200902303 九、發明說明 【發明所屬之技術領域] 本發明係關於一種電磁波吸收性優異的層合型塗裝樹 脂之金屬板’具體地而言之，關於在導電性樹脂皮膜和金 屬板之間具有不含導電性粒子的樹脂皮膜的層合型塗裝樹 脂之金屬板。本發明的塗裝樹脂之金屬板，可以適用例如 於電子、電、光學設備等（以下，有時以電子設備代表）中 的筐體等的構成材料，例如可以用於〇〇、1^、0¥0、€0_ ROM、CD-RAM、PDP、LCD等的資訊記錄產品；個人電 腦、汽車導航儀、汽車音響/視聽設備等的電、電子、通 信相關產品；投影儀、電視機、錄影機、遊戲機等的AV 設備；影印機、印表機等的複寫器；空調室外機等的電源 箱蓋、控制箱蓋、自動販賣機、電冰箱等。 【先前技術】 隨著電子設備的高性能化、小型化的發展，要求電子 設備等的筐體電磁波遮罩性優異，以防止電子設備的內部 產生的電磁破洩漏到外部，或者侵入之電磁波從電子設備 的外部侵入到內部。所謂電磁波遮罩性，係指無論是電子 設備的內部還是外部，均能防止電磁波洩漏的特性。 自此，提出各式各樣的電子設備筐體的電磁波遮罩性 提高的方法。例如，著眼於「電磁波不僅從空氣孔和佈線 孔洩漏’亦由鋼板之間的空隙洩漏」的問題，提出了藉由 採用電鍍鋅鋼板等之這般導電性優異的材料，提高鋼板之 -5- 200902303 間的電連接，使電磁波減少洩漏的方法。但是，於該方法 中，不能充分有效地防止電磁波從空氣孔和佈線孔的洩漏 〇 另一方面，本發明的申請人公開了一種塗裝樹脂之金 屬板（特開2005 -2 1 5 72號公報及特開2006-1 61 129號公報）， 爲電磁波遮罩性得到提高的電磁波吸收性優異的鋼板，至 少於鋼板的背面（構成筐體的內部側面）上，被覆有包含磁 性粉末等的電磁波吸收添加劑的磁性塗膜。於特開2005 -21572號公報中，作爲金屬板，採用電鍍鋅鋼板（EG)，於 特開2006- 1 6 1 1 29號公報中，將金屬板的種類限定爲合金 化熔融鍍鋅鋼板（GA)。 此等技術皆著眼於「由電子設備產生的電磁波，往往 被鋼板反射而不是被鋼板吸收」這一點而開發的，如上所 述，於背面側設置磁性塗膜的話，由於在筐內產生的電磁 波在鋼板上進行多重反射後被吸收，最終發揮了從空氣孔 等洩漏到筐體外部的電磁波衰減的效果。對於多重反射的 推斷原理，於特開2005 -2 1 572號公報中有詳細的說明。另 外，於上述方法中，不僅電磁波吸收性之外，爲了使鋼板 兼具良好的加工性，將磁性塗膜的厚度控制到不妨礙電磁 波吸收性的程度。由此，上述特許公報中所述的鋼板，可 以適用於被要求能夠承受彎曲加工等嚴格加工的電子設備 用筐體的構成材料。 【發明內容】 -6- 200902303 發明所欲解決之課題 本發明的目係提供一種電磁波吸收性及加工性兩者優 異的塗裝樹脂之金屬板。 用以解決課題之手段 能夠解決上述問題之本發明的層合型塗裝樹脂之金屬 板，爲於金屬板的至少一面上，具備含有導電性粒子的導 電性樹脂皮膜（A)的塗裝樹脂之金屬板，其特徵爲於前述 金屬板和前述導電性樹脂皮膜（A)之間，具有不包含前述 導電性粒子的樹脂皮膜（B)，前述導電性樹脂皮膜（A)含有 10〜60%(質量％之意思，以下相同）的導電性粒子，且厚度 於3〜50μιη的範圍，不含前述導電性粒子的樹脂皮膜（B)的 厚度於3〜50μιη的範圍。 於最佳實施形態中，前述導電性粒子爲磁性粉末。 於最佳實施形態中，前述金屬板爲合金化熔融鍍鋅鋼 板。 根據本發明，可以得到電磁波吸收性及加工性的兩者 優異之塗裝樹脂之金屬板，故可以提供一種適用於電子設 備用筐體的構成材料。 用以實施本發明之最佳形態 本發明者們，於提出前述的特開2005 -2 1 5 72號公報及 特開2 0 0 6 - 1 6 1 1 2 9號公報所述的技術之後，欲提供一種能 夠發揮出更高的水準的電磁波吸收性，且加工性亦優異的 200902303 塗裝樹脂之金屬板，以具備磁性塗膜的塗裝樹脂之金屬板 爲中心，繼續進行了硏究。其結果’得到下述（一）~(二）的 見解。 (一） 於前述之專利公報中公開的磁性塗膜和金屬板之 間，形成作爲間隔物的不含導電性粒子的樹脂塗膜的層合 構造時，如後述的實施例所示，可以得到比原來更佳的電 磁波吸收性。如果不僅考慮到電磁波吸收性，還考慮到加 工性的話，需要將上述的間隔物的膜厚控制到指定範圍內 〇 (二） 於上述的層合型塗裝樹脂之金屬板中，用於吸收 電磁波的添加劑的種類，並不限定於迄今爲止使用的磁性 金屬粉末（代表性的有鐵矽鋁磁合金（SENDUST )與坡莫 合金（Permalloy)等），亦可使用不具備磁性的導電性金屬 粉末（例如：Al、Cu等的金屬單體等）（參考後述的實施例） 。特別是判明了使用扁平率大的導電性粒子，可以提高電 磁波吸收作用。如後述的實施例所示，與使用磁性粉末時 (實施例2)相比，採用扁平率大的金屬粉末時（實施例1)， 大致具有提高電磁波吸收性的趨勢，特別是作爲金屬板（ 原板），與採用磁性粉末時相比，採用電鍍鋅鋼板（EG)時 ，可得到顯著提高電磁波吸收性的效果（對比後述之表1與 表3) 〇 藉由製成本發明所述的層合構造，與現有的僅具有磁 性塗膜的單層構造相比，可以提高電磁波吸收性，其詳細 原理尙不清楚，但是原因可以推斷爲經由於金屬板和磁性 -8- 200902303 塗膜之間設置間隔物，於筐體內部產生的電磁波的一部份 經由磁性塗膜，於磁性塗膜和金屬板之間多重反射後被吸 收。 在本說明書中，「電磁波吸收性優異」爲指如後述的 實施例所詳述，採用後述圖5~圖7所示的測量裝置對電磁 波吸收性進行評估時，採用合金化熔融鍍鋅鋼板（GA)時的 電磁波吸收性爲4.0dB以上，採用電鍍鋅鋼板（EG)時的電 磁波吸收特性爲〇 . 5 dB以上。如此，於本說明書中，根據 金屬板（原板）的種類，對電磁波吸收性的合格標準進行了 變更，這是因爲，如所述特開2006-1 6 1 1 29號公報所公開 的那樣，與電鍍鋅鋼板（EG)相比，合金化熔融鍍鋅鋼板 (GA)的電磁波吸收性得到顯著提高。如後述的實施例所示 ，若採用本發明的層合型塗裝樹脂之金屬板，與所述特許 公報中記載的單層型塗裝樹脂之金屬板相比，不僅將GA 用作金屬板時，電磁波吸收性得到提高，將EG用作金屬 板時的電磁波吸收性也得到提高，故於本發明中，設定兩 金屬板的合格標準。 又，在本發明中，與所述特許公報中的測量相比，爲 了進一步提高電磁波吸收性的測量精度，採用圖5〜圖7所 示的測量裝置。用於評估電磁波吸收性的方法自身，於本 發明中與所述特許公報中都是一樣的，但經由本發明的發 明人員的後續硏究，結果判明採用所述專利公報中所示的 裝置（參考特開2005 -2 1572號公報中所述的圖12〜圖14，以 及特開2006- 1 6 1 1 29號公報中所述的圖6〜圖8)進行測量時 200902303 ，使樣品鋼板的被測表面與SUS製框架面（frame surface ) 接觸，顯示出包含接觸電阻損失量的電磁波吸收量（比實 際還高的測量値）。因此，在本發明中，採用圖5〜圖7的測 量裝置，改變樣品鋼板的形狀，不使樣品鋼板的被測表面 與SUS製框架面接觸，或者即使接觸也使接觸面積變小。 具體而言，將如圖5所示的貼附於SUS製框架上的樣品鋼 板的形狀，控制爲與圖6(a)、圖6(b)、圖7(a)的內側的線 一致（詳細情況如後所述）。與採用原有的測量裝置的情況 相比，採用本發明的測量裝置得到的電磁波吸收量，測量 誤差存在變少約0.1〜〇.2dB左右的傾向。 因此，對於電磁波吸收性的合格標準，比較本發明與 所述專利公報，無論爲於電鍍鋅鋼板及合金化熔融鍍鋅鋼 板中任何一方，本發明的合格標準皆定得高於所述專利公 報。首先，關於電鍍鋅鋼板，無論爲於所述的特開2005-2 1 572號公報還是於本發明中，都將合格標準定爲〇.50dB 以上，但考慮到與特開2005-2 1 572號公報相比，於本發明 中測量値被算得比較低，於是本發明的合格標準變得比較 高。另一方面，關於合金化熔融鍍鋅鋼板，於所述特開 2006-1 61 1 29號公報中，將合格標準定爲3.5dB以上，但考 慮到於本發明中將合格標準定爲比該値更高的4. OdB以上 ，因此本發明的合格標準設定的非常高。 以下，參考圖1對本發明的層合型塗裝樹脂之金屬板 進行詳細說明。 如圖1所示，本發明的塗裝樹脂之金屬板1 0，具有於 -10- 200902303 金屬板11上依次層合不含有導電性粒子的樹脂皮膜（B、下 層皮膜）12與含有導電性粒子（圖中的X)的樹脂皮膜（A、上 層皮膜）13而層合的層合構造。上述的層合構造至少被設 置於鋼板的背面（從電子設備的筐體來看爲內側）爲佳。因 爲一般要求電子設備零件的內側具有電磁波吸收性。圖1 所示爲僅於金屬板11的單面上具有上述的層合構造的方式 ，但本發明並不限定於此，對於鋼板的表面（構成筐體的 外部側面），下述任何一種方式都包含於本發明的範圍內 :(一）僅具有不含導電性粒子的樹脂皮膜的方式、（二）僅 具有包含導電性粒子的導電性樹脂皮膜的方式、（三）如本 發明，具有不含導電性粒子的樹脂皮膜與包含導電性粒子 的導電性樹脂皮膜層層合而成的層合構造的方式。 以下爲了便於說明，將不含導電性粒子的樹脂皮膜 (B)稱爲「間隔物層」；將包含導電性粒子的導電性樹脂 皮膜（A)僅稱爲「導電性皮膜」。導電性皮膜和間隔物層 ’於是否包含導電性粒子這一點上存在大的差異，樹脂皮 膜的組成可相同或是可不相同（詳情如後所述）。 於圖1中，包含導電性粒子的導電性樹脂皮膜（A) 1 3， 含有10〜60%(質量％的意思，以下相同）的導電性粒子，且 厚度於3〜5 0 μ m的範圍。藉由此，可以提高電磁波吸收性 和加工性。對比本發明的導電性皮膜和所述的特開2 0 0 5 -2 1 572號公報及特開2006- 1 6 1 1 29號公報中公開的磁性皮膜 ’兩者的差異在於使用的電磁波吸收添加劑的種類及含有 量（下限）。於本發明中’（一）不像上述專利公報那樣，將 -11 - 200902303 電磁波吸收添加劑的種類限定爲磁性粉末，而是將其擴大 至無磁性的導電性粒子（導電性粒子的詳細如後所述）’且 (二）將導電性粒子的含量之下限設爲1 〇%，與上述專利公 報中的磁性粉末的含量的下限（20%)相比，有所擴大。這 些效果皆是因爲於本發明中，採用了層合構造的構成，即 在金屬板和導電性皮膜之間設置間隔物層。 於此，用於導電性皮膜的「導電性粒子'」係指具有導 電性的金屬粒子（金屬粉末）之意思，除了具有磁性的金屬 粒子（金屬粉末）之外，亦包含無磁性的金屬粒子（金屬粉 末）。此等可單獨使用，亦可將2種以上合倂使用。 作爲具有磁性的金屬粒子（金屬粉末），例如所述特開 20 0 5 -2 1 5 72號公報及特開2 006- 1 6 1 1 29號公報中公開的磁 性粉末，代表性的有磁性合金粉末。作爲磁性合金粉末， 舉如坡莫合金（Ni-Fe系和金，Ni含量爲3 5%以上）和鐵矽鋁 磁合金（Si-Al-Fe系合金）等。 作爲無磁性的金屬粒子（金屬粉末），例如A1和Cu等的 金屬單體等。 考慮到電磁波吸收性及加工性，將上述導電性粒子的 含量設爲10-60%。導電性粒子的含量低於10%時，不能得 到期望的電磁波吸收特性。另一方面，超過60%時，除了 會降低加工性之外，還會使間隔物層和皮膜的密著性和耐 腐鈾性下降’從而不能滿足作爲電子設備零件用鋼板所要 求的特性。導電性粒子的含量最佳大致爲1 5 %以上5 5 %以 下，較佳大致爲2 0 %以上5 0 %以下。 -12- 200902303。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 A metal plate of a laminated resin coated with a resin film containing no conductive particles. The metal plate of the resin-coated resin of the present invention can be applied to, for example, a casing such as an electronic, electrical or optical device (hereinafter sometimes referred to as an electronic device), and can be used, for example, for 〇〇, 1^, Information recording products such as 0¥0, €0_ROM, CD-RAM, PDP, LCD, etc.; electrical, electronic, and communication related products such as personal computers, car navigation systems, car audio/audio equipment; projectors, televisions, and video recordings AV equipment such as computers and game machines; copywriters for photocopiers, printers, etc.; power box covers, control box covers, vending machines, refrigerators, etc. for air conditioner outdoor units. [Prior Art] With the development of high performance and miniaturization of electronic equipment, it is required that the casing of an electronic device or the like be excellent in electromagnetic wave shielding properties, so as to prevent electromagnetic leakage inside the electronic device from leaking to the outside or intrusion of electromagnetic waves. The outside of the electronic device intrudes into the interior. The electromagnetic wave shielding property is a property that prevents electromagnetic wave leakage regardless of whether it is inside or outside the electronic device. Since then, a method for improving the electromagnetic wave shielding property of various electronic device housings has been proposed. For example, focusing on the problem that the electromagnetic wave leaks not only from the air hole and the wiring hole but also from the gap between the steel sheets, it is proposed to improve the steel sheet by using a material having excellent conductivity such as an electrogalvanized steel sheet. - The electrical connection between 200902303, which reduces the leakage of electromagnetic waves. However, in this method, leakage of electromagnetic waves from the air holes and the wiring holes cannot be sufficiently effectively prevented. On the other hand, the applicant of the present invention discloses a metal plate coated with a resin (Specially Opened No. 2005 - 2 1 5 72) Japanese Laid-Open Patent Publication No. 2006-1 61 129) A steel sheet having excellent electromagnetic wave absorbability, which is improved in electromagnetic wave shielding properties, is coated with magnetic powder or the like on at least the back surface of the steel sheet (the inner side surface constituting the casing). A magnetic coating film of an electromagnetic wave absorbing additive. In Japanese Laid-Open Patent Publication No. 2005-21572, an electrogalvanized steel sheet (EG) is used as a metal plate, and the type of the metal plate is limited to an alloyed hot-dip galvanized steel sheet (JP-A-2006-0616). GA). These technologies have been developed with the aim of "electromagnetic waves generated by electronic devices are often reflected by steel sheets instead of being absorbed by steel sheets." As described above, when magnetic coating films are provided on the back side, electromagnetic waves generated in the baskets are generated. After multiple reflections are applied to the steel sheet, they are absorbed, and finally, the effect of damaging electromagnetic waves leaking from the air holes or the like to the outside of the casing is exhibited. The principle of inference for multiple reflections is described in detail in Japanese Patent Laid-Open Publication No. 2005-251. Further, in the above method, in addition to electromagnetic wave absorptivity, in order to achieve good workability of the steel sheet, the thickness of the magnetic coating film is controlled so as not to impede electromagnetic wave absorptivity. Therefore, the steel sheet described in the above-mentioned patent publication can be applied to a constituent material of a housing for an electronic device that is required to be able to withstand strict processing such as bending. OBJECT OF THE INVENTION PROBLEM TO BE SOLVED BY THE INVENTION The object of the present invention is to provide a metal plate for coating resin which is excellent in both electromagnetic wave absorbability and workability. In order to solve the above problems, the metal plate of the laminated coating resin of the present invention which is capable of solving the above problems is a coating resin containing a conductive resin film (A) containing conductive particles on at least one surface of the metal plate. The metal plate is characterized in that a resin film (B) containing the conductive particles is not contained between the metal plate and the conductive resin film (A), and the conductive resin film (A) contains 10 to 60%. The conductive particles (the same as the mass %, the same applies hereinafter) have a thickness in the range of 3 to 50 μm, and the thickness of the resin film (B) containing the conductive particles is in the range of 3 to 50 μm. In a preferred embodiment, the conductive particles are magnetic powders. In a preferred embodiment, the metal sheet is an alloyed hot-dip galvanized steel sheet. According to the present invention, it is possible to obtain a metal plate for coating resin which is excellent in both electromagnetic wave absorbability and workability, and therefore, it is possible to provide a constituent material suitable for use in an electronic housing. The present invention has been proposed by the inventors of the present invention, after the technique described in the above-mentioned Japanese Patent Publication No. Hei. No. 2005-251, and the Japanese Patent Publication No. WO 06-161 In order to provide a metal plate of a coating resin which is capable of exhibiting a higher level of electromagnetic wave absorptivity and which is excellent in workability, the metal plate of the resin coated with a magnetic coating film has been continuously studied. As a result, the following findings (1) to (2) were obtained. (1) When a laminated structure of a resin coating film containing no conductive particles as a spacer is formed between the magnetic coating film and the metal plate disclosed in the above-mentioned patent publication, as shown in the examples described later, Better electromagnetic wave absorption than the original. If not only the electromagnetic wave absorptivity is considered, but also the workability is considered, it is necessary to control the film thickness of the above-mentioned spacer to a specified range. (2) In the metal plate of the above-mentioned laminated type coating resin, for absorption. The type of the electromagnetic wave additive is not limited to the magnetic metal powder used so far (typically, such as SENDUST and Permalloy), and conductive metal having no magnetic property may be used. Powder (for example, a metal monomer such as Al or Cu) (refer to Examples described later). In particular, it has been found that the use of conductive particles having a large flattening ratio can improve the electromagnetic wave absorbing effect. As shown in the examples described later, when a metal powder having a large flat ratio is used (Example 1), it tends to have an improvement in electromagnetic wave absorptivity, particularly as a metal plate (in the case of using the magnetic powder (Example 2)). In the original plate), when an electrogalvanized steel sheet (EG) is used, an effect of remarkably improving electromagnetic wave absorptivity (compared with Tables 1 and 3 described later) can be obtained by forming the laminate according to the present invention. The structure can improve electromagnetic wave absorption compared with the existing single-layer structure having only a magnetic coating film, and the detailed principle thereof is not clear, but the reason can be inferred to be set between the metal plate and the magnetic-8-200902303 coating film. The spacer, a part of the electromagnetic wave generated inside the casing is absorbed by the magnetic coating film after multiple reflection between the magnetic coating film and the metal plate. In the present specification, the term "excellent electromagnetic wave absorptivity" refers to an alloyed hot-dip galvanized steel sheet when the electromagnetic wave absorbability is evaluated by a measuring device shown in FIGS. 5 to 7 described later, as described in detail later in the examples. The electromagnetic wave absorptivity at the time of GA) is 4.0 dB or more, and the electromagnetic wave absorption characteristic when using an electrogalvanized steel sheet (EG) is 〇. 5 dB or more. As described above, in the present specification, the eligibility criteria for electromagnetic wave absorptivity are changed according to the type of the metal plate (original plate), as disclosed in Japanese Laid-Open Patent Publication No. 2006-1 6 1 1 29 The electromagnetic wave absorbability of the alloyed hot-dip galvanized steel sheet (GA) is remarkably improved as compared with the electrogalvanized steel sheet (EG). As shown in the examples to be described later, when the metal plate of the laminated coating resin of the present invention is used, not only the GA is used as the metal plate as compared with the metal plate of the single-layer coating resin described in the above-mentioned patent publication. In this case, the electromagnetic wave absorbability is improved, and the electromagnetic wave absorbability when EG is used as a metal plate is also improved. Therefore, in the present invention, the qualification criteria of the two metal plates are set. Further, in the present invention, in order to further improve the measurement accuracy of the electromagnetic wave absorptivity, the measuring device shown in Figs. 5 to 7 is used as compared with the measurement in the above-mentioned patent publication. The method for evaluating the electromagnetic wave absorptivity itself is the same as in the above-mentioned patent publication, but it is found through the subsequent study of the inventors of the present invention that the device shown in the patent publication is used ( Referring to Figs. 12 to 14 described in Japanese Laid-Open Patent Publication No. Hei. No. 2005-2 1572, and FIG. 6 to FIG. The surface to be measured is in contact with a frame surface of SUS, and exhibits an electromagnetic wave absorption amount (measurement 値 higher than the actual value) including the amount of contact resistance loss. Therefore, in the present invention, the shape of the sample steel sheet is changed by using the measuring device of Figs. 5 to 7, so that the surface to be tested of the sample steel sheet is not brought into contact with the surface of the SUS frame, or the contact area is made small even if it is in contact. Specifically, the shape of the sample steel sheet attached to the SUS frame as shown in FIG. 5 is controlled to match the line on the inner side of FIGS. 6( a ), 6 ( b ), and 7 ( a ) ( The details are as described later). Compared with the case where the conventional measuring device is used, the electromagnetic wave absorption amount obtained by the measuring device of the present invention tends to be less than about 0.1 to about 2. dB. Therefore, for the eligibility criteria for electromagnetic wave absorptivity, comparing the present invention with the above-mentioned patent publication, the qualification criteria of the present invention are set higher than either of the electrogalvanized steel sheets and the alloyed hot-dip galvanized steel sheets. . First, regarding the electrogalvanized steel sheet, the qualification standard is set to 〇.50 dB or more in the above-mentioned Japanese Patent Publication No. 2005-2 1 572 or in the present invention, but considering the special opening 2005-2 1 572 Compared with the bulletin, in the present invention, the measurement enthalpy is calculated to be relatively low, and thus the qualification standard of the present invention becomes relatively high. On the other hand, in the alloyed hot-dip galvanized steel sheet, the qualification standard is set to 3.5 dB or more in the above-mentioned Japanese Patent Publication No. 2006-1 61 1 29, but it is considered that the qualification standard is determined as compared with the present invention.値 Higher than 4. OdB, so the qualification criteria of the present invention are set very high. Hereinafter, the metal plate of the laminated coating resin of the present invention will be described in detail with reference to Fig. 1 . As shown in Fig. 1, the resin-coated metal sheet 10 of the present invention has a resin film (B, lower layer film) 12 which does not contain conductive particles in the order of -10 200902303 metal plate 11, and contains conductivity. A laminated structure in which a resin film (A, an upper film) 13 of particles (X in the drawing) is laminated. It is preferable that the above laminated structure is provided at least on the back surface of the steel sheet (the inner side as viewed from the casing of the electronic device). This is because electromagnetic wave absorption is generally required on the inside of parts of electronic equipment. 1 shows an embodiment in which the above-described laminated structure is provided only on one surface of the metal plate 11, but the present invention is not limited thereto, and the surface of the steel sheet (the outer side surface constituting the casing) may be any of the following methods. It is included in the scope of the present invention: (1) a method having only a resin film containing no conductive particles, (2) a method having only a conductive resin film containing conductive particles, and (3) having the present invention, A laminate structure in which a resin film containing no conductive particles and a conductive resin film layer containing conductive particles are laminated. Hereinafter, for convenience of explanation, the resin film (B) containing no conductive particles is referred to as a "spacer layer", and the conductive resin film (A) containing conductive particles is simply referred to as "conductive film". The conductive film and the spacer layer have a large difference in whether or not the conductive particles are contained, and the composition of the resin film may be the same or different (details will be described later). In Fig. 1, the conductive resin film (A) 13 containing conductive particles contains 10 to 60% by mass of the conductive particles, and the thickness is in the range of 3 to 50 μm. . Thereby, electromagnetic wave absorption and workability can be improved. The difference between the conductive film of the present invention and the magnetic film disclosed in Japanese Laid-Open Patent Publication No. Hei. No. 2006-61 1 1 29 is the electromagnetic wave absorption used. The type and content of the additive (lower limit). In the present invention, (a), unlike the above-mentioned patent publication, the type of the electromagnetic wave absorbing additive of -11 - 200902303 is limited to a magnetic powder, but is expanded to non-magnetic conductive particles (the details of the conductive particles are as follows) The above-mentioned "and (2) the lower limit of the content of the conductive particles is set to 1% by weight, which is larger than the lower limit (20%) of the content of the magnetic powder in the above-mentioned patent publication. These effects are all due to the fact that in the present invention, a laminate structure is employed, that is, a spacer layer is provided between the metal plate and the conductive film. Here, the "electroconductive particle" used for the conductive film means a metal particle (metal powder) having conductivity, and includes magnetic particles (metal powder) and non-magnetic metal particles. (mineral powder). These may be used alone or in combination of two or more. The magnetic powder disclosed in Japanese Laid-Open Patent Publication No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. Alloy powder. Examples of the magnetic alloy powder include permalloy (Ni-Fe system and gold, Ni content of 35% or more) and iron-bismuth aluminum magnetic alloy (Si-Al-Fe alloy). As the non-magnetic metal particles (metal powder), for example, a metal monomer such as A1 or Cu or the like. The content of the above conductive particles is set to 10 to 60% in consideration of electromagnetic wave absorbability and workability. When the content of the conductive particles is less than 10%, the desired electromagnetic wave absorption characteristics cannot be obtained. On the other hand, when it exceeds 60%, in addition to the decrease in workability, the adhesion between the separator layer and the film and the uranium resistance of the film are lowered, and the characteristics required for the steel sheet for electronic device parts cannot be satisfied. The content of the conductive particles is preferably substantially 15% or more and 55% or less, preferably about 20% or more and 50% or less. -12- 200902303
導電性粒子的平均粒徑最佳大致爲以下，盡可 能除去大粒徑（例如3 0 μ m以上）的粉末爲佳。藉由此，使導 電性皮膜的形成變得容易，從而抑制加工性和耐腐鈾性的 下降。導電性粒子的平均粒徑，表示經由一般的粒度分佈 計，對分級後的粒子的粒度分佈進行測量’於基於該測量 結果算出的小粒徑一側得到出的積算値50%的粒度（D50)。 關於的粒度分佈，可以經由將光照射到粒子上產生的衍射 和散射的強度圖案進行測量，作爲這樣的粒度分佈計，例 如日機裝公司製作的Microtrac 9229FRA和Microtrac HRA 等。 又，滿足上述最佳平均粒徑的導電性粒子，亦可使用 市場銷售產品。例如，坡莫合金（78%Ni)〔日本ATOMIZE 加工（股份有限公司）製作的SFR-PCl、平均粒徑5.7μιη〕 、坡莫合金（45 %Ni)〔日本ATOMIZE加工（股有限公司） 製作的SFR-PB45、平均粒徑5·8μιη 〕；鐵矽鋁磁合金〔 日本ATOMIZE加工（股份有限公司）製作的SFR_ FeSiAl(84.5-10-5.5)、平均粒徑 6·9μιη〕等。 又’最佳導電性粒子的形狀爲扁平狀。如後述的實施 例所示’採用具有扁平形狀的添加劑〔旭化成鋁粉漿Μ· 3 0 1、粒徑1 9 μ m、厚〇. 4 μ m〕時，與採用具有不規則形狀 的添加劑〔坡莫合金（7 8 %N i )、三菱製鋼（股份有限公司） 製作、平均粒徑7 · 8 μηι〕時相比’電磁波吸收性顯著提高 〇 導電性皮膜的厚度設爲3〜50μιη(參考後述的實施例）。 -13- 200902303 導電性皮膜的厚度低於3 μιη時，除了不能得到期望的電磁 波吸收性之外’多數導電性粒子還會出現在皮膜上，導致 外觀性不佳、導電性粒子脫落等之問題。另一方面，導電 性皮膜的厚度超過5 0 μ m時，則導致彎曲加工性下降。導 電性皮膜的最佳厚度，詳細地可以藉由使用的導電性粉末 的種類與含量等發生變化，但大致爲4μιη以上40μιη以下， 較佳的厚度約爲5 μιη以上3 0 μιη以下。 導電性皮膜以及後述的間隔物層的厚度，可以經由比 重換算方法由皮膜重量測出’或者可以經由顯微鏡觀察 (S ΕΜ照片觀察）測量樹脂皮膜的截面而得到。 另一方面’欲同時使電磁波吸收性及加工性之兩者提 高’將間隔物層（不含導電性粒子的樹脂皮膜）1 2的厚度設 爲3〜5 0 μ m的範圍。如後述的實施例所述，間隔物層的厚 度低於3 μηι時’則電磁波吸收性的提高效果變小，反之， 厚度超過5 0 μ m時加工性下降。間隔物的最佳厚度約爲5 ^ m 以上30μηι以下，較佳厚度大致爲8μηι以上2〇μηι以下。 上述的導電性皮膜1 3及間隔物層1 2的樹脂可以爲相同 材料或是可爲不同。無論如何，作爲構成此等樹脂皮膜的 基底樹脂’例如聚酯類樹脂、丙烯酸類樹脂、尿烷類樹脂 、聚烯烴類樹脂、氟類樹脂、矽類樹脂以及此等樹脂的混 合物或改性了的樹脂等。此外，本發明的塗裝樹脂之金屬 板，主要用於電子設備的筐體，考慮到對彎曲加工性、皮 膜密著性、耐腐蝕性等特性具有更高的要求，最佳使用聚 酯樹脂或者改性聚酯樹脂（例如，在不飽和聚酯中加入環 -14- 200902303 氧樹脂而使之改性的樹脂）。 樹脂皮膜中除了包含所述的基底樹脂外’還可以再含 有交聯劑。對於交聯劑的種類並不作特殊的限定’只要是 塗裝樹脂之金屬板中通常採用的交聯劑即可’例如三聚氰 胺（melamine )類化合物、異氰酸脂類化合物等。此等化 合物可以單獨使用或適亦可以合倂使用。最佳交聯劑的含 量（合計量）大致位於0.5〜30質量％的範圍內。 樹脂皮膜中除了包含所述的基底樹脂與交聯劑之外， 還可以包含公知的添加劑（例如：防銹劑、消光劑、顏料 等）。 對用於本發明使用之金屬板1 1並不作特殊的限定，冷 軋鋼板、熱軋鋼板、電鍍鋅鋼板（EG)、熔融鍍鋅鋼板（GI) 、鋅與鐵族元素（Fe、Co、Ni)的合金鍍敷鋼板〔特別是合 金化熔融鍍鋅鋼板（GA)〕、5%A1-Zn鍍敷鋼板、55%A1-Zn 鍍敷鋼板、A1等的各種鍍敷鋼板、不銹鋼鋼板等的鋼板類 ，與公知的金屬板等全部可以適用。 從提高電磁波吸收性的觀點來看，最佳採用鋅和鐵族 元素（Fe、Co、Ni)的合金鍍敷鋼板。作爲鋅和鐵族元素的 合金鑛敷鋼板'例如Zn和Fe的合金鑛敷鋼板、Zn與Ni的 合金鍍敷鋼板、Ζ η和C 〇的合金鍍敷鋼板。從確保電磁波 吸收性的觀點來看，最佳將F e、N i、C 〇的含量皆控制於約 5〜2 0 %的範圍內。此外，對電鍍的方法也不作特殊限定， 可以採用熱浸鍍法、電鍍法的任何一種。此外，對於熱浸 鍍法、電鍍法的詳細電鍍條件也不作特殊限定，可以採用 -15- 200902303 通常使用的方法。 考慮到電磁波吸收性，鍍敷附著量 佳爲50g/m2以下，較佳爲40g/m2以下， ，最佳爲3 Og/m2以下。從電磁波吸收性 敷附著量的下限並不作特殊限定，但考 題，例如最佳爲5g/m2，較佳爲10g/m2。 再者，考慮到成本等問題，最佳使 造的合金化熔融鍍鋅鋼板（經由熱浸鑛； 的鋼板、GA)。 如上所述，在本發明中，作爲金屬 鍍敷鋼板，但除此之外，也可以使用將 約1 5 g/m2以下的純鋅鍍敷鋼板和冷軋鋼 進行這般合金化的鋼板，可以避免因使 的問題（例如，於彎曲加工時產生的裂，彳 等）。 例如，若採用沒有進行電鍍的冷軋 嚴格加工的用途。但是，由於冷乳鋼板 慮到適用於電子設備的筐體時，其綜合 故比冷軋鋼板，最佳使用合金化鍍敷鋼; 另一方面，若採用純鋅鍍敷鋼板， 烈、且要求具有耐腐蝕性的用途。爲了 蝕性，最佳鍍敷附著量爲約3g/m2以上， 。此外，考慮到電磁波吸收性，最佳鍍 15g/m2，較佳爲 12g/m2，更佳爲 10g/m2 ' 以少爲優，例如最 更佳爲35g/m2以下 的觀點來看，對鍍 慮到耐腐蝕性的問 用可廉價且簡便製 去將Zn和Fe合金化 板推薦使用合金化 鍍敷附著量控制於 板。經由採用沒有 用合金化鋼板引發 改等的裂縫和剝離 鋼板，可以使用於 的耐腐蝕性差，考 性特性評估變低， 板。 可以適用於加工劇 有效充分發揮耐腐 較佳爲6g/m2以上 敷附著量的上限爲 -16- 200902303 爲了提高金屬板的耐腐蝕性，和金屬板與樹脂皮膜的 密著性，也可以對金屬板進行鍍鉻處理和磷酸鹽處理等表 面處理（底層處理）。或者考慮到環境污染問題，也可以使 用非鉻處理的金屬板，任何一種進行了底層處理的金屬板 亦包含在本發明的範圍內。 另外，對於非鉻處理的方法也不作特殊限定，通常， 只要進行使用的公知的底層處理即可。具體而言，可以推 薦單獨或合併使用磷酸鹽類、氧化矽類、鈦類、锆類等的 底層處理。 此外，一般情況下進行非鉻處理時會導致耐腐蝕性下 降，故，爲了提高耐腐蝕性，也可以於塗膜中或底層處理 時使用防銹劑。作爲上述防銹劑，例如氧化矽類化合物、 磷酸鹽類化合物、亞磷酸鹽類化合物、聚磷酸鹽類化合物 、硫黃類有機化合物、苯并三唑、丹寧酸、鉬酸鹽類化合 物、鎢酸鹽類化合物、釩類化合物、矽烷偶聯劑等。此等 可單獨使用或適亦可合倂使用。特別最佳合併使用氧化矽 類化合物（例如：鈣離子交換氧化矽等）與磷酸鹽類化合物 、亞磷酸鹽類化合物、聚磷酸鹽類化合物（例如：三聚磷 酸鋁等），推薦於質量比率爲0.5-9.5: 9.5〜0.5(較佳爲1: 9~9 : 1)的範圍內合倂使用氧化矽類化合物（磷酸鹽類化合 物、亞磷酸鹽類化合物或者聚磷酸鹽類化合物）。藉由將 氧化矽類化合物控制於該範圍內，可以同時確保得到期望 的耐腐蝕性和加工性。 經由使用上述防銹劑，可以確保無鉻處理金屬板的耐 -17- 200902303 腐蝕性，但相反也會因爲添加防銹劑導致加工性下降。因 此’作爲塗膜的形成成份，特別推薦將環氧改性聚酯類樹 脂以及/或者酚醛衍生物導入到骨架中而成的聚酯類樹脂 以及交聯劑（最佳異氰酸脂樹脂以及/或者三聚氰胺類樹脂 ’較佳爲兩者合倂使用）組合後使用。 其中，與聚酯類樹脂相比，將環氧改性聚酯類樹脂以 及/或者酚醛衍生物導入到骨架中而成的聚酯類樹脂（例如 :將雙酚A導入導骨架中而成的聚酯類樹脂等）具有更優的 耐腐蝕性及塗膜密著性。 另一方面，異氰酸脂類交聯劑具有提高加工性的作用 (指提高加工後的外觀性的作用，在後述的實施例中，用 密著性試驗中的裂紋數進行評估），藉由此即使添加了防 銹劑，也能夠確保優良的加工性。 又，三聚氰胺類交聯劑具有優良的耐腐飩性。因此於 本發明中，經由與所述的防銹劑合倂使用，可以得到非常 優良的耐腐蝕性。 也可以單獨使用此等異氰酸脂類交聯劑及三聚氰胺類 交聯劑，但兩者合倂使用時，可以進一步提高非鉻處理金 屬板的加工性及耐腐蝕性。具體而言，推薦相對於.1 〇 〇質 量份的異氰酸脂類樹脂’以5〜80質量份的比例包含三聚氰 胺類樹脂。三聚氰胺類樹脂低於5質量份時，不能得到期 望的耐腐蝕性，反之’三聚氰胺類樹脂超過80質量份時， 不能很好地發揮添加異氰酸脂類樹脂的作用，因此不能得 到期望的提高加工性的效果。較佳爲對於1 0 0質量份的異 -18- 200902303 氰酸脂類樹脂’添加10質量份以上、40質量份以下的三聚 氰胺類樹脂；更佳爲添加15質量份以上、30質量份以下的 三聚氰胺類樹脂。 本發明的塗裝樹脂之金屬板，爲於金屬板（亦包含進 行了上述底層處理的金屬板）的表面上，被覆包含上述各 種添加劑的樹脂皮膜而成者，根據需要，爲了達到賦予耐 瑕疵性和耐指紋性等的目的，亦可於導電性皮膜的表面上 ，再施加其他的樹脂皮膜而形成三層的皮膜構造。 接者，對本發明的塗裝樹脂之金屬板的製造方法進行 說明。 本發明的塗裝樹脂之金屬板係以公知的塗裝方法，將 除了基底樹脂及交聯劑之外，根據需要包含各種添加劑的 塗料’塗佈於金屬板的表面上，經由燒成，依次形成指定 的間隔物層及導電性樹脂皮膜。即，於進行用於形成間隔 物層的塗裝進行燒成後，進行於該塗裝上形成導電性樹脂 皮膜的塗裝，進行燒成，形成於間隔物層上形成了導電性 樹脂皮膜的構成。 塗料的固形成份濃度，可以根據使用的塗料的黏度和 塗裝條件等進行適當調整，使其達到容易塗佈的程度，最 tfc大：tj(爲1〇〜50%的範圍內。 考慮到由於用於稀釋塗料的溶劑種類的不同，使塗料 流入到金屬板的榖部（凹部）的程度發生變化等，最佳燒成 條件爲於大致丨分鐘之內完成燒成。 對塗裝方法並不作特殊限定’例如對表面進行清潔後 -19- 200902303 ，根 理等 式淋 行乾 塗裝 零件 件， 述電 設備 PDP 汽車 儀、 表機 自動 【實 發明 後述 於本 據需要施加塗裝前處理（例如：磷酸鹽處理、鍍鉻處 )的長尺狀金屬帶表面上，採用輥塗法、噴塗法、幕 塗法等對塗料進行塗佈，然後使其經由熱風乾燥爐進 文荣的方法等。考慮到被膜厚度的均勻性和處理成本、 效率等綜合因素，從實用上最佳爲輥塗法。 作爲本發明的塗裝樹脂之金屬板能夠適用的電子設備 ’例如有於封閉空間中內藏半導體元件的電子設備零 也包含該電子設備零件的外壁的全部或者一部份由上 子設備零件用塗裝體構成的電子設備零件。上述電子 零件’例如 CD、LD、DVD、CD-ROM ' CD-RAM、 、：LCD等的資訊記錄產品；個人電腦、汽車導航儀、 音響/視聽設備等的電、電子、通信相關產品；投影 電視機、錄影機、遊戲機等的A V設備；影印機、印 等的複寫器；空調室外機等的電源箱蓋、控制箱蓋、 販賣機、電冰箱等。 施方式】 實施例 以下’舉出實施例對本發明進行更具體的說明，但本 並不受下述實施例的限制，也可以於能夠適合前述、 的宗旨的範圍內’適當加以變更後實施，此等均包含 發明的技術範圍內。 實施例1 -20- 200902303 於本實施例中’作爲導電性粒子，對使用沒有磁性的 金屬粒子時的電磁波吸收性及加工性進行了調查。作爲金 屬板，使用了電鍍鋅鋼板（板厚：〇.8mm;表面和背面分別 形成有鍍敷附著量爲20g/m2的電鍍層）及合金化熔融鍍鋅 鋼板（板厚：〇.8mm;表面和背面分別形成有鍍敷附著量爲 3〇g/m2的電鍍層，鍍敷中的Fe含量爲1〇.3%)2種。 用於形成導電性皮膜及間隔物層的塗料的調製方法如 下。 (導電性皮膜用塗料的調製） 首先，作爲基底樹脂使用東洋紡織（股份有限公司）製 作的聚酯樹脂「BYLON GK780」作爲交聯劑使用住友化 學（股份有限公司）製作的三聚氰胺樹脂「SUMI MARL Μ-4〇ST」’以重量比80 : 20混合基底樹脂與交聯劑（固形成 份占80%)製成基質樹脂，作爲導電性粒子，添加旭化成（ 股份有限公司）製作的「鋁粉漿Μ - 3 0 1」（固形成份6 6 %、 粒徑19μιη、厚0·4μιη)，添加量如表1及表2所表示之量（樹 脂皮膜中的含量）。爲了使該原料組成物的固形成份濃度 達到1 5 %或3 0 %，用二甲苯/環己酮混合溶劑（二甲苯：環 己酮=1: 1)進行稀釋，以l〇〇〇〇rpm的轉速用手動勻獎器 攪拌1 〇分鐘，調製成原料組成物。 (間隔物層用塗料的調製） 除了不添加導電性粒子之外，其他與在前述的導電性 -21 - 200902303 皮膜用塗料的調製相同，調製成原料組成物。 將由此製成的各樹脂皮膜用原料組成物使用棒塗佈法 塗佈於各種金屬板上’使其達到表丨及表2所表示的膜厚， 於熱風乾燥爐內，於到達板溫2 3 0。(：時進行大約1 2 0秒鐘的 燒成，製成塗裝樹脂之金屬板。經由改變稀釋塗料的固形 成份濃度以及棒塗裝所使用棒的支數，使樹脂皮膜的厚度 於2〜6 0 μ m的範圍內變化。例如，於表2的N 〇. 2 (比較例） 中’使用No.18的棒於GA (合金化熔融鍍鋅鋼板）上，塗 佈固形成份30%的塗料（鋁粉漿M-301係固形成份中30重 量％ ) ’塗佈間隔物層組成物或導電性組成物時，於設定 爲板溫度到達2 3 0 °C的熱風乾燥爐內，加熱1 2 0秒使塗料硬 化。得到的塗裝膜的厚度爲8 μ m。另外，於表2的N 〇. 3 ( 實施例）中，使用No.12的棒於GA(合金化熔融鍍鋅鋼板 )上，塗佈固形成份33.4%的聚酯塗料，於設定爲板溫度 到達23 0°C的熱風乾燥爐內，加熱1 20秒使塗料硬化。得到 的塗裝膜的厚度爲5 μιη。將該皮膜作爲下層皮膜（間隔物 層）經由與所述No.2相同的條件賦予含有鋁粉漿Μ-301的 塗膜（上層皮膜）。合計的塗裝膜厚度爲13 μιη。 樹脂皮膜的平均厚度可以藉由如下所表示的方法求出 。首先，向塗料中以1〜1 〇重量％的重量比例添加二氧化矽 (si〇2)作爲指示物，經由螢光X射線分析法對si附著量進 行了測量。對s i附著量進行測量時’預先製成表示s i量和 螢光X射線強度的關係的檢量線’根據該檢量線對S i附著 量進行測量。其次’經由比重換算’由如上所述測得的s i -22- 200902303 附著量，進行比重換算，算出樹脂皮膜的重量’求出平均 厚度ί(μιη)。具體的換算方法如下所表示。 樹脂皮膜的平均厚度{A/(BxCxD)} χίοοο 公式中 A = Si附著量（mg/m2) B = 2 8/60(Si/SiO2) C = S i O 2的重量比例 D =樹脂皮膜的比重（g/cm3) 關於由此製得的塗裝樹脂之金屬板’如下所述對其電 磁波吸收性及加工性進行了評估。 (電磁波吸收性的評估） 圖2係表示塗裝樹脂之金屬板的電磁波吸收性能的評 估方法的說明圖。如圖2所示，於直方體形狀的筐體1內， 設置有高頻環形天線5，構成爲磁場結合。高頻環形天線5 經由端子（未圖示）連接於同軸電纜6的一端上，同軸電纜6 的另一端連接在網路分析儀7上。在網路分析儀7中，在掃 引頻率的同時產生電磁波，經同軸電纜6、高頻環形天線5 ，電磁波被輸入（高頻輸入波：箭頭B)到筐體1內。在筐體 1的共振頻率數中，因爲輸入的電磁波被蓄積，可以觀察 到反射量變少的特性（參考圖3)。而且，用箭頭C表示的高 頻反射波，作爲觀察値被輸入（高頻反射波：箭頭C)到網 -23- 200902303 路分析儀7中。 此時，如果計測筐體1中經由下述公式（1)求出的Q値 的話，可知蓄積在筐體1內的能量的大小。此外’經由下 述公式（1)求出的Q値，因爲滿足導納軌道（admittance track)的條件，可以由求得的頻率差値△ f和共振頻率數fr 算出（例如：中島將光著，《森北電工學系列3微波工 學一基礎和原理一》，森北出版股份有限公司發行，第 159〜163頁）。 Q値=fr/Δ f ....(1) 有上述公式（2)求出的Q値越小，表示於筐體1內蓄積 的能量減少。所以，Q値變得越小，被從筐體1反射到內 部的電磁場水準也減少。 圖4所表示爲此時狀態的模式圖，該圖所表示爲於E z =〇、TEqh即最低頻率的共振模式下的電磁場分佈，圖中 E表示高頻磁場，F表示高頻電場。上述Ez表示z方向的電 場強度，TEo 1!表示共振模式的電磁場分佈的姿態。該TE 表示電磁波向z方向前進，其橫方向上存在於電場。數字 「011」表示對於X、y、z方向，在y及z方向上存在1個電 場的強度分佈，在X方向上電場的強度分佈不發生變化（例 如’參考上述文獻第141〜丨44頁）。 另外，圖4所示的電磁場分佈，可以用以下公式表示 -24- 200902303The average particle diameter of the conductive particles is preferably substantially equal to or less, and it is preferable to remove a powder having a large particle diameter (for example, 30 μm or more) as much as possible. Thereby, formation of a conductive film is facilitated, and deterioration in workability and uranium resistance is suppressed. The average particle diameter of the conductive particles is measured by measuring the particle size distribution of the classified particles by a general particle size distribution meter, and the particle size obtained by the small particle diameter calculated based on the measurement result is 50% (D50). ). The particle size distribution can be measured by a diffraction pattern of diffraction and scattering generated by irradiating light onto the particles. Examples of such a particle size distribution meter include Microtrac 9229 FRA and Microtrac HRA manufactured by Nikkiso Co., Ltd., and the like. Further, a conductive product which satisfies the above-mentioned optimum average particle diameter may be used as a commercially available product. For example, permalloy (78% Ni) [SFR-PCl manufactured by ATOMIZE Processing Co., Ltd., Japan, average particle size 5.7μιη], permalloy (45% Ni) [made by Japan ATOMIZE Processing Co., Ltd.) SFR-PB45, average particle size 5·8 μιη]; iron-bismuth aluminum magnetic alloy [SFR_FeSiAl (84.5-10-5.5), average particle size 6.9 μm] produced by ATOMIZE Processing Co., Ltd., Japan. Further, the shape of the optimum conductive particles is flat. As shown in the examples to be described later, when an additive having a flat shape [Asahi Kasei Aluminum Powder Pulp · 3 0 1 , a particle diameter of 19 μm, a thickness of 4 μm] is used, an additive having an irregular shape is used. When the permalloy (78% N i ) and Mitsubishi Steel Co., Ltd. were produced and the average particle size was 7 · 8 μηι], the electromagnetic wave absorption was significantly improved, and the thickness of the conductive film was set to 3 to 50 μm. Examples described later). -13- 200902303 When the thickness of the conductive film is less than 3 μm, in addition to the inability to obtain the desired electromagnetic wave absorptivity, most of the conductive particles may also appear on the film, resulting in poor appearance and loss of conductive particles. . On the other hand, when the thickness of the conductive film exceeds 50 μm, the bending workability is deteriorated. The optimum thickness of the conductive film can be changed in detail by the type and content of the conductive powder to be used, but is preferably 4 μm or more and 40 μm or less, and more preferably 5 μm or more and 30 μm or less. The thickness of the conductive film and the spacer layer to be described later can be obtained by measuring the weight of the film by the weight conversion method or by measuring the cross section of the resin film through a microscope observation (S ΕΜ photo observation). On the other hand, it is desirable to increase both electromagnetic wave absorbability and workability at the same time. The thickness of the spacer layer (resin film containing no conductive particles) 1 2 is in the range of 3 to 50 μm. As described in the examples below, when the thickness of the spacer layer is less than 3 μηι, the effect of improving electromagnetic wave absorptivity is small, and conversely, when the thickness exceeds 50 μm, the workability is lowered. The optimum thickness of the spacer is about 5 μm or more and 30 μηι or less, and the thickness is preferably about 8 μηι or more and 2 μηηι or less. The resin of the above-mentioned conductive film 13 and spacer layer 12 may be the same material or may be different. In any case, as a base resin constituting such a resin film, for example, a polyester resin, an acrylic resin, a urethane resin, a polyolefin resin, a fluorine resin, a ruthenium resin, and a mixture or modification of such resins Resin and so on. Further, the metal plate for coating resin of the present invention is mainly used for a casing of an electronic device, and it is preferable to use a polyester resin in consideration of characteristics such as bending workability, film adhesion, and corrosion resistance. Or a modified polyester resin (for example, a resin obtained by adding a ring-14-200902303 oxygen resin to an unsaturated polyester). The resin film may further contain a crosslinking agent in addition to the base resin. The type of the crosslinking agent is not particularly limited as long as it is a crosslinking agent generally used in a metal plate to which a resin is applied, for example, a melamine compound or an isocyanate compound. These compounds may be used singly or in combination. The content (total amount) of the optimum crosslinking agent is approximately in the range of 0.5 to 30% by mass. The resin film may contain a known additive (for example, a rust preventive, a matting agent, a pigment, etc.) in addition to the base resin and the crosslinking agent. The metal plate 1 1 used in the present invention is not particularly limited, and cold-rolled steel sheets, hot-rolled steel sheets, electrogalvanized steel sheets (EG), hot-dip galvanized steel sheets (GI), zinc and iron group elements (Fe, Co, Alloy plated steel sheet of Ni) (especially alloyed hot-dip galvanized steel sheet (GA)), 5% A1-Zn plated steel sheet, 55% A1-Zn plated steel sheet, various plated steel sheets such as A1, stainless steel sheet, etc. The steel sheets and all known metal sheets can be applied. From the viewpoint of improving electromagnetic wave absorptivity, an alloy plated steel sheet of zinc and an iron group element (Fe, Co, Ni) is preferably used. As an alloy ore-plated steel sheet of zinc and an iron group element, for example, an alloy-alloyed steel sheet of Zn and Fe, an alloy-plated steel sheet of Zn and Ni, and an alloy-plated steel sheet of Ζ and C 。. From the viewpoint of ensuring electromagnetic wave absorbability, it is preferable to control the contents of F e, N i, and C 控制 in the range of about 5 to 20%. Further, the method of electroplating is not particularly limited, and any of hot dip plating and electroplating may be employed. Further, the detailed plating conditions for the hot dip plating method and the electroplating method are not particularly limited, and the method generally used in -15-200902303 can be employed. In view of electromagnetic wave absorptivity, the plating adhesion amount is preferably 50 g/m2 or less, preferably 40 g/m2 or less, and most preferably 3 Og/m2 or less. The lower limit of the amount of adhesion to the electromagnetic wave is not particularly limited, but the test is, for example, preferably 5 g/m2, preferably 10 g/m2. Further, in consideration of the cost and the like, the alloyed hot-dip galvanized steel sheet (via hot-dip ore; steel sheet, GA) is preferably produced. As described above, in the present invention, as the metal plated steel sheet, in addition to the above, a steel sheet in which a pure zinc plated steel sheet of about 15 g/m 2 or less and cold-rolled steel are alloyed may be used. Avoid problems caused by (for example, cracks, flaws, etc. generated during bending). For example, if it is used for cold rolling without electroplating, it is strictly processed. However, since the cold-milk steel plate is considered to be suitable for the housing of electronic equipment, it is better to use alloyed plated steel than the cold-rolled steel sheet; on the other hand, if pure zinc-plated steel is used, it is required and required. Use for corrosion resistance. For the etchability, the optimum plating adhesion amount is about 3 g/m2 or more. Further, in view of electromagnetic wave absorptivity, the optimum plating is 15 g/m2, preferably 12 g/m2, more preferably 10 g/m2', which is less preferred, for example, most preferably 35 g/m2 or less. In consideration of corrosion resistance, it is possible to inexpensively and easily manufacture Zn and Fe alloyed sheets, and it is recommended to use alloying plating adhesion amount to control the sheet. By using cracks and peeling steel sheets which are not modified by alloyed steel sheets, the corrosion resistance can be used poorly, and the evaluation of the properties is lowered. It can be applied to the processing drama to effectively exert the corrosion resistance. The upper limit of the adhesion amount of 6g/m2 or more is -16-200902303. In order to improve the corrosion resistance of the metal plate and the adhesion between the metal plate and the resin film, it is also possible to The metal plate is subjected to surface treatment such as chrome plating and phosphate treatment (underlayer treatment). Alternatively, a non-chromium treated metal sheet may be used in consideration of environmental pollution, and any metal sheet subjected to the underlayer treatment is also included in the scope of the present invention. Further, the method of non-chromium treatment is not particularly limited, and generally, a known underlayer treatment to be used may be used. Specifically, it is recommended to use a primer treatment of a phosphate, a cerium oxide, a titanium, a zirconium or the like alone or in combination. Further, in general, when non-chromium treatment is performed, corrosion resistance is lowered. Therefore, in order to improve corrosion resistance, a rust preventive agent may be used in the coating film or in the underlayer treatment. Examples of the rust preventive agent include a cerium oxide compound, a phosphate compound, a phosphite compound, a polyphosphate compound, a sulfur organic compound, benzotriazole, tannic acid, and a molybdate compound. A tungstate compound, a vanadium compound, a decane coupling agent, or the like. These may be used alone or in combination. It is particularly preferable to use a combination of a cerium oxide compound (for example, calcium ion exchange yttrium oxide), a phosphate compound, a phosphite compound, or a polyphosphate compound (for example, aluminum tripolyphosphate), and is recommended for a mass ratio. A cerium oxide compound (phosphate compound, phosphite compound or polyphosphate compound) is used in combination in the range of 0.5 to 9.5: 9.5 to 0.5 (preferably 1: 9 to 9: 1). By controlling the cerium oxide compound within this range, it is possible to simultaneously ensure desired corrosion resistance and processability. By using the above rust inhibitor, it is possible to ensure the corrosion resistance of the chromium-free metal sheet, but on the contrary, the workability is lowered due to the addition of the rust inhibitor. Therefore, as a component for forming a coating film, a polyester resin and a crosslinking agent (optimal isocyanate resin) obtained by introducing an epoxy-modified polyester resin and/or a phenolic derivative into a skeleton are particularly recommended. / or melamine resin 'preferably used in combination" and used in combination. Among them, a polyester resin obtained by introducing an epoxy-modified polyester resin and/or a phenolic derivative into a skeleton (for example, a method in which bisphenol A is introduced into a guide skeleton) is used as compared with a polyester resin. A polyester resin or the like has better corrosion resistance and coating film adhesion. On the other hand, the isocyanate-based crosslinking agent has an effect of improving workability (refers to an effect of improving the appearance property after processing, and is evaluated by the number of cracks in the adhesion test in the examples described later). Thereby, even if a rust preventive agent is added, excellent workability can be ensured. Further, the melamine-based crosslinking agent has excellent corrosion resistance. Therefore, in the present invention, it is possible to obtain very excellent corrosion resistance by using it in combination with the above-mentioned rust preventive agent. These isocyanate-based crosslinking agents and melamine-based crosslinking agents may be used singly, but when used in combination, the workability and corrosion resistance of the non-chromium-treated metal sheets can be further improved. Specifically, it is recommended to contain the melamine-based resin in a ratio of 5 to 80 parts by mass with respect to the isocyanate resin of the mass fraction of . When the amount of the melamine-based resin is less than 5 parts by mass, the desired corrosion resistance cannot be obtained. On the other hand, when the amount of the melamine-based resin exceeds 80 parts by mass, the effect of adding the isocyanate-based resin cannot be exhibited satisfactorily, and thus the desired improvement cannot be obtained. The effect of processing. It is preferable to add 10 parts by mass or more and 40 parts by mass or less of the melamine-based resin to 100 parts by mass of the iso-18-200902303 cyanate-based resin, and more preferably 15 parts by mass or more and 30 parts by mass or less. Melamine resin. The metal plate for coating resin of the present invention is formed by coating a resin film containing the above various additives on the surface of a metal plate (including a metal plate subjected to the above-described underlayer treatment), and is required to impart heat resistance as needed. For the purpose of the properties of the film and the like, it is also possible to form a three-layer film structure by applying another resin film on the surface of the conductive film. Next, a method of producing a metal plate coated with a resin of the present invention will be described. The metal plate for coating resin of the present invention is coated on the surface of a metal plate by a coating method in addition to the base resin and the crosslinking agent, in addition to the base resin and the crosslinking agent, and is sequentially fired. A predetermined spacer layer and a conductive resin film are formed. In other words, after the coating for forming the spacer layer is baked, the coating of the conductive resin film is formed on the coating, and baking is performed to form a conductive resin film on the spacer layer. Composition. The solid content concentration of the coating material can be appropriately adjusted according to the viscosity of the coating material to be used and the coating conditions, and the like, so that the maximum tfc is large: tj (in the range of 1 〇 to 50%). The difference in the kind of solvent used to dilute the coating material changes the degree of the coating material flowing into the crotch portion (concave portion) of the metal plate, and the optimum firing condition is that the firing is completed within approximately 丨 minutes. Special restrictions ' For example, after cleaning the surface -19- 200902303, the basics of the dry-coating parts, the electric equipment PDP car, the table machine automatically [the invention is described later in this application according to the need to apply pre-painting ( For example, on the surface of a long-sized metal strip of a phosphate treatment or a chrome plating, a coating method is applied by a roll coating method, a spray coating method, a curtain coating method, or the like, and then passed through a hot air drying furnace into a method of Wen Rong. The roll coating method is practically optimal in consideration of the uniformity of the thickness of the film, the processing cost, and the efficiency, etc. The electronic device to which the metal plate of the coated resin of the present invention can be applied is applicable. For example, an electronic device having a semiconductor component embedded in an enclosed space also includes all or a part of an electronic device component of the outer wall of the electronic device component. The electronic component such as a CD. , LD, DVD, CD-ROM 'CD-RAM,: LCD information recording products; PC, car navigation, audio / audio-visual equipment, electrical, electronic, communication-related products; projection TV, video recorder, AV equipment such as game machines; copywriters for photocopiers, printers, etc.; power box covers, control box covers, vending machines, refrigerators, etc. for air conditioner outdoor units, etc. Embodiments Hereinafter, the present invention will be described by way of examples. The present invention is not limited to the following embodiments, and may be appropriately modified within the scope of the above-described gist of the invention, and these are all included in the technical scope of the invention. 20-200902303 In the present embodiment, as the conductive particles, electromagnetic wave absorptivity and workability when metal particles having no magnetic properties were used were investigated. The plate was made of an electrogalvanized steel sheet (thickness: 〇.8 mm; an electroplated layer having a plating adhesion of 20 g/m 2 was formed on the front and back surfaces) and an alloyed hot-dip galvanized steel sheet (plate thickness: 〇.8 mm; surface and On the back surface, a plating layer having a plating adhesion of 3 〇g/m 2 and a plating content of 1 〇.3% in plating are formed, respectively. The preparation method of the coating material for forming the conductive film and the spacer layer is as follows (Preparation of a coating for a conductive coating film) First, a polyester resin "BYLON GK780" manufactured by Toyobo Co., Ltd. was used as a base resin, and a melamine resin "SUMI" manufactured by Sumitomo Chemical Co., Ltd. was used as a crosslinking agent. MARL Μ-4〇ST"' is a matrix resin prepared by mixing a base resin and a crosslinking agent (80% solid content) in a weight ratio of 80:20, and adding "aluminum powder" by Asahi Kasei Co., Ltd. as a conductive particle. Pulp - 3 0 1" (solid content: 6 6 %, particle size: 19 μm, thickness: 0.4 μm), and the amounts thereof are as shown in Tables 1 and 2 (content in the resin film). In order to achieve a solid concentration of the raw material composition of 15% or 30%, it is diluted with a xylene/cyclohexanone mixed solvent (xylene: cyclohexanone = 1 : 1) to l rpm The rotation speed was stirred by a manual grater for 1 , minute to prepare a raw material composition. (Preparation of coating material for spacer layer) The raw material composition was prepared in the same manner as in the above-mentioned conductive coating of the coating film No. 21 - 200902303, except that the conductive particles were not added. The raw material composition for each of the resin films thus produced was applied to various metal plates by a bar coating method to achieve a film thickness as shown in Table 2 and Table 2, and reached a plate temperature in a hot air drying furnace. 3 0. (:: baking is performed for about 120 seconds to form a metal plate for coating resin. The thickness of the resin film is made 2~ by changing the solid concentration of the diluted coating material and the number of rods used for the bar coating. Change in the range of 60 μm. For example, in N 〇. 2 (Comparative Example) of Table 2, 'No. 18 rod is used on GA (alloyed hot-dip galvanized steel sheet), and 30% of the solid content is applied. Coating (30% by weight of the aluminum powder M-301 solid component) When the spacer layer composition or the conductive composition is applied, the heating is performed in a hot air drying oven set to a plate temperature of 203 °C. The coating was hardened for 20 seconds. The thickness of the obtained coating film was 8 μm. In addition, in the N 〇. 3 (Example) of Table 2, the rod of No. 12 was used for GA (alloyed hot-dip galvanized steel sheet) The coating was applied to a polyester coating of 33.4%, and the coating was cured in a hot air drying oven set to a plate temperature of 23 ° C for 1 to 20 seconds. The thickness of the obtained coating film was 5 μm. This film was used as a lower layer film (spacer layer) to impart a coating film containing aluminum powder pulp-301 under the same conditions as those of No. 2. (Upper film) The total thickness of the coating film is 13 μm. The average thickness of the resin film can be determined by the method shown below. First, cerium oxide is added to the coating in a weight ratio of 1 to 1% by weight. (si〇2) The amount of si adhesion was measured by a fluorescent X-ray analysis method as an indicator. When the amount of si adhesion was measured, a calibration curve indicating the relationship between the amount of si and the intensity of the fluorescent X-ray was prepared in advance. 'Measure the amount of adhesion of Si according to the calibration curve. Next, 'the specific gravity is converted from the specific gravity of the si -22-200902303 measured by the above-mentioned specific gravity, and calculate the weight of the resin film'. (μιη) The specific conversion method is as follows: Average thickness of resin film {A/(BxCxD)} χίοοο In the formula, A = Si adhesion amount (mg/m2) B = 2 8/60 (Si/SiO2) C = The weight ratio of S i O 2 D = specific gravity of the resin film (g/cm 3 ) The electromagnetic wave absorptivity and workability of the metal plate of the resin resin thus obtained were evaluated as follows. Evaluation) Figure 2 shows the coating resin An explanatory diagram of a method for evaluating electromagnetic wave absorption performance of a metal plate. As shown in Fig. 2, a high-frequency loop antenna 5 is provided in a housing 1 having a rectangular parallelepiped shape, and is configured by magnetic field coupling. The high-frequency loop antenna 5 is connected via a terminal ( Not shown) is connected to one end of the coaxial cable 6, and the other end of the coaxial cable 6 is connected to the network analyzer 7. In the network analyzer 7, electromagnetic waves are generated at the same time as the scanning frequency, via the coaxial cable 6, high The frequency loop antenna 5, electromagnetic waves are input (high frequency input wave: arrow B) into the casing 1. In the resonance frequency of the casing 1, since the input electromagnetic waves are accumulated, the characteristic that the amount of reflection is small can be observed (refer to Fig. 3). Further, the high-frequency reflected wave indicated by the arrow C is input as an observation ( (high-frequency reflected wave: arrow C) to the network analyzer -23-200902303. In this case, when the Q 求出 obtained by the following formula (1) is measured in the casing 1, the magnitude of the energy stored in the casing 1 is known. Further, Q 求出 obtained by the following formula (1) can be calculated from the obtained frequency difference 値 Δ f and the resonance frequency number fr because the condition of the admittance track is satisfied (for example, Nakajima will be light) , "Senbei Electrical Engineering Series 3 Microwave Engineering, a Foundation and Principles I", issued by Senbei Publishing Co., Ltd., pp. 159~163). Q 値 = fr / Δ f (1) The smaller the Q 求出 obtained by the above formula (2), the smaller the energy accumulated in the casing 1 is. Therefore, the smaller the Q値 becomes, the lower the level of the electromagnetic field reflected from the casing 1 to the inside. Fig. 4 is a schematic view showing a state at this time, which is shown as an electromagnetic field distribution in a resonance mode of E z = 〇, TEqh, i.e., the lowest frequency, in which E represents a high frequency magnetic field, and F represents a high frequency electric field. The above Ez represents the electric field intensity in the z direction, and TEo 1! represents the posture of the electromagnetic field distribution in the resonance mode. This TE indicates that the electromagnetic wave advances in the z direction and exists in the lateral direction in the electric field. The number "011" indicates that there is an intensity distribution of one electric field in the y and z directions for the X, y, and z directions, and the intensity distribution of the electric field does not change in the X direction (for example, refer to the above-mentioned document No. 141 to page 44). ). In addition, the electromagnetic field distribution shown in Figure 4 can be expressed by the following formula -24- 200902303
Hz = H〇n-cos(ky-y)-sin(kz-z)Hz = H〇n-cos(ky-y)-sin(kz-z)
Hy= (-k2 · ky/kc2) · H〇i i · sin (ky · y) · co s(kz · z)Hy= (-k2 · ky/kc2) · H〇i i · sin (ky · y) · co s(kz · z)
Ex=(-jtopky/kc2).H(ni.sin (ky.y).sin (kz-z) 此處，ky=u/b、kz=n/c、ke=ky。b、c表示圖 4的直 方體（筐體1)的y、z方向的長度’j表示虛數’ ω表示各個 頻率數、μ表示空氣的透磁率。 本發明的發明人員，製成了可以將樣品鋼板在內面上 所占的比例提高到接近100%爲止（即，筐體內面的整面）的 筐體。圖5是表示構成該筐體的SUS製框架（筐體）的說明圖 。圖5(a)、圖5(b)、圖5(c)分別表示平面圖、正面圖、左 側面圖。此外，該框架被構成爲上下左右對稱，因此底面 圖與平面圖〔圖5(a)〕、背面圖與正面圖〔圖5(b)〕、右 側面圖與左側面圖〔圖5(c)〕各自相同。 對圖5所示的框架上貼附（安裝螺絲）圖6、圖7所示的 SUS板，製成筐體（24 0x 1 80x90m)。此外，圖6(a)表示配置 於框架的正面、背面部份上的SUS鋼板（2張）、圖6(b)表示 配置於框架的左右側面部份上的SUS板（2張）、圖7(a)表示 配置於頂面部份上的SUS板、圖7(b)表示配置於底面部份 上的sus板。貼附的樣品鋼板的形狀與圖6(a)、圖6(b)、 圖7 (a)的內側的線相吻合。 經由上述的構成製成筐體的話’可以使樣品鋼板占到 其內面的接近1 〇 〇 °/❶的面積。另外，將安裝螺絲的間距設 -25- 200902303 爲20〜4 0mm，由於接觸電阻低，需要進行多個螺絲固定。 螺絲固定係經由對扭力進行控制，可以提高Q値測量的再 現性。使用這樣的筐體對Q値進行測量（所述圖2)，經由下 述公式算出電磁波吸收性。 樣品鋼板的電子波吸收性（dB ) = 10xl〇g1() ( [EG]/[A]) 但是，[EG]:作爲基板的電鍍鋅鋼板的Q値 [A]:樣品鋼板的Q値 經由上述方法算出的値（dB)越高，表明電磁波吸收性 越優。在本實施例中，在合金化熔融鍍鋅鋼板（GA)的情況 下，將如上所述算出的値超過4.0 dB以上的評估爲具有優 異的電磁波吸收性（合格）；在電鍍鋅鋼板（EG)的情況下， 將5 .OdB以上的評估爲具有優異的電磁波吸收性（合格）。 (加工性的評估） 採用JIS K5 6 00-5 - 1的耐屈曲試驗記載的2型試驗裝置 ，進行0T彎曲（18(TC彎曲），用目視觀察彎曲後的樹脂皮 膜（彎曲後樹脂皮膜位於彎曲部外側）的剝離狀態進行觀察 ’用如下標準進行了評估。在本實施例中，將◎及〇定爲 口格。 ◎ 完全沒有出現剝離。 〇於加工部的一部份上出現少許微小的裂紋。 △ 於加工部的整體上出現微小的裂紋。 -26- 200902303 χ 於加工部的整體上出現龜裂。 * 表面外觀劣化，出現粒子脫落。 表1及表2—倂表示此等結果。於上述表中，「下層皮 膜」表示隔離物層、「上層皮膜」表示導電性皮膜。在此 等表中’設置綜合評估欄，將電磁波吸收性及加工性兩項 均合格的標示爲〇，任何一項不合格的標示爲X，將綜合 評估標示爲〇的定爲「本發明例」。 [表1]Ex=(-jtopky/kc2).H(ni.sin (ky.y).sin (kz-z) Here, ky=u/b, kz=n/c, ke=ky. b, c denotes a graph The length y in the y and z directions of the rectangular body (the housing 1) indicates that the imaginary number 'ω indicates the number of frequencies, and μ indicates the magnetic permeability of the air. The inventors of the present invention have made it possible to coat the sample steel sheet inside. The case where the ratio of the upper portion is increased to approximately 100% (that is, the entire surface of the inner surface of the casing). Fig. 5 is an explanatory view showing a SUS frame (housing) constituting the casing. Fig. 5(a) 5(b) and 5(c) show a plan view, a front view, and a left side view, respectively, and the frame is configured to be vertically symmetrical, so that the bottom view and the plan view (Fig. 5(a)) and the rear view are The front view (Fig. 5(b)), the right side view, and the left side view (Fig. 5(c)) are the same. The SUS shown in Fig. 6 and Fig. 7 is attached to the frame shown in Fig. 5 (mounting screws). The plate is made into a casing (24 0x 1 80x90m). In addition, Fig. 6(a) shows SUS steel plates (2 sheets) placed on the front and back portions of the frame, and Fig. 6(b) shows the left and right sides of the frame. SUS plate on the side part (2 sheets), Figure 7(a) The SUS plate disposed on the top surface portion and the SUS plate disposed on the bottom surface portion are shown in Fig. 7(a), Fig. 6(b), and Fig. 7 The line on the inner side of (a) is matched. If the case is made by the above-described configuration, the sample steel plate can occupy the area of the inner surface of the inner surface of approximately 1 〇〇°/❶. In addition, the pitch of the mounting screws is set to -25. - 200902303 is 20~4 0mm. Due to the low contact resistance, multiple screws need to be fixed. The screw fixing can improve the reproducibility of Q値 measurement by controlling the torsion force. The Q値 is measured using such a housing. 2), the electromagnetic wave absorptivity is calculated by the following formula: Electron wave absorbability (dB) of the sample steel sheet = 10xl 〇g1() ([EG]/[A]) However, [EG]: electrogalvanized as a substrate Q 値 [A] of the steel sheet: The higher the enthalpy (dB) calculated by the above method, the higher the electromagnetic wave absorptivity of the Q 样品 of the sample steel sheet. In the present embodiment, in the case of alloyed hot-dip galvanized steel sheet (GA) Next, the evaluation of 値 more than 4.0 dB calculated as described above is excellent in electromagnetic wave absorption ( In the case of an electrogalvanized steel sheet (EG), an evaluation of 5.2 dB or more is considered to have excellent electromagnetic wave absorption (qualified). (Evaluation of workability) Resistance to buckling using JIS K5 6 00-5 -1 The type 2 test apparatus described in the test was subjected to 0T bending (18 (TC bending)), and the peeled state of the resin film after bending (the resin film was bent outside the curved portion) was visually observed and observed. The evaluation was carried out by the following criteria. In the present embodiment, ◎ and 〇 are designated as slogans. ◎ There is no peeling at all. There was a slight crack in a part of the processing section. △ A slight crack appears in the entire processed portion. -26- 200902303 裂 Cracks appear in the entire processing section. * The surface appearance is degraded and particles fall off. Table 1 and Table 2 - 倂 indicate these results. In the above table, the "lower layer film" means a separator layer, and the "upper layer film" means a conductive film. In these tables, 'the comprehensive evaluation column is set, and the electromagnetic wave absorbability and the workability are both marked as 〇, any one of the unqualified marks is X, and the comprehensive evaluation is marked as 〇. "." [Table 1]
No. 原板 下層皮膜 (間隔物層） 上層皮膜(導電性皮膜） 評估 膜厚 -(μηι) 樹脂固形成 份含量(％) 含量 (%) 膜厚 (μηι) 電磁波吸收性 (dB) 加工性 綜合 評估 1 EG 1~~ 2 30 30 8 1.19 〇 X 3 5 30 30 8 2.08 〇 〇 -27- 200902303 [表2] 原 下層皮膜 (間隔物層） 上層皮膜(導電性皮膜） 評估 No. 板 膜厚 樹脂固形成 含量 膜厚 電磁波吸收性 綜合 (卿） 份含量(％) (%) (μηι) (dB) 加工性 評估 1 — - — 3.29 一 2 一 30 30 8 3.05 ◎ X 3 5 30 30 8 4.85 ◎ 〇 4 30 30 30 8 4.93 〇 〇 5 60 30 30 8 4.02 Δ X 6 8 30 30 30 4.63 〇 〇 7 GA 8 30 30 60 4.08 X X 8 8 15 30 2 3.40 氺 X 9 8 30 5 8 3.95 ◎ X 10 8 30 10 8 4.87 ◎ 〇 11 8 30 20 8 4.74 ◎ 〇 12 8 30 30 8 4.87 ◎ 〇 13 8 30 40 8 4.93 ◎ 〇 表1所示爲採用電鍍鋅鋼板（EG)時的結果。如表1所示 ，與沒有間隔物層（下層皮膜）的單層構造（No.2)相比，如 果採用本發明的層合構造（No. 3)，可以提高電磁波吸收性 〇 表2表示採用合金化熔融鍍鋅鋼板（GA)時的結果。如 表2所示，與沒有間隔物層（下層皮膜）的單層構造（No.2)相 比，如果採用在金屬板和導電性皮膜（上層皮膜）之間’具 有厚度被適當控制的間隔物層（下層皮膜）的層合構造 -28- 200902303 (Ν ο · 3〜4、6、1 0〜1 3 )，可以提高電磁波吸收性。 與此相對，在間隔物層（下層皮膜）的厚度厚的N 〇. 5、 導電性皮膜（上層皮膜）的厚度厚的No.7中，加工性都出現 下降。另外，導電性皮膜（上層皮膜）的厚度薄的No. 8以及 導電性皮膜中包含的導電性粒子的含量少的No.9中，電磁 波吸收性都出現下降，除此之外在No . 8中還出現了表面外 觀劣化，粒子脫落等問題。 實施例2 在本實施例中，除了導電性粒子採用坡莫合金 (78%Ni)(三菱製鋼（股份有限公司）製作，平均粒徑7_8μηι) ，調整到表3及表4所表示的範圍之外’與實施例1同樣製 成塗裝樹脂之金屬板，對其電磁波吸收性及加工性進行了 評估，結果如表3及表4一倂所表示。 [表3]No. Original film (spacer layer) Upper film (conductive film) Evaluation film thickness - (μηι) Resin solid content (%) Content (%) Film thickness (μηι) Electromagnetic wave absorption (dB) Comprehensive evaluation of processability 1 EG 1~~ 2 30 30 8 1.19 〇X 3 5 30 30 8 2.08 〇〇-27- 200902303 [Table 2] Original lower layer film (spacer layer) Upper layer film (conductive film) Evaluation No. Plate thickness resin Solid content film thickness Electromagnetic wave absorption synthesis (Q) Content (%) (%) (μηι) (dB) Processability evaluation 1 — — — 3.29 2 2 30 30 8 3.05 ◎ X 3 5 30 30 8 4.85 ◎ 〇4 30 30 30 8 4.93 〇〇5 60 30 30 8 4.02 Δ X 6 8 30 30 30 4.63 〇〇7 GA 8 30 30 60 4.08 XX 8 8 15 30 2 3.40 氺X 9 8 30 5 8 3.95 ◎ X 10 8 30 10 8 4.87 ◎ 〇11 8 30 20 8 4.74 ◎ 〇12 8 30 30 8 4.87 ◎ 〇13 8 30 40 8 4.93 ◎ Table 1 shows the results when galvanized steel sheets (EG) are used. As shown in Table 1, compared with the single layer structure (No. 2) having no spacer layer (lower layer film), the electromagnetic wave absorptivity can be improved by using the laminated structure (No. 3) of the present invention. The result when alloyed hot-dip galvanized steel sheet (GA) was used. As shown in Table 2, compared with the single layer structure (No. 2) having no spacer layer (lower layer film), if the thickness between the metal plate and the conductive film (upper layer film) is appropriately controlled, The laminated structure of the layer (lower layer film) -28-200902303 (Ν ο · 3 to 4, 6, 1 0 to 1 3 ) can improve electromagnetic wave absorption. On the other hand, in No. 7 in which the thickness of the spacer layer (lower layer film) was thick, and the thickness of the conductive film (upper layer film) was thick, the workability was lowered. In addition, in No. 8 in which the thickness of the conductive film (upper film) is small and the content of the conductive particles contained in the conductive film is small, the electromagnetic wave absorbability is lowered, and otherwise, No. 8 There are also problems such as deterioration in surface appearance and particle shedding. [Example 2] In the present embodiment, the conductive particles were made of permalloy (78% Ni) (manufactured by Mitsubishi Steel Corporation, average particle size 7_8 μηι), and adjusted to the ranges shown in Tables 3 and 4. In the same manner as in Example 1, a metal plate coated with a resin was prepared, and electromagnetic wave absorbability and workability were evaluated. The results are shown in Tables 3 and 4. [table 3]
No. 原板 下層皮膜 澗隔物層） 上層皮膜(導電性皮膜） 評估 膜厚 (μηι) 樹脂固形成 ί始量(％) 含量 (%) 膜厚 (μιη) 電磁波吸收性 (dB) 加工性 綜合 評估 1 EG 30 50 5 0.48 ◎ X 2 5 30 50 5 0.62 ◎ 〇 -29- 200902303 [表4]No. Original layer underlying film barrier layer) Upper layer film (conductive film) Evaluation film thickness (μηι) Resin solid formation ί Initial amount (%) Content (%) Film thickness (μιη) Electromagnetic wave absorption (dB) Processability synthesis Evaluation 1 EG 30 50 5 0.48 ◎ X 2 5 30 50 5 0.62 ◎ 〇-29- 200902303 [Table 4]
No. 原板 下層皮膜 (間隔物層） 上層皮膜(導電性皮膜） 評估 膜厚 (μηι) 樹脂固形成 份含量(％) 含量 (%) 膜厚 (μιη) 電磁波吸收性 _ 加工性 綜合 評估. 1 GA - 30 50 5 3.37 ◎ X 2 5 30 50 5 4.15 ◎ 〇 3 2 30 50 5 3.45 ◎ X 4 8 30 50 5 4.36 ◎ 〇 5 30 30 50 5 4.45 〇 〇 6 60 30 50 5 4.49 Δ X 7 8 30 50 30 5.13 〇 〇 8 8 30 50 60 6.04 X X 9 8 30 50 2 4.20 氺 X 10 8 30 5 5 3.40 ◎ X 11 δ 30 10 5 3.98 ◎ X 12 8 30 20 5 4.05 ◎ 〇 13 8 30 30 5 4.05 ◎ 〇 14 8 30 40 5 4.18 ◎ 〇 15 8 30 60 5 4.39 〇 〇 16 8 30 70 5 4.44 Δ X 表3所表示爲採用電鍍鋅鋼板（EG)時的結果。如表3所 示，與沒有間隔物層（下層皮膜）的單層構造（No.!)相比， 如果採用本發明的層合構造（No. 2)，可以提高電磁波吸收 性。 -30 - 200902303 表4表示採用合金化熔融鍍鋅鋼板（GA)時的結果。如 表4所示，與沒有間隔物層（下層皮膜）的單層構造（No . 1)相 比，如果採用在金屬板和導電性皮膜（上層皮膜）之間，具 有厚度被適當控制的間隔物層（下層皮膜）的層合構造 (Νο·2、4~5、7、12〜15)，可以提局電磁波吸收性。 與此相對，在間隔物層（下層皮膜）的厚度薄的No.3、 導電性皮膜（上層皮膜）的厚度薄的Νο·9以及導電性皮膜中 包含的導電性粒子的含量少的Ν ο · 1 0、1 1中，電磁波吸收 性都出現下降。另外，在Νο.9中出現了表面外觀劣化，粒 子脫落等問題。另外，在間隔物層（下層皮膜）的厚度厚的 Νο.6、導電性皮膜（上層皮膜）的厚度厚的Νο.8中，以及導 電性皮膜中包含的導電性粒子的含量多的No. 1 6中，加工 性都出現下降。 【圖式簡單說明】 圖1爲對本發明的塗裝樹脂之金屬板的一例進行模式 說明的截面圖。 圖2爲塗裝鋼板中的電磁波吸收性能的評估方法的說 明圖。 圖3爲於筐體的共振頻率作用下輸入的電磁波的反射 量變少的狀態說明圖。 圖4爲模式顯示測量電磁波吸收性時的狀態說明圖。 圖5爲構成測量電磁波吸收性的框體的SUS製框架（框 體）的說明圖。 -31 - 200902303 圖6爲配置於框體的左右側面部份上的SUS板的形狀 說明圖。 圖7爲配置於框體的頂面部份及底面部份上的SUS板 的形狀說明圖。 -32-No. Original film (spacer layer) Upper film (conductive film) Evaluation film thickness (μηι) Resin solid content (%) Content (%) Film thickness (μιη) Electromagnetic wave absorption _ Comprehensive evaluation of processability. 1 GA - 30 50 5 3.37 ◎ X 2 5 30 50 5 4.15 ◎ 〇3 2 30 50 5 3.45 ◎ X 4 8 30 50 5 4.36 ◎ 〇5 30 30 50 5 4.45 〇〇6 60 30 50 5 4.49 Δ X 7 8 30 50 30 5.13 〇〇8 8 30 50 60 6.04 XX 9 8 30 50 2 4.20 氺X 10 8 30 5 5 3.40 ◎ X 11 δ 30 10 5 3.98 ◎ X 12 8 30 20 5 4.05 ◎ 〇13 8 30 30 5 4.05 ◎ 〇14 8 30 40 5 4.18 ◎ 〇15 8 30 60 5 4.39 〇〇16 8 30 70 5 4.44 Δ X Table 3 shows the results when galvanized steel sheets (EG) are used. As shown in Table 3, the electromagnetic wave absorptivity can be improved by using the laminated structure (No. 2) of the present invention as compared with the single layer structure (No.!) having no spacer layer (lower layer film). -30 - 200902303 Table 4 shows the results when alloyed hot-dip galvanized steel sheets (GA) were used. As shown in Table 4, compared with the single layer structure (No. 1) having no spacer layer (lower layer film), if the thickness between the metal plate and the conductive film (upper layer film) is appropriately controlled, the interval is appropriately controlled. The laminated structure of the object layer (lower layer film) (Νο·2, 4~5, 7, 12~15) can extract electromagnetic wave absorption. On the other hand, in the case where the thickness of the spacer layer (lower layer film) is small, the thickness of the conductive film (upper layer film) is small, and the content of the conductive particles contained in the conductive film is small. · In 1 0 and 1 1 , electromagnetic wave absorption decreased. In addition, problems such as surface appearance deterioration and particle dropping occurred in Νο. In addition, in the case where the thickness of the spacer layer (lower layer film) is thicker, the thickness of the conductive film (upper layer film) is thicker, and the content of the conductive particles contained in the conductive film is large. In 1 6 , the processability decreased. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view showing an example of a metal plate of a coated resin of the present invention. Fig. 2 is an explanatory view showing a method of evaluating electromagnetic wave absorption performance in a coated steel sheet. Fig. 3 is an explanatory diagram showing a state in which the amount of reflection of electromagnetic waves input under the resonance frequency of the casing is reduced. Fig. 4 is an explanatory diagram showing a state in which a mode display electromagnetic wave absorptivity is measured. Fig. 5 is an explanatory view of a SUS frame (frame) constituting a frame for measuring electromagnetic wave absorptivity. -31 - 200902303 Fig. 6 is a view showing the shape of the SUS plate disposed on the left and right side portions of the housing. Fig. 7 is a view showing the shape of a SUS plate disposed on the top surface portion and the bottom surface portion of the casing. -32-