) | 2012-01-04 |
| KR20060044518A (en) | 2006-05-16 |
| TWI374007B (en) | 2012-10-01 |
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