592968 五、發明說明（1 ) 技術範圍 本發明係關於一種使用於製備在上面壓印特別圖案的撓 性石墨物品之材料及方法。藉由本發明之進行，可提供一 種作爲基材的材料，而可在上面形成具有壓印圖案的改善 式撓性石墨物品（諸如薄片）。本發明之材料的用途包括形 成一種壓印物品，其可使用作爲電化學燃料電池的組件。 發明背景592968 V. Description of the invention (1) Technical scope The present invention relates to a material and a method for preparing a flexible graphite article with a special pattern imprinted thereon. By carrying out the present invention, it is possible to provide a material as a base material on which an improved flexible graphite article (such as a sheet) having an embossed pattern can be formed. The use of the material of the present invention includes forming an embossed article which can be used as a component of an electrochemical fuel cell. Background of the invention
離子交換薄膜燃料電池，更特別是質子交換薄膜 [proton exchange membrane(PEM)]燃料電池，可透過氫 與空氣中的氧進行化學反應而產生電力。在燃料電池中， 電極意指爲由聚合物電解質包圍的陽極及陰極，以形成通 常所S胃的薄膜電極組件[membrane electrode assembly (MEA )]。往往，該電極亦可作爲燃料電池的氣體擴散層 [gas diffusion layers( GDL)]。觸媒材料會激發氫分子 而使其分裂成氫原子，然後，在薄膜處每個原子會分裂成 質子及電子。電子則使用作爲電能。質子則漂移過電解質 而與氧及電子結合以形成水。 PEM燃料電池有利地由夾在二片石墨流場板間之薄膜電 極組件形成。傳統上，薄膜電極組件由含觸媒材料薄層之 無規定向的碳纖維紙電極（陽極及陰極）組成，特別是塗敷 在等向碳粒子（諸如燈黑）上之鉑或鉑族金屬，而黏合至配 置在電極間的質子交換薄膜之任一邊。在操作上，氫流經 一片流場板中的溝槽至陽極，於此觸媒會促進其分裂成氫 592968 五、 發明說明 ( 2) 原 子 ， 而 在 通 過薄膜後再分離成質子，電子則流經 外 部 負 載 〇 空 氣 則 流 經另一流場板中的溝槽至陰極（於此 空 氣 中 的 氧 會 分 離 成 氧原子），而於此結合通過質子交換 薄 膜 的 質 子 與 通 >SJEL 過 電 路的電子，將其結合形成水。因爲該 薄 膜 爲 絕 緣 體 > 電 子 需經歷外部電路（於此形成可使用的電力）才 能 在 陰 極 處 與 質子連結。在陰極邊上的空氣流爲一 種 可 移 除 由 氫 與 氧 組 合而形成的水之機構。此燃料電池組 合 可以 燃 料 電 池堆 疊 方式使用，以提供想要的電壓。 限 制 撓 性石 墨材料使用作爲PEM燃料電池組件的 因 素 之 一 爲 壓 印 在材料上的圖案輪廓淸晰度，其若不足則 會 妨 礙 燃 料 電 池 的 功 能（因流體漏出，或不足夠的流體流 經 燃 料 電 池 )< 3此外 ，撓性石墨材料的熱及電性質雖然優 於 先 述 技 藝 的材料 但其仍然可進一步最佳化。 石 墨 由 7^ 角 形陣列或網狀的碳原子平面層組成。 追 些 排 成 角 形 的 碳 原子平面層實質上是平坦的，且已定 向 或 已 整 齊 排列 成 實 質上彼此平行且等距。該些平坦、平行 等 距 離 的 碳 原 子 薄 片或層（通常指爲石墨層或基面）實質 上 連 結 或 黏 合在 一 起 ’該群組會排列成結晶狀。高度排列的 石 墨 則 由 相 當 尺 寸 的結晶組成：該些結晶彼此已高度良 好 地排 列或 已 定 向 ， 而具有相當整齊的碳層。換句話說， 高 度 排 列 整 齊 的 石 墨 具有高度較佳的結晶定向。應注意的 是 石 墨 可 藉 由 定出 輪 廓而具有異方向性結構，因此可顯示 或 具 有 許 多 局 方 向性的性質，例如熱與電的傳導性及流體彳 -4- mi 教 0Ion exchange membrane fuel cells, and more particularly proton exchange membrane (PEM) fuel cells, can generate electricity through the chemical reaction of hydrogen with oxygen in the air. In a fuel cell, an electrode means an anode and a cathode surrounded by a polymer electrolyte to form a membrane electrode assembly (MEA) that is commonly used in the stomach. Often, this electrode can also be used as a gas diffusion layer (GDL) for a fuel cell. The catalyst material excites hydrogen molecules and splits them into hydrogen atoms. Then, each atom at the film will split into protons and electrons. Electronics are used as electrical energy. Protons drift through the electrolyte and combine with oxygen and electrons to form water. The PEM fuel cell is advantageously formed by a thin-film electrode assembly sandwiched between two graphite flow field plates. Traditionally, thin-film electrode assemblies consist of carbon fiber paper electrodes (anodes and cathodes) containing a thin layer of catalyst material, especially platinum or platinum group metals coated on isotropic carbon particles such as lamp black. It is bonded to either side of the proton exchange film disposed between the electrodes. In operation, hydrogen flows through the grooves in a flow field plate to the anode, where the catalyst will promote its splitting into hydrogen 592968 V. Description of the invention (2) Atoms, which are separated into protons after passing through the membrane, and electrons are The air flowing through the external load passes through the groove in another flow field plate to the cathode (where the oxygen in the air is separated into oxygen atoms), and the protons passing through the proton exchange membrane are combined with the SJEL circuit. The electrons combine to form water. Because the film is an insulator > the electrons need to go through an external circuit (which forms a usable electric power here) to be able to connect with the protons at the cathode. The air flow at the cathode is a mechanism that removes the water formed by the combination of hydrogen and oxygen. This fuel cell stack can be used in a fuel cell stack to provide the desired voltage. One of the factors limiting the use of flexible graphite materials as PEM fuel cell components is the sharpness of the pattern profile embossed on the material, which if insufficient will hinder the function of the fuel cell (because of fluid leakage or insufficient fluid flow through) Fuel cell) < 3 In addition, although the thermal and electrical properties of the flexible graphite material are superior to those of the prior art materials, they can be further optimized. Graphite consists of a 7 ^ angular array or a network of planar layers of carbon atoms. The plane layers of the carbon atoms arranged in an angle are essentially flat, and they have been oriented or neatly arranged to be substantially parallel and equidistant from each other. These flat, parallel and equally spaced carbon atom sheets or layers (usually referred to as graphite layers or basal planes) are essentially connected or glued together ’The group will be arranged in a crystalline state. The highly aligned graphite is composed of crystals of a similar size: the crystals are aligned or oriented to each other with a high degree of neatness, and have a fairly neat carbon layer. In other words, the highly aligned lithographs have a highly preferred crystal orientation. It should be noted that Shi Mo can have a different directional structure by defining the profile, so it can show or have many local directional properties, such as thermal and electrical conductivity and fluid 彳 -4- mi 教 0
五、發明說明（3) 簡單地說，石墨之特徵爲碳的積層結構（也就是說，由 碳原子的疊置層或薄層所組成之結構），其藉由弱的凡得 瓦爾力連結在一起。在考慮的石墨結構中，通常會提到二 個軸或方向，即，“c”軸或方向及“a”軸或方向。爲了簡單 起見，“c”軸或方向可視爲垂直於碳層的方向。“a”軸或方 向可視爲平行於碳層的方向或垂直於“c”方向之方向。合 適用來製造可撓性石墨薄片的石墨擁有非常高程度的定向 〇 如上述所提及，將碳原子的平行層保持在一起之黏合力 量僅有弱的凡得瓦爾力。天然石墨可經化學處理而使在疊 置的碳層或薄層間之間隔可明顯地打開，以便在垂直於層 的方向（亦即，在“C”方向）上提供明顯的擴張，因此形成 擴張或膨脹的石墨結構（其中碳層的片狀特徵實質上還保 留）。 已化學或熱擴張且更特別地擴張的片狀石墨粉末（以便 具有最後厚度或“C”方向維度如原始的“C”方向維度之約80 倍或更多）可不使用黏合劑而形成黏合或積合的擴張石墨 薄片，例如纖維網、紙、條狀物、帶狀物或其類似物（典 型地指爲“可撓性石墨”）。咸信可藉由在沒有使用任何黏 結材料下壓縮石墨粒子（其已擴張成最後厚度或“c”維度如 原始的“c”方向維度之約80倍或更多），而形成積合的可 撓性薄片，此乃由於機械聯鎖或內聚力（其可在大量擴張 的石墨粒子間獲得）。 五、發明說明（4) 除了撓性外，該薄片材料（如上述提及）亦已發現擁有與 熱和電的傳導性及流體擴散有關之高程度異方向性；比較 至天然石墨起始材料，由於已擴張的石墨粒子之定向爲實 質上平行於由壓縮所產生的薄片之相對面。因此所產生的 薄片材料具有優良的撓性、好的強度及非常高的定向程度 〇 簡單地說，可撓的、無黏合劑的異方向性石墨薄片材料 (例如纖維網、紙、條狀物、帶狀物、箔、襯墊或其類似 物）之製造方法包括，在預定的負載及缺乏黏合劑下壓縮 或壓塑該已在“c”方向維度擴張成原始粒子的約80倍或更 多之石墨粒子，以便形成實質上平坦、可撓的、積合的石 墨薄片。該已擴張的石墨粒子之外觀通常爲蛆狀（worm-like)或蠕蟲狀（vermiform)，一旦壓縮，其將維持壓縮設 定且排列成與薄片的相對主要表面平行。薄片材料的密度 及厚度可藉由控制壓縮程度而改變。薄片材料的密度範圍 在約0.04 g/cc至約1.4 g/cc中。該撓性石墨薄片材料 具有可評價的異方向性程度，由於石墨粒子會排列成將薄 片的主要相對平行的表面平行，而異方向性程度會在薄片 材料經輥壓增加密度後增加。在經輥壓的異方向薄片材料 中，包含“c”方向（即垂直於相對平行的薄片表面之方向） 的厚度、沿著長度及寬度（即沿著或平行於相對的主要表 面）變化而包含“a”方向之方向、和薄片的熱、電及流體擴 散性質在“c”及“a”方向上非常不同，典型地會差異到級數 592968 五、發明說明（5) 的大小。 此相當大的性質差異（即異方向性，其具方向依賴性）在 某些應用上爲不利的。例如，在襯墊應用中，若將撓性石 墨薄片使用作爲襯墊材料且用途爲緊緊地保持在金屬表面 之間時，在平行於及在撓性石墨薄片的主要表面間將更容 易發生流體（例如氣體或液體）的擴散。在大部分的例子中 ，若平行於石墨薄片的主要表面（“a”方向）之流體流動阻 抗增加時（甚至是付出在正交於石墨薄片的主要面（“c”方 向）上減低對流體擴散流動的阻抗之代價），其將提供較大 的襯墊性能。關於電性質，異方向撓性石墨薄片之電阻率 在正交至撓性石墨薄片的主要表面之方向上（“c”方向）較 高，而實質上在平行於撓性石墨薄片的主要面之方向上 (“a”方向）較低。在諸如燃料電池的電極之應用中’若能 減少正交至撓性石墨薄片的主要表面（“c”方向）之電阻（甚 至是付出平行於撓性石墨薄片的主要面之方向（“a”方向） 的電阻率增加之代價），則更優良。 關於熱性質，撓性石墨薄片之導熱度在平行於撓性石墨 薄片的主要表面方向上相當高’同時在正交至主要表面的 “c”方向上則相當低。 可對撓性石墨薄片提供溝槽’其較佳地加上平滑的側邊 ，且其通過在平行相對的撓性石墨薄片表面間而由經壓縮 的膨脹石墨之邊壁隔離。當該撓性石墨薄片作爲電化學燃 料電池的電極時，將其配置成與離子交換薄膜毗連，所以V. Explanation of the invention (3) In short, graphite is characterized by a laminated structure of carbon (that is, a structure composed of a superposed layer or a thin layer of carbon atoms), which is connected by a weak Van der Waals force. Together. In the graphite structure under consideration, two axes or directions are usually mentioned, namely the "c" axis or direction and the "a" axis or direction. For simplicity, the "c" axis or direction can be considered as the direction perpendicular to the carbon layer. The "a" axis or direction can be regarded as a direction parallel to the carbon layer or a direction perpendicular to the "c" direction. Graphite suitable for making flexible graphite flakes has a very high degree of orientation. As mentioned above, the amount of adhesive force that holds parallel layers of carbon atoms together is only weak Van der Waals force. Natural graphite can be chemically treated so that the space between stacked carbon layers or thin layers can be clearly opened to provide a significant expansion in the direction perpendicular to the layer (ie, in the "C" direction), thus forming Expanded or expanded graphite structure (in which the flaky features of the carbon layer are essentially retained). The flake graphite powder that has been chemically or thermally expanded and more particularly expanded (so as to have a final thickness or "C" direction dimension such as about 80 times or more of the original "C" direction dimension) can form a cohesive or Accumulated expanded graphite flakes, such as webs, paper, strips, ribbons, or the like (typically referred to as "flexible graphite"). Xianxin can form an integrated polymer by compressing graphite particles (which have expanded to the final thickness or "c" dimension, such as about 80 times or more of the original "c" direction dimension) without using any bonding material. Flexible flakes due to mechanical interlocking or cohesion (which can be obtained between a large number of expanded graphite particles). V. Description of the invention (4) In addition to flexibility, the sheet material (as mentioned above) has also been found to have a high degree of anisotropy related to thermal and electrical conductivity and fluid diffusion; compared to natural graphite starting materials Since the expanded graphite particles are oriented substantially parallel to the opposite faces of the flakes produced by compression. The resulting sheet material has excellent flexibility, good strength, and a very high degree of orientation. Briefly, flexible, non-adhesive, non-directional graphite sheet materials (such as fiber webs, paper, strips) , Ribbons, foils, pads, or the like) includes compressing or compression molding under a predetermined load and lack of an adhesive, which have expanded approximately 80 times or more in the dimension of the "c" direction to the original particles More graphite particles to form a substantially flat, flexible, integrated graphite sheet. The expanded graphite particles generally have a worm-like or vermiform appearance. Once compressed, they will maintain the compression setting and be aligned parallel to the opposite major surface of the sheet. The density and thickness of the sheet material can be changed by controlling the degree of compression. The sheet material has a density in the range of about 0.04 g / cc to about 1.4 g / cc. This flexible graphite sheet material has a measurable degree of anisotropy. Since the graphite particles are arranged so that the main relatively parallel surfaces of the sheet are parallel, the degree of anisotropy increases after the sheet material is increased in density by rolling. In the rolled sheet material with different directions, the thickness of the "c" direction (that is, the direction perpendicular to the relatively parallel surface of the sheet), the change along the length and width (that is, along or parallel to the opposite major surface) The direction including the "a" direction, and the thermal, electrical, and fluid diffusion properties of the sheet are very different in the "c" and "a" directions, and typically differ to the level 592968. V. The size of the invention description (5). This considerable difference in properties (i.e., different directionality, which is direction dependent) is disadvantageous for some applications. For example, in a gasket application, if a flexible graphite sheet is used as a gasket material and is held tightly between metal surfaces, it will be more likely to occur parallel to and between the major surfaces of the flexible graphite sheet. Diffusion of a fluid, such as a gas or liquid. In most cases, if the flow resistance of the fluid parallel to the major surface of the graphite sheet ("a" direction) increases (or even if it is orthogonal to the major surface of the graphite sheet ("c" direction), the fluid flow resistance is reduced. At the cost of resistance to diffusion flow), which will provide greater pad performance. Regarding electrical properties, the resistivity of the flexible graphite flakes with different directions is higher in the direction orthogonal to the main surface of the flexible graphite flakes ("c" direction), and is substantially parallel to the main surface of the flexible graphite flakes. Direction ("a" direction) is low. In applications such as fuel cell electrodes, 'if the resistance orthogonal to the main surface of the flexible graphite sheet ("c" direction) can be reduced (or even the direction parallel to the main surface of the flexible graphite sheet ("a" Direction) at the cost of increased resistivity). Regarding the thermal properties, the thermal conductivity of the flexible graphite sheet is relatively high in the direction parallel to the main surface of the flexible graphite sheet 'while being relatively low in the direction "c" orthogonal to the main surface. The flexible graphite sheet may be provided with grooves' which are preferably provided with smooth sides, and which are separated by the walls of the compressed expanded graphite by parallel between the surfaces of the flexible graphite sheets which are opposed in parallel. When the flexible graphite sheet is used as an electrode of an electrochemical fuel cell, it is arranged adjacent to the ion exchange film, so
五、發明說明（6 ) 該撓性石墨薄片的邊壁“頂端，，會毗連至離子交換薄膜。 本發明可滿足一種能在撓性石墨薄片上壓印高清晰度圖 案之方法用的材料，以提供能專一使用作爲PEM燃料電池 中的組件材料；及一種能在撓性石墨薄片上壓印高淸晰度 圖案之方法。 發明槪述 本發明提供一種合適用來形成壓印物品的材料及一種使 用以形成壓印物品的方法。該材料及方法可用來製造PEM 燃料電池。該材料由壓縮大量經膨脹的石墨粒子而形成之 薄片所形成。該些粒子可具有一經控制的空隙狀態（及許 多情況中伴隨的爲密度），以便形成具有經控制的形態學 之壓印物品。此可例如藉由在壓印之前輪壓或加壓該撓性 石墨而達成。 藉由控制該薄片的空隙狀態（因此該壓印物品的形態學） ，可控制該壓印物品的某些特徵。例如，可控制熱異方向 性比率（也就是說，面內導熱度與透平面導熱度之比率）， 以便提供熱異方向性度量以提供想要的熱分散能力。同樣 地，可以相同方法控制電異方向性。 該壓印圖案可有利地在本發明的材料中形成，其藉由機 械地衝擊該石墨薄片的相對表面以在薄片的預定位置處位 移石墨，所以提供一溝槽圖案。 本發明之方法包括提供一種壓印裝置，其通常包含二個 相對的元件，此二相對元件之一包含在上面具有壓印圖案 592968 五、發明說明（7) 之壓 印 元 件，該壓 印圖案藉由繞著該壓印 元件排列 一 系 列 具有 壟 的 邊壁（即 ，邊壁頂端）而形成，從 壓印元件 表 面 至 溝槽 底 層 則具有預 定的高度；及此二相對 元件的 另 一 個 則 包含 —► 具 有衝擊表 面的平底元件；其中該 壓印元 件及平 底 元件排 列 在壓印裝 置中，如此平底元件的 衝擊表 面 與 壓 印 元件 的 溝 槽底層分 離開一距離“d”，其至少等於（及 較 佳 地 大於 )該壟的高度 ;藉由將本發明的撓性 石墨薄 片 材料 通 過壓 印 裝 置的壓印 元件及平底元件間而進 行壓印 1 如 此 壓 印元件 的 壟可在該 撓性石墨薄片上發揮壓 力，其 中 該 撓 性 石墨 薄 片 在壓印圖案區域中的厚度在壓1 印之前 小 於 距 離 “d，，） 但是大於在平底元件的衝擊表面及 壓印元 件 的 壟 間 之距 離 1 因此在該 撓性石墨薄片及壓印元 件之溝 槽 底 層 間 形成 —^ 間 距，進一 步該撓性石墨薄片在壓 印裝置 中 的 壓 印 會使 該 撓 性石墨薄 片在遇到從壓印元件的 壟來之 壓 力 的 區 域處 之 材料，流至 在撓性石墨薄片與壓印 元件的 溝 槽 底 層 間之 間 距 〇 本 發 明 的薄片較 佳地以樹脂浸漬，諸如 一熱塑 性或 熱 固 性樹 脂 〇 爲 了 示 範目的， 該熱固性樹脂可選自於 聚碳化 亞 二 胺 樹 脂、 酚 樹 脂、丙烯 酸樹脂、糠醇樹脂、環 氣樹脂 類 、 纖 維 素、 尿 素 樹脂、馬 來胺樹脂及苯二甲酸二 烯丙酯 樹 脂 〇 該 熱固 性 樹 脂亦可包括橡膠彈性聚合物類樹 脂，諸 如 苯 乙 烯 -丁二烯橡膠樹脂、 >丙烯腈-丁二烯橡膠樹 -9- 脂及氯 丁 烯 橡 五、發明說明（8) 膠樹脂；聚矽氧烷樹脂類，諸如矽酮彈性體樹脂類及室溫 交聯型矽氧橡膠樹脂類；及聚胺基甲酸酯樹脂類。 該熱塑性樹脂可選自於烯烴樹脂、苯乙烯樹脂、乙烯基 樹脂、乙烯-醋酸乙烯酯共聚物樹脂、醯胺樹脂、酯樹脂 、碳酸酯樹脂、醋酸酯樹脂及丙烯酸樹脂。更特別地，該 熱塑性樹脂可包括聚乙烯樹脂、聚苯乙烯樹脂、聚丙烯樹 月旨、聚甲基丙烯酸甲酯樹脂、聚對苯二甲酸乙酯樹脂、聚 對苯二甲酸丁酯樹脂、聚醚風樹脂、聚碳酸酯樹脂、聚甲 醛樹脂、聚醯胺樹脂、聚醯亞胺樹脂、聚醯胺醯亞胺樹脂 、聚乙烯醇樹脂、聚氯乙烯樹脂、氟樹脂、聚苯楓樹脂、 聚醚酮醚樹脂、聚風樹脂、聚酮醚樹脂、聚芳基化合物樹 月旨、聚醚醯亞胺樹脂及聚甲基戊烯樹脂、乙烯-丙烯樹脂 共聚物樹脂、乙烯-丙烯酸酯共聚物樹脂、聚苯乙烯樹脂 、丙烯青-苯乙烯共聚物樹脂、丙烯青-苯乙烯共聚物樹脂 、氯乙烯樹脂、聚甲基丙烯酸甲酯樹脂、聚酯樹脂、6 -耐 綸樹脂、66 -耐綸樹脂、聚對苯二甲酸乙酯樹脂及聚對苯 二甲酸丁酯樹脂。該熱塑性樹脂可爲混合物、共聚物或其 改質的聚合物。亦特別地包括醋酸酯樹脂及丙烯酸樹脂。 較佳地，該樹脂爲一種熱固性樹脂，更佳地爲丙烯酸-、環氧-或酚-系樹脂系統，而該薄片在壓印之前則以其浸 漬，且有利地在該撓性石墨薄片壓印後交聯該樹脂。該浸 漬樹脂的撓性石墨薄片材料之樹脂含量較佳地至少約5%， 更佳地至少約1 0%，以重量計。 -10- 592968 五、發明說明（9) 圖形簡述 本發明可參考下列詳細說明而較好了解且更明瞭其優點 ，特別是當參考至附加圖形閱讀時，其中： 第1圖爲根據本發明所製造的壓印石墨物品之部分側截 面平面圖； 第1(A)圖爲第1圖之薄片的上視平面圖；5. Description of the invention (6) The "top end" of the side wall of the flexible graphite sheet will be adjacent to the ion exchange film. The present invention can satisfy a material capable of imprinting a high-definition pattern on the flexible graphite sheet. In order to provide a material that can be exclusively used as a component material in a PEM fuel cell; and a method capable of embossing a high-resolution pattern on a flexible graphite sheet. SUMMARY OF THE INVENTION The present invention provides a material suitable for forming an embossed article and a use thereof. A method for forming an embossed article. The material and method can be used to make a PEM fuel cell. The material is formed by flakes formed by compressing a large number of expanded graphite particles. The particles can have a controlled void state (and in many cases) Is accompanied by density) in order to form an embossed article with a controlled morphology. This can be achieved, for example, by rolling or pressing the flexible graphite before embossing. By controlling the void state of the sheet ( Therefore, the morphology of the embossed article) can control certain characteristics of the embossed article. For example, it can control the thermal anisotropy ratio (that is, the That is, the ratio of the in-plane thermal conductivity to the through-plane thermal conductivity) in order to provide a measure of thermal anisotropy to provide the desired heat dissipating ability. Similarly, the electrical anisotropy can be controlled in the same way. The embossed pattern can be advantageously used Formed in the material of the present invention, which provides a groove pattern by mechanically striking the opposite surface of the graphite sheet to displace graphite at a predetermined position of the sheet. The method of the present invention includes providing an embossing device, which is generally Containing two opposing elements, one of the two opposing elements includes an embossing pattern 592968 on the fifth, invention description (7), the embossing pattern is arranged around a series of ridges around the embossing element. The side wall (ie, the top of the side wall) is formed, and has a predetermined height from the surface of the embossed element to the bottom of the groove; and the other of the two opposite elements includes—► a flat-bottomed element with an impact surface; The printing element and the flat-bottom element are arranged in the imprinting device, so that the impact surface of the flat-bottom element and the imprinting element The bottom layer of the groove is separated by a distance "d", which is at least equal to (and preferably greater than) the height of the ridge; by passing the flexible graphite sheet material of the present invention between the embossing element and the flat-bottom element of the embossing device And embossing 1 so that the ridges of the embossing element can exert pressure on the flexible graphite sheet, wherein the thickness of the flexible graphite sheet in the area of the embossing pattern is less than the distance "d," but greater than 1 The distance 1 between the impact surface of the flat-bottomed element and the ridges of the imprinted element 1 therefore forms a space between the flexible graphite sheet and the bottom layer of the groove of the imprinted element, and further the pressure of the flexible graphite sheet in the imprinting device. The printing will cause the material of the flexible graphite sheet in the area where it encounters the pressure from the ridge of the imprinting element to flow between the flexible graphite sheet and the groove bottom layer of the imprinting element. Preferably impregnated with a resin, such as a thermoplastic or thermosetting resin. For demonstration purposes, the The thermosetting resin may be selected from the group consisting of a polycarbodiimide resin, a phenol resin, an acrylic resin, a furfuryl alcohol resin, an epoxy resin, cellulose, a urea resin, a maleamine resin, and a diallyl phthalate resin. It can also include rubber elastic polymer resins, such as styrene-butadiene rubber resin, > acrylonitrile-butadiene rubber tree-9-lipid and chloroprene rubber. 5. Description of the invention (8) rubber resin; polysilicon Oxane resins, such as silicone elastomer resins and room temperature crosslinked silicone rubber resins; and polyurethane resins. The thermoplastic resin may be selected from olefin resins, styrene resins, vinyl resins, ethylene-vinyl acetate copolymer resins, ammonium resins, ester resins, carbonate resins, acetate resins, and acrylic resins. More specifically, the thermoplastic resin may include polyethylene resin, polystyrene resin, polypropylene tree, polymethyl methacrylate resin, polyethylene terephthalate resin, polybutylene terephthalate resin, Polyether resin, polycarbonate resin, polyoxymethylene resin, polyamido resin, polyamido resin, polyamido resin, polyvinyl alcohol resin, polyvinyl chloride resin, fluororesin, polyphenyl maple resin , Polyether ketone ether resin, polywind resin, polyketone ether resin, polyarylate resin, polyetherimine resin and polymethylpentene resin, ethylene-propylene resin copolymer resin, ethylene-acrylate Copolymer resin, polystyrene resin, acrylic blue-styrene copolymer resin, acrylic blue-styrene copolymer resin, vinyl chloride resin, polymethyl methacrylate resin, polyester resin, 6-nylon resin, 66 -Nylon resin, polyethylene terephthalate resin and polybutylene terephthalate resin. The thermoplastic resin may be a mixture, a copolymer, or a modified polymer thereof. Also specifically included are acetate resins and acrylic resins. Preferably, the resin is a thermosetting resin, more preferably an acrylic-, epoxy-, or phenol-based resin system, and the sheet is impregnated with it prior to embossing, and is advantageously pressed on the flexible graphite sheet. The resin was crosslinked after printing. The resin content of the impregnated flexible graphite sheet material is preferably at least about 5%, more preferably at least about 10% by weight. -10- 592968 V. Description of the invention (9) Brief description of the present invention The present invention can be better understood and its advantages can be better understood by referring to the following detailed descriptions, especially when reference is made to the reading of additional graphics, in which: Figure 1 is according to the present invention Partial cross-sectional plan view of the manufactured embossed graphite article; Figure 1 (A) is a top plan view of the sheet of Figure 1;
第2圖爲在本發明之方法中使用的壓印裝置之具體實施 例的部分截面圖； 第2(A)圖爲在本發明之方法中使用的壓印裝置之具體實 施例的部分截面圖，當壓印開始時的立即圖示； 第2(B)圖爲第2圖的壓印裝置，當壓印發生時的圖示； 第2(C)圖爲第2圖的壓印裝置之立體圖式；FIG. 2 is a partial cross-sectional view of a specific embodiment of an imprint apparatus used in the method of the present invention; FIG. 2 (A) is a partial cross-sectional view of a specific embodiment of an imprint apparatus used in the method of the present invention , Immediate illustration when imprinting starts; Fig. 2 (B) is the imprinting device of Fig. 2 when imprinting occurs; Fig. 2 (C) is the imprinting device of Fig. 2 Stereogram
第3，4圖爲顯微照片，其爲根據本發明所製備之壓印撓 性石墨薄片的邊壁之一的截面5 Ox倍放大圖，其顯示出使 用無空隙（第3圖）及非無空隙（第4圖）撓性石墨薄片可達 成的形態學；及 第5圖爲具有“鰭狀”或“稜紋”之壓印撓性石墨薄片的側 視圖，如於下文中所描述。 發明之詳細說明 石墨爲一種晶狀碳形式，其包括原子呈共價鍵結的平坦 平面層且其平面間的鍵結較弱。藉由將石墨粒子（諸如天 然片狀石墨粉末）與夾層劑（intercalant)(例如硫酸及硝 酸溶液）處理，石墨的結晶結構會反應而形成含夾層劑的 -11- 592968 五、發明說明（彳〇) 石墨化合物。該經處理的石墨粒子此後指爲"已夾層的石 墨粒子"。在曝露至高溫後，石墨中的夾層劑會分解及揮 發，而造成該已夾層的石墨粒子會於ncn方向上（即在垂直 於石墨的晶狀平面之方向上）以折疊似的方式擴張其維度 至如原始體積的約80倍或更多。該層離的石墨粒子之外 觀如蠕蟲狀，因此通常指爲蛆狀物。該些蛆狀物可壓縮在 一起而形成可撓性薄片，不像原始的片狀石墨粉末，其可 形成及切割成不同形狀，亦可藉由變形機械擠壓而提供小 的橫切開口。 合適於本發明之用途的石墨起始材料包括具高石墨碳的 材料，其能內插有機及無機酸類和鹵素類，然後當將其曝 露至加熱時其會擴張。這些含高石墨碳的材料最佳地具有 約1 . 0的石墨化程度。如於此公告中所使用的名稱”石墨 化程度"指爲g値，其根據下式： g= 3.45-d(002) 0.095 其中d ( 0 0 2 )爲碳石墨層間之間距，其於結晶結構中以埃 爲單位度量。石墨層間之間距d可利用標準X-射線繞射技 術來測量。所測量到的繞射波峰位置與（〇〇2 )、（ 004 )及 ( 006 )的米勒標誌索引相符合，且使用標準最小平方技巧（ 其可最小化這些波峰的全部總誤差）導出該間距。具高石 墨碳的材料之實例包括從不同來源來的天然石墨和其它含 碳的材料（諸如利用化學氣相沉積及其類似的方法所製備 的碳）。天然石墨最佳。 -12- 五、發明說明（11) 本發明所使用的石墨起始材料可包含非碳組分，只要該 起始材料的結晶結構可維持所需要的石墨化程度且能層離 即可。通常地，可合適地使用任何含碳材料（其結晶結構 擁有所需的石墨化程度且其可夾層及層離）用於本發明之 用途。此石墨較佳地具有少於6重量百分比的灰分含量。 更佳地，可用於本發明之石墨具有至少約98%的純度。在 最佳的具體實施例中，使用的石墨具有至少約99%的純度 〇 製造石墨薄片的一般方法則由仙（Shane)等人在美國專 利案號3,404,061中描述，此公告以參考方式倂入本文。 在進行典型的仙等人之方法中，天然片狀石墨粉末可藉由 將其分散在溶液（包含例如硝酸與硫酸之混合物）中而夾層 ，其程度爲每100重量份的片狀石墨粉末約20至約300 重量份的夾層劑溶液（pph)。該夾層溶液包括於技藝中所 熟知的氧化及其它夾層劑。其實例包括含氧化劑及氧化混 合物的那些，諸如溶液，包括硝酸、氯酸鉀、鉻酸、過錳 酸鉀、鉻酸鉀、重鉻酸鉀、過氯酸及其類似物；或混合物 ，諸如例如濃硝酸與氯酸、鉻酸與磷酸、硫酸與硝酸；或 強有機酸（例如三氟醋酸）與可溶在有機酸之強氧化劑的混 合物。額外地，可使用電壓來引發石墨的氧化反應。可使 用電解氧化反應而導入石墨結晶的化學物種包括硫酸和其 它酸類。 在較佳的具體實施例中，該夾層劑爲硫酸（或硫酸及磷 -13- 592968 五、發明說明（12 ) 酸）與氧化劑（即硝酸、過氯酸、鉻酸、過錳酸鉀、過氧化 氫、碘酸或過碘酸或其類似物）之混合物溶液。該夾層溶 液亦可包含金屬鹵化物諸如氯化鐵、與硫酸混合的氯化鐵 :或鹵化物，諸如溴（如溴與硫酸的溶液或在有機溶劑中 的溴）。 該夾層溶液的量範圍可從約2 0至約1 5 0 p p h，更典型地 約50至約120pph。在該片狀物夾層後，可將任何過量的 溶液從該片狀物中排出，且以水淸洗該片狀物。額外地， 該夾層溶液之量可限制在約10及約50pph之間，此可消 除洗滌步驟（如在美國專利案號4,895, 7 1 3中所教導及描 述，該公告亦以參考方式倂入本文）。 以夾層溶液處理的片狀石墨粉末粒子可例如藉由混合而 選擇性地與選自於醇類、糖類、醛類及酯類之還原有機試 劑（其會在25°C至125°C的溫度範圍內與氧化夾層溶液的 表面薄膜反應）接觸。合適之特定有機試劑包括十六醇、 十八醇、1-辛醇、2-辛醇、癸醇、1,10 -癸二醇、癸醛、 1-丙醇、1，3-丙二醇、乙二醇、聚丙二醇、右旋糖、果糖 、乳糖、蔗糖、馬鈴薯澱粉、單硬脂酸乙二醇酯、二苯甲 酸二甘醇酯、單硬脂酸丙二醇酯、單硬脂酸甘油酯、二甲 基草酸鹽、二乙基草酸鹽、甲酸甲酯、甲酸乙酯、抗壞血 酸酸；及木質素-衍生化合物類，諸如木質硫酸鈉。該有 機還原劑的量合適地爲約片狀石墨粉末粒子的〇 . 5至4重 量％ 〇Figures 3 and 4 are photomicrographs showing a magnified cross section of one of the side walls of an embossed flexible graphite sheet prepared in accordance with the present invention at 5 Ox times, showing the use of void-free (Figure 3) and non- The morphology achievable with void-free (Figure 4) flexible graphite flakes; and Figure 5 is a side view of an embossed flexible graphite sheet with "fins" or "ribs" as described below. DETAILED DESCRIPTION OF THE INVENTION Graphite is a form of crystalline carbon that includes a flat planar layer with covalently bonded atoms and weak bonding between the planes. By treating graphite particles (such as natural flake graphite powder) and intercalants (such as sulfuric acid and nitric acid solution), the crystal structure of graphite will react to form interlayer-containing -11-592968 5. Description of the invention (彳〇) Graphite compounds. The treated graphite particles are hereinafter referred to as " sandwiched graphite particles ". After being exposed to high temperature, the intercalating agent in graphite will decompose and volatilize, causing the intercalated graphite particles to expand in a fold-like manner in the ncn direction (that is, in the direction perpendicular to the crystalline plane of graphite). Dimensions to about 80 times or more as the original volume. This delaminated graphite particle looks like a worm, so it is usually referred to as a maggot. These slugs can be compressed together to form flexible flakes, unlike the original flake graphite powder, which can be formed and cut into different shapes, and can also be provided with small cross-cut openings by deformation mechanical extrusion. Graphite starting materials suitable for the use of the present invention include materials with high graphite carbon, which can interpolate organic and inorganic acids and halogens, and then expand when exposed to heat. These high graphitic carbon-containing materials optimally have a degree of graphitization of about 1.0. The name "degree of graphitization" as used in this announcement refers to g 値, which is based on the following formula: g = 3.45-d (002) 0.095 where d (0 0 2) is the distance between carbon graphite layers, which is The crystal structure is measured in angstroms. The distance d between graphite layers can be measured using standard X-ray diffraction techniques. The measured diffraction peak positions are in meters with (002), (004), and (006). The Lexmark index matches and derives the spacing using standard least squares techniques that minimize the total total error of these peaks. Examples of materials with high graphitic carbon include natural graphite from different sources and other carbon-containing materials (Such as carbon prepared by chemical vapor deposition and similar methods). Natural graphite is the best. -12- V. Description of the invention (11) The graphite starting material used in the present invention may contain non-carbon components as long as The crystal structure of the starting material can maintain the required degree of graphitization and can be delaminated. Generally, any carbon-containing material can be suitably used (its crystal structure has the required degree of graphitization and it can be sandwiched and layered) From) for Uses of the invention. The graphite preferably has an ash content of less than 6 weight percent. More preferably, the graphite useful in the present invention has a purity of at least about 98%. In the preferred embodiment, the graphite used has A general method of making graphite flakes with a purity of at least about 99% is described by Shane et al. In U.S. Patent No. 3,404,061, which is incorporated herein by reference. In performing the typical Xian et al. Method, Natural flake graphite powder can be sandwiched by dispersing it in a solution (containing, for example, a mixture of nitric acid and sulfuric acid) to an extent of about 20 to about 300 parts by weight of an interlayer solution per 100 parts by weight of flake graphite powder ( pph). The interlayer solution includes oxidation and other interlayer agents well known in the art. Examples include those containing oxidants and oxidation mixtures, such as solutions, including nitric acid, potassium chlorate, chromic acid, potassium permanganate, potassium chromate, Potassium dichromate, perchloric acid, and the like; or mixtures such as, for example, concentrated nitric acid and chloric acid, chromic acid and phosphoric acid, sulfuric acid and nitric acid; or strong organic acids (such as A mixture of acetic acid) and a strong oxidant soluble in organic acids. In addition, voltage can be used to initiate the oxidation of graphite. Chemical species that can be used to introduce graphite crystals using electrolytic oxidation include sulfuric acid and other acids. In the embodiment, the interlayer agent is sulfuric acid (or sulfuric acid and phosphorus-13-592968 V. Description of the Invention (12) acid) and oxidizing agent (ie, nitric acid, perchloric acid, chromic acid, potassium permanganate, hydrogen peroxide, iodine Acid or periodic acid or the like). The interlayer solution may also contain metal halides such as ferric chloride, ferric chloride mixed with sulfuric acid: or halides such as bromine (such as a solution of bromine and sulfuric acid or Bromine in an organic solvent). The amount of the interlayer solution may range from about 20 to about 150 pph, more typically from about 50 to about 120 pph. After the sheet is sandwiched, any excess solution can be drained from the sheet and the sheet can be rinsed with water. Additionally, the amount of the interlayer solution may be limited to between about 10 and about 50 pph, which eliminates the washing step (as taught and described in U.S. Patent No. 4,895, 7 1 3, which is also incorporated by reference This article). The flake graphite powder particles treated with the interlayer solution can be selectively mixed with a reducing organic agent selected from alcohols, sugars, aldehydes, and esters (which will be at a temperature of 25 ° C to 125 ° C, for example, by mixing). Contact with the surface film of the oxidized interlayer solution within the range). Suitable specific organic reagents include cetyl alcohol, stearyl alcohol, 1-octanol, 2-octanol, decanol, 1,10-decanediol, decanal, 1-propanol, 1,3-propanediol, ethyl alcohol Glycol, polypropylene glycol, dextrose, fructose, lactose, sucrose, potato starch, ethylene glycol monostearate, diethylene glycol dibenzoate, propylene glycol monostearate, glyceryl monostearate, Dimethyl oxalate, diethyl oxalate, methyl formate, ethyl formate, ascorbic acid; and lignin-derived compounds such as sodium lignosulfate. The amount of the organic reducing agent is suitably about 0.5 to 4% by weight of the flake graphite powder particles.
-14- 五、發明說明·（13) 使用在夾層之前、在夾層期間或立即地在夾層之後施加 的膨脹輔助劑亦可提供改良。這些改良爲可減低層離溫度 及可增加擴張的體積（亦指爲”蛆狀物體積"）。在此上下文 中之膨脹輔助劑有利地爲可充分地溶在夾層溶液中之有機 材料，以獲得膨脹上的改良。更狹窄地，可較佳地專門使 用包含碳、氫及氧之型式的有機材料。羧酸類已發現特別 有效。可有用地作爲膨脹輔助劑之合適的羧酸有選自於芳 香族、脂肪族或環脂族、直鏈或枝鏈、飽和及不飽和的單 羧酸類、二羧酸類及多羧酸類（其具有至少1個碳原子， 較佳地最高約1 5個碳原子），可將其以有效的量溶於夾層 溶液中，以提供一種或多種層離方面可測量的改良。可使 用合適的有機溶劑來改良該有機膨脹輔助劑在夾層溶液中 的溶解度。 飽和脂肪族羧酸類的典型實例有酸類，諸如式 H(CH2)nCOOH的那些（其中η爲0至約5的數字），包括蟻 酸、醋酸、丙酸、丁酸、戊酸、己酸及其類似物。除了該 些羧酸類，亦可使用酐類或反應性羧酸衍生物類，諸如烷 基酯類。典型的烷基酯類有甲酸甲酯及甲酸乙酯。硫酸、 硝酸及其它熟知的水性夾層劑具有將蟻酸分解，最終後成 水及二氧化碳的能力。爲此，蟻酸及其它敏感的膨脹輔助 劑可有利地在該片狀石墨粉末浸入水性夾層劑之前與其接 觸。典型的二羧酸類有含2-12個碳原子的脂肪族二羧酸 類，特別是草酸、反丁烯二酸、丙二酸、順丁烯二酸、琥 15- 五、發明說明（14) 珀酸、戊二酸、己二酸、1，5 -戊二羧酸、1,6-己二羧酸、 1，10·癸二羧酸、環己烷-1,4-二羧酸；及芳香族的二羧酸 類，諸如太酸或對苯二甲酸。典型的烷基酯類有二甲基草 酸鹽及二乙基草酸鹽。典型的環脂酸類有環己《完殘酸；及 芳香族羧酸類有苯甲酸、萘酸、胺茴酸、對-胺基苯甲酸 、水楊酸、鄰-、間-及對-甲苯基酸類、甲氧基及乙氧基 苯甲酸、乙醯乙醯胺基苯甲酸類及乙醯胺基苯甲酸類、苯 基醋酸及萘酸類。典型的羥基芳香族酸類有羥基苯甲酸、 3 ·羥基-卜萘酸、3 -羥基-2 -萘酸、4 -羥基-2 -萘酸、5 -羥 基-1-萘酸、5-羥基-2-萘酸、6-羥基-2-萘酸及7-羥基- 2-萘酸。在多元羧酸當中，卓越的爲檸檬酸。 該夾層溶液爲水性的且較佳地包含量約1至1 〇%的膨脹 輔助劑，此量可有效地促進層離。於該片狀石墨粉末浸入 水性夾層溶液之前或之後將其與膨脹輔助劑接觸的具體實 施例中，該膨脹輔助劑可利用合適的設備（諸如V-攪和器） 與石墨混合，其典型的量爲約片狀石墨粉末的0 . 2%至約 1 0重量％。 在該片狀石墨粉末夾層、接著將該經夾層劑塗敷之已夾 層的片狀石墨粉末與有機還原劑混合後，將該混合物曝露 至25°到125°C的溫度範圍，以促進還原劑與夾層劑塗層 反應。加熱時間最高約20小時，對上述提到的範圍之較 高溫度來說，較短的加熱時期爲例如至少約1 〇分鐘。在 較高溫度時，可使用一個半小時或較少（例如，10至25分 -16- 五、發明說明（15) 鐘的級數）的時間。 因此該經處理的石墨粒子有時指爲"已夾層的石墨粒子" 。在曝露至高溫後，例如溫度至少約1 60 °C (特別地約 700°C至1 000°C及較高），該已夾層的石墨粒子會在c-方 向（即在垂直於構成石墨粒子的晶狀平面之方向）上以折疊 似的方式擴張到如原始體積的約80至1 000倍或更多。該 已擴張（即層離）的石墨粒子之外觀呈蠕蟲狀，因此通常指 爲蛆狀物。該蛆狀物可壓縮在一起而形成可撓性薄片，不 像原始的片狀石墨粉末，其可形成及切割成不同的形狀及 /或同時以變形機械擠壓而提供小的橫切開口。 可撓性石墨薄片及箔具黏性、好的處理強度且可合適地 壓縮（例如藉由輥壓）至厚度約0.075毫米至3.75毫米， 典型的密度約每立方公分0.1至1.4克（g/cc)。可如在美 國專利案號5,902，762 (其以參考方式倂於本文）中所描述 般，將約1.5-30重量％的陶瓷添加劑與該經夾層的片狀石 墨粉末摻合，以在最後的可撓性石墨產物中提供加強用的 樹脂浸漬。該些添加劑包括長度約0 . 1 5至1 . 5毫米的陶 瓷纖維粒子。該些粒子的寬度合適地爲約0.04至0.004 毫米。該些陶瓷纖維粒子不具反應性、不會黏附至石墨且 在最高約1100 °C的溫度下安定（較佳地約1 400 °C或較高） 。合適的陶瓷纖維粒子可由經浸漬的石英玻璃纖維、碳及 石墨纖維、氧化锆、氮化硼、碳化矽及氧化鎂纖維、天然 產生的無機纖維類（諸如偏矽酸鈣纖維、矽酸鋁鈣纖維、 -17- 五、發明說明（16) 氧化鋁纖維及其類似物）而形成。 如所提及，有時該可撓性石墨薄片亦可有利地以樹脂處 理，而該經吸收的樹脂可在硬化後加強該可撓性石墨薄片 的防潮性和處理強度（即硬性），且可形成”固定的”石墨形 態。合適的樹脂含量較佳地至少約5重量％，更佳地，約 10至35%重量及合適地上至約60%重量。在本發明的實行 中，經發現特別有用的樹脂包括丙烯酸-、環氧-及酚-系 樹脂系統或其混合物。合適的環氧樹脂系統包括那些以二 縮水甘油醚爲主的雙酚A(DGEBA)及其它多官能樹脂系統； 可使用的酚樹脂包括酚醛樹脂A及酚醛淸漆酚酸塑膠。典 型地（但是非必需地），該樹脂系統可溶劑化以使其可容易 地塗佈至該可撓性石墨薄片。 在典型的樹脂浸漬步驟中，該可撓性石墨薄片可通過一 容器且利用例如霧化噴嘴浸漬該樹脂系統，而該樹脂系統 可藉由真空艙室有利地"拉過該襯墊”。之後，較佳地乾燥 該樹脂以減低該樹脂的黏性，其後加工該浸漬樹脂的薄片 (其起始密度約0 . 1至約1 . 1 g / c c )以改變該薄片的空隙狀 態。空隙狀態意謂著薄片的空隙百分比，其通常以捕捉空 氣的形式來度量。通常地，此可藉由施加壓力（例如以輪 壓硏磨或平台加壓）至該薄片（其亦具有緻密化該薄片的效 應）以便減低該薄片中的空隙程度而達成。有利地，該撓 性石墨薄片可密實成至少約1 · 3 g / c c的密度（然而可在系 統中使用樹脂來減低空隙而不需要密實化至如此高的程度） -18- 592968 五、發明說明（ 空隙狀態可有利地使用來控制及調整最後壓印物品的形 態學及功能特徵。例如，熱及電的傳導性、滲透速率及濾 取特徵可藉由在壓印之前控制薄片的空隙狀態（及，通常 地，密度）而達成及潛在地控制。因此，若在操作空隙狀 態之前已設定好最後壓印物品想要的特徵時，則可修改空 隙狀態至可能的程度以獲得那些特徵。如上所描述，此可 例如藉由在壓印之前輪壓或加壓該撓性石墨而達成。 最有利地，特別是當欲將最後壓印物品使用作爲電化學 燃料電池的組件時，可操控浸漬樹脂的撓性石墨薄片以便 相當地無空隙，以有效地最佳化燃料電池應用所需的電及 熱傳導性。通常地，此可藉由獲得至少約1.4 g/cc的密 度而達成，更佳地至少約1 . 7 g / c c (其指出爲相當無空隙 的狀態），其導致所產生的壓印物品具有相當高的異方向 性比率（潛在級數約1 50及較高）。若想要較低的異方向性 比率（諸如在某些熱撒佈機應用上），則較高的空隙狀態密 度較佳，其通常與約1.1至約1.3 g/cc的密度範圍相符 合（再次，依系統中樹脂的存在/程度而定）。 現在參照至第3、4圖，其顯現使用本發明之材料製備 的二種薄片每種之邊壁的截面部分之顯微照片。第3圖的 薄片在壓印之前操控爲相當無空隙狀態。第4圖之薄片在 壓印之前根本不操控。其形態學差異很明顯。可容易地看 見在第3圖中其石墨層更對準（即，平行至）表面邊壁。更-14- V. Description of the invention (13) The use of an expansion aid applied before, during or immediately after the interlayer also provides improvements. These improvements are to decrease the delamination temperature and increase the volume of expansion (also referred to as "volume volume"). Expansion aids in this context are advantageously organic materials that are sufficiently soluble in the interlayer solution, In order to obtain improvement in swelling. More narrowly, organic materials containing carbon, hydrogen and oxygen can be preferably used exclusively. Carboxylic acids have been found to be particularly effective. Suitable carboxylic acids that are useful as swelling aids are selected From aromatic, aliphatic or cycloaliphatic, linear or branched, saturated and unsaturated monocarboxylic acids, dicarboxylic acids and polycarboxylic acids (which have at least 1 carbon atom, preferably up to about 1 5 Carbon atoms), which can be dissolved in the interlayer solution in an effective amount to provide a measurable improvement in one or more delaminations. A suitable organic solvent can be used to improve the solubility of the organic swelling aid in the interlayer solution Typical examples of saturated aliphatic carboxylic acids are acids, such as those of formula H (CH2) nCOOH (where η is a number from 0 to about 5), including formic acid, acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid, and Analogs. In addition to these carboxylic acids, anhydrides or reactive carboxylic acid derivatives, such as alkyl esters. Typical alkyl esters are methyl formate and ethyl formate. Sulfuric acid, nitric acid, and other well-known Aqueous interlayers have the ability to decompose formic acid and eventually into water and carbon dioxide. For this reason, formic acid and other sensitive expansion aids can be advantageously contacted with the flake graphite powder before it is dipped into the aqueous interlayer. Typical dicarboxylic acid The acids are aliphatic dicarboxylic acids containing 2-12 carbon atoms, especially oxalic acid, fumaric acid, malonic acid, maleic acid, succinic acid, 15-five, and description of the invention (14) Diacid, adipic acid, 1,5-pentanedicarboxylic acid, 1,6-hexanedicarboxylic acid, 1,10 · sebacic acid, cyclohexane-1,4-dicarboxylic acid; and aromatic Dicarboxylic acids, such as too acid or terephthalic acid. Typical alkyl esters are dimethyl oxalate and diethyl oxalate. Typical cycloaliphatic acids are cyclohexanone and aromatics. Carboxylic acids are benzoic acid, naphthoic acid, anthranilic acid, p-aminobenzoic acid, salicylic acid, o-, m- and p-tolyl Acids, methoxy and ethoxybenzoic acids, acetoacetamidobenzoic acids and acetoaminobenzoic acids, phenylacetic acid and naphthoic acids. Typical hydroxyaromatic acids are hydroxybenzoic acid, 3 · Hydroxy-naphthoic acid, 3-hydroxy-2-naphthoic acid, 4-hydroxy-2-naphthoic acid, 5-hydroxy-1-naphthoic acid, 5-hydroxy-2-naphthoic acid, 6-hydroxy-2-naphthoic acid And 7-hydroxy-2-naphthoic acid. Among the polycarboxylic acids, the superior is citric acid. The interlayer solution is aqueous and preferably contains an expansion aid in an amount of about 1 to 10%, which amount is effective Promote delamination. In specific embodiments where the flake graphite powder is contacted with an expansion aid before or after being immersed in the aqueous interlayer solution, the expansion aid may be mixed with graphite using suitable equipment, such as a V-blender. Its typical amount is about 0.2% to about 10% by weight of the flake graphite powder. After the flake graphite powder is sandwiched, and then the sandwiched flake graphite powder coated with the interlayer is mixed with an organic reducing agent, the mixture is exposed to a temperature range of 25 ° to 125 ° C to promote the reducing agent. Reacts with interlayer coatings. The heating time is up to about 20 hours, and for higher temperatures in the above-mentioned range, a shorter heating period is, for example, at least about 10 minutes. At higher temperatures, a period of one and a half hours or less (for example, 10 to 25 minutes -16- five, the series of invention description (15) minutes) can be used. The treated graphite particles are therefore sometimes referred to as " sandwiched graphite particles ". After exposure to high temperatures, such as at least about 1 60 ° C (particularly about 700 ° C to 1 000 ° C and higher), the intercalated graphite particles will be in the c-direction (that is, perpendicular to the constituent graphite particles). In the direction of the crystalline plane) in a fold-like manner to expand to about 80 to 1,000 times or more as the original volume. The expanded (ie, delaminated) graphite particles have a worm-like appearance and are therefore commonly referred to as maggots. The slugs can be compressed together to form flexible flakes, unlike the original flake graphite powder, which can be formed and cut into different shapes and / or simultaneously extruded with deforming machinery to provide small cross-cut openings. Flexible graphite flakes and foils are tacky, have good processing strength, and can be appropriately compressed (for example, by rolling) to a thickness of about 0.075 mm to 3.75 mm, with a typical density of about 0.1 to 1.4 grams per cubic centimeter (g / cc). As described in U.S. Patent No. 5,902,762 (which is incorporated herein by reference), about 1.5-30% by weight of a ceramic additive is blended with the intercalated flake graphite powder to provide a final Flexible graphite products provide resin impregnation for reinforcement. The additives include ceramic fiber particles having a length of about 0.1 to 1.5 mm. The width of these particles is suitably about 0.04 to 0.004 mm. These ceramic fiber particles are non-reactive, do not adhere to graphite, and are stable at temperatures up to about 1100 ° C (preferably about 1 400 ° C or higher). Suitable ceramic fiber particles can be impregnated quartz glass fibers, carbon and graphite fibers, zirconia, boron nitride, silicon carbide and magnesium oxide fibers, naturally occurring inorganic fibers such as calcium metasilicate fiber, calcium aluminum silicate Fiber, -17- V. Description of the invention (16) Alumina fiber and the like). As mentioned, sometimes the flexible graphite sheet can also be advantageously treated with a resin, and the absorbed resin can strengthen the moisture resistance and processing strength (ie, rigidity) of the flexible graphite sheet after hardening, and Can form a "fixed" graphite form. A suitable resin content is preferably at least about 5% by weight, more preferably about 10 to 35% by weight and suitably up to about 60% by weight. Resins that have been found to be particularly useful in the practice of the present invention include acrylic-, epoxy-, and phenol-based resin systems or mixtures thereof. Suitable epoxy resin systems include those based on diglycidyl ether (DGEBA) and other polyfunctional resin systems. Phenolic resins that can be used include phenolic resin A and phenolic lacquer phenolic plastics. Typically (but not necessarily), the resin system is solvated so that it can be easily applied to the flexible graphite flakes. In a typical resin impregnation step, the flexible graphite flakes can be passed through a container and the resin system can be impregnated using, for example, an atomizing nozzle, and the resin system can be advantageously " pulled through the gasket " by a vacuum chamber. " It is preferable to dry the resin to reduce the viscosity of the resin, and then process the resin-impregnated sheet (its initial density is about 0.1 to about 1.1 g / cc) to change the void state of the sheet. Void State means the percentage of voids in a sheet, which is usually measured in the form of trapped air. Generally, this can be applied to the sheet (which also has densified by applying pressure (such as wheel honing or platform pressing)). Flake effect) in order to reduce the degree of voids in the flakes. Advantageously, the flexible graphite flakes can be densified to a density of at least about 1.3 g / cc (however, resins can be used in the system to reduce voids without the need Densification to such a high degree) -18- 592968 V. Description of the invention (The void state can be advantageously used to control and adjust the morphological and functional characteristics of the final imprinted article. For example, thermal and electrical Conductivity, permeation rate, and leaching characteristics can be achieved and potentially controlled by controlling the void state (and, typically, density) of the sheet prior to imprinting. Therefore, if the final imprint has been set before the void state is manipulated When the desired characteristics of the article, the void state can be modified to the extent possible to obtain those characteristics. As described above, this can be achieved, for example, by rolling or pressing the flexible graphite before embossing. Most advantageously, Especially when the final imprinted article is intended to be used as a component of an electrochemical fuel cell, the flexible graphite sheet impregnated with resin can be manipulated so as to be relatively void-free, so as to effectively optimize the electrical and thermal conductivity required for fuel cell applications Generally, this can be achieved by obtaining a density of at least about 1.4 g / cc, more preferably at least about 1.7 g / cc (which is indicated as a rather void-free state), which results in the resulting embossed article Has a fairly high anisotropy ratio (potential levels around 150 and higher). If you want a lower anisotropy ratio (such as in some thermal spreader applications), a higher void shape The density is better, which generally corresponds to a density range of about 1.1 to about 1.3 g / cc (again, depending on the presence / degree of resin in the system). Referring now to Figures 3 and 4, it appears that using the present invention A photomicrograph of a cross-section of each of the two types of flakes made of materials. The flakes in Figure 3 were manipulated to be quite void-free before imprinting. The flakes in Figure 4 were not manipulated at all before imprinting. Their morphology The difference is obvious. It can be easily seen in Figure 3 that its graphite layer is more aligned (that is, parallel to) the surface edges.
-19- 五、發明說明（18) 確切地，在邊壁的上部分處的“反三角形，，區域明顯且已顯 露出石墨流前端相遇的交叉線，其將邊壁的內部結構基本 地分成相當對稱的部分。當此與第4圖的邊壁比較時’藉 由控制空隙狀態所產生的結構已顯現。如將由熟練的人士 所熟知，在壓印撓性石墨邊壁中相當量的結構可及將如上 所述般導致不同性質。 然後，將該經輪壓的撓性石墨薄片通過如於下文描述的 壓印裝置，其後於烘箱加熱以交聯樹脂。依系統使用的樹 脂本質和特別地使用的溶劑型式及程度（其可有利地修改 至特定的樹脂系統，如將由熟練的人士所熟知）而定，可 在壓印步驟之前包括一蒸發乾燥步驟。在此乾燥步驟中， 曝露該經樹脂浸漬的撓性石墨薄片至加熱下以蒸發，因此 移除某些或全部的溶劑而沒有影響樹脂系統的交聯。在此 方法中，應避免在交聯步驟期間起泡，其可由蒸發溶劑（ 其在表面塑形期間因密實化該薄片而捕捉在薄片中）而造 成。加熱的程度及時間將隨溶劑的本質及量而不同，對此 目的來說較佳地在至少約65t的溫度，更佳地從約80°C 至約9 5 °C，約3至約2 0分鐘。 用來連續地形成浸漬樹脂和輪壓的撓性石墨薄片之裝置 的一個具體實施例則顯示在國際公告案號W0 00 / 64808中 ，該公告以參考之方式倂於本文。 如在第2-2(C)圖中闡明，壓印裝置10通常包含二個相 對的元件20及30，至少一個爲壓印元件20且具有壓印圖 -20- 592968 五、發明說明（19 ) 案在上面。壓印圖案由繞著壓印元件2 0表面排列的一系 列邊壁22形成，其頂端（或壟）22a至壓印元件20表面具 有預定的高度，而由溝槽底層24隔開。典型地，溝槽底 層24事實上爲壓印元件20的表面。平底元件3 0較佳地 包含通常爲平坦表面的元件，其逆著壓印元件20操作以 將該壓印圖案強壓到該浸漬樹脂的撓性石墨薄片上。平底 元件30的衝擊表面32亦可具有紋理結構或其它花紋（無 顯示），以使壓印製程容易或可將想要的紋理結構或圖案 施加至撓性石墨薄片的非壓印表面。 再者，因爲預期壓印在撓性石墨薄片上的圖案可不同， 該狀況將潛在地發生若撓性石墨薄片100的某些部分具有 與其他部分不同的橫截面積時。在此例子中，可想要對平 底元件30的衝擊表面32應用一結構（諸如凹處）（無顯示） ，以讓該石墨/樹脂流入在撓性石墨薄片1 00的低截面區 域中之凹處，以便維持該撓性石墨薄片1 00相當均勻的上 (或操作）表面。所產生的撓性石墨薄片100將在其底面上 具有“鰭狀”或“稜紋”1 02a，如第5圖所顯示，其可使用或 移除（諸如藉由機器）。 壓印元件20及平底元件30可包含滾筒、板、其組合或 其它結構，其限制條件爲它們能共操作以將圖案壓印在撓 性石墨薄片上，較佳地包含如在第2 ( C )圖顯示的滾筒。壓 印元件20及平底元件30排列在壓印裝置10中，如此平 底元件30的表面32與壓印元件20的溝槽底層24分離一-19- V. Description of the invention (18) Exactly, the "inverse triangle" at the upper part of the side wall has a clear and exposed cross line that meets the front end of the graphite flow, which basically divides the internal structure of the side wall into Quite symmetrical part. When this is compared with the side wall of Fig. 4, the structure created by controlling the state of the void has emerged. As will be known to those skilled in the art, a considerable amount of structure is stamped in the flexible graphite side wall Accessible will result in different properties as described above. Then, the wheeled flexible graphite flakes are passed through an embossing device as described below, followed by heating in an oven to cross-link the resin. Depending on the nature of the resin used in the system and Depending on the type and extent of the solvent used (which can be advantageously modified to a particular resin system, as will be familiar to those skilled in the art), an evaporation drying step can be included before the imprinting step. In this drying step, the exposure The resin-impregnated flexible graphite flakes are heated to evaporate, thus removing some or all of the solvent without affecting the crosslinking of the resin system. In this method, avoid Foaming during the coupling step can be caused by evaporation of the solvent (which is trapped in the flakes by densifying the flakes during surface shaping). The degree and time of heating will vary depending on the nature and amount of the solvent. Said preferably at a temperature of at least about 65t, more preferably from about 80 ° C to about 95 ° C, for about 3 to about 20 minutes. It is used to continuously form flexible graphite flakes impregnated with resin and rollers. A specific embodiment of the device is shown in International Publication No. WO 00/64808, which is incorporated herein by reference. As illustrated in Figure 2-2 (C), the imprint device 10 typically includes two Opposite elements 20 and 30, at least one of which is an embossed element 20 and has an embossed figure -20- 592968 5. The description of the invention (19) is provided above. The embossed pattern is a series of arrangements around the surface of the embossed element 20 The side wall 22 is formed, and its top (or ridge) 22a has a predetermined height to the surface of the embossing element 20 and is separated by a groove bottom layer 24. Typically, the groove bottom layer 24 is actually the surface of the embossing element 20. Flat bottom Element 30 preferably comprises an element that is generally a flat surface, which Operate against the embossing element 20 to force the embossing pattern onto the flexible graphite sheet impregnated with resin. The impact surface 32 of the flat-bottomed element 30 may also have a texture structure or other pattern (not shown) to enable the embossing process It is easy or possible to apply the desired texture structure or pattern to the non-embossed surface of the flexible graphite sheet. Furthermore, since the pattern that is expected to be imprinted on the flexible graphite sheet may be different, this situation will potentially occur if it is flexible When some parts of the graphite sheet 100 have a different cross-sectional area than others. In this example, it may be desirable to apply a structure (such as a recess) (not shown) to the impact surface 32 of the flat-bottomed element 30 so that the Graphite / resin flows into the recesses in the low section area of the flexible graphite sheet 100 in order to maintain a fairly uniform upper (or operating) surface of the flexible graphite sheet 100. The resulting flexible graphite sheet 100 will have "fins" or "ribs" 102a on its bottom surface, as shown in Figure 5, which can be used or removed (such as by a machine). The embossing element 20 and the flat-bottom element 30 may include a roller, a plate, a combination thereof, or other structures, with the limitation that they can co-operate to imprint a pattern on a flexible graphite sheet, preferably as described in Section 2 (C ) The drum shown in the figure. The imprinting element 20 and the flat-bottomed element 30 are arranged in the imprinting device 10, so that the surface 32 of the flat-bottomed element 30 is separated from the groove bottom layer 24 of the imprinted element 20 by one.
-21 - 592968 五、發明說明（2〇) 距離“d”，其至少等於邊壁22的高度。更確切地，在最佳 的具體實施例中，平底元件30的表面32與壓印元件20 的溝槽底層24分離一距離“d”，其等於邊壁22的高度加 上在撓性石墨薄片100的薄片底層1〇2之位置處想要的壓 印撓性石墨薄片100之厚度。 形成已輪壓且已浸漬樹脂的可撓性石墨薄片1 〇〇a，以便 在壓印之前使壓印圖案區域中的厚度少於距離” d ”，但是 大於在平底元件3 0的表面3 2與壓印元件2 0的邊壁2 2間 之距離，如闡明在第2圖。在壓印期間，薄片1 〇〇a中的 材料（即，石墨與樹脂）會從薄片l〇〇a區域流至在薄片 1 00a和壓印元件20的溝槽底部24間之間距，如闡明在第 2-2(B)圖。該經輪壓且已浸漬樹脂的可撓性石墨薄片i〇〇a 的石墨/樹脂之”再排列"很令人驚訝，其可使該經壓印的 可撓性石墨薄片100具有薄片底部102及薄片壟104，而 形成與壓印元件20的壓印圖案相符合之溝槽圖案（如顯示 在第1圖及1(A))，薄片100的溝槽圖案如與先述技藝的 製程比較具有改善的溝槽輪廓。 所產生的壓印石墨薄片可使用在不同應用上，包括作爲 電化學燃料電池的組件。 上述之描述意欲使熟知此技藝者能夠實行本發明。並無 詳細地描述全部可能的變化及改質，但此將由熟練的人士 在閱讀本說明後而明瞭。但是，此全部的改質及變化意欲 包含在由下列申請專利範圍所定義之本發明的範圍中。本-21-592968 5. Description of the invention (20) The distance "d" is at least equal to the height of the side wall 22. More precisely, in the preferred embodiment, the surface 32 of the flat-bottomed element 30 is separated from the groove bottom layer 24 of the embossed element 20 by a distance "d", which is equal to the height of the side wall 22 plus the flexible graphite sheet The desired thickness of the flexible graphite sheet 100 is embossed at the position of the sheet bottom layer 100 of 100. Form a flexible graphite sheet 100a which has been pressed and impregnated with resin so that the thickness in the imprinted pattern area is less than the distance "d" before imprinting, but larger than the surface 3 of the flat-bottomed element 3 2 The distance from the side wall 22 of the embossing element 20 is as illustrated in FIG. 2. During embossing, the material in sheet 100a (ie, graphite and resin) will flow from the sheet 100a area to the distance between sheet 100a and the bottom 24 of the groove of the imprint element 20, as stated In Figure 2-2 (B). The graphite / resin "rearrangement" of the wheel-pressed and resin-impregnated flexible graphite sheet i00a is very surprising, which enables the embossed flexible graphite sheet 100 to have a sheet bottom 102 and sheet ridge 104 to form a groove pattern corresponding to the embossing pattern of the embossing element 20 (as shown in FIG. 1 and 1 (A)), and the groove pattern of the sheet 100 is compared with the manufacturing process described earlier Has an improved groove profile. The resulting embossed graphite flakes can be used in different applications, including as a component of an electrochemical fuel cell. The foregoing description is intended to enable those skilled in the art to practice the invention. Not all of them are described in detail Possible changes and modifications, but this will become clear to those skilled in the art after reading this description. However, all the modifications and changes are intended to be included in the scope of the invention as defined by the following patent application scope.
-22- 592968 五、發明說明（21 ) 申I靑專利範圍意欲涵蓋在可有效地滿足本發明所意欲的目 標之任何安排或程序中所指出的元件及歩驟，除非上下文 有特別地指出其反面。 元件符號說明 10 壓印裝置 20 壓印元件 22 邊壁 22a 壟 24 溝槽底層 30 平底元件 32 衝擊表面 100 可撓性石墨薄片 100a 可撓性石墨薄片 102 薄片底部 102a 稜紋 104 薄片壟 24a 間距 -23--22- 592968 V. Description of the Invention (21) The scope of the patent application is intended to cover the elements and steps indicated in any arrangement or procedure that can effectively meet the intended objectives of the present invention, unless the context specifically indicates otherwise. The reverse. Explanation of component symbols 10 Imprinting device 20 Imprinting element 22 Side wall 22a Ridge 24 Groove bottom 30 Flat bottom element 32 Impact surface 100 Flexible graphite sheet 100a Flexible graphite sheet 102 Sheet bottom 102a Rib 104 Sheet ridge 24a Pitch- twenty three-