JP4002426B2 - Carbon fiber spun woven fabric structure for polymer electrolyte fuel cell electrode material and method for producing the same - Google Patents
Carbon fiber spun woven fabric structure for polymer electrolyte fuel cell electrode material and method for producing the same Download PDFInfo
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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
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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
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Description
【０００１】
【発明の属する技術分野】
本発明は、高分子電解質型燃料電池電極材用炭素繊維紡績糸織物構造体、及びその製造方法に関する。特に高分子電解質型燃料電池内のセパレーターと高分子電解質膜の間に介在させ、集電性とガス拡散性を有する電極材として有用な炭素繊維紡績糸織物構造体、及びその製造方法に関する。
【０００２】
【従来の技術】
炭素材料は、その導電性、耐熱性、耐薬品安定性に優れているので、従来電池用電極材に用いられている。近年、炭素繊維は、その柔軟性、加工性、成形性等の繊維形態の特徴を活かせる電極材として注目され、高分子電解質型燃料電池に応用されている。
【０００３】
高分子電解質型燃料電池の電極材に用いる炭素繊維材料としては、特に薄型のシート状で、強度があり、電気抵抗値が低く、柔軟性がある炭素繊維材料の要望が多く、種々の炭素繊維構造体が開発されている。
【０００４】
高分子電解質型燃料電池用の炭素繊維構造体としては、（１）Ｃ／Ｃペーパー（シート状の炭素繊維強化炭素材料）、（２）炭素繊維不織布、（３）炭素繊維フィラメント織物、並びに、（４）炭素繊維紡績糸織物構造体などが例示され、それぞれ以下のような特徴がある。
【０００５】
（１）Ｃ／Ｃペーパー
Ｃ／Ｃペーパーは、例えば炭素繊維カットファイバーを抄紙して炭素繊維紙を得、この炭素繊維紙に３０〜６０質量％の樹脂を含浸させた後、圧縮処理し、次いで焼成を行うことにより得られる。
【０００６】
得られたＣ／Ｃペーパーは、樹脂マトリックスに起因する炭素繊維以外の炭素成分が多い。炭素繊維含有率は８５質量％以下と低く、表面ケバは少ないが、硬く、脆く、且つ柔軟性がなく、ガスの通過性及び拡散性が悪いなどの問題がある。
【０００７】
（２）炭素繊維不織布
炭素繊維不織布は、例えばポリアクリロニトリル系酸化繊維ステープルを不織布加工して酸化繊維不織布を得、これを焼成することにより得られる。
【０００８】
得られる炭素繊維不織布は、Ｃ／Ｃペーパーに較べ、柔軟性があり、撥水処理、触媒処理等を連続的に行うことができ、より低コストであり、電極材として期待されている。
【０００９】
（３）炭素繊維フィラメント織物
炭素繊維織物は通常、その単繊維の直径が４〜２５μｍ程度である。５００〜５００００本の連続糸繊維束の織物（炭素繊維フィラメント織物）や、撚りのある紡績糸（スパンヤーン）からなる炭素繊維紡績糸織物構造体がある。 炭素繊維フィラメント織物は、例えば炭素繊維フィラメントを製織することによって得られる。
【００１０】
得られる炭素繊維フィラメント織物は、面方向の熱伝導率及び電気伝導率が高く、表面ケバは比較的少ないが、フィラメントが平面方向に揃っているため、前記の炭素繊維不織布や後記の炭素繊維紡績糸織物構造体より厚さ方向の電気抵抗値がより高い。
【００１１】
（４）炭素繊維紡績糸織物構造体
炭素繊維紡績糸織物構造体は、例えばポリアクリロニトリル系酸化繊維ステープルを紡績して酸化繊維紡績糸を得、これを製織して酸化繊維紡績糸織物にした後、焼成することにより得られる。
【００１２】
得られる炭素繊維紡績糸織物構造体は、柔軟性があり、炭素繊維フィランメント織物に比べ厚さ方向の通電性が高い。しかも炭素繊維不織布に比べ引張強度が高い。
【００１３】
しかし、精紡時や製織時及び炭素化時に繊維切れが発生し易い為、炭素繊維紡績糸織物構造体表面ケバが多量に発生し易い。
【００１４】
即ち、炭素繊維紡績糸織物構造体は、嵩高で、厚さ方向への繊維配列度が高い為、ガス透過性及び通電性に優れている。しかし、紡績糸が撚り糸（ヤーン）であり、紡績糸のケバ、並びに、織物炭素化時の繊維収縮に伴う繊維切れ及び炭素化炉内壁面での擦れ等により織物表面上にケバ（表面ケバ）が発生し易い。
【００１５】
これらのケバは、剛直で、高分子電解質膜を傷つけたり膜を貫通させたりする。
【００１６】
高分子電解質型燃料電池は、その内部に電極材と、厚さ１０〜４０μｍの非常に薄く、しかも脆く破れ易い高分子電解質膜との積層構造を有する。従って、この電解質膜と、炭素繊維紡績糸織物電極材とを積層一体化して積層構造を形成する電池製造時に、電解質膜の破損が生じないよう配慮する必要がある。
【００１７】
図１は、電極材として炭素繊維紡績糸織物構造体を用いた高分子電解質型燃料電池における、炭素繊維紡績糸織物構造体２と高分子電解質膜４との積層体の断面を示す概略図である。
【００１８】
上記したように、炭素繊維紡績糸織物構造体２は、表面ケバ６が発生し易い。
【００１９】
炭素繊維紡績糸織物構造体２表面に多量の繊維切断端子部（ケバ）６が存在すると、高分子電解質膜４の損傷の原因となり、最終的には得られる電池の性能を低下させる。
【００２０】
この為、ケバの少ない炭素繊維紡績糸織物構造体の開発が要望されている。
【００２１】
【発明が解決しようとする課題】
本発明者等は、上記問題を解決すべく鋭意検討した結果、厚さ、目付、比抵抗値、及び表面ケバ数を所定範囲にした炭素繊維紡績糸織物構造体を用いることによって、高分子電解質膜の損傷のない、電池性能を低下させない高分子電解質型燃料電池電極材を得ることができることを知得し、本発明を完成するに至った。
【００２２】
本発明の目的とするところは、上記問題を解決した高分子電解質型燃料電池電極材用炭素繊維紡績糸織物構造体、及びその製造方法を提供することにある。
【００２３】
【課題を解決するための手段】
上記の目的を達成する本発明は、以下に記載するものである。
【００２４】
〔１〕 厚さが０．１５〜０．６０ｍｍ、目付が５０〜１５０ｇ／ｍ2、厚さ方向の比抵抗値が０．２０Ωｃｍ以下、表面ケバ数が１５ヶ／ｍｍ2以下である高分子電解質型燃料電池電極材用炭素繊維紡績糸織物構造体。
【００２５】
〔２〕 炭素繊維紡績糸織物構造体の炭素質において、炭素繊維に由来しない炭素質が２質量％以下である〔１〕に記載の高分子電解質型燃料電池電極材用炭素繊維紡績糸織物構造体。
【００２６】
〔３〕 炭素繊維紡績糸の撚り数について、下撚り数が４００〜６００回／ｍ、上撚り数が１００〜４００回／ｍである〔１〕に記載の高分子電解質型燃料電池電極材用炭素繊維紡績糸織物構造体。
【００２７】
〔４〕 ポリアクリロニトリル系繊維に紡糸オイルを０．０１〜０．０５質量％添着し、空気中で初期酸化温度２２５〜２４５℃で酸化後、更に２５０〜２８０℃の温度にて酸化し比重１．３０〜１．３９の酸化繊維を得、得られた酸化繊維に、更に紡糸オイルを０〜０．５質量％添着せしめ、紡績加工、次いで織物加工して酸化繊維紡績糸織物を得、得られた酸化繊維紡績糸織物を、温度１５０〜４００℃、圧力１〜５０ＭＰａで圧縮処理後、不活性ガス雰囲気下、１３００〜２２００℃の温度にて焼成し炭素化する高分子電解質型燃料電池電極材用炭素繊維紡績糸織物構造体の製造方法。
【００２８】
【発明の実施の形態】
以下、本発明を詳細に説明する。
【００２９】
本発明の高分子電解質型燃料電池用電極材を形成する炭素繊維紡績糸織物構造体は、厚さが０．１５〜０．６０ｍｍであり、目付が３０〜１５０ｇ／ｍ2であり、比抵抗値が０．２０Ωｃｍ以下であり、且つケバ数が１５ヶ／ｍｍ2以下である。
【００３０】
炭素繊維紡績糸織物構造体の厚さが０．１５ｍｍ未満の場合は、炭素繊維織物構造体の強力が低下し、電池形成加工時における、切断、伸びが発生し易くなり、ケバが多量に発生するなどの不具合を生ずるので好ましくない。
【００３１】
炭素繊維紡績糸織物構造体の厚さが０．６０ｍｍを超える場合は、厚さ方向の電気抵抗値が増加するので好ましくない。
【００３２】
炭素繊維紡績糸織物構造体の目付が３０ｇ／ｍ2より低い場合は、炭素繊維織物構造体の強力が低下し、加工時における、切断、伸びが発生し易くなるので好ましくない。
【００３３】
炭素繊維紡績糸織物構造体の目付が１５０ｇ／ｍ2より高い場合は、厚さ方向の電気抵抗値が増加するので好ましくない。
【００３４】
炭素繊維紡績糸織物構造体の比抵抗値が０．２０Ωｃｍを超える場合は、電池性能が低下するので好ましくない。
【００３５】
本発明の高分子電解質型燃料電池用電極材を形成する炭素繊維紡績糸織物構造体は、表面ケバ数が１５ヶ／ｍｍ2以下である。
【００３６】
炭素繊維紡績糸織物構造体の表面ケバとは、炭素繊維織物表面の繊維切断端子のことをいう。
【００３７】
表面ケバの発生要因及び種類としては以下のものが挙げられる。
・原料繊維の切断に起因する繊維切断端子
・紡績加工（カード加工、及び精紡での紡績糸加工）での繊維損傷による繊維切断端子
・織物加工での繊維損傷による繊維切れ
・炭素化時の炉内壁面やガイド接触による擦れによる繊維切断端子
・炭素化時の繊維収縮による繊維切断端子
炭素繊維紡績糸織物構造体の表面ケバ数が１５ヶ／ｍｍ2を超える場合は、高分子電解質膜にキズが発生したり、膜に貫通孔が発生するなど、高分子電解質膜を損傷する可能性が高くなり好ましくない。更に表面ケバは、表面の擦れ等により脱落し微粉末（フリーケバ）となり高分子電解質膜の損傷や、紡績糸織物構造体における空隙を閉塞させガス拡散性を阻害する。
【００３８】
また、炭素繊維紡績糸織物構造体は、炭素繊維不織布に比べ、厚さ方向の剛性が高い為、表面ケバの上限値は低く制限される。
【００３９】
本発明の高分子電解質型燃料電池用電極材を形成する炭素繊維紡績糸織物構造体のＸ線結晶サイズは、１．３〜３．５ｎｍが好ましい。
【００４０】
炭素繊維紡績糸織物構造体のＸ線結晶サイズが１．３ｎｍ未満の場合は、電気伝導性が悪い、電池性能が低下するなどの不具合を生ずるので好ましくない。
【００４１】
炭素繊維紡績糸織物構造体のＸ線結晶サイズが３．５ｎｍを超える場合は、繊維が脆くなり、ケバ発生が大となるので好ましくない。
【００４２】
本発明の炭素繊維紡績糸織物構造体の炭素質において、樹脂マトリックス等に起因する、炭素繊維に由来しない炭素質は２質量％以下であることが好ましい。
【００４３】
炭素繊維紡績糸織物構造体の炭素質において、炭素繊維に由来しない炭素質が２質量％を超える場合、この構造体で形成された電極材は、硬く、脆く、且つ柔軟性がない、ガスの通過性及び拡散性が悪いなどの不具合を生ずるので好ましくない。
【００４４】
本発明の炭素繊維紡績糸織物構造体は、その物性が上記範囲内にあれば、その製造方法としては、特に限定されるものではないが、例えば以下の製造方法により製造することができる。
【００４５】
（プリカーサー）
一般に炭素繊維の原料であるプリカーサーは、ポリアクリロニトリル系繊維（プリカーサー）、セルロース系繊維（プリカーサー）、及びピッチ系繊維（プリカーサー）に分類することができる。
【００４６】
本発明の炭素繊維紡績糸織物構造体の原料であるプリカーサーは、上記プリカーサーのうちでもポリアクリロニトリル系繊維（プリカーサー）が好ましい。このプリカーサーはアクリロニトリルモノマーとコモノマーとの共重合体が好ましい。
【００４７】
プリカーサー中のアクリロニトリル単位は、モノマー単位及びコモノマー単位総量に対して９０〜９８質量％が好ましい。コモノマーとしては、アクリル酸メチルエステル、アクリルアミド、イタコン酸等のビニルモノマーなどが例示される。
【００４８】
本発明の炭素繊維紡績糸織物構造体の製造方法の初期工程においては、ポリアクリロニトリル系繊維（プリカーサー）の紡糸オイル（油剤）として燐系オイルを用い、プリカーサーに対する油剤付着量を０．０１〜０．０５質量％にする。
【００４９】
ポリアクリロニトリル系プリカーサーの紡糸オイル（油剤）としては、アルキル基又はアリル基を有するホスフォネート又はホスフェート、並びに、これらの混合物等（アニオン系、カチオン系、又はノニオン系分散剤を含む）が例示できる。具体的には、ブチルホスフェート（Ｃ4Ｈ9ＰＯ4）からなる油剤などがある。
【００５０】
油剤付着量が０．０１質量％未満の場合は、プリカーサー紡糸時プリカーサーのローラーへの巻きつきが発生するので好ましくない。
【００５１】
油剤付着量が０．０５質量％を超える場合は、プリカーサーを酸化処理時、繊維間の膠着が発生して繊維表面欠陥が生じ、酸化繊維の紡績時、酸化繊維織物加工時及び酸化繊維の炭素化時に、表面ケバ発生が多発するので好ましくない。
【００５２】
（酸化処理）
上記プリカーサーは、空気中で、初期酸化温度２２０〜２４５℃で１０〜６０分酸化処理後、温度勾配０．２〜０．９℃／ｍｉｎで最高温度２５０〜２８０℃まで昇温され酸化処理される。
【００５３】
得られる酸化繊維の比重を１．３０〜１．３９に制御する。この酸化繊維に、更に燐系オイルを０〜０．５質量％付着させると共に、燐含有量を２０〜２５０ｐｐｍに調整することが好ましい。
【００５４】
初期酸化温度が２４５℃より高いと繊維と繊維表面間の融着が生じ、これが繊維表面の欠陥部となり、繊維強度が低下し、表面ケバ発生の要因となるので好ましくない。
【００５５】
初期酸化温度が２２０℃より低いと、酸化繊維の所定の比重到達までに長時間を要し生産性が低下するので好ましくない。
【００５６】
酸化繊維の適正な繊度は、０．８〜４．４ｄｔｅｘである。
【００５７】
繊度の調整は、用いられるプリカーサーの繊度、酸化時のリラックス条件により実施することができる。
【００５８】
酸化繊維の繊度が０．８ｄｔｅｘより低い場合は、単繊維の強力が低い為、織物加工時及び炭素化時に糸切れが生じ易い、繊維の収束（分散性低下）により加工性が低下する、並びに、表面ケバが発生し易いなどの不具合を生ずるので好ましくない。
【００５９】
酸化繊維の繊度が４．４ｄｔｅｘより高い場合は、酸化時間が長時間となり生産性が悪い、炭素化時に繊維強度低下し表面ケバが発生し易いなどの不具合を生ずるので好ましくない。
【００６０】
酸化繊維の適正な比重は１．３０〜１．３９が好ましい。
【００６１】
酸化繊維の比重が１．３０より低い場合は、耐熱性が悪いため、炭素化時に炭素繊維強度が劣化する、炭素繊維織物表面にケバが発生し易いなどの不具合を生ずるので好ましくない。
【００６２】
酸化繊維の比重が１．３９より高い場合は、酸化繊維の強度及び伸度が低下する、炭素繊維織物表面にケバが発生し易いなどの不具合を生ずるので好ましくない。
【００６３】
酸化繊維の適正な乾強度は１．５ｇ／ｄｔｅｘ以上であり、適正な乾伸度は８％以上である。
【００６４】
酸化繊維の乾強度が１．５ｇ／ｄｔｅｘより低い場合は、紡績加工性が低下する、表面ケバが発生し易いなどの不具合を生ずるので好ましくない。
【００６５】
酸化繊維の乾伸度が８％より低い場合も、紡績加工性が低下する、表面ケバが発生し易いなどの不具合を生ずるので好ましくない。
【００６６】
酸化繊維の適正な結節強度は０．８ｇ／ｄｔｅｘ以上であり、適正な結節伸度は４％以上である。
【００６７】
酸化繊維の結節強度が０．８ｇ／ｄｔｅｘより低い場合は、紡績加工性低下及び炭素繊維紡績糸織物構造体の強度低下、並びに、表面ケバが発生し易いなどの不具合を生ずるので好ましくない。
【００６８】
酸化繊維の結節伸度が４％より低い場合も、紡績加工性低下及び炭素繊維紡績糸織物構造体の強度低下、並びに、表面ケバが発生し易いなどの不具合を生ずるので好ましくない。
【００６９】
（紡績加工）
上記酸化繊維は、定長カット又はトウリアクターでバイアスカットして短繊維にされ、この短繊維は酸化繊維紡績糸に紡績加工される。
【００７０】
短繊維の平均カット長は２５〜６５ｍｍが好ましく、この範囲以外の場合は、紡績時糸切れを生ずる、表面ケバが発生し易いなどの不具合を生ずるので好ましくない。
【００７１】
酸化繊維紡績糸のクリンプ率は８〜２５％が好ましい。
【００７２】
酸化繊維紡績糸のクリンプ率が８％より低い場合は、繊維同士の絡み合いが少なく、織物加工時糸切れを生じ易いので好ましくない。
【００７３】
酸化繊維紡績糸のクリンプ率が２５％より高い場合は、酸化繊維紡績糸を構成する単繊維の強度が低下し、織物加工時糸切れを生じ易いので好ましくない。
【００７４】
酸化繊維紡績糸のクリンプ数は２．０〜５．５ヶ／ｃｍが好ましい。
【００７５】
酸化繊維紡績糸のクリンプ数が２．０ヶ／ｃｍより低い場合は、繊維同士の絡み合いが少なく、織物加工時糸切れを生じ易いので好ましくない。
【００７６】
酸化繊維紡績糸のクリンプ数が５．５ヶ／ｃｍより高い場合は、酸化繊維紡績糸を構成する単繊維の強度が低下し、織物加工時糸切れを生じ易いので好ましくない。
【００７７】
酸化繊維の紡績加工に用いる油剤の種類としては、アルキル基又はアリル基を有するホスフォネート又はホスフェート、並びに、これらの混合物等（アニオン系、カチオン系、又はノニオン系分散剤を含む）が例示される。
【００７８】
上記燐系油剤の酸化繊維への付着量は０．５０質量％以下が好ましく、また酸化繊維中の燐含有量で２０〜２５０ｐｐｍになるように、燐系油剤を付着させるのが好ましい。
【００７９】
油剤付着量が０．５０質量％を超える場合は、プリカーサーを酸化処理時、繊維間の膠着が発生して繊維表面欠陥が生じ、酸化繊維の紡績時、酸化繊維織物加工時及び酸化繊維の炭素化時に、表面ケバ発生が多発するので好ましくない。
【００８０】
酸化繊維中の燐含有量が２０ｐｐｍ未満の場合は、酸化繊維の耐熱性が低下し、炭素化時に繊維切れを生じ織物の表面ケバ発生の原因となるので好ましくない。
【００８１】
酸化繊維中の燐含有量が２５０ｐｐｍを超える場合は、炭素化時に繊維表面が膠着（繊維と繊維表面が微接着）し繊維切れの原因となるので好ましくない。
【００８２】
得られる酸化繊維紡績糸の番手としては、３０〜５０番手の双糸が好ましく、撚り数は、１００〜８００回／ｍが好ましく、更に好ましくは、下撚り４００〜６００回／ｍ、上撚り１００〜４００回／ｍである。
【００８３】
下撚りの撚り数が４００回／ｍ未満の場合、又は上撚りの撚り数が１００回／ｍ未満の場合は、紡績糸強度が低いため、製織時に紡績糸切れが発生し、製織加工性が低下する、表面ケバが発生し易い、並びに、炭素繊維紡績糸織物強度が著しく低下するなどの不具合を生ずるので好ましくない。
【００８４】
下撚りの撚り数が６００回／ｍを超える場合、又は上撚りの撚り数が４００回／ｍを超える場合は、紡績糸織物の加工性は良いが、炭素化時に繊維収縮に伴う繊維切れが生じ、織物表面ケバが発生し易いので好ましくない。
【００８５】
酸化繊維紡績糸１本当たりに用いられる単繊維本数は９０〜９００本が好ましい。
【００８６】
（製織）
この酸化繊維紡績糸を製織して酸化繊維紡績糸織物を得る。
【００８７】
酸化繊維紡績糸織物の織り形態は、この織物を炭素化後電極材として用いた場合、電極材のカット時目ずれの少ない平織りが好ましい。
【００８８】
酸化繊維紡績糸織物について、厚さは０．５〜２．０ｍｍ，嵩密度は０．１５〜０．４５ｇ／ｃｍ3、目付は７０〜２５０ｇ／ｍ2が好ましい。
【００８９】
また、酸化繊維紡績糸織物中の紡績糸の打ち込み本数は４〜２４本／ｃｍが好ましい。
【００９０】
（圧縮処理）
この酸化繊維紡績糸織物を樹脂処理して又は樹脂処理せずに圧縮処理した後、炭素化炉高温部内壁やガイドに直接接触しない方法にて、不活性ガス中で１３００〜２２００℃の温度で炭素化することにより得ることができる。
表面ケバ発生の改善の為には、酸化繊維紡績糸織物を圧縮処理して表面ケバを表層の内部方向へ抑え込むことが好ましい。
【００９１】
圧縮処理前に樹脂処理を行うことは、圧縮処理の効果がより発揮されるので、より好ましい。
【００９２】
この樹脂処理においては、酸化繊維紡績糸織物を所定の濃度の樹脂浴に浸漬し、樹脂を１０．０質量％以下の範囲で添着させることが好ましい。
【００９３】
樹脂の添着量が１０．０質量％より多い場合は、炭素繊維紡績糸織物の柔軟性が損なわれ、脆性が高くなるので好ましくない。
【００９４】
樹脂処理に用いる樹脂の種類としては、ポリアクリル酸エステル、カルボキシメチルセローズ及び、ポリビニルアルコール等の（環境面から有機溶剤を使用しない）水溶性の樹脂が好ましい。
【００９５】
圧縮処理は、樹脂処理なし又は樹脂処理後に行われるが、上述したように、圧縮処理時によるケバ抑制効果は、あらかじめ樹脂処理後、圧縮処理する方が発揮し易い。
【００９６】
圧縮処理温度は１５０〜４００℃が好ましい。
【００９７】
圧縮処理温度が１５０℃より低い場合は、ケバ抑制効果が小さいので好ましくない。
【００９８】
圧縮処理温度が４００℃より高い場合は、圧縮処理後の酸化繊維紡績糸織物の強度低下、炭素化時の炭素繊維紡績糸織物構造体の強度低下などの不具合を生ずるので好ましくない。
【００９９】
圧縮処理の圧力は１〜５０ＭＰａが好ましい。
【０１００】
圧縮処理の圧力が１ＭＰａより低い場合は、ケバ抑制効果が小さいので好ましくない。
【０１０１】
圧縮処理の圧力が５０ＭＰａより高い場合は、圧縮処理後の酸化繊維紡績糸織物の強度が低下する、炭素化時の炭素繊維紡績糸織物構造体の強度が低下する、並びに、ケバ発生の要因となるなどの不具合を生ずるので好ましくない。
【０１０２】
圧力処理装置は、ホットプレス又は熱ローラーのいずれでも良い。
【０１０３】
（炭素化）
圧縮処理した酸化繊維紡績糸織物は、連続的に、不活性ガス雰囲気下、１３００〜２２００℃の温度にて焼成し炭素化する。不活性ガスとしては、窒素、アルゴン、ヘリウム等が用いられる。
【０１０４】
焼成温度が１３００℃より低い場合は、得られる炭素繊維紡績糸織物構造体の電気抵抗値が増加するので好ましくない。
【０１０５】
焼成温度が２２００℃より高い場合は、電気抵抗値が低下し、測定値のバラツキが少なく安定した値を示すが、炭素繊維紡績糸織物構造体の強度が低下する、ケバが発生し易いなどの不具合を生ずるので好ましくない。
【０１０６】
炭素化時における紡績糸織物の収縮率は０〜１５％が好ましい。
【０１０７】
紡績糸織物にかける張力が少ないと酸化繊維は炭素化時に熱収縮する。炭素化時における紡績糸織物の収縮率が０％未満の場合（紡績糸織物に張力をかけ収縮を抑え、引っ張って伸ばした状態の場合）は、過度な張力をかけ収縮を規制し伸ばし過ぎる場合に相当する。この場合は、繊維切れを生じ表面ケバ発生の要因となるので好ましくない。
【０１０８】
炭素化時における紡績糸織物の収縮率が１５％を超える場合は、繊維強度が低下する、並びに、炭素化時に、織物に皺、折れを生じ、炭素化炉内部で蛇行し、炉内への垂れ込みにより、炉壁に接触する為、ケバ発生の要因となるなどの不具合を生ずるので好ましくない。
【０１０９】
焼成炉の形式については、タテ型炉及びヨコ型炉どちらでもよいが、紡績糸織物表面を焼成炉内部（粗な壁面、ガイド）で擦らないようにすることが好ましい。ヨコ型炉の場合は、炉底において紡績糸織物素材の底面を擦らないようにすることが好ましい。例えば、炭素材のベルトコンベヤー、又は、柔軟性があり、高目付、且つ高強度の炭素繊維フェルトを並走させ炭素化することにより、擦過によるケバの発生を抑制することができる。
【０１１０】
【実施例】
本発明を以下の実施例及び比較例により詳述する。
【０１１１】
以下の実施例及び比較例の条件により酸化繊維紡績糸織物、炭素繊維紡績糸織物等を作製し、得られた酸化繊維紡績糸織物、炭素繊維紡績糸織物等の諸物性値を、以下の方法により測定した。
【０１１２】
厚さ：直径３０ｍｍの円形圧板で２００ｇの荷重(2.8kPa)時の厚さを測定した。
【０１１３】
比重：液置換法（ＪＩＳＲ７６０１、置換液：エチルアルコール）により測定した。
【０１１４】
繊維性能：乾強度、乾伸度、結節強度、結節伸度はＪＩＳＬ１０１５により測定した。
【０１１５】
表面ケバ数：炭素繊維織物の上面及び下面の顕微鏡写真（倍率５０倍）をとり、それぞれ５ｍｍ角の繊維切断端子の数を測定し、下式により算出した。
ケバ数（ヶ／ｍｍ2）
＝［（上面の表面の繊維切断端子の数＋下面の表面の繊維切断端子の数）／２］÷２５
Ｘ線結晶サイズ：広角Ｘ線回折測定での２θのピークの半値幅と下記のシェラーの式より求めた。
Ｘ線結晶サイズ（ｎｍ）＝（ｋ×λ）／β×ｃｏｓθ
ｋ：装置定数 ０．９０
λ：Ｘ線波長 ０．１５４ｎｍ
β：２θ＝２６．０°付近の最大ピークの半値幅
通電性（比抵抗値）：２枚の５０ｍｍ角（厚さ１０ｍｍ）の金メッキした電極に炭素繊維紡績糸織物構造体の両面を圧力１ＭＰａで挟み、両電極間の電気抵抗値（Ｒ）を測定し、厚さ（Ｔ）と接触面積（Ｓ）より下式にて算出した。
通電性（比抵抗値：Ωcm）＝（Ｒ×Ｓ）／Ｔ
実施例１〜３
アクリロニトリル９３質量％、アクリル酸メチル４質量％、イタコン酸２質量％を共重合させた繊度１．６ｄｔｅｘのアクリル繊維にブチルホスフェート０．０１質量％、エチレングリコール０．０１質量％付着させ、この繊維を空気中にて初期酸化温度２２５℃で１ｈｒｓ、更に２６０℃で１．５ｈｒｓ酸化処理した。
【０１１６】
得られた繊度２．３ｄｔｅｘ、比重１.３７、クリンプ数３．８ヶ／ｃｍ、クリンプ率１３％、乾強度２．９ｇ／ｄｔｅｘ、乾伸度２５％、結節強度０．７ｇ／ｄｔｅｘ、結節伸度５％、平均カット長５１ｍｍの酸化繊維ステープルは、更にブチルホスフェート０．２５質量％を添着処理した（燐含有量は５３ｐｐｍ）。
【０１１７】
得られた酸化繊維を紡績し、上撚り２５０回／ｍ、下撚り５５０回／ｍの４０番手双糸を得た。
【０１１８】
この紡績糸を縦、緯共に織り密度が１７本／ｃｍの平織りを作製した。
【０１１９】
得られた酸化繊維紡績糸織物の目付は２０９ｇ／ｍ2、厚さは０．５４ｍｍであった。
【０１２０】
更に、この酸化繊維紡績糸織物を表１に示すように樹脂処理した後、酸化繊維織物又は未樹脂処理の酸化繊維織物を圧縮処理し、ヨコ型炉にて、１８５０℃、窒素気流中で、目付５００ｇ／ｍ2の炭素繊維フェルトの上に載せ、連続的に並走させ炭素化することにより表面ケバの少ない炭素繊維紡績糸織物を得ることができた。
【０１２１】
【表１】
比較例１
アクリロニトリル９３質量％、アクリル酸メチル４質量％、イタコン酸２質量％ を共重合させた繊度１．６ｄｔｅｘのアクリル繊維にブチルホスフェート０．６５質量％付着させ、この繊維を空気中にて２２５℃で１ｈｒｓ、更に２６０℃で１．５ｈｒｓ酸化処理した。
【０１２３】
得られた繊度２．３ｄｔｅｘ，比重１.３８、クリンプ数４．１ヶ／ｃｍ、クリンプ率１２％、乾強度２．１ｇ／ｄｔｅｘ、乾伸度２１％、結節強度０．３ｇ／ｄｔｅｘ、結節伸度２％、平均カット長５１ｍｍの酸化繊維ステープル（燐含有量は１５５ｐｐｍ）を紡績し、上撚り２５０回／ｍ、下撚り５５０回／ｍの４０番手双糸を得た。
【０１２４】
この紡績糸を用い、縦、緯共に織り密度が１７本／ｃｍの平織りを作製した。
【０１２５】
得られた酸化繊維紡績糸織物の目付は２１１ｇ／ｍ2、厚さは０．５３ｍｍであった。
【０１２６】
更に、ヨコ型炉にて、１８５０℃、窒素気流中で、目付５００ｇ／ｍ2の炭素繊維フェルトの上に載せ、連続的に並走させ炭素化を行った。しかし、得られた炭素繊維紡紡績糸織物は、表２に示すように表面ケバの多いものであった。
【０１２７】
比較例２
アクリロニトリル９３質量％、アクリル酸メチル４質量％、イタコン酸２質量％を共重合させた繊度１．６ｄｔｅｘのアクリル繊維にブチルホスフェート０．０１質量％、エチレングリコール０．０１質量％付着させ、この繊維を空気中にて初期酸化温度２２５℃で１ｈｒｓ、更に２７０℃で５．０ｈｒｓ酸化処理した。
【０１２８】
得られた繊度２．３ｄｔｅｘ、比重１.４３、クリンプ数３．３ヶ／ｃｍ、クリンプ率１１％、乾強度１．９ｇ／ｄｔｅｘ、乾伸度１８％、結節強度０．２ｇ／ｄｔｅｘ、結節伸度１％、平均カット長５１ｍｍの酸化繊維ステープル（燐含有量は１１ｐｐｍ）を紡績し、上撚り２７０回／ｍ、下撚り５８０回／ｍの４０番手双糸を得た。
【０１２９】
この紡績糸を用い、縦、緯共に織り密度が１７本／ｃｍの平織りを作製した。
【０１３０】
得られた酸化繊維紡績糸織物の目付は２２３ｇ／ｍ2、厚さは０．５２ｍｍであった。
【０１３１】
更に、この酸化繊維紡績糸織物をヨコ型炉にて、１８５０℃、窒素気流中で、目付５００ｇ／ｍ2の炭素繊維フェルトの上に載せ、連続的に並走させ炭素化を行った。しかし、得られた炭素繊維紡紡績糸織物は、表２に示すように表面ケバの多いものであった。
【０１３２】
比較例３
アクリロニトリル９３質量％、アクリル酸メチル４質量％、イタコン酸２質量％を共重合させた繊度１．６ｄｔｅｘのアクリル繊維にブチルホスフェート０．０１質量％、エチレングリコール ０．０１質量％付着させ、この繊維を空気中にて初期酸化温度２２５℃で１ｈｒｓ、更に２５０℃で０．３ｈｒｓ酸化処理した。
【０１３３】
得られた繊度２．２ｄｔｅｘ、比重１.２７、クリンプ数４．１ヶ／ｃｍ、クリンプ率１３％、乾強度２．２ｇ／ｄｔｅｘ、乾伸度２４％、結節強度０．８ｇ／ｄｔｅｘ、結節伸度６％、平均カット長５１ｍｍの酸化繊維ステープルは、更にブチルホスフェート０．２５質量％を添着処理した（燐含有量は５５ｐｐｍ）。
【０１３４】
得られた酸化繊維を紡績し、上撚り２４０回／ｍ、下撚り６００回／ｍの４０番手双糸を得た。
【０１３５】
この紡績糸を用い、縦、緯共に織り密度が１７本／ｃｍの平織りを作製した。
【０１３６】
得られた酸化繊維紡績糸織物の目付は２１０ｇ／ｍ2、厚さは０．５２ｍｍであった。
【０１３７】
更に、この酸化繊維紡績糸織物を表２に示すように樹脂処理後の酸化繊維織物を圧縮処理し、ヨコ型炉にて、１８５０℃、窒素気流中で、目付５００ｇ／ｍ2の炭素繊維フェルトの上に載せ、連続的に並走させ炭素化を行った。しかし、得られた炭素繊維紡紡績糸織物は、表２に示すように表面ケバの多いものであった。
【０１３８】
比較例４
アクリロニトリル９３質量％、アクリル酸メチル４質量％、イタコン酸２質量％を共重合させた繊度１．６ｄｔｅｘのアクリル繊維にブチルホスフェート０．０１質量％、エチレングリコール ０．０１質量％付着させ、この繊維を空気中にて初期酸化温度２２５℃で１ｈｒｓ、更に２６０℃で１．５ｈｒｓ酸化処理した。
【０１３９】
得られた繊度２．３ｄｔｅｘ、比重１.３７、クリンプ数３．８ヶ／ｃｍ、クリンプ率１３％、乾強度２．９ｇ／ｄｔｅｘ、乾伸度２５％、結節強度０．７ｇ／ｄｔｅｘ、結節伸度５％、平均カット長５１ｍｍの酸化繊維ステープルは、更にブチルホスフェート０．７５質量％を添着処理した（燐含有量は１５３ｐｐｍ）。
【０１４０】
得られた酸化繊維を紡績し、上撚り２５０回／ｍ、下撚り５５０回／ｍの４０番手双糸を得た。
【０１４１】
この紡績糸を縦、緯共に織り密度が１７本／ｃｍの平織りを作製した。
【０１４２】
得られた酸化繊維紡績糸織物の目付は２０９ｇ／ｍ2、厚さは０．５３ｍｍであった。
【０１４３】
更に、この酸化繊維紡績糸織物を表２に示すように樹脂処理した酸化繊維織物を圧縮処理し、ヨコ型炉にて１８５０℃、窒素気流中で、目付５００ｇ／ｍ2の炭素繊維フェルトの上に載せ、連続的に並走させ炭素化を行った。しかし、得られた炭素繊維紡紡績糸織物は、表２に示すように表面ケバの多いものであった。
【０１４４】
比較例５
アクリロニトリル９３質量％、アクリル酸メチル４質量％、イタコン酸２質量％を共重合させた繊度１．６ｄｔｅｘのアクリル繊維にブチルホスフェート０．０１質量％、エチレングリコール ０．０１質量％付着させ、この繊維を空気中にて初期酸化温度２２５℃で１ｈｒｓ、更に２６０℃で１．５ｈｒｓ酸化処理した。
【０１４５】
得られた繊度２．３ｄｔｅｘ、比重１.３７、クリンプ数３．８ヶ／ｃｍ、クリンプ率１３％、乾強度２．９ｇ／ｄｔｅｘ、乾伸度２５％、結節強度０．７ｇ／ｄｔｅｘ、結節伸度５％、平均カット長５１ｍｍの酸化繊維ステープルは、更にブチルホスフェート０．２５質量％を添着処理した（燐含有量は５３ｐｐｍ）。
【０１４６】
得られた酸化繊維を紡績し、上撚り２５０回／ｍ、下撚り５５０回／ｍの４０番手双糸を得た。
【０１４７】
この紡績糸を用い、縦、緯共に織り密度が１７本／ｃｍの平織りを作製した。
【０１４８】
得られた酸化繊維紡績糸織物の目付は２０９ｇ／ｍ2、厚さは０．５４ｍｍであった。
【０１４９】
更に、この酸化繊維紡績糸織物を表２に示すようにカルボキシメチルセルローズ（ＣＭＣ）にて処理した酸化繊維織物を圧縮処理しヨコ型炉にて、２５５０℃、窒素気流中で、目付５００ｇ／ｍ2の炭素繊維フェルトの上に載せ、連続的に並走させ炭素化を行った。しかし、得られた炭素繊維紡紡績糸織物は、表２に示すように表面ケバの多いものであった。
【０１５０】
【表２】
【発明の効果】
本発明の高分子電解質型燃料電池電極材用炭素繊維紡績糸織物構造体は、厚さ、目付、比抵抗値、及び表面ケバ数を所定範囲にしているので、高分子電解質膜の損傷のない、電池性能を低下させない高分子電解質型燃料電池電極材を得ることができる。
【図面の簡単な説明】
【図１】電極材として炭素繊維紡績糸織物構造体を用いた高分子電解質型燃料電池における、炭素繊維紡績糸織物構造体と高分子電解質膜との積層体の断面を示す概略図である。
【符号の説明】
２ 炭素繊維紡績糸織物構造体
４ 高分子電解質膜
６ 表面ケバ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a carbon fiber spun yarn fabric structure for a polymer electrolyte fuel cell electrode material, and a method for producing the same. In particular, the present invention relates to a carbon fiber spun yarn fabric structure that is interposed between a separator and a polymer electrolyte membrane in a polymer electrolyte fuel cell and is useful as an electrode material having current collecting properties and gas diffusibility, and a method for producing the same.
[0002]
[Prior art]
Since carbon materials are excellent in conductivity, heat resistance and chemical resistance, they are conventionally used for battery electrode materials. In recent years, carbon fiber has attracted attention as an electrode material that can make use of the characteristics of the fiber form such as flexibility, processability, and moldability, and has been applied to polymer electrolyte fuel cells.
[0003]
As the carbon fiber material used for the electrode material of the polymer electrolyte fuel cell, there is a great demand for a carbon fiber material having a particularly thin sheet shape, strength, low electrical resistance, and flexibility, and various carbon fibers. A structure has been developed.
[0004]
Carbon fiber structures for polymer electrolyte fuel cells include (1) C / C paper (sheet-like carbon fiber reinforced carbon material), (2) carbon fiber nonwoven fabric, (3) carbon fiber filament fabric, and (4) Carbon fiber spun yarn fabric structures and the like are exemplified, and each has the following characteristics.
[0005]
(1) C / C paper
The C / C paper is obtained, for example, by making a carbon fiber cut fiber to obtain a carbon fiber paper, impregnating the carbon fiber paper with 30 to 60% by mass of resin, compressing, and then firing. It is done.
[0006]
The obtained C / C paper has many carbon components other than the carbon fiber resulting from the resin matrix. The carbon fiber content is as low as 85% by mass or less, and there are few surface cracks, but there are problems such as being hard, brittle, inflexible, and poor in gas permeability and diffusibility.
[0007]
(2) Carbon fiber nonwoven fabric
The carbon fiber non-woven fabric is obtained, for example, by processing a polyacrylonitrile-based oxidized fiber staple into a non-woven fabric to obtain an oxidized fiber non-woven fabric, and firing the non-woven fabric.
[0008]
The obtained carbon fiber nonwoven fabric is more flexible than C / C paper, can be continuously subjected to water-repellent treatment, catalyst treatment, and the like, is lower in cost, and is expected as an electrode material.
[0009]
(3) Carbon fiber filament fabric
Carbon fiber fabrics usually have a single fiber diameter of about 4 to 25 μm. There are carbon fiber spun yarn fabric structures composed of 500 to 50,000 continuous yarn fiber bundle fabrics (carbon fiber filament fabrics) and twisted spun yarns (spun yarns). A carbon fiber filament fabric is obtained, for example, by weaving carbon fiber filaments.
[0010]
The resulting carbon fiber filament woven fabric has high thermal conductivity and electrical conductivity in the plane direction and relatively few surface fluffs, but the filaments are aligned in the plane direction. The electric resistance value in the thickness direction is higher than that of the yarn fabric structure.
[0011]
(4) Carbon fiber spun yarn fabric structure
The carbon fiber spun yarn fabric structure is obtained, for example, by spinning a polyacrylonitrile-based oxidized fiber staple to obtain an oxidized fiber spun yarn, weaving it into an oxidized fiber spun yarn fabric, and then firing it.
[0012]
The resulting carbon fiber spun yarn fabric structure is flexible and has higher electrical conductivity in the thickness direction than the carbon fiber filament fabric. Moreover, the tensile strength is higher than that of the carbon fiber nonwoven fabric.
[0013]
However, since fiber breakage is likely to occur during spinning, weaving, and carbonization, a large amount of carbon fiber spun yarn fabric surface cracks is likely to occur.
[0014]
That is, the carbon fiber spun yarn fabric structure is bulky and has a high degree of fiber alignment in the thickness direction, and therefore has excellent gas permeability and electrical conductivity. However, the spun yarn is a twisted yarn (yarn), and the spun yarn is crumpled on the surface of the fabric due to fiber breakage due to fiber shrinkage at the time of carbonization of the fabric and rubbing on the inner wall of the carbonization furnace. Is likely to occur.
[0015]
These incisions are rigid and damage the polymer electrolyte membrane or penetrate the membrane.
[0016]
The polymer electrolyte fuel cell has a laminated structure of an electrode material and a very thin polymer electrolyte membrane having a thickness of 10 to 40 μm that is brittle and easily broken. Therefore, it is necessary to consider that the electrolyte membrane is not damaged during the manufacture of a battery in which this electrolyte membrane and the carbon fiber spun yarn electrode material are laminated and integrated to form a laminated structure.
[0017]
FIG. 1 is a schematic view showing a cross section of a laminate of a carbon fiber spun yarn fabric structure 2 and a polymer electrolyte membrane 4 in a polymer electrolyte fuel cell using a carbon fiber spun yarn fabric structure as an electrode material. is there.
[0018]
As described above, the carbon fiber spun yarn fabric structure 2 is liable to generate surface cracks 6.
[0019]
The presence of a large amount of fiber cutting terminal portions (barbs) 6 on the surface of the carbon fiber spun yarn fabric structure 2 causes damage to the polymer electrolyte membrane 4 and ultimately deteriorates the performance of the obtained battery.
[0020]
For this reason, development of a carbon fiber spun yarn woven fabric structure with less fluff is desired.
[0021]
[Problems to be solved by the invention]
As a result of intensive studies to solve the above problems, the present inventors have used a carbon fiber spun yarn woven structure having a predetermined range of thickness, basis weight, specific resistance value, and number of surface indentations, thereby providing a polymer electrolyte. It has been found that a polymer electrolyte fuel cell electrode material that does not damage the membrane and does not deteriorate the cell performance can be obtained, and the present invention has been completed.
[0022]
An object of the present invention is to provide a carbon fiber spun woven fabric structure for a polymer electrolyte fuel cell electrode material that has solved the above-mentioned problems, and a method for producing the same.
[0023]
[Means for Solving the Problems]
The present invention which achieves the above object is described below.
[0024]
[1] The thickness is 0.15 to 0.60 mm, and the basis weight is 50 to 150 g / m. 2 The specific resistance value in the thickness direction is 0.20 Ωcm or less, and the number of surface markings is 15 / mm. 2 A carbon fiber spun yarn fabric structure for a polymer electrolyte fuel cell electrode material, which is the following.
[0025]
[2] The carbon fiber spun yarn fabric structure for a polymer electrolyte fuel cell electrode material according to [1], wherein the carbonaceous material of the carbon fiber spun yarn fabric structure has 2% by mass or less of carbonaceous matter not derived from carbon fibers. body.
[0026]
[3] The polymer electrolyte fuel cell electrode material according to [1], wherein the number of twists of the carbon fiber spun yarn is 400 to 600 times / m and the number of upper twists is 100 to 400 times / m. Carbon fiber spun yarn fabric structure.
[0027]
[4] Polyacrylonitrile fiber was impregnated with 0.01 to 0.05 mass% of spinning oil, oxidized in air at an initial oxidation temperature of 225 to 245 ° C., and further oxidized at a temperature of 250 to 280 ° C. to give a specific gravity of 1 .Oxidized fibers of 30 to 1.39 were obtained, and the obtained oxidized fibers were further impregnated with 0 to 0.5% by mass of spinning oil, and were subjected to spinning processing and then textile processing to obtain oxidized fiber spun yarn fabrics. The obtained oxidized fiber spun yarn fabric is subjected to a compression treatment at a temperature of 150 to 400 ° C. and a pressure of 1 to 50 MPa, and then calcined and carbonized in an inert gas atmosphere at a temperature of 1300 to 2200 ° C. Method for producing carbon fiber spun yarn fabric structure for material.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
[0029]
The carbon fiber spun yarn fabric structure forming the polymer electrolyte fuel cell electrode material of the present invention has a thickness of 0.15 to 0.60 mm and a basis weight of 30 to 150 g / m. 2 The specific resistance value is 0.20 Ωcm or less, and the number of ribs is 15 / mm. 2 It is as follows.
[0030]
When the thickness of the carbon fiber spun yarn fabric structure is less than 0.15 mm, the strength of the carbon fiber fabric structure is reduced, cutting and elongation are likely to occur during battery formation processing, and a large amount of cracks are generated. This is not preferable because it causes problems such as
[0031]
When the thickness of the carbon fiber spun yarn fabric structure exceeds 0.60 mm, the electrical resistance value in the thickness direction increases, which is not preferable.
[0032]
Carbon fiber spun yarn fabric structure weight per unit area is 30g / m 2 If it is lower, the strength of the carbon fiber woven fabric structure is lowered, and cutting and elongation during processing are likely to occur, which is not preferable.
[0033]
The weight of the carbon fiber spun yarn fabric structure is 150 g / m 2 If it is higher, the electric resistance value in the thickness direction increases, which is not preferable.
[0034]
When the specific resistance value of the carbon fiber spun yarn fabric structure exceeds 0.20 Ωcm, the battery performance deteriorates, which is not preferable.
[0035]
The carbon fiber spun yarn woven fabric structure forming the electrode material for a polymer electrolyte fuel cell of the present invention has a surface number of 15 / mm. 2 It is as follows.
[0036]
The surface mark of the carbon fiber spun yarn fabric structure means a fiber cutting terminal on the surface of the carbon fiber fabric.
[0037]
Examples of the factors and types of surface cracks include the following.
・ Fiber cutting terminals caused by cutting raw fibers
・ Fiber cutting terminals due to fiber damage in spinning processing (card processing and spinning yarn processing in fine spinning)
・ Fiber breakage due to fiber damage in textile processing
・ Fiber cutting terminal due to rubbing due to furnace inner wall and guide contact during carbonization
・ Fiber cutting terminals due to fiber shrinkage during carbonization
Carbon fiber spun yarn fabric structure has a surface scrap count of 15 / mm 2 In the case where it exceeds 1, there is a high possibility that the polymer electrolyte membrane will be damaged, such as scratches in the polymer electrolyte membrane or through holes in the membrane. Further, the surface mark falls off due to surface rubbing or the like and becomes a fine powder (free mark), which damages the polymer electrolyte membrane or closes the voids in the spun yarn fabric structure, thereby inhibiting gas diffusion.
[0038]
Further, since the carbon fiber spun yarn fabric structure has higher rigidity in the thickness direction than the carbon fiber nonwoven fabric, the upper limit value of the surface fluff is limited to be low.
[0039]
The X-ray crystal size of the carbon fiber spun yarn fabric structure forming the electrode material for a polymer electrolyte fuel cell of the present invention is preferably 1.3 to 3.5 nm.
[0040]
When the X-ray crystal size of the carbon fiber spun yarn fabric structure is less than 1.3 nm, it is not preferable because problems such as poor electrical conductivity and reduced battery performance occur.
[0041]
When the X-ray crystal size of the carbon fiber spun yarn fabric structure exceeds 3.5 nm, the fiber becomes brittle and the occurrence of fluffing becomes large, which is not preferable.
[0042]
In the carbonaceous material of the carbon fiber spun yarn fabric structure of the present invention, the carbonaceous matter that is not derived from carbon fiber due to a resin matrix or the like is preferably 2% by mass or less.
[0043]
When the carbonaceous matter of the carbon fiber spun yarn fabric structure exceeds 2% by mass, the electrode material formed with this structure is hard, brittle and inflexible, This is not preferable because it causes problems such as poor passage and diffusion.
[0044]
The carbon fiber spun yarn fabric structure of the present invention is not particularly limited as long as its physical properties are within the above range, but can be produced by, for example, the following production method.
[0045]
(Precursor)
Generally, precursors which are raw materials for carbon fibers can be classified into polyacrylonitrile fibers (precursors), cellulose fibers (precursors), and pitch fibers (precursors).
[0046]
The precursor which is a raw material of the carbon fiber spun yarn fabric structure of the present invention is preferably a polyacrylonitrile fiber (precursor) among the precursors. This precursor is preferably a copolymer of an acrylonitrile monomer and a comonomer.
[0047]
The acrylonitrile unit in the precursor is preferably 90 to 98% by mass based on the total amount of monomer units and comonomer units. Examples of the comonomer include vinyl monomers such as acrylic acid methyl ester, acrylamide, and itaconic acid.
[0048]
In the initial step of the method for producing a carbon fiber spun yarn fabric structure of the present invention, phosphorus oil is used as the spinning oil (oil agent) of polyacrylonitrile fiber (precursor), and the amount of oil agent attached to the precursor is 0.01-0. .05 mass%.
[0049]
Examples of the spinning oil (oil agent) of the polyacrylonitrile precursor include phosphonates or phosphates having an alkyl group or an allyl group, and mixtures thereof (including anionic, cationic, or nonionic dispersants). Specifically, butyl phosphate (C Four H 9 PO Four ).
[0050]
When the amount of the oil agent is less than 0.01% by mass, winding of the precursor around the roller during spinning of the precursor is not preferable.
[0051]
When the amount of the oil agent is more than 0.05% by mass, when the precursor is oxidized, fiber sticking occurs, resulting in fiber surface defects, and when oxidized fiber is spun, oxidized fiber fabric processed, and oxidized fiber carbon. This is not preferable because surface cracks frequently occur during conversion.
[0052]
(Oxidation treatment)
The precursor is oxidized in air at an initial oxidation temperature of 220 to 245 ° C. for 10 to 60 minutes and then heated to a maximum temperature of 250 to 280 ° C. with a temperature gradient of 0.2 to 0.9 ° C./min. The
[0053]
The specific gravity of the resulting oxidized fiber is controlled to 1.30 to 1.39. It is preferable to further add 0 to 0.5 mass% of a phosphorus-based oil to the oxidized fiber and adjust the phosphorus content to 20 to 250 ppm.
[0054]
When the initial oxidation temperature is higher than 245 ° C., fusion between the fiber and the fiber surface occurs, and this becomes a defective portion on the fiber surface, resulting in a decrease in fiber strength and a cause of surface cracking.
[0055]
When the initial oxidation temperature is lower than 220 ° C., it takes a long time to reach a predetermined specific gravity of the oxidized fiber, and this is not preferable because the productivity is lowered.
[0056]
The appropriate fineness of the oxidized fiber is 0.8 to 4.4 dtex.
[0057]
The fineness can be adjusted according to the fineness of the precursor used and relaxation conditions during oxidation.
[0058]
When the fineness of the oxidized fiber is lower than 0.8 dtex, the strength of the single fiber is low, so that yarn breakage is likely to occur at the time of fabric processing and carbonization, and the processability is reduced due to the convergence (decrease in dispersibility) of the fiber, and This is not preferable because it causes defects such as surface cracks.
[0059]
When the fineness of the oxidized fiber is higher than 4.4 dtex, it is not preferable because the oxidation time is long and the productivity is poor, and the fiber strength is reduced during carbonization and surface cracks are likely to occur.
[0060]
The appropriate specific gravity of the oxidized fiber is preferably 1.30 to 1.39.
[0061]
When the specific gravity of the oxidized fiber is lower than 1.30, the heat resistance is poor, and therefore, the carbon fiber strength is deteriorated during carbonization, and problems such as the occurrence of scuffing on the carbon fiber fabric surface are not preferable.
[0062]
When the specific gravity of the oxidized fiber is higher than 1.39, the strength and elongation of the oxidized fiber are lowered, and defects such as erosion are likely to occur on the surface of the carbon fiber fabric are not preferable.
[0063]
An appropriate dry strength of the oxidized fiber is 1.5 g / dtex or more, and an appropriate dry elongation is 8% or more.
[0064]
When the dry strength of the oxidized fiber is lower than 1.5 g / dtex, it is not preferable because problems such as a decrease in spinning processability and easy occurrence of surface scratches occur.
[0065]
When the dry elongation of the oxidized fiber is lower than 8%, it is not preferable because problems such as a decrease in spinning processability and a tendency to cause surface scratches occur.
[0066]
The proper nodule strength of the oxidized fiber is 0.8 g / dtex or more, and the proper nodule elongation is 4% or more.
[0067]
When the knot strength of the oxidized fiber is lower than 0.8 g / dtex, it is not preferable because problems such as a decrease in spinnability, a decrease in strength of the carbon fiber spun woven fabric structure, and surface flaking are likely to occur.
[0068]
When the knot elongation of the oxidized fiber is lower than 4%, it is not preferable because problems such as a decrease in spinning processability, a decrease in strength of the carbon fiber spun yarn fabric structure, and surface flaking are likely to occur.
[0069]
(Spinning processing)
The oxidized fiber is made into a short fiber by bias cutting with a constant length cut or a tow reactor, and the short fiber is spun into oxidized fiber spun yarn.
[0070]
The average cut length of the short fibers is preferably 25 to 65 mm. When the average length is outside this range, problems such as yarn breakage during spinning and the occurrence of surface cracks are undesirable.
[0071]
The crimp rate of the oxidized fiber spun yarn is preferably 8 to 25%.
[0072]
When the crimp ratio of the oxidized fiber spun yarn is lower than 8%, it is not preferable because there is little entanglement between the fibers and yarn breakage is liable to occur during textile processing.
[0073]
When the crimp ratio of the oxidized fiber spun yarn is higher than 25%, the strength of the single fiber constituting the oxidized fiber spun yarn is lowered, and the yarn breakage is liable to occur during textile processing, which is not preferable.
[0074]
The number of crimps of oxidized fiber spun yarn is preferably 2.0 to 5.5 / cm.
[0075]
When the number of crimps of oxidized fiber spun yarn is lower than 2.0 pcs / cm, it is not preferable because there is little entanglement between the fibers and yarn breakage tends to occur during textile processing.
[0076]
When the number of crimps of oxidized fiber spun yarn is higher than 5.5 / cm, it is not preferable because the strength of the single fiber constituting the oxidized fiber spun yarn is lowered and yarn breakage tends to occur during textile processing.
[0077]
As a kind of oil agent used for spinning processing of oxidized fiber, it has an alkyl group or an allyl group. Ho Examples include sulfonates or phosphates, and mixtures thereof (including anionic, cationic, or nonionic dispersants).
[0078]
The amount of the phosphorus oil agent attached to the oxidized fiber is preferably 0.50% by mass or less, and the phosphorus oil agent is preferably attached so that the phosphorus content in the oxidized fiber is 20 to 250 ppm.
[0079]
When the amount of the oil agent is more than 0.50% by mass, the precursor is oxidized, the fiber is stuck, and the fiber surface defect is generated. The oxidized fiber is spun, oxidized fiber fabric processed, and oxidized fiber carbon. This is not preferable because surface cracks frequently occur during conversion.
[0080]
When the phosphorus content in the oxidized fiber is less than 20 ppm, the heat resistance of the oxidized fiber is lowered, and the fiber is cut off during carbonization, which causes the occurrence of surface cracks on the fabric.
[0081]
When the phosphorus content in the oxidized fiber exceeds 250 ppm, the fiber surface is agglomerated (finely bonded between the fiber and the fiber surface) during carbonization, and this is not preferable.
[0082]
As the count of the oxidized fiber spun yarn obtained, 30-50 count yarn The number of twists is preferably 100 to 800 times / m, more preferably 400 to 600 times / m, and 100 to 400 times / m of the upper twist.
[0083]
When the number of twists of the lower twist is less than 400 times / m, or when the number of twists of the upper twist is less than 100 times / m, the spun yarn breakage occurs during weaving because the spun yarn strength is low, and weaving processability This is not preferable because it causes problems such as reduction, surface cracking, and carbon fiber spun yarn fabric strength.
[0084]
When the number of twists of the lower twist exceeds 600 times / m, or when the number of twists of the upper twist exceeds 400 times / m, the workability of the spun yarn fabric is good, but fiber breakage due to fiber shrinkage during carbonization This is not preferable because the surface of the woven fabric is easily generated.
[0085]
The number of single fibers used per oxidized fiber spun yarn is preferably 90 to 900.
[0086]
(Weaving)
This oxidized fiber spun yarn is woven to obtain an oxidized fiber spun yarn fabric.
[0087]
As the weaving form of the oxidized fiber spun yarn fabric, when this fabric is used as an electrode material after carbonization, a plain weaving with little misalignment when the electrode material is cut is preferable.
[0088]
For oxidized fiber spun yarn fabric, thickness is 0.5-2.0mm, bulk density is 0.15-0.45g / cm Three The basis weight is 70 to 250 g / m 2 Is preferred.
[0089]
The number of spun yarns in the oxidized fiber spun yarn fabric is preferably 4 to 24 yarns / cm.
[0090]
(Compression process)
This oxidized fiber spun yarn fabric is subjected to a resin treatment or a compression treatment without resin treatment, and then in a method that does not directly contact the inner wall and guide of the carbonization furnace at a high temperature of 1300 to 2200 ° C. in an inert gas. It can be obtained by carbonization.
In order to improve the generation of surface cracks, it is preferable to compress the oxidized fiber spun yarn fabric to suppress the surface cracks in the inner direction of the surface layer.
[0091]
It is more preferable to perform the resin treatment before the compression treatment because the effect of the compression treatment is more exhibited.
[0092]
In this resin treatment, it is preferable that the oxidized fiber spun yarn fabric is dipped in a resin bath having a predetermined concentration, and the resin is attached in a range of 10.0% by mass or less.
[0093]
When the amount of the resin applied is more than 10.0% by mass, the flexibility of the carbon fiber spun yarn fabric is impaired and the brittleness is increased, which is not preferable.
[0094]
As a kind of resin used for the resin treatment, a water-soluble resin (not using an organic solvent from the environmental aspect) such as polyacrylic acid ester, carboxymethyl cellulose, and polyvinyl alcohol is preferable.
[0095]
The compression process is performed without the resin process or after the resin process, but as described above, the effect of suppressing the blur due to the compression process is more likely to be exhibited after the resin process in advance.
[0096]
The compression treatment temperature is preferably 150 to 400 ° C.
[0097]
When the compression treatment temperature is lower than 150 ° C., it is not preferable because the effect of suppressing the cracking is small.
[0098]
When the compression treatment temperature is higher than 400 ° C., problems such as a decrease in strength of the oxidized fiber spun yarn fabric after the compression treatment and a decrease in strength of the carbon fiber spun yarn fabric structure during carbonization are not preferable.
[0099]
The pressure for the compression treatment is preferably 1 to 50 MPa.
[0100]
When the pressure of the compression treatment is lower than 1 MPa, it is not preferable because the effect of suppressing the cracking is small.
[0101]
When the pressure of the compression treatment is higher than 50 MPa, the strength of the oxidized fiber spun yarn fabric after the compression treatment decreases, the strength of the carbon fiber spun yarn fabric structure during carbonization decreases, This is not preferable because it causes problems such as.
[0102]
The pressure processing device may be either a hot press or a hot roller.
[0103]
(Carbonization)
The compressed oxidized fiber spun yarn fabric is continuously fired and carbonized at a temperature of 1300 to 2200 ° C. in an inert gas atmosphere. Nitrogen, argon, helium or the like is used as the inert gas.
[0104]
When the firing temperature is lower than 1300 ° C., the electric resistance value of the carbon fiber spun yarn fabric structure obtained is not preferable.
[0105]
When the firing temperature is higher than 2200 ° C., the electric resistance value decreases and the measured value is less varied and shows a stable value. However, the strength of the carbon fiber spun yarn fabric structure is decreased, and cracking is likely to occur. This is not preferable because it causes problems.
[0106]
The shrinkage ratio of the spun yarn fabric during carbonization is preferably 0 to 15%.
[0107]
If the tension applied to the spun yarn fabric is small, the oxidized fiber will heat shrink during carbonization. When the shrinkage rate of the spun yarn fabric during carbonization is less than 0% (when the spun yarn fabric is tensioned to suppress shrinkage and pulled and stretched), when excessive tension is applied to restrict shrinkage and stretch too much It corresponds to. In this case, it is not preferable because fiber breakage occurs and causes surface cracks.
[0108]
When the shrinkage ratio of the spun yarn fabric during carbonization exceeds 15%, the fiber strength decreases, and at the time of carbonization, the fabric is wrinkled and bent, and it is meandered inside the carbonization furnace to enter the furnace. This is not preferable because it causes contact with the furnace wall due to sagging and causes defects such as fluffing.
[0109]
The type of the firing furnace may be either a vertical type furnace or a horizontal type furnace, but it is preferable not to rub the surface of the spun yarn fabric inside the firing furnace (coarse wall surface, guide). In the case of a horizontal furnace, it is preferable not to rub the bottom surface of the spun yarn material at the furnace bottom. For example, the carbon material belt conveyor or the flexible, high-weight, and high-strength carbon fiber felt can be run side by side and carbonized to suppress the occurrence of scuffing due to abrasion.
[0110]
【Example】
The present invention is described in detail by the following examples and comparative examples.
[0111]
Oxidized fiber spun yarn fabric, carbon fiber spun yarn fabric, etc. were produced under the conditions of the following examples and comparative examples, and various physical properties of the obtained oxidized fiber spun yarn fabric, carbon fiber spun yarn fabric, etc. It was measured by.
[0112]
Thickness: The thickness at a load (2.8 kPa) of 200 g was measured with a circular pressure plate having a diameter of 30 mm.
[0113]
Specific gravity: Measured by liquid replacement method (JIS R7601, replacement liquid: ethyl alcohol).
[0114]
Fiber performance: Dry strength, dry elongation, knot strength, and knot elongation were measured according to JISL1015.
[0115]
Number of surface markings: Micrographs (50 times magnification) of the upper and lower surfaces of the carbon fiber fabric were taken, and the number of 5 mm square fiber cutting terminals was measured and calculated according to the following formula.
Number of ribs (months / mm 2 )
= [(Number of fiber cutting terminals on upper surface + number of fiber cutting terminals on lower surface) / 2] ÷ 25
X-ray crystal size: It was determined from the half width of the 2θ peak in wide-angle X-ray diffraction measurement and the following Scherrer equation.
X-ray crystal size (nm) = (k × λ) / β × cos θ
k: device constant 0.90
λ: X-ray wavelength 0.154 nm
β: full width at half maximum of 2θ = 26.0 °
Conductivity (specific resistance value): sandwiching both sides of a carbon fiber spun yarn fabric structure at a pressure of 1 MPa between two 50 mm square (10 mm thick) gold-plated electrodes and measuring the electrical resistance value (R) between the two electrodes The thickness was calculated from the thickness (T) and the contact area (S) by the following formula.
Conductivity (specific resistance value: Ωcm) = (R × S) / T
Examples 1-3
This fiber was made to adhere 0.01% by weight of butyl phosphate and 0.01% by weight of ethylene glycol to acrylic fiber having a fineness of 1.6 dtex obtained by copolymerizing 93% by weight of acrylonitrile, 4% by weight of methyl acrylate, and 2% by weight of itaconic acid. Was oxidized in air at an initial oxidation temperature of 225 ° C. for 1 hrs and further at 260 ° C. for 1.5 hrs.
[0116]
Obtained fineness 2.3 dtex, specific gravity 1.37, crimp number 3.8 pcs / cm, crimp rate 13%, dry strength 2.9 g / dtex, dry elongation 25%, nodule strength 0.7 g / dtex, nodule The oxidized fiber staple having an elongation of 5% and an average cut length of 51 mm was further subjected to an addition treatment with 0.25% by mass of butyl phosphate (phosphorus content was 53 ppm).
[0117]
The obtained oxidized fiber was spun to obtain a 40th yarn having an upper twist of 250 times / m and a lower twist of 550 times / m.
[0118]
A plain weave having a weaving density of 17 yarns / cm in both length and weft was produced.
[0119]
The basis weight of the obtained oxidized fiber spun yarn fabric is 209 g / m. 2 The thickness was 0.54 mm.
[0120]
Further, after this oxidized fiber spun yarn fabric was resin-treated as shown in Table 1, the oxidized fiber fabric or the non-resin-treated oxidized fiber fabric was compression-treated in a horizontal furnace at 1850 ° C. in a nitrogen stream. 500g / m 2 The carbon fiber spun woven fabric with less surface fluff could be obtained by placing it on the carbon fiber felt and carbonizing it continuously.
[0121]
[Table 1]
Comparative Example 1
0.65% by mass of butyl phosphate is attached to acrylic fiber having a fineness of 1.6 dtex obtained by copolymerizing 93% by mass of acrylonitrile, 4% by mass of methyl acrylate, and 2% by mass of itaconic acid. Oxidation treatment was carried out at 1 hrs and at 260 ° C. for 1.5 hrs.
[0123]
Obtained fineness 2.3 dtex, specific gravity 1.38, crimp number 4.1 pcs / cm, crimp rate 12%, dry strength 2.1 g / dtex, dry elongation 21%, nodule strength 0.3 g / dtex, nodule Oxidized fiber staples having an elongation of 2% and an average cut length of 51 mm (phosphorus content: 155 ppm) were spun to obtain a 40th yarn having an upper twist of 250 times / m and a lower twist of 550 times / m.
[0124]
Using this spun yarn, a plain weave having a weaving density of 17 pieces / cm in both length and weft was produced.
[0125]
The basis weight of the resulting oxidized fiber spun yarn fabric is 211 g / m. 2 The thickness was 0.53 mm.
[0126]
Furthermore, in a horizontal furnace, in a nitrogen stream at 1850 ° C., the basis weight is 500 g / m. 2 It was placed on the carbon fiber felt and carbonized by continuously running in parallel. However, the obtained carbon fiber spun yarn fabric had a lot of surface scratches as shown in Table 2.
[0127]
Comparative Example 2
This fiber was made to adhere 0.01% by weight of butyl phosphate and 0.01% by weight of ethylene glycol to acrylic fiber having a fineness of 1.6 dtex obtained by copolymerizing 93% by weight of acrylonitrile, 4% by weight of methyl acrylate, and 2% by weight of itaconic acid. Was oxidized in air at an initial oxidation temperature of 225 ° C. for 1 hrs and further at 270 ° C. for 5.0 hrs.
[0128]
Obtained fineness 2.3 dtex, specific gravity 1.43, crimp number 3.3 pcs / cm, crimp rate 11%, dry strength 1.9 g / dtex, dry elongation 18%, nodule strength 0.2 g / dtex, nodule Oxidized fiber staples having an elongation of 1% and an average cut length of 51 mm (phosphorus content: 11 ppm) were spun to obtain 40-count twin yarns with an upper twist of 270 times / m and a lower twist of 580 times / m.
[0129]
Using this spun yarn, a plain weave having a weaving density of 17 pieces / cm in both length and weft was produced.
[0130]
The basis weight of the resulting oxidized fiber spun yarn fabric is 223 g / m. 2 The thickness was 0.52 mm.
[0131]
Furthermore, this oxidized fiber spun yarn fabric was weighed in a horizontal furnace at 1850 ° C. in a nitrogen stream at 500 g / m. 2 It was placed on the carbon fiber felt and carbonized by continuously running in parallel. However, the obtained carbon fiber spun yarn fabric had a lot of surface scratches as shown in Table 2.
[0132]
Comparative Example 3
This fiber was made to adhere 0.01% by mass of butyl phosphate and 0.01% by mass of ethylene glycol to acrylic fiber having a fineness of 1.6 dtex obtained by copolymerizing 93% by mass of acrylonitrile, 4% by mass of methyl acrylate, and 2% by mass of itaconic acid. Was oxidized in air at an initial oxidation temperature of 225 ° C. for 1 hrs and further at 250 ° C. for 0.3 hrs.
[0133]
Obtained fineness 2.2 dtex, specific gravity 1.27, crimp number 4.1 pcs / cm, crimp rate 13%, dry strength 2.2 g / dtex, dry elongation 24%, nodule strength 0.8 g / dtex, nodule The oxidized fiber staple having an elongation of 6% and an average cut length of 51 mm was further subjected to an adhesion treatment with 0.25% by mass of butyl phosphate (phosphorus content was 55 ppm).
[0134]
The obtained oxidized fiber was spun to obtain 40-twisted double yarn having an upper twist of 240 times / m and a lower twist of 600 times / m.
[0135]
Using this spun yarn, a plain weave having a weaving density of 17 pieces / cm in both length and weft was produced.
[0136]
The basis weight of the obtained oxidized fiber spun yarn fabric is 210 g / m. 2 The thickness was 0.52 mm.
[0137]
Further, this oxidized fiber spun yarn fabric was subjected to a compression treatment on the oxidized fiber fabric after resin treatment as shown in Table 2, and in a horizontal furnace at 1850 ° C. in a nitrogen stream, the basis weight was 500 g / m. 2 It was placed on the carbon fiber felt and carbonized by continuously running in parallel. However, the obtained carbon fiber spun yarn fabric had a lot of surface scratches as shown in Table 2.
[0138]
Comparative Example 4
This fiber was made to adhere 0.01% by mass of butyl phosphate and 0.01% by mass of ethylene glycol to acrylic fiber having a fineness of 1.6 dtex obtained by copolymerizing 93% by mass of acrylonitrile, 4% by mass of methyl acrylate, and 2% by mass of itaconic acid. Was oxidized in air at an initial oxidation temperature of 225 ° C. for 1 hrs and further at 260 ° C. for 1.5 hrs.
[0139]
Obtained fineness 2.3 dtex, specific gravity 1.37, crimp number 3.8 pcs / cm, crimp rate 13%, dry strength 2.9 g / dtex, dry elongation 25%, nodule strength 0.7 g / dtex, nodule The oxidized fiber staple having an elongation of 5% and an average cut length of 51 mm was further subjected to an adhesion treatment with 0.75% by mass of butyl phosphate (phosphorus content was 153 ppm).
[0140]
The obtained oxidized fiber was spun to obtain a 40th yarn having an upper twist of 250 times / m and a lower twist of 550 times / m.
[0141]
A plain weave having a weaving density of 17 yarns / cm in both length and weft was produced.
[0142]
The basis weight of the obtained oxidized fiber spun yarn fabric is 209 g / m. 2 The thickness was 0.53 mm.
[0143]
Further, this oxidized fiber spun yarn fabric was subjected to a compression treatment on the oxidized fiber fabric treated with resin as shown in Table 2, and the basis weight was 500 g / m in a horizontal furnace at 1850 ° C. in a nitrogen stream. 2 The carbon fiber felt was placed on a carbon fiber felt and carbonized by continuously running in parallel. However, the obtained carbon fiber spun yarn fabric had a lot of surface scratches as shown in Table 2.
[0144]
Comparative Example 5
This fiber was made to adhere 0.01% by mass of butyl phosphate and 0.01% by mass of ethylene glycol to acrylic fiber having a fineness of 1.6 dtex obtained by copolymerizing 93% by mass of acrylonitrile, 4% by mass of methyl acrylate, and 2% by mass of itaconic acid. Was oxidized in air at an initial oxidation temperature of 225 ° C. for 1 hrs and further at 260 ° C. for 1.5 hrs.
[0145]
Obtained fineness 2.3 dtex, specific gravity 1.37, crimp number 3.8 pcs / cm, crimp rate 13%, dry strength 2.9 g / dtex, dry elongation 25%, nodule strength 0.7 g / dtex, nodule The oxidized fiber staple having an elongation of 5% and an average cut length of 51 mm was further subjected to an addition treatment with 0.25% by mass of butyl phosphate (phosphorus content was 53 ppm).
[0146]
The obtained oxidized fiber was spun to obtain a 40th yarn having an upper twist of 250 times / m and a lower twist of 550 times / m.
[0147]
Using this spun yarn, a plain weave having a weaving density of 17 pieces / cm in both length and weft was produced.
[0148]
The basis weight of the obtained oxidized fiber spun yarn fabric is 209 g / m. 2 The thickness was 0.54 mm.
[0149]
Further, the oxidized fiber woven fabric treated with carboxymethyl cellulose (CMC) as shown in Table 2 was subjected to compression treatment in a horizontal furnace at 2550 ° C. in a nitrogen stream, and the basis weight was 500 g / m. 2 The carbon fiber felt was placed on a carbon fiber felt and carbonized by continuously running in parallel. However, the obtained carbon fiber spun yarn fabric had a lot of surface scratches as shown in Table 2.
[0150]
[Table 2]
【The invention's effect】
The carbon fiber spun yarn fabric structure for polymer electrolyte fuel cell electrode material of the present invention has a predetermined range of thickness, basis weight, specific resistance value, and number of surface defects, so that the polymer electrolyte membrane is not damaged. Thus, a polymer electrolyte fuel cell electrode material that does not deteriorate battery performance can be obtained.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a cross section of a laminate of a carbon fiber spun yarn fabric structure and a polymer electrolyte membrane in a polymer electrolyte fuel cell using a carbon fiber spun yarn fabric structure as an electrode material.
[Explanation of symbols]
2 Carbon fiber spun yarn fabric structure
4 Polymer electrolyte membrane
6 Surface markings
Claims (4)
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| JP2001358917A JP4002426B2 (en) | 2001-07-27 | 2001-11-26 | Carbon fiber spun woven fabric structure for polymer electrolyte fuel cell electrode material and method for producing the same |
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| JP2001-227057 | 2001-07-27 | ||
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| JP2001358917A JP4002426B2 (en) | 2001-07-27 | 2001-11-26 | Carbon fiber spun woven fabric structure for polymer electrolyte fuel cell electrode material and method for producing the same |
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| JP4446721B2 (en) | 2003-12-01 | 2010-04-07 | 株式会社クレハ | Carbon fiber spun yarn and its woven fabric |
| CN1934303B (en) | 2004-03-22 | 2012-10-03 | 株式会社吴羽 | Spun isotropic pitch-based carbon fiber yarn, composite yarn and woven fabric made by using the same, and processes for the production of them |
| DE102004034139A1 (en) * | 2004-07-15 | 2006-02-02 | Pemeas Gmbh | Process for the preparation of membrane-electrode assemblies |
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