JP2008214120A - Method of manufacturing carbon fiber sheet - Google Patents

Method of manufacturing carbon fiber sheet Download PDF

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JP2008214120A
JP2008214120A JP2007052319A JP2007052319A JP2008214120A JP 2008214120 A JP2008214120 A JP 2008214120A JP 2007052319 A JP2007052319 A JP 2007052319A JP 2007052319 A JP2007052319 A JP 2007052319A JP 2008214120 A JP2008214120 A JP 2008214120A
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carbon fiber
fiber sheet
precursor
carbon
sheet
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Mikio Inoue
幹夫 井上
Kenya Okada
賢也 岡田
Hiroyuki Takagishi
宏至 高岸
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Toray Industries Inc
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Toray Industries Inc
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells

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Abstract

<P>PROBLEM TO BE SOLVED: To provide a long carbon fiber sheet which is prevented from occurrence of wrinkle, unevenness, break or the like. <P>SOLUTION: In the method of manufacturing the carbon fiber sheet, the long carbon fiber sheet is obtained by cylindrically winding a carbon fiber sheet precursor comprising a carbon fiber or a carbon fiber precursor fiber to form a package and heating the package under an inert gas atmosphere at a maximum temperature of ≥1,000°C to fire the carbon fiber sheet precursor. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description


本発明は、シワや凹凸の発生が少ない長尺の炭素繊維シートの製造方法に関する。
The present invention relates to a method for producing a long carbon fiber sheet with less occurrence of wrinkles and unevenness.

炭素繊維の不織布、織物から構成される炭素繊維シートは、燃料電池電極基材やＣＦＲＰ（炭素繊維強化プラスチック）の成形や、コンクリート構造物の補修・補強や、電波吸収体等、多種多様な用途に利用されている。   Carbon fiber sheets composed of carbon fiber non-woven fabrics and woven fabrics are used in a wide variety of applications, such as molding fuel cell electrode substrates and CFRP (carbon fiber reinforced plastic), repairing and reinforcing concrete structures, and electromagnetic wave absorbers. Has been used.

炭素繊維シートを製造する方法として、炭素短繊維を抄紙してなるシートに樹脂を含浸した後、樹脂を硬化した樹脂含浸硬化シートを連続的に炭素化する方法がある。（たとえば、特許文献１参照）。   As a method for producing a carbon fiber sheet, there is a method of continuously carbonizing a resin-impregnated cured sheet obtained by curing a resin after impregnating a resin into a sheet made of short carbon fibers. (For example, refer to Patent Document 1).

また、炭素繊維シートの別の製造方法としては、原料繊維や耐炎化繊維をあらかじめ織物や不織布としておき、それをバッチ式或いは連続式に焼成して炭素繊維シートとする方法がある（たとえば、特許文献２参照）。   As another method for producing a carbon fiber sheet, there is a method in which raw material fibers and flame-resistant fibers are preliminarily made into a woven fabric or a non-woven fabric, and then fired batchwise or continuously into a carbon fiber sheet (for example, a patent Reference 2).

炭素繊維シートのバッチ式焼成に際しては、基材の反り防止のためにグラファイト板に挟んで焼成する方法が取られる（例えば、特許文献３参照）。しかし、この方法では、炭素繊維シートをグラファイト板と同じないしは小さいサイズにする必要があり、長さ２ｍを越えるような長尺の炭素繊維シートを得ることができないという問題がある。   In the case of batch-type firing of carbon fiber sheets, a method of firing by sandwiching between graphite plates is used to prevent warping of the base material (see, for example, Patent Document 3). However, in this method, the carbon fiber sheet needs to be the same or smaller in size than the graphite plate, and there is a problem that a carbon fiber sheet having a length exceeding 2 m cannot be obtained.

一方、連続式の焼成によって、炭素繊維シート前駆体を巻き出し、焼成後に巻取ることで長尺の炭素繊維シートを得ることができるが、焼成時にシートにシワや凹凸が発生したり、シートが切れてしまうといった問題や、バッチ焼成に比較して昇温時間や最高温度での焼成時間が短くなり、電気抵抗が低くなりにくい課題もある。
国際公開第０２／００６０３２号パンフレット 特公昭６１−１１３２３号公報 特開平４−３７６６９号公報 On the other hand, the carbon fiber sheet precursor is unwound by continuous firing, and a long carbon fiber sheet can be obtained by winding up after firing. There are also problems such as breakage, and a problem that the heating time at the highest temperature and the baking time at the maximum temperature are shortened compared to batch baking, and the electrical resistance is difficult to decrease.
International Publication No. 02/006032 Pamphlet Japanese Examined Patent Publication No. 61-11323 JP-A-4-37669

本発明は、かかる従来技術の問題点に鑑み、シワや凹凸、切れ等の発生を抑制した長尺の炭素繊維シートを提供することを目的とする。   An object of this invention is to provide the elongate carbon fiber sheet which suppressed generation | occurrence | production of a wrinkle, an unevenness | corrugation, a cut | disconnection, etc. in view of the problem of this prior art.

本発明は、かかる課題を解決するために、次のような手段を採用する。すなわち、炭素繊維または炭素繊維前駆体繊維を含んでなる炭素繊維シート前駆体を筒状体に巻回してパッケージを形成し、このパッケージを不活性雰囲気中、最高温度１０００℃以上の温度で熱処理することにより、前記炭素繊維シート前駆体を焼成して長尺の炭素繊維シートを得ることを特徴とする炭素繊維シートの製造方法である。   The present invention employs the following means in order to solve such problems. That is, a carbon fiber sheet precursor comprising carbon fibers or carbon fiber precursor fibers is wound around a cylindrical body to form a package, and the package is heat-treated at a maximum temperature of 1000 ° C. or higher in an inert atmosphere. Thus, the carbon fiber sheet precursor is fired to obtain a long carbon fiber sheet.

本発明によれば、被処理シートを筒状体に巻くことにより、被処理シートの両面が内層および外層の被処理シートと接した状態で熱処理されるため、焼成時のシワ、凹凸発生が抑制される。また、シートは搬送張力のない状態で焼成されるため、焼成時にシートが切れることもなくなる。   According to the present invention, since the sheet to be treated is wound around the cylindrical body, both surfaces of the sheet to be treated are heat-treated in contact with the inner layer and the outer layer of the sheet to be processed, so that generation of wrinkles and unevenness during firing is suppressed. Is done. Further, since the sheet is fired in a state where there is no conveyance tension, the sheet is not cut during firing.

本発明者は、前記課題、つまりシワや凹凸、切れ等の発生を抑制することができる長尺の炭素繊維シートの製造方法について、鋭意検討し、かかる課題を一挙に解決することができたものである。   The inventor has earnestly studied the above-mentioned problem, that is, a method for producing a long carbon fiber sheet capable of suppressing the occurrence of wrinkles, irregularities, cuts, and the like, and was able to solve such problems all at once. It is.

本発明において熱処理される炭素繊維シート前駆体は、炭素繊維または炭素繊維前駆体繊維を含んでなる。   The carbon fiber sheet precursor to be heat-treated in the present invention comprises carbon fiber or carbon fiber precursor fiber.

炭素繊維としては、ポリアクリロニトリル（以下、ＰＡＮと略記する）系炭素繊維、ピッチ系炭素繊維、レーヨン系炭素繊維およびフェノール系炭素繊維のいずれでもよいが、得られた炭素繊維シートの曲げ強度や、引張強度の高くなるＰＡＮ系炭素繊維またはピッチ系炭素繊維を用いることが好ましく、ＰＡＮ系炭素繊維を用いることがさらに好ましい。   As the carbon fiber, any of polyacrylonitrile (hereinafter abbreviated as PAN) -based carbon fiber, pitch-based carbon fiber, rayon-based carbon fiber and phenol-based carbon fiber, but the bending strength of the obtained carbon fiber sheet, It is preferable to use a PAN-based carbon fiber or a pitch-based carbon fiber that increases the tensile strength, and it is more preferable to use a PAN-based carbon fiber.

本発明でいう炭素繊維前駆体繊維としては、ＰＡＮ系炭素繊維、ピッチ系炭素繊維、レーヨン系炭素繊維、フェノール系炭素繊維のいずれの炭素繊維の前駆体でもよいが、得られた炭素繊維シートの曲げ強度や、引張強度の高くなるＰＡＮ系炭素繊維またはピッチ系炭素繊維の前駆体繊維が好ましく、織物や不織布への加工が容易なＰＡＮ系炭素繊維前駆体繊維、例えばＰＡＮ酸化繊維（耐炎化繊維ともいう）を用いることがさらに好ましい。かかる炭素繊維前駆体繊維は、炭素繊維と混用してもよい。炭素繊維前駆体繊維として、ＰＡＮ酸化繊維を用いた場合には、それを用いて織物や水流交絡不織布とすることにより、炭素繊維シート前駆体とすることができる。炭素繊維シート前駆体には、製織時の糊剤や不織布化時の油剤を含んでもよく、その比率は１０重量％以下が好ましく、５重量％以下がより好ましい。また、炭素繊維シート前駆体は、後述する有機物、特にバインダーを含んでなるのが良い。     The carbon fiber precursor fiber referred to in the present invention may be a precursor of any carbon fiber of PAN-based carbon fiber, pitch-based carbon fiber, rayon-based carbon fiber, and phenol-based carbon fiber. A PAN-based carbon fiber or a pitch-based carbon fiber precursor fiber having high bending strength and tensile strength is preferable, and a PAN-based carbon fiber precursor fiber that can be easily processed into a woven fabric or a non-woven fabric, such as PAN-oxidized fiber (flame-resistant fiber) It is more preferable to use (also referred to as). Such carbon fiber precursor fibers may be mixed with carbon fibers. When a PAN oxidized fiber is used as the carbon fiber precursor fiber, a carbon fiber sheet precursor can be obtained by using it as a woven fabric or a hydroentangled nonwoven fabric. The carbon fiber sheet precursor may contain a sizing agent during weaving or an oil agent during forming into a non-woven fabric, and the ratio is preferably 10% by weight or less, and more preferably 5% by weight or less. Further, the carbon fiber sheet precursor may contain an organic material, particularly a binder, which will be described later.

本発明でいう有機物は、炭素繊維シート前駆体に含まれる繊維間を結着する目的で使用される、たとえばポリビニルアルコール（以下、ＰＶＡと略記する）等の熱可塑性樹脂やフェノール樹脂等の熱硬化性樹脂やピッチや澱粉等のバインダーや前記した製織時の糊剤や不織布化時の油剤を含むものである。有機物のうちフェノール樹脂やピッチは、熱処理で炭化してできた炭化物によって、炭素繊維シート中の炭素繊維間を結着する機能を発揮し、また、澱粉やＰＶＡ等は、炭素繊維シート前駆体を得る工程での通過性を高める機能を発揮する。なお、炭素繊維前駆体シートには、炭素繊維、炭素繊維前駆体繊維、有機物以外にも、炭素粉末や金属粉末、無機粉末、金属繊維、無機繊維等の無機物を含んでいてもよいが、燃料電池電極基材として用いる場合には、導電性向上、不純物低減のために、炭素粉末を含ませることが好ましい。炭素粉末の例としては、フェノール樹脂、フラン樹脂やピッチ等の有機物を炭素化した粉末、黒鉛粉末、カーボンブラック、カーボンナノチューブなどが上げられるが、体積平均による平均粒径１μm以上の炭素粉末であることが、炭素繊維シートの電気抵抗を低くするために好ましく、体積平均による平均粒径２０μm以下の炭素粉末であることが、シート中への均一な分散やシート表面の平滑性維持のために好ましい。   The organic substance referred to in the present invention is used for the purpose of binding fibers contained in the carbon fiber sheet precursor, for example, a thermoplastic resin such as polyvinyl alcohol (hereinafter abbreviated as PVA) or a thermosetting such as a phenol resin. And a binder such as pitch resin and starch, a pasting agent at the time of weaving, and an oil agent at the time of forming a non-woven fabric. Among organic substances, phenolic resin and pitch exhibit the function of binding carbon fibers in the carbon fiber sheet by the carbide formed by heat treatment, and starch and PVA are carbon fiber sheet precursors. The function to improve the passability in the obtaining process is exhibited. The carbon fiber precursor sheet may contain inorganic substances such as carbon powder, metal powder, inorganic powder, metal fiber, and inorganic fiber in addition to carbon fiber, carbon fiber precursor fiber, and organic substance. When used as a battery electrode substrate, it is preferable to include carbon powder in order to improve conductivity and reduce impurities. Examples of the carbon powder include powders obtained by carbonizing organic substances such as phenol resin, furan resin and pitch, graphite powder, carbon black, carbon nanotubes, and the like, which are carbon powders having an average particle diameter of 1 μm or more by volume average. Is preferable for reducing the electrical resistance of the carbon fiber sheet, and a carbon powder having an average particle diameter of 20 μm or less by volume average is preferable for uniform dispersion in the sheet and maintenance of the smoothness of the sheet surface. .

次に、本発明における炭素繊維シート前駆体は、炭素繊維または炭素繊維前駆体繊維の含有比率は１０〜９０重量％が好ましく、２０〜６０重量％がより好ましく、３０〜５０重量％が特に好ましい。すなわち、炭素繊維または炭素繊維前駆体繊維の含有比率が１０重量％より下回ると、得られる炭素繊維シートの引張強さが低下したり、脆く折れやすい炭素繊維シートになる傾向がある。また、炭素繊維または炭素繊維前駆体繊維の比率が９０重量％を超えると、得られる炭素繊維シートが嵩高になり、引張強度や圧縮強度が低下し、燃料電池の電極用としても適さなくなる。   Next, in the carbon fiber sheet precursor in the present invention, the content ratio of carbon fiber or carbon fiber precursor fiber is preferably 10 to 90% by weight, more preferably 20 to 60% by weight, and particularly preferably 30 to 50% by weight. . That is, when the content ratio of the carbon fiber or the carbon fiber precursor fiber is less than 10% by weight, the resulting carbon fiber sheet tends to have a reduced tensile strength or a brittle and easy-to-break carbon fiber sheet. On the other hand, when the ratio of the carbon fiber or the carbon fiber precursor fiber exceeds 90% by weight, the resulting carbon fiber sheet becomes bulky, the tensile strength and the compressive strength are lowered, and it is not suitable for an electrode of a fuel cell.

炭素繊維シート前駆体の製造法としては、炭素短繊維または炭素繊維前駆体繊維短繊維を抄紙後、フェノール樹脂等の熱硬化性樹脂を含浸、硬化させる方法や、ＰＡＮ酸化繊維を用いて、カーディング後、ニードルパンチまたは水流交絡により不織布を得る方法や、ＰＡＮ酸化繊維を用いて、カーディング後、ニードルパンチまたは水流交絡により不織布を得、さらにフェノール樹脂等の熱硬化性樹脂を含浸、硬化させる方法や、ＰＡＮ酸化繊維を用いて紡績糸を得、紡績糸を製織した織物等が挙げられるが、燃料電池電極用としては、平滑で曲げ剛性の高い材料を得ることのできる、炭素短繊維または炭素繊維前駆体繊維短繊維を抄紙後、フェノール樹脂等の熱硬化性樹脂を含浸、硬化させる方法が好ましい。また、熱硬化性樹脂の代わりにピッチを用いてもよい。   The carbon fiber sheet precursor can be produced by making a carbon short fiber or carbon fiber precursor fiber short fiber after paper impregnation and curing with a thermosetting resin such as phenol resin, or by using PAN oxidized fiber. After wrapping, a method of obtaining a nonwoven fabric by needle punch or hydroentanglement, or using PAN oxidized fiber, after carding, obtain a nonwoven fabric by needle punch or hydroentanglement, and further impregnate and cure with a thermosetting resin such as phenol resin For example, a method for producing a spun yarn using a PAN-oxidized fiber and a woven fabric obtained by weaving the spun yarn can be used. A method of impregnating and curing a thermosetting resin such as a phenol resin after paper making of carbon fiber precursor fiber short fibers is preferable. Further, a pitch may be used instead of the thermosetting resin.

本発明では、前記した炭素繊維シート前駆体を筒状体に巻回してパッケージを形成する。   In the present invention, the above-described carbon fiber sheet precursor is wound around a cylindrical body to form a package.

筒状体としては、その軸に垂直な面での断面が円形であるものを用いるのが好ましい。かかる断面が四角形や楕円など円形でない場合、均一な巻き付けが難しい。さらに、焼成後の炭素繊維シートは長手方向に巻きグセがつく傾向を示すが、断面が円形でない場合、巻きグセが不連続に変動し取り扱いが難しくなる。筒状体は芯部が空間ではない柱状体であっても構わないが、取り扱い重量や加熱時の熱容量のため、芯部が空間の筒状体であることが好ましい。筒状体は焼成温度に耐える、黒鉛などの炭素やセラミックス、熱処理後も筒状体が炭素として残る紙等を用いることができるが、紙製の筒は焼成によって収縮変形して後工程での取り扱いが難しくなるため、焼成前後で形状の変わらない炭素やセラミックス製が好ましく、耐熱温度が高く、安価で加工性がよく、炭素繊維シートに炭素以外の不純物を付着させにくい炭素製が好ましい。炭素繊維シート前駆体を筒状体に巻回してパッケージを形成する。炭素繊維シート前駆体を筒状体に巻回した後、その外周を炭素繊維シートや紙で巻いたり、さらに炭素繊維で結んだりして、筒状体に巻き付けた炭素繊維シート前駆体がほどけない様にしても良い。   It is preferable to use a cylindrical body having a circular cross section in a plane perpendicular to the axis. If the cross section is not a circle such as a rectangle or an ellipse, uniform winding is difficult. Furthermore, the carbon fiber sheet after firing has a tendency to wind up in the longitudinal direction. However, when the cross section is not circular, the winding gaze varies discontinuously and is difficult to handle. The cylindrical body may be a columnar body whose core is not a space, but it is preferable that the core is a space-based cylindrical body because of the handling weight and the heat capacity during heating. The cylindrical body can use carbon and ceramics such as graphite that can withstand the firing temperature, paper that remains after the heat treatment as carbon, etc. Since it becomes difficult to handle, it is preferably made of carbon or ceramics whose shape does not change before and after firing, preferably made of carbon that has a high heat resistance, is inexpensive, has good workability, and hardly attaches impurities other than carbon to the carbon fiber sheet. A carbon fiber sheet precursor is wound around a cylindrical body to form a package. After winding the carbon fiber sheet precursor around the cylindrical body, the carbon fiber sheet precursor wound around the cylindrical body cannot be unwound by wrapping the outer periphery with a carbon fiber sheet or paper, or further tying with a carbon fiber. You may do it.

このようにして形成したパッケージを不活性雰囲気中で熱処理して、炭素繊維シートを焼成する。不活性雰囲気とは、窒素やアルゴンなどの不活性ガス雰囲気や真空雰囲気を意味する。熱処理の温度は最高温度１０００℃以上とするが、燃料電池電極基材用の炭素繊維シートを製造する場合、電気抵抗が低下、熱伝導や耐腐食性を高くするため、最高温度２０００℃以上とするのが好ましく、２４００℃以上とするのがさらに好ましい。また、熱処理炉に用いる炉材の耐久性の点から最高温度は２８００℃以下とするのが好ましい。パッケージを熱処理することにより、炭素繊維シート前駆体は焼成され、その結果、炭素繊維シート前駆体に含まれる炭素繊維前駆体繊維や有機物は炭化ないしは熱分解され、炭素繊維は黒鉛化が進行して、炭素繊維シートが得られる。   The package formed in this manner is heat-treated in an inert atmosphere, and the carbon fiber sheet is fired. The inert atmosphere means an inert gas atmosphere such as nitrogen or argon or a vacuum atmosphere. The temperature of the heat treatment is a maximum temperature of 1000 ° C. or higher. However, when producing a carbon fiber sheet for a fuel cell electrode base material, the electrical resistance is lowered, and the heat conduction and corrosion resistance are increased. It is preferable to set it to 2400 ° C. or higher. Moreover, it is preferable that the maximum temperature shall be 2800 degrees C or less from the point of durability of the furnace material used for a heat treatment furnace. By heat-treating the package, the carbon fiber sheet precursor is fired. As a result, the carbon fiber precursor fibers and organic substances contained in the carbon fiber sheet precursor are carbonized or pyrolyzed, and the carbon fibers are graphitized. A carbon fiber sheet is obtained.

得られる炭素繊維シートは、炭素繊維シート前駆体における炭素繊維や炭素繊維前駆体の構造を反映し、炭素繊維の単繊維間に隙間を有する多孔質体であり、通常、炭素繊維が、抄紙、不織布および織物から選ばれた少なくとも１種の構造を有している。すなわち、抄紙構造や、カーディング後、ニードルパンチまたは水流交絡を行って得られる乾式の不織布構造や織物構造を有しているが、燃料電池電極基材として用いるためには、炭素繊維シートの均一性、表面平滑性、曲げ剛性が高いことから抄紙構造のものが好ましい。特に抄紙構造の炭素繊維を炭素で結着した炭素繊維シートのように、炭素繊維を炭素で結着した多孔質体であるのが好ましい。   The obtained carbon fiber sheet reflects the structure of the carbon fiber or carbon fiber precursor in the carbon fiber sheet precursor, and is a porous body having a gap between the single fibers of the carbon fiber. It has at least one structure selected from non-woven fabrics and woven fabrics. That is, it has a papermaking structure, a dry nonwoven fabric structure or a woven structure obtained by performing card punching, needle punching or hydroentanglement, but for use as a fuel cell electrode substrate, a uniform carbon fiber sheet is used. Papermaking structures are preferred because of their high properties, surface smoothness and bending rigidity. In particular, a porous body in which carbon fibers are bound with carbon is preferable, such as a carbon fiber sheet in which carbon fibers having a papermaking structure are bound with carbon.

パッケージを熱処理する際には、筒状体をその軸が縦になるように支持することも、横になるように支持することもできるが、軸を縦にして支持した場合は、熱処理時に厚さが減少した炭素繊維シートが筒状体に添って下に下がり、炭素繊維シート端部と床面が接触することで、接触部の炭素繊維シートが反ったり、欠けたりしやすいため、筒状体の軸が実質的に水平方向になるよう支持することが好ましい。なお、筒状体の軸とは、筒状体の開口面を貫通する方向であり、筒状体が円柱や円筒の場合には、回転対称の中心軸に相当する。   When heat-treating the package, the cylindrical body can be supported so that its axis is vertical or horizontal. The carbon fiber sheet with reduced thickness falls down along the cylindrical body, and the carbon fiber sheet at the contact portion tends to warp or chip because the carbon fiber sheet end and the floor surface come into contact with each other. It is preferable to support the body axis so that it is substantially horizontal. In addition, the axis | shaft of a cylindrical body is a direction which penetrates the opening surface of a cylindrical body, and when a cylindrical body is a cylinder or a cylinder, it corresponds to a rotationally symmetrical central axis.

筒状体を、その軸が水平方向になるよう支持する方法としては、筒状体端部を支持部材で支えたり、筒状体芯部に棒を通して棒を支持部材で支えたりして、炭素繊維シート前駆体に直接触れないように支えることが好ましい。なお、上記支持部材は筒状体同様、炭素製であることが好ましい。   As a method of supporting the cylindrical body so that the axis thereof is in the horizontal direction, the end of the cylindrical body is supported by a support member, the rod is passed through the cylindrical body core portion, the rod is supported by the support member, and carbon It is preferable to support the fiber sheet precursor so as not to touch it directly. The support member is preferably made of carbon like the cylindrical body.

焼成後の炭素繊維シートは巻き付けた形状に反って巻きグセがつく傾向がある。特に炭素繊維シート前駆体が、炭素繊維や炭素繊維前駆体繊維と、その繊維を結着する炭素化可能な有機物を含む場合、すなわち炭素繊維を炭素で結着した炭素繊維シートを焼成により得るような場合、巻きグセが強く発生しやすい。巻きグセが強い場合、得られた炭素繊維シートを後工程で巻き出し、加工する際に割れやすくなったり、燃料電池電極基材として用いるために炭素繊維シートをカットして触媒付きの固体高分子電解質膜と貼り合わせるような場合に剥がれやすくなったりする。巻きグセを抑制するために筒状体としては、その外径が１５０ｍｍ以上、好ましくは２２０ｍｍ以上、より好ましくは３００ｍｍ以上であるものを用いるのが良い。なお、熱処理炉内スペースを有効に活用するため、用いる筒状体の外径は６００ｍｍ以下にとどめておく方が良い。   The carbon fiber sheet after firing has a tendency to get wound due to warping of the wound shape. In particular, when the carbon fiber sheet precursor includes carbon fiber or carbon fiber precursor fiber and a carbonizable organic substance that binds the fiber, that is, a carbon fiber sheet obtained by bonding carbon fibers with carbon is obtained by firing. In such a case, winding gusset is likely to occur strongly. When the winding gusset is strong, the obtained carbon fiber sheet is unwound in a later process and becomes easy to break when processed, or the carbon fiber sheet is cut for use as a fuel cell electrode base material, and a solid polymer with catalyst It may be easy to peel off when it is attached to the electrolyte membrane. In order to suppress curling, it is preferable to use a cylindrical body having an outer diameter of 150 mm or more, preferably 220 mm or more, more preferably 300 mm or more. In order to effectively use the space in the heat treatment furnace, it is better to keep the outer diameter of the cylindrical body used to 600 mm or less.

炭素繊維シートの厚さが厚いものを得ようとすれば、用いる炭素繊維シート前駆体も厚さの厚いものを用いることになるが、炭素繊維シート前駆体の厚さが厚いほど、筒状体への巻き付けが難しくなるとともに、前記したような巻きグセがつきやすくなる。したがって、得られる炭素繊維シートの厚さは０．２５mm以下、好ましくは０．２mm以下となるようにしておくことが好ましい。なお、長尺の炭素繊維シートを、巻き出し、巻き取り等の加工に耐える強度とするためには、得られる炭素繊維シートは厚さが０．１ｍｍ以上となるようにしておくことが好ましい。炭素繊維シートの厚さは、圧力０．１５ＭＰａで測定した厚さとする。   If a carbon fiber sheet having a large thickness is to be obtained, the carbon fiber sheet precursor to be used is also a thick one. However, the thicker the carbon fiber sheet precursor is, the more the cylindrical body is. It becomes difficult to wind the wire around, and the above-described winding gusset is likely to occur. Therefore, it is preferable that the thickness of the obtained carbon fiber sheet is 0.25 mm or less, preferably 0.2 mm or less. In order to make the long carbon fiber sheet strong enough to withstand processing such as unwinding and winding, it is preferable that the obtained carbon fiber sheet has a thickness of 0.1 mm or more. The thickness of the carbon fiber sheet is a thickness measured at a pressure of 0.15 MPa.

最高温度での熱処理時間は、熱処理中の最高温度から最高温度−５０℃の範囲内で熱処理された時間とする。最高温度での熱処理時間を長くすることで、温度分布が均一になることや、炭化や黒鉛化が進行し、電気抵抗が低くなる、熱伝導性が高くなる、燃料電池電極基材としての耐腐食性が高くなる等の効果が得られるので、最高温度での熱処理時間は１０分以上であるのが好ましく２０分以上であるのがより好ましい。焼成効率の点から最高温度での熱処理時間は１時間以下が好ましい。熱処理はバッチ炉による方法でも連続炉による方法でも構わない。炭素繊維シート前駆体が筒状体に巻かれたパッケージを連続炉で熱処理する場合、炭素繊維シート前駆体を巻き出して同様の連続炉で連続的に焼成し巻き取る場合に比べ、単位時間に処理する炭素繊維シート前駆体の量を多くできるため、単位時間に処理する炭素繊維シート前駆体の量を減少させることなく、昇温速度を遅くしたり、最高温度での熱処理時間を長く取ることができるようになる。   The heat treatment time at the maximum temperature is a time during which the heat treatment is performed within the range from the maximum temperature during the heat treatment to the maximum temperature −50 ° C. By extending the heat treatment time at the maximum temperature, the temperature distribution becomes uniform, the carbonization and graphitization progress, the electrical resistance decreases, the thermal conductivity increases, and the resistance as a fuel cell electrode substrate. Since effects such as high corrosivity can be obtained, the heat treatment time at the maximum temperature is preferably 10 minutes or more, and more preferably 20 minutes or more. From the viewpoint of firing efficiency, the heat treatment time at the maximum temperature is preferably 1 hour or less. The heat treatment may be performed by a batch furnace or a continuous furnace. When heat-treating a package in which a carbon fiber sheet precursor is wound in a cylindrical body in a continuous furnace, compared to the case where the carbon fiber sheet precursor is unwound and continuously fired and wound in a similar continuous furnace Since the amount of carbon fiber sheet precursor to be processed can be increased, the heating rate can be slowed or the heat treatment time at the maximum temperature can be increased without decreasing the amount of carbon fiber sheet precursor to be processed per unit time. Will be able to.

本発明は、炭素繊維シート前駆体を巻き出して連続焼成した後、筒状体に巻き取った炭素繊維シートを、さらに高温、長時間焼成する場合にも適用することができる。   The present invention can also be applied to a case in which a carbon fiber sheet precursor is unwound and continuously fired, and then the carbon fiber sheet wound on a cylindrical body is fired at a higher temperature for a longer time.


以下、実施例により、本発明をさらに具体的に説明する。
Hereinafter, the present invention will be described more specifically with reference to examples.

実施例１
東レ（株）製ＰＡＮ系炭素繊維“トレカ（登録商標）”Ｔ３００−６Ｋ（平均単繊維径：７μｍ、単繊維数：６，０００本）を１２ｍｍの長さにカットし、水を抄造媒体として連続的に抄造し、さらにポリビニルアルコールの１０重量％水溶液に浸漬し、乾燥して、炭素繊維の目付が約２０ｇ／ｍ２の長尺の炭素繊維紙を得てロール状に巻き取った。ポリビニルアルコールの付着量は、炭素繊維紙１００重量部に対して２０重量部であった。 Example 1
PAN-based carbon fiber “Torayca (registered trademark)” T300-6K (average single fiber diameter: 7 μm, number of single fibers: 6,000 fibers) manufactured by Toray Industries, Inc. is cut to a length of 12 mm, and water is used as a papermaking medium. The paper was continuously made, further immersed in a 10% by weight aqueous solution of polyvinyl alcohol and dried to obtain a long carbon fiber paper having a carbon fiber basis weight of about 20 g / m 2 and wound into a roll. The adhesion amount of polyvinyl alcohol was 20 parts by weight with respect to 100 parts by weight of carbon fiber paper.

次いで、（株）中越黒鉛工業所製鱗片状黒鉛ＢＦ−５Ａ（平均粒径５μｍ）、フェノール樹脂、メタノールを１：４：１６の重量比で混合した分散液を用意した。上記炭素繊維紙に、炭素繊維紙１００重量部に対してフェノール樹脂が１１０重量部になるように、上記分散液に連続的に含浸し、９０℃で３分間乾燥することにより樹脂含浸炭素繊維紙を得てロール状に巻き取った。フェノール樹脂としては、レゾール型フェノール樹脂とノボラック型フェノール樹脂とを１：１の重量比で混合した樹脂を用いた。この樹脂含浸炭素繊維紙２枚を重ねて成形材料とし、
以下の（１）〜（３）の工程を繰り返し間欠成形を行いフェノール樹脂を硬化させて、炭素繊維シート前駆体を得た。
（１）プレス機の加圧面を開く（成形面温度１７０℃）。
（２）成形材料をプレス機に送り、成形品を引き取る（間欠送り長さ１００ｍｍ、所要時間約５秒）。
（３）プレス機加圧面を閉じ、加熱加圧を行う（圧力０．７５ＭＰａ，所要時間約２５秒）。 Next, a dispersion was prepared by mixing scale-like graphite BF-5A (average particle size 5 μm), phenol resin, and methanol by a weight ratio of 1: 4: 16 manufactured by Chuetsu Graphite Industries Co., Ltd. The carbon fiber paper is continuously impregnated with the dispersion so that the phenol resin becomes 110 parts by weight with respect to 100 parts by weight of the carbon fiber paper, and dried at 90 ° C. for 3 minutes, thereby impregnating the resin-impregnated carbon fiber paper. And rolled up into a roll. As the phenol resin, a resin in which a resol type phenol resin and a novolac type phenol resin were mixed at a weight ratio of 1: 1 was used. Two resin impregnated carbon fiber papers are stacked to form a molding material.
The following steps (1) to (3) were repeated and intermittent molding was performed to cure the phenol resin to obtain a carbon fiber sheet precursor.
(1) Open the pressing surface of the press (molding surface temperature 170 ° C.).
(2) The molding material is sent to a press machine and the molded product is taken (intermittent feed length 100 mm, required time about 5 seconds).
(3) The press machine pressurization surface is closed and heating and pressurization are performed (pressure 0.75 MPa, required time about 25 seconds).

炭素繊維シート前駆体は５００ｍｍ、厚さ０．１６ｍｍ、目付９５ｇ／ｍ２である。 The carbon fiber sheet precursor has a thickness of 500 mm, a thickness of 0.16 mm, and a basis weight of 95 g / m 2 .

長さ３ｍ、幅２０ｃｍの炭素繊維前駆体シートを外径２９０mmの黒鉛円筒に巻き、その外側に炭素繊維織物を巻き、さらにその外側に炭素繊維を巻きつけて結び、パッケージを形成した。このパッケージを、黒鉛円筒の中心軸を水平方向に向けて最高温度２４００℃で２０分熱処理し、炭素繊維前駆体シートを焼成することにより、炭素繊維シートを得た。得られた炭素繊維シートは、巻きグセはついているものの局部的な凹凸はなく、黒鉛円筒から巻き出し、外径１６０ｍｍの紙管に巻き取ることができ、後工程の連続加工に耐える長尺の炭素繊維シートであった。   A carbon fiber precursor sheet having a length of 3 m and a width of 20 cm was wound around a graphite cylinder having an outer diameter of 290 mm, a carbon fiber woven fabric was wound around the outside, and a carbon fiber was wound around the outside to form a package. This package was heat-treated at a maximum temperature of 2400 ° C. for 20 minutes with the central axis of the graphite cylinder in the horizontal direction, and the carbon fiber precursor sheet was fired to obtain a carbon fiber sheet. Although the obtained carbon fiber sheet has a winding gusset, there is no local unevenness, it can be unwound from a graphite cylinder and wound up on a paper tube with an outer diameter of 160 mm, and it can be used for continuous processing in the subsequent process. It was a carbon fiber sheet.

実施例２
外径２９０mmの黒鉛円筒を、外径２３０ｍｍの黒鉛円筒に変更した以外は、実施例１と同様にして炭素繊維シートを得た。得られた炭素繊維シートは、巻きグセはついているものの局部的な凹凸はなく、黒鉛円筒から巻き出し、外径１６０ｍｍの紙管に巻き取ることができ、後工程の連続加工に耐える長尺の炭素繊維シートであった。 Example 2
A carbon fiber sheet was obtained in the same manner as in Example 1 except that the graphite cylinder having an outer diameter of 290 mm was changed to a graphite cylinder having an outer diameter of 230 mm. Although the obtained carbon fiber sheet has a winding gusset, there is no local unevenness, it can be unwound from a graphite cylinder and wound up on a paper tube with an outer diameter of 160 mm, and it can be used for continuous processing in the subsequent process. It was a carbon fiber sheet.

実施例３
外径２９０mmの黒鉛円筒を、外径１００ｍｍの黒鉛円筒に変更した以外は、実施例１と同様にして炭素繊維シートを得た。得られた炭素繊維シートは、巻きグセがきつく、巻き出す際に、巻きグセと逆方向に基材を曲げると炭素繊維シートが割れた。 Example 3
A carbon fiber sheet was obtained in the same manner as in Example 1 except that the graphite cylinder having an outer diameter of 290 mm was changed to a graphite cylinder having an outer diameter of 100 mm. The obtained carbon fiber sheet was tightly wound, and when the substrate was unwound, the carbon fiber sheet was cracked when the substrate was bent in the opposite direction to the wound gusset.

実施例４
パッケージを熱処理するに際して、黒鉛円筒の中心軸を垂直方向に向けた以外は実施例２と同様にして炭素繊維シートを得た。得られた炭素繊維シートは、黒鉛円筒から巻き出し外径１６０ｍｍの紙管に巻き取ることはできたが、焼成時に下側にあったシート端部に局部的な反りが観察された。 Example 4
When heat treating the package, a carbon fiber sheet was obtained in the same manner as in Example 2 except that the central axis of the graphite cylinder was oriented in the vertical direction. The obtained carbon fiber sheet could be unwound from a graphite cylinder and wound on a paper tube having an outer diameter of 160 mm, but local warping was observed at the end of the sheet that was on the lower side during firing.

本発明は、固体高分子型燃料電池の電極基材として用いられる炭素繊維シートに限らず、補強用や電波吸収体用の炭素繊維シートにも応用することができる。   The present invention is not limited to a carbon fiber sheet used as an electrode substrate of a polymer electrolyte fuel cell, but can also be applied to a carbon fiber sheet for reinforcement or a radio wave absorber.

Claims (6)

炭素繊維または炭素繊維前駆体繊維を含んでなる炭素繊維シート前駆体を筒状体に巻回してパッケージを形成し、このパッケージを不活性雰囲気中、最高温度１０００℃以上の温度で熱処理することにより、前記炭素繊維シート前駆体を焼成して長尺の炭素繊維シートを得ることを特徴とする炭素繊維シートの製造方法。 A carbon fiber sheet precursor comprising carbon fibers or carbon fiber precursor fibers is wound around a cylindrical body to form a package, and the package is heat treated at a maximum temperature of 1000 ° C. or higher in an inert atmosphere. The carbon fiber sheet precursor is fired to obtain a long carbon fiber sheet. 熱処理に際して、筒状体を、その軸が概ね水平になるように支持する、請求項１に記載の炭素繊維シートの製造方法。 The method for producing a carbon fiber sheet according to claim 1, wherein the cylindrical body is supported so that the axis thereof is substantially horizontal during the heat treatment. 筒状体は、その外径が１５０mm以上である、請求項１または２に記載の炭素繊維シートの製造方法。 The method for producing a carbon fiber sheet according to claim 1 or 2, wherein the cylindrical body has an outer diameter of 150 mm or more. 得られる炭素繊維シートが、炭素繊維を炭素で結着した多孔質体である、請求項１〜３のいずれかに記載の炭素繊維シートの製造方法。 The manufacturing method of the carbon fiber sheet in any one of Claims 1-3 whose carbon fiber sheet obtained is a porous body which bound carbon fiber with carbon. 得られる炭素繊維シートは、その厚さが０．２５ｍｍ以下である、請求項１〜４のいずれかに記載の炭素繊維シートの製造方法。 The method for producing a carbon fiber sheet according to any one of claims 1 to 4, wherein the obtained carbon fiber sheet has a thickness of 0.25 mm or less. 最高温度での熱処理時間が１０分以上である、請求項１〜５のいずれかに記載の炭素繊維シートの製造方法。 The manufacturing method of the carbon fiber sheet in any one of Claims 1-5 whose heat processing time in the highest temperature is 10 minutes or more.
JP2007052319A 2007-03-02 2007-03-02 Method of manufacturing carbon fiber sheet Pending JP2008214120A (en)

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012018824A (en) * 2010-07-08 2012-01-26 Mitsubishi Rayon Co Ltd Porous electrode base material and method for manufacturing the same
JP2012033269A (en) * 2010-07-08 2012-02-16 Mitsubishi Rayon Co Ltd Porous electrode base material and manufacturing method for the same
JP2012099302A (en) * 2010-11-01 2012-05-24 Mitsubishi Rayon Co Ltd Porous electrode base material and manufacturing method thereof
JP2017025281A (en) * 2015-07-27 2017-02-02 積水化学工業株式会社 Heat-conductive member, heat-conductive member laminated body and heat-conductive member molded body
CN109888231A (en) * 2019-03-04 2019-06-14 河北师范大学 A method of lithium cell cathode material is prepared using waste and old cement as raw material
WO2024204020A1 (en) * 2023-03-30 2024-10-03 東レ株式会社 Carbon fiber sheet, gas diffusion electrode base material, fuel cell, and method for manufacturing carbon fiber sheet

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012018824A (en) * 2010-07-08 2012-01-26 Mitsubishi Rayon Co Ltd Porous electrode base material and method for manufacturing the same
JP2012033269A (en) * 2010-07-08 2012-02-16 Mitsubishi Rayon Co Ltd Porous electrode base material and manufacturing method for the same
JP2012099302A (en) * 2010-11-01 2012-05-24 Mitsubishi Rayon Co Ltd Porous electrode base material and manufacturing method thereof
JP2017025281A (en) * 2015-07-27 2017-02-02 積水化学工業株式会社 Heat-conductive member, heat-conductive member laminated body and heat-conductive member molded body
CN109888231A (en) * 2019-03-04 2019-06-14 河北师范大学 A method of lithium cell cathode material is prepared using waste and old cement as raw material
WO2024204020A1 (en) * 2023-03-30 2024-10-03 東レ株式会社 Carbon fiber sheet, gas diffusion electrode base material, fuel cell, and method for manufacturing carbon fiber sheet

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