JP4017772B2 - Continuous heat treatment method for acrylic fiber bundles - Google Patents
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Description
【０００１】
【発明の属する技術分野】
本発明は、品質の高い耐炎化繊維を効率よく生産することのできるアクリル系繊維束の連続熱処理方法に関する。
【０００２】
【従来の技術】
炭素繊維は他の繊維に比較して優れた比強度、及び比弾性率を具備し、又金属に比較して優れた比抵抗、及び高い耐薬品性を有しており、これらの優れた各種の特性によって樹脂との複合材料の補強用繊維として使用されており、工業用途、スポーツ用途、航空宇宙分野用途等に幅広く利用されている。
【０００３】
炭素繊維は、一般的にはポリアクリロニトリル、レーヨン、ピッチ類等の有機繊維を酸化性雰囲気中にて２００℃以上で熱処理する耐炎化工程によって耐炎化繊維にした後、続いてこの耐炎化繊維を不活性雰囲気中にて３００℃以上で熱処理する炭素化工程を実施することによって得られるが、炭素繊維を得るための工程中の処理時間の最も長い耐炎化工程において酸化反応による激しい発熱を伴うために、該耐炎化工程は通常除熱サイドでの運転条件で行なわれる。
【０００４】
炭素繊維の生産性の向上のためには、その製造工程中の処理時間の最も長い耐炎化工程の生産性の向上が必要であり、例えば耐炎化工程での反応時間の短縮により耐炎化工程の生産性を向上させる手段として、２０ｖｏｌ．％以上の酸素を含有する酸化性雰囲気中にて耐炎化工程を実施する法が、特開平２−１５４０１３号公報に説明されている。
【０００５】
しかしながら、上記の特開平２−１５４０１３号公報には、品質のよい炭素繊維の生産性を向上させるために、耐炎化繊維にする耐炎化工程での生産性の向上を達成すると共に、単繊維処理斑の小さい処理繊維束からなる耐炎化繊維を炭素化工程に供給することができるようするのに必要な耐炎化工程でのパラメータ、つまり耐炎化炉内の被熱処理繊維束の密度、耐炎化炉内の風速、耐炎化工程での被熱処理繊維束の工程張力等の適正化を図ることについては言及されていない。
【０００６】
又、耐炎化工程の生産性の向上を図る方法としては、耐炎化炉内への被熱処理繊維束の投入量を増大させ、耐炎化炉を高容積密度にして被熱処理繊維束を熱処理する、つまり耐炎化炉の底面に対して平行する面で隣接する繊維束同士の間の距離を小さくして耐炎化工程を実施するか、或いは太い被熱処理繊維束を供給して耐炎化工程を実施する等の方法が考えられる。
【０００７】
しかるに、隣接する繊維束同士の間の距離を小さくすると、耐炎化炉内での酸化反応に伴う発熱量の増大によって炉内の温度制御が困難になるだけでなく、除熱不良により、有害ガスの発生につながるスモークも生じ易くなる。又、隣接する繊維束同士が発熱の影響を相互に受けることになるために、熱処理温度を上げることができなく、結果として生産性の向上を図ることができない。更に、耐炎化炉の底面に対して平行する面で隣接する繊維束同士の接触により単糸切れが発生し、これが炭素繊維の品質の低下を招くことになる。
【０００８】
又太い被熱処理繊維束を供給して耐炎化工程を実施する場合でも、被熱処理繊維束を単に太くするだけでは、耐炎化炉内での除熱不良がさらに顕著になり、有害ガスの発生につながるスモーク発生の要因となるだけでなく、熱処理温度を低くせざるを得ないために、結果として生産性の向上を図ることができない。
【０００９】
仮に、被熱処理繊維束を太くし、しかも熱処理時間の短縮を試みると、スモーク発生温度付近での運転を余儀なくされるために、非常に厳しい温度管理が要求されるだけでなく、単繊維処理斑の大きな耐炎化繊維になるために、これが炭素繊維の品質低下を招くことになる。
【００１０】
【発明が解決しようとする課題】
従って本発明が解決しようとする課題は、品質の高い炭素繊維を高生産し得ることにつながるアクリル系繊維束の連続熱処理方法、つまり品質の良い耐炎化繊維を効率よく生産することのできるアクリル系繊維束の連続熱処理方法を提供することにある。
【００１１】
品質のよい炭素繊維の生産性を向上させるためには、耐炎化繊維にする耐炎化工程での生産性の向上を達成すると共に、単繊維処理斑の小さい処理繊維束からなる耐炎化繊維を炭素化工程に供給することであり、本発明が解決しようとする課題はそのために必要な耐炎化工程でのパラメータである耐炎化炉内の被熱処理繊維束の密度、耐炎化炉内の風速、耐炎化工程での被熱処理繊維束の工程張力等の適正化を図ったアクリル系繊維束の連続熱処理方法を提供することである。
【００１２】
【課題を解決するための手段】
上記の課題は、以下に記載する構成による本発明のアクリル系繊維束の連続熱処理方法によって解決される。
すなわち本第１の発明は、アクリル系繊維束の多数本を引き揃えた繊維束シート状物を、熱風循環型対流加熱炉からなる耐炎化炉内に走行させながら熱処理することによって耐炎化繊維にするアクリル系繊維束の連続熱処理方法において、耐炎化炉の底面に対する耐炎化炉内に導入する繊維束シート状物の面占有率を３６〜６５％にすると共に、耐炎化炉内の風向きを繊維束シート状物に対して垂直にし、かつその風速を０．３〜１．５ｍ／ｓｅｃにし、しかも耐炎化炉内を走行するアクリル系繊維束の工程張力を０．５〜２．５ｇ／ｔｅｘにするアクリル系繊維束の連続熱処理方法からなる。
【００１３】
上記の構成を備えてなる本第１の発明のアクリル系繊維束の連続熱処理方法においては、被熱処理繊維束の走行路の規制を溝ローラーによって行なうことが好ましい。
【００１４】
又本第２の発明は、アクリル系繊維束の多数本を引き揃えた繊維束シート状物を、熱風循環型対流加熱炉からなる耐炎化炉内に走行させながら熱処理することによって耐炎化繊維にするアクリル系繊維束の連続熱処理方法において、耐炎化炉の底面に対する耐炎化炉内に導入する繊維束シート状物の面占有率を３６〜６５％にすると共に、耐炎化炉内の風向きを繊維束シート状物に対して平行にし、かつその風速を１．５〜５ｍ／ｓｅｃにし、しかも耐炎化炉内を走行するアクリル系繊維束の工程張力を０．５〜２．５ｇ／ｔｅｘにするアクリル系繊維束の連続熱処理方法からなる。
【００１５】
上記の構成を備えてなる本第２の発明のアクリル系繊維束の連続熱処理方法においては、被熱処理繊維束の走行路の規制を溝ローラーによって行なうことが好ましい。
【００１６】
上記の構成による本各発明のアクリル系繊維束の連続熱処理方法において、耐炎化炉の底面に対する耐炎化炉内に導入する繊維束シート状物の面占有率は、使用する耐炎化炉の有効炉長と有効炉幅との積（＝耐炎化炉の底面の有効面積）に対する耐炎化炉内に導入する繊維束シート状物の平面積の比率である。
【００１７】
耐炎化炉内に導入する繊維束シート状物の平面積は、耐炎化炉内に繊維束シート状物を導入するときのローラー上で測定した単一の繊維束の巾×耐炎化炉の有効炉長×アクリル系繊維束の本数であり、耐炎化炉の底面に対する耐炎化炉内に導入する繊維束シート状物の面占有率（％）＝（単一のアクリル系繊維束の巾×アクリル系繊維束の本数×１００／耐炎化炉の有効炉幅）である。
又、耐炎化炉内の風速は、常温時における測定値である。
【００１８】
【発明の実施の形態】
本発明のアクリル系繊維束の連続熱処理方法において被熱処理繊維束として使用するアクリル系繊維束は、アクリロニトリル１００％のアクリル繊維、又はアクリロニトリルを９０モル％以上含有するアクリル共重合繊維が好適である。アクリル共重合繊維における共重合成分としては、アクリル酸、メタクリル酸、イタコン酸、及びこれらのアルカリ金属塩、アンモニウム金属塩、アクリルアミド、アクリル酸メチル等が好ましいが、被熱処理繊維束としてのアクリル系繊維束の化学的性状、物理的性状、寸法等は特に制限されるものではない。
【００１９】
アクリル系繊維束の耐炎化処理を行なう熱風循環型対流加熱炉内を、２００℃〜３６０℃の酸化性雰囲気に維持し、この熱風循環型対流加熱炉内にアクリル系繊維束の多数本を引き揃えた繊維束シート状物を導入し、該シート状物を複数本のローラーを介して複数段に亙って並行状態で走行させながら熱処理することによって耐炎化繊維にする。
【００２０】
単一のチャンバーに対する繊維束シート状物の段数は、被熱処理繊維束であるアクリル系繊維束の性状、該アクリル系繊維束に付与すべき熱履歴、加熱炉内の風向き、風量（風速）、熱風温度等によって異なる。なお、整流効果及び安全性確保の面から、各段毎に仕切を入れることもできる。
【００２１】
被熱処理繊維束の耐炎化反応を制御するうえでの最も重要なパラメータは、発熱反応により生じる繊維束内の蓄熱の除去であり、過剰蓄熱が生じた場合にはスモークの発生、繊維束切れ、単糸間同士の間の融着などの問題を生じる。
【００２２】
つまり、繊維束シート状物を形成している多数本の繊維束の全てに均一な風速と温度を与えることによって前述の問題を回避することができ、工程安定性を向上させることができる。このためには、耐炎化炉内への被熱処理繊維束の投入量を少なくして、発熱反応により生じる繊維束内の蓄熱を無くすると共に、被熱処理繊維束のバタツキによる相互干渉を無くせばよいが、これには工程生産性の犠牲が伴う。
【００２３】
しかるに、アクリル系繊維束の多数本を引き揃えた繊維束シート状物を熱風循環型対流加熱炉からなる耐炎化炉内に走行させながら連続熱処理する耐炎化工程を、耐炎化炉の底面に対する耐炎化炉内に導入する繊維束シート状物の面占有率を３６〜６５％にすると共に、耐炎化炉内の風向きを繊維束シート状物に対して垂直にし、かつその風速を０．３〜１．５ｍ／ｓｅｃにし、しかも耐炎化炉内を走行するアクリル系繊維束の工程張力を０．５〜２．５ｇ／ｔｅｘにして行なうことにより、品質の良い耐炎化繊維を高い工程生産性の維持の下に得ることができる。
【００２４】
又、耐炎化炉の底面に対する耐炎化炉内に導入する繊維束シート状物の面占有率を３６〜６５％にすると共に、耐炎化炉内の風向きを繊維束シート状物に対して平行にし、かつその風速を１．５〜５ｍ／ｓｅｃにし、しかも耐炎化炉内を走行するアクリル系繊維束の工程張力を０．５〜２．５ｇ／ｔｅｘにして行なうことにより、品質の良い耐炎化繊維を高い工程生産性の維持の下に得ることができる。
【００２５】
なお、耐炎化炉内を走行する繊維束シート状物の面占有率を３６％未満にすると、工程安定性はより向上する。しかしながら、耐炎化炉内へのアクリル系繊維束からなる被熱処理繊維束の投入量の減少、及びユーティリティーコストの増大によって工程生産性が著しくダウンし、これによって耐炎化繊維の製造コストが増大し、ひいては炭素繊維の製造コストの増大に繋がる。
【００２６】
又、耐炎化炉内を走行する繊維束シート状物の面占有率を６５％よりも高くすると、工程安定性が急激に低下し、過剰蓄熱によるスモークの発生、糸切れ、及び単糸同士の間の融着が発生するために、品質の良い耐炎化繊維を得ることが難しくなり、これによって品質のよい炭素繊維が得られなくなり、又歩留まりの低下により工程生産性がダウンする。
【００２７】
更に本発明のアクリル系繊維束の連続熱処理方法においては、耐炎化炉として熱風循環型対流加熱炉を使用しており、対流加熱方式によって被熱処理繊維束を加熱しているので、熱風によって被熱処理繊維束であるアクリル系繊維束を加熱して酸化反応及び環化反応を促進させると同時に、被熱処理繊維束の蓄熱の除熱を有効に行なえる。
【００２８】
本発明のアクリル系繊維束の連続熱処理方法においては、熱風循環型対流加熱炉からなる耐炎化炉内の風速を、風向きを繊維束シート状物に対して垂直にする場合には、０．３ｍ／ｓｅｃ〜１．５ｍ／ｓｅｃの範囲内にし、又風向きを繊維束シート状物に対して平行にする場合には、１．５ｍ／ｓｅｃ〜５ｍ／ｓｅｃの範囲内にすることが必要である。
【００２９】
つまり風向きを被熱処理繊維束であるアクリル系繊維束の多数本を引き揃えた繊維束シート状物に対して垂直にする場合に、その風速を０．３ｍ／ｓｅｃ未満にしたり、或いは風向きを被熱処理繊維束であるアクリル系繊維束の多数本を引き揃えた繊維束シート状物に対して平行にする場合に、その風速を１．５ｍ／ｓｅｃ未満にしたりすると、耐炎化炉内の風による被熱処理繊維束の蓄熱の除熱作用が得られなくなり、除熱不良によるスモークを生じ易くなる。
【００３０】
又風向きを被熱処理繊維束であるアクリル系繊維束の多数本を引き揃えた繊維束シート状物に対して垂直にする場合に、その風速が１．５ｍ／ｓｅｃを超えたり、或いは風向きを被熱処理繊維束であるアクリル系繊維束の多数本を引き揃えた繊維束シート状物に対して平行にする場合に、その風速が５ｍ／ｓｅｃを超えたりすると、耐炎化炉内の風による繊維束のバタツキが大きくなり、耐炎化炉の底面に対して平行する面で隣接する繊維束同士の接触による単糸切れを生じ、毛羽の多い耐炎化繊維が得られ易くなる。
【００３１】
更に、熱風循環型対流加熱炉からなる耐炎化炉内を走行するアクリル系繊維束の工程張力を０．５ｇ／ｔｅｘ未満にすると、被熱処理繊維束のバタツキによる単糸切れや、耐炎化炉の底面に対して平行する面で隣接する繊維束同士の接触に伴なう単糸同士の間の融着が生じやすくなり、更にローラーで規制した繊維束形状が保持できなくなることがある。又、２．５ｇ／ｔｅｘよりも高くすると、工程張力切れを起こしやすくなるだけでなく、耐炎化炉の出入り口での物理的接触に対する被熱処理繊維束の耐久性が弱くなる。
【００３２】
アクリル系繊維束からなる被熱処理繊維束を連続熱処理して耐炎化繊維にする本発明方法において、被熱処理繊維束の走行路の規制やトウ幅の規制を行なうための手段としては、例えばガイドを使用することができ、何らの制限を受けるものではないが、溝ローラーを使用するのが最も好ましい。この溝ローラーの溝の断面形状は、図１に示すような平底型、図２に示すような丸底型、図３に示すような波底型のいずれでもよく、その溝形状や溝ピッチは被熱処理繊維束の総繊度、及びローラーの製作上の問題点を考慮した上で適宜決定される。
【００３３】
【実施例】
以下、本発明のアクリル系繊維束の連続熱処理方法の具体的な構成を実施例に基づいて説明する。
なお、各実施例及び比較例において使用した被熱処理繊維束及び耐炎化炉は、下記の通りのものである。
被熱処理繊維束：アクリロニトリル９６モル％を含有するアクリル共重合体繊維による単糸テックス０．１３のアクリル系繊維束
耐炎化炉：熱風循環型対流加熱炉
【００３４】
実施例１
図４及び図５において、有効炉長Ｌ1 ：１０ｍ、有効炉幅Ｌ2 ：１ｍ、炉内の風向き：繊維束シート状物に対して垂直、炉内温度：２３０℃、炉内の風速：０．６ｍ／ｓｅｃの耐炎化炉１内に、フィラメント数３６，０００の被熱処理繊維束Ｓの１２０本によって形成される繊維束シート状物２を、３往復半に亙って走行させる連続熱処理を行なうことにより耐炎化繊維３を得た。このときの耐炎化炉の底面に対する耐炎化炉内に導入する繊維束シート状物の面占有率は４３％である。
【００３５】
なお、上記のアクリル系繊維束の連続熱処理においては、耐炎化炉１内に導入する１本当たりの被熱処理繊維束Ｓの幅を、溝ローラー４によって３．６ｍｍに規制し、繊維束Ｓ，Ｓ同士のピッチ、すなわち耐炎化炉１内に耐炎化炉の底面に対して平行する面で並列させて導入する被熱処理繊維束Ｓの中心から隣接する被熱処理繊維束Ｓの中心迄の距離を８．０ｍｍに規制した。又耐炎化炉内を走行するアクリル系繊維束の工程張力を１．４ｇ／ｔｅｘ（１本当たり６ｋｇ）にした。
【００３６】
上記のアクリル系繊維束の連続熱処理工程中には、暴走反応によるスモークの発生がなく安定した連続運転ができた。又、耐炎化炉内で隣接する繊維束同士の接触による単糸切れ、単糸間の融着、繊維表面の汚染等がなく、繊維束シート状物の幅方向の処理斑や単糸処理斑の少ない耐炎化繊維が得られた。この連続熱処理によるアクリル系繊維の耐炎化密度上昇度は０．０６ｇ／ｃｍ3 ／１７ｍｉｎ．であった。
【００３７】
実施例２
有効炉長：１４ｍ、有効炉幅：１ｍ、炉内の風向き：繊維束シート状物に対して垂直、炉内温度：２４０℃、炉内の風速：１．０ｍ／ｓｅｃの耐炎化炉内に、フィラメント数１２，０００の被熱処理繊維束の２００本からなる繊維束シート状物を通してアクリル系繊維束の連続熱処理を行なうことにより、耐炎化繊維を得た。このときの耐炎化炉の底面に対する耐炎化炉内に導入する繊維束シート状物の面占有率は４０％である。
【００３８】
なお、上記のアクリル系繊維束の連続熱処理においては、溝ローラーによって１本当たりの被熱処理繊維束の幅を２．０ｍｍ、繊維束同士のピッチを５．０ｍｍに規制し、又耐炎化炉内を走行するアクリル系繊維束の工程張力を０．８ｇ／ｔｅｘ（１本当たり１．２ｋｇ）にした。
【００３９】
上記のアクリル系繊維束の連続熱処理工程中には、暴走反応によるスモークの発生がなく安定した連続運転ができた。又、隣接する繊維束同士の接触による単糸切れ、単糸間の融着、繊維表面の汚染等がなく、繊維束シート状物の幅方向の処理斑や単糸処理斑の少ない耐炎化繊維が得られた。この連続熱処理によるアクリル系繊維の耐炎化密度上昇度は０．０６ｇ／ｃｍ3 ／１５ｍｉｎ．であった。
【００４０】
実施例３
有効炉長：１０ｍ、有効炉幅：１ｍ、炉内の風向き：繊維束シート状物に対して垂直、炉内温度：２２０℃、炉内の風速：０．５ｍ／ｓｅｃの耐炎化炉内に、フィラメント数７２，０００の被熱処理繊維束の６０本からなる繊維束シート状物を通してアクリル系繊維束の連続熱処理を行なうことにより、耐炎化繊維を得た。このときの耐炎化炉の底面に対する耐炎化炉内に導入する繊維束シート状物の面占有率は４８％である。
【００４１】
なお、上記のアクリル系繊維束の連続熱処理においては、溝ローラーによって１本当たりの被熱処理繊維束の幅を８．０ｍｍ、繊維束同士のピッチを１６．０ｍｍに規制し、又耐炎化炉内を走行するアクリル系繊維束の工程張力を１．４ｇ／ｔｅｘ（１本当たり１２ｋｇ）にした。
【００４２】
上記のアクリル系繊維束の連続熱処理工程中には、暴走反応によるスモークの発生がなく安定した連続運転ができた。又、隣接する繊維束同士の接触による単糸切れ、単糸間の融着、繊維表面の汚染等がなく、繊維束シート状物の幅方向の処理斑や単糸処理斑の少ない耐炎化繊維が得られた。この連続熱処理によるアクリル系繊維の耐炎化密度上昇度は０．０６ｇ／ｃｍ3 ／２４ｍｉｎ．であった。
【００４３】
実施例４
有効炉長：１４ｍ、有効炉幅：１．５ｍ、炉内の風向き：繊維束シート状物に対して平行、炉内温度：２２０℃、炉内の風速：２．８ｍ／ｓｅｃの耐炎化炉内に、フィラメント数７２，０００の被熱処理繊維束の９０本からなる繊維束シート状物を通して、アクリル系繊維束の連続熱処理を行なうことにより耐炎化繊維を得た。このときの耐炎化炉の底面に対する耐炎化炉内に導入する繊維束シート状物の面占有率は４８％である。
【００４４】
なお、上記のアクリル系繊維束の連続熱処理においては、溝ローラーによって１本当たりの被熱処理繊維束の幅を８．０ｍｍ、繊維束同士のピッチを１６．０ｍｍに規制し、又耐炎化炉内を走行するアクリル系繊維束の工程張力を１．０ｇ／ｔｅｘ（１本当たり９ｋｇ）にした。
【００４５】
上記のアクリル系繊維束の連続熱処理工程中には、暴走反応によるスモークの発生がなく安定した連続運転ができた。又、隣接する繊維束同士の接触による単糸切れ、単糸間の融着、繊維表面の汚染等のない耐炎化繊維が得られた。なお、若干の単糸処理斑が確認されたが、繊維束シート状物の幅方向の処理斑は小さく、十分に満足し得る耐炎化繊維になった。この連続熱処理によるアクリル系繊維の耐炎化密度上昇度は０．０６ｇ／ｃｍ3 ／２０ｍｉｎ．であった。
【００４６】
実施例５
有効炉長：１４ｍ、有効炉幅：１．５ｍ、炉内の風向き：繊維束シート状物に対して平行、炉内温度：２１５℃、炉内の風速：２．８ｍ／ｓｅｃの耐炎化炉内に、フィラメント数７２，０００の被熱処理繊維束の９０本からなる繊維束シート状物を通してアクリル系繊維束の連続熱処理を行なうことにより、耐炎化繊維を得た。このときの耐炎化炉の底面に対する耐炎化炉内に導入する繊維束シート状物の面占有率は５６％である。
【００４７】
なお、上記のアクリル系繊維束の連続熱処理においては、平ローラーとコームガイドとによって１本当たりの被熱処理繊維束の幅を１０．５ｍｍ、繊維束同士のピッチを１７．０ｍｍに規制し、又耐炎化炉内を走行するアクリル系繊維束の工程張力を１．４ｇ／ｔｅｘ（１本当たり２ｋｇ）にした。
【００４８】
上記のアクリル系繊維束の連続熱処理工程中には、暴走反応によるスモークの発生がなく安定した連続運転ができた。又、隣接する繊維束同士の接触による単糸切れ、単糸間の融着、繊維表面の汚染等のない耐炎化繊維が得られた。なお、若干の単糸処理斑が確認されたが、繊維束シート状物の幅方向の処理斑は小さく、十分に満足し得る耐炎化繊維になった。この連続熱処理によるアクリル系繊維の耐炎化密度上昇度は０．０６ｇ／ｃｍ3 ／２７ｍｉｎ．であった。
【００４９】
比較例１
有効炉長：１０ｍ、有効炉幅：１ｍ、炉内の風向き：繊維束シート状物に対して垂直、炉内温度：２３０℃、炉内の風速：０．６ｍ／ｓｅｃの耐炎化炉内に、フィラメント数３６，０００の被熱処理繊維束の５０本からなる繊維束シート状物を通してアクリル系繊維束の連続熱処理を行なった。このときの耐炎化炉の底面に対する耐炎化炉内に導入する繊維束シート状物の面占有率は３０％である。
【００５０】
なお、上記のアクリル系繊維束の連続熱処理においては、溝ローラーによって１本当たりの被熱処理繊維束の幅を６．０ｍｍ、繊維束同士のピッチを１４．０ｍｍに規制し、又耐炎化炉内を走行するアクリル系繊維束の工程張力を１．４ｇ／ｔｅｘ（１本当たり６ｋｇ）にした。
【００５１】
上記のアクリル系繊維束の連続熱処理工程中には、暴走反応によるスモークの発生がなく安定した連続運転ができた。又、隣接する繊維束同士の接触による単糸切れ、単糸間の融着、繊維表面の汚染等がなく、繊維束シート状物の幅方向の処理斑や単糸処理斑の少ない耐炎化繊維が得られた。この連続熱処理によるアクリル系繊維の耐炎化密度上昇度は０．０６ｇ／ｃｍ3 ／１７ｍｉｎ．であり、耐炎化炉の底面に対する耐炎化炉内に導入する繊維束シート状物の面占有率の低下をアクリル系繊維の耐炎化密度上昇度でカバーすることはできなかった。
【００５２】
比較例２
有効炉長：１０ｍ、有効炉幅：１ｍ、炉内の風向き：繊維束シート状物に対して垂直、炉内温度：２３０℃、炉内の風速：０．６ｍ／ｓｅｃの耐炎化炉内に、フィラメント数３６，０００の被熱処理繊維束の１２０本からなる繊維束シート状物を通してアクリル系繊維束の連続熱処理を行なった。このときの耐炎化炉の底面に対する耐炎化炉内に導入する繊維束シート状物の面占有率は７２％である。
【００５３】
なお、上記のアクリル系繊維束の連続熱処理においては、溝ローラーによって１本当たりの被熱処理繊維束の幅を６．０ｍｍ、繊維束同士のピッチを８．０ｍｍに規制し、又耐炎化炉内を走行するアクリル系繊維束の工程張力を１．４ｇ／ｔｅｘ（１本当たり６ｋｇ）にした。
【００５４】
上記のアクリル系繊維束の連続熱処理工程中には、耐炎化炉の底面に対して平行する面で隣接する繊維束同士の接触による単糸切れが多発し、しかも繊維束内の単糸処理斑の多い耐炎化繊維が得られた。この連続熱処理によるアクリル系繊維の耐炎化密度上昇度は０．０６ｇ／ｃｍ3 ／１７ｍｉｎ．であり、工程安定性が非常に悪かった。
【００５５】
比較例３
有効炉長：１４ｍ、有効炉幅：１ｍ、炉内の風向き：繊維束シート状物に対して垂直、炉内温度：２４０℃、炉内の風速：１．０ｍ／ｓｅｃの耐炎化炉内に、フィラメント数１２，０００の被熱処理繊維束の２００本からなる繊維束シート状物を通してアクリル系繊維束の連続熱処理を行なった。このときの耐炎化炉の底面に対する耐炎化炉内に導入する繊維束シート状物の面占有率は４０％である。
【００５６】
なお、上記のアクリル系繊維束の連続熱処理においては、溝ローラーによって１本当たりの被熱処理繊維束の幅を２．０ｍｍ、繊維束同士のピッチを５．０ｍｍに規制し、又耐炎化炉内を走行するアクリル系繊維束の工程張力を０．３ｇ／ｔｅｘ（１本当たり０．５ｋｇ）にした。
【００５７】
上記のアクリル系繊維束の連続熱処理工程中に、耐炎化炉の底面に対して平行する面で隣接する繊維束同士の接触による束切れ発生した。この連続熱処理によるアクリル系繊維の耐炎化密度上昇度は０．０６ｇ／ｃｍ3 ／１５ｍｉｎ．であり、工程安定性が非常に悪かった。
【００５８】
比較例４
有効炉長：１４ｍ、有効炉幅：１ｍ、炉内の風向き：繊維束シート状物に対して垂直、炉内温度：２４０℃、炉内の風速：２．０ｍ／ｓｅｃの耐炎化炉内に、フィラメント数１２，０００の被熱処理繊維束の２００本からなる繊維束シート状物を通してアクリル系繊維束の連続熱処理を行なった。このときの耐炎化炉の底面に対する耐炎化炉内に導入する繊維束シート状物の面占有率は４０％である。
【００５９】
なお、上記のアクリル系繊維束の連続熱処理においては、溝ローラーによって１本当たりの被熱処理繊維束の幅を２．０ｍｍ、繊維束同士のピッチを５．０ｍｍに規制し、又耐炎化炉内を走行するアクリル系繊維束の工程張力を０．３ｇ／ｔｅｘ（１本当たり０．５ｋｇ）にした。
【００６０】
上記のアクリル系繊維束の連続熱処理工程中には、暴走反応によるスモークの発生はなかったが、耐炎化炉内の風からなる繊維束のバタツキが大きく、耐炎化炉の底面に対して平行する面で隣接する繊維束同士の接触による単糸切れを生じ、毛羽の多い耐炎化繊維が得られた。この連続熱処理によるアクリル系繊維の耐炎化密度上昇度は０．０６ｇ／ｃｍ3 ／１５ｍｉｎ．であった。
【００６１】
比較例５
有効炉長：１４ｍ、有効炉幅：１．５ｍ、炉内の風向き：繊維束シート状物に対して平行、炉内温度：２１５℃、炉内の風速：１．０ｍ／ｓｅｃの耐炎化炉内に、フィラメント数７２，０００の被熱処理繊維束の９０本からなる繊維束シート状物を通してアクリル系繊維束の連続熱処理を行なった。このときの耐炎化炉の底面に対する耐炎化炉内に導入する繊維束シート状物の面占有率は５６％である。
【００６２】
なお、上記のアクリル系繊維束の連続熱処理においては、平ローラーとコームガイドとによって１本当たりの被熱処理繊維束の幅を１０．５ｍｍ、繊維束同士のピッチを１７．０ｍｍに規制し、又耐炎化炉内を走行するアクリル系繊維束の工程張力を１．４ｇ／ｔｅｘ（１本当たり２．０ｋｇ）にした。
【００６３】
上記のアクリル系繊維束の連続熱処理工程中には、除熱不良からなるスモークの発生があった。又、この熱処理によるアクリル系繊維の耐炎化密度上昇度は０．０６ｇ／ｃｍ3 ／２７ｍｉｎ．であった。
【００６４】
以上の実施例及び比較例における耐炎化炉の底面に対する耐炎化炉内に導入する繊維束シート状物の面占有率、工程生産性、及び得られた耐炎化繊維の目視による性状をまとめて表１に示す。
【００６５】
【表１】
【発明の効果】
本発明のアクリル系繊維束の連続熱処理方法によれば、品質の良い耐炎化繊維を効率よく生産することができるので、高品質の炭素繊維を高生産することが可能になり、炭素繊維製造のためのコストの低減を図ることができる。
【図面の簡単な説明】
【図１】平底型溝ロールの溝の概略形状を示す切断端面図である。
【図２】丸底型溝ロールの溝の概略形状を示す切断端面図である。
【図３】波底型溝ロールの溝の概略形状を示す切断端面図である。
【図４】耐炎化炉内を走行する繊維束シート状物の状態を示す耐炎化炉の縦断面略示図である。
【図５】図４の耐炎化炉のＸ−Ｙ線断面略示図である。
【符号の説明】
１・・・・耐炎化炉
２・・・・繊維束シート状物
３・・・・耐炎化繊維
４・・・・溝ローラー
Ｓ・・・・被熱処理繊維束
Ｌ1・・・有効炉長
Ｌ2・・・有効炉幅[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a continuous heat treatment method for an acrylic fiber bundle capable of efficiently producing high-quality flame-resistant fibers.
[0002]
[Prior art]
Carbon fiber has excellent specific strength and specific elastic modulus compared to other fibers, and has excellent specific resistance and high chemical resistance compared to metal. It is used as a reinforcing fiber for composite materials with resin due to its characteristics, and is widely used in industrial applications, sports applications, aerospace applications and the like.
[0003]
Carbon fibers are generally made into flame-resistant fibers by a flame-resistant process in which organic fibers such as polyacrylonitrile, rayon, and pitches are heat-treated at 200 ° C. or higher in an oxidizing atmosphere. It is obtained by carrying out a carbonization process in which heat treatment is performed at 300 ° C. or higher in an inert atmosphere, but it involves intense heat generation due to an oxidation reaction in the flameproofing process having the longest processing time in the process for obtaining carbon fibers. In addition, the flameproofing step is usually performed under operating conditions on the heat removal side.
[0004]
In order to improve the productivity of carbon fiber, it is necessary to improve the productivity of the flameproofing process with the longest processing time in the manufacturing process, for example, by reducing the reaction time in the flameproofing process. As a means for improving productivity, 20 vol. JP-A-2-154013 describes a method for carrying out the flameproofing step in an oxidizing atmosphere containing at least% oxygen.
[0005]
However, in the above-mentioned Japanese Patent Application Laid-Open No. 2-154003, in order to improve the productivity of high-quality carbon fibers, the improvement in productivity in the flameproofing process to make flameproof fibers is achieved, and the single fiber treatment Parameters in the flameproofing process necessary to be able to supply flameproofing fibers consisting of bundles of treated fibers with small spots to the carbonization process, that is, the density of the heat treated fiber bundles in the flameproofing furnace, the flameproofing furnace No mention is made of optimization of the wind speed and the process tension of the heat-treated fiber bundle in the flameproofing process.
[0006]
Further, as a method for improving the productivity of the flameproofing process, the amount of the fiber bundle to be heat-treated into the flameproofing furnace is increased, the heat-treating fiber bundle is heat-treated with the flameproofing furnace having a high volume density, That is, the flameproofing process is performed by reducing the distance between adjacent fiber bundles in a plane parallel to the bottom surface of the flameproofing furnace, or the flameproofing process is performed by supplying a thick heat-treated fiber bundle. Such a method is conceivable.
[0007]
However, if the distance between adjacent fiber bundles is reduced, not only does the temperature control inside the furnace become difficult due to an increase in the amount of heat generated by the oxidation reaction in the flame-proofing furnace, but harmful gases are removed due to poor heat removal. Smoke that leads to the occurrence of this is also likely to occur. Moreover, since adjacent fiber bundles are mutually affected by heat generation, the heat treatment temperature cannot be raised, and as a result, productivity cannot be improved. Furthermore, single yarn breakage occurs due to contact between adjacent fiber bundles in a plane parallel to the bottom surface of the flameproofing furnace, which leads to a deterioration in the quality of the carbon fiber.
[0008]
Even when a flame-resistant process is carried out by supplying a thick heat-treated fiber bundle, simply increasing the thickness of the heat-treated fiber bundle makes the heat removal failure in the flame-resistant furnace more prominent, resulting in the generation of harmful gases. Not only is it a cause of connected smoke generation, but the heat treatment temperature must be lowered, and as a result, productivity cannot be improved.
[0009]
If the bundle of fibers to be heat-treated is thickened and the heat treatment time is shortened, operation near the smoke generation temperature is forced, so not only extremely strict temperature control is required, but also the single fiber treatment spots. This leads to a deterioration in the quality of the carbon fiber.
[0010]
[Problems to be solved by the invention]
Therefore, the problem to be solved by the present invention is a continuous heat treatment method for an acrylic fiber bundle that leads to high production of high-quality carbon fibers, that is, an acrylic system that can efficiently produce high-quality flame-resistant fibers. The object is to provide a continuous heat treatment method for fiber bundles.
[0011]
In order to improve the productivity of high-quality carbon fibers, it is possible to improve the productivity in the flame-proofing process to make flame-resistant fibers, and to convert the flame-resistant fibers made of treated fiber bundles with small single fiber treatment spots into carbon. The problem to be solved by the present invention is the density of the heat-treated fiber bundle in the flameproofing furnace, the wind speed in the flameproofing furnace, and the flame resistance. Another object of the present invention is to provide a continuous heat treatment method for an acrylic fiber bundle in which the process tension of the heat treated fiber bundle in the process is optimized.
[0012]
[Means for Solving the Problems]
Said subject is solved by the continuous heat processing method of the acrylic fiber bundle of this invention by the structure described below.
That is, in the first invention, the fiber bundle sheet-like material in which a large number of acrylic fiber bundles are arranged is heat-treated while being run in a flame-resistant furnace comprising a hot-air circulation type convection heating furnace. In the continuous heat treatment method for an acrylic fiber bundle, the surface occupancy ratio of the fiber bundle sheet to be introduced into the flameproofing furnace with respect to the bottom face of the flameproofing furnace is set to 36 to 65%, and the wind direction in the flameproofing furnace is set to fiber. The process tension of the acrylic fiber bundle that is perpendicular to the bundle sheet and has a wind speed of 0.3 to 1.5 m / sec and travels in the flameproofing furnace is 0.5 to 2.5 g / tex. It consists of a continuous heat treatment method for the acrylic fiber bundle.
[0013]
In the continuous heat treatment method for an acrylic fiber bundle according to the first aspect of the present invention having the above-described configuration, it is preferable that the travel path of the fiber bundle to be heat treated is regulated by a groove roller.
[0014]
In the second aspect of the invention, the fiber bundle sheet-like material in which a large number of acrylic fiber bundles are aligned is heat-treated while being run in a flame-resistant furnace composed of a hot air circulation type convection heating furnace. In the continuous heat treatment method for an acrylic fiber bundle, the surface occupancy ratio of the fiber bundle sheet to be introduced into the flameproofing furnace with respect to the bottom face of the flameproofing furnace is set to 36 to 65%, and the wind direction in the flameproofing furnace is set to fiber. Parallel to the bundle sheet, the wind speed is 1.5 to 5 m / sec, and the process tension of the acrylic fiber bundle running in the flameproofing furnace is 0.5 to 2.5 g / tex. It consists of a continuous heat treatment method for an acrylic fiber bundle.
[0015]
In the continuous heat treatment method for an acrylic fiber bundle according to the second aspect of the present invention having the above-described configuration, it is preferable that the travel path of the fiber bundle to be heat treated is regulated by a groove roller.
[0016]
In the continuous heat treatment method for acrylic fiber bundles of the present invention according to the above-described configurations, the area occupation ratio of the fiber bundle sheet material introduced into the flameproofing furnace with respect to the bottom surface of the flameproofing furnace is the effective furnace of the flameproofing furnace used. This is the ratio of the flat area of the fiber bundle sheet material introduced into the flameproofing furnace to the product of the length and the effective furnace width (= effective area of the bottom of the flameproofing furnace).
[0017]
The flat area of the fiber bundle sheet to be introduced into the flameproofing furnace is the width of a single fiber bundle measured on the roller when the fiber bundle sheetlike material is introduced into the flameproofing furnace x the effective flameproofing furnace. Furnace length x number of acrylic fiber bundles. Area occupancy (%) of fiber bundle sheet to be introduced into flameproofing furnace with respect to bottom of flameproofing furnace = (width of single acrylic fiber bundle x acrylic) Number of fiber bundles × 100 / effective furnace width of the flameproofing furnace).
The wind speed in the flameproofing furnace is a measured value at normal temperature.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
The acrylic fiber bundle used as the heat-treated fiber bundle in the continuous heat treatment method of the acrylic fiber bundle of the present invention is preferably 100% acrylonitrile acrylic fiber or acrylic copolymer fiber containing 90% by mole or more of acrylonitrile. As the copolymer component in the acrylic copolymer fiber, acrylic acid, methacrylic acid, itaconic acid, and their alkali metal salts, ammonium metal salts, acrylamide, methyl acrylate, etc. are preferable. The chemical properties, physical properties, dimensions, etc. of the bundle are not particularly limited.
[0019]
The hot air circulation type convection heating furnace that performs the flame resistance treatment of the acrylic fiber bundle is maintained in an oxidizing atmosphere of 200 ° C. to 360 ° C., and a large number of acrylic fiber bundles are drawn into the hot air circulation type convection heating furnace. The aligned fiber bundle sheet material is introduced, and the sheet material is subjected to heat treatment while running in parallel over a plurality of stages via a plurality of rollers, thereby forming flame-resistant fibers.
[0020]
The number of stages of the fiber bundle sheet for a single chamber is the properties of the acrylic fiber bundle that is the heat-treated fiber bundle, the heat history to be applied to the acrylic fiber bundle, the wind direction in the heating furnace, the air volume (wind speed), Varies depending on hot air temperature. In addition, from the aspect of ensuring the rectification effect and ensuring safety, a partition can be provided for each stage.
[0021]
The most important parameter for controlling the flameproofing reaction of the heat-treated fiber bundle is the removal of the heat storage in the fiber bundle caused by the exothermic reaction. If excessive heat storage occurs, the occurrence of smoke, the fiber bundle being broken, Problems such as fusion between single yarns occur.
[0022]
That is, by giving uniform wind speed and temperature to all of the many fiber bundles forming the fiber bundle sheet-like material, the above-mentioned problems can be avoided and the process stability can be improved. For this purpose, it is only necessary to reduce the amount of fiber bundles to be heat-treated into the flameproofing furnace to eliminate heat accumulation in the fiber bundles caused by the exothermic reaction and to eliminate mutual interference due to fluttering of the fiber bundles to be heat-treated. However, this comes at the expense of process productivity.
[0023]
However, a flameproofing process for continuously heat-treating a fiber bundle sheet-like material in which a large number of acrylic fiber bundles are arranged in a flameproofing furnace consisting of a hot air circulation type convection heating furnace is performed on the bottom of the flameproofing furnace. The surface occupancy ratio of the fiber bundle sheet to be introduced into the forming furnace is set to 36 to 65%, the wind direction in the flameproofing furnace is made perpendicular to the fiber bundle sheet and the wind speed is set to 0.3 to By setting the process tension of the acrylic fiber bundle running at 1.5 m / sec and the inside of the flameproofing furnace to 0.5 to 2.5 g / tex, high-quality flameproof fiber can be produced with high process productivity. Can be obtained under maintenance.
[0024]
In addition, the surface occupancy ratio of the fiber bundle sheet to be introduced into the flameproofing furnace with respect to the bottom surface of the flameproofing furnace is set to 36 to 65%, and the wind direction in the flameproofing furnace is made parallel to the fiber bundle sheet. In addition, by setting the wind speed at 1.5 to 5 m / sec and setting the process tension of the acrylic fiber bundle running in the flameproofing furnace to 0.5 to 2.5 g / tex, high quality flame resistance can be achieved. Fibers can be obtained while maintaining high process productivity.
[0025]
In addition, process stability improves more when the surface occupation rate of the fiber bundle sheet-like thing which drive | works the inside of a flame-proofing furnace shall be less than 36%. However, process productivity is significantly reduced due to a decrease in the input amount of heat-treated fiber bundles consisting of acrylic fiber bundles in the flameproofing furnace and an increase in utility costs, thereby increasing the manufacturing cost of flameproofing fibers, As a result, the production cost of the carbon fiber is increased.
[0026]
Also, if the surface occupancy of the fiber bundle sheet running in the flameproofing furnace is higher than 65%, the process stability is drastically reduced, the occurrence of smoke due to excessive heat storage, yarn breakage, and Since fusion occurs in the meantime, it becomes difficult to obtain a high-quality flame-resistant fiber, which makes it impossible to obtain a high-quality carbon fiber, and also reduces the process productivity due to a decrease in yield.
[0027]
Furthermore, in the continuous heat treatment method of the acrylic fiber bundle of the present invention, a hot air circulation type convection heating furnace is used as a flameproofing furnace, and the heat treated fiber bundle is heated by a convection heating method. The acrylic fiber bundle as the fiber bundle is heated to promote the oxidation reaction and the cyclization reaction, and at the same time, the heat removal of the heat-treated fiber bundle can be effectively performed.
[0028]
In the continuous heat treatment method for acrylic fiber bundles according to the present invention, the wind speed in a flameproofing furnace comprising a hot air circulation type convection heating furnace is 0.3 m when the wind direction is perpendicular to the fiber bundle sheet. / Sec to 1.5 m / sec, and when the wind direction is parallel to the fiber bundle sheet, it is necessary to set the range to 1.5 m / sec to 5 m / sec. .
[0029]
In other words, when the wind direction is perpendicular to the fiber bundle sheet-like material in which a large number of acrylic fiber bundles as heat treated fiber bundles are aligned, the wind speed is set to less than 0.3 m / sec, or the wind direction is covered. If the wind speed is set to less than 1.5 m / sec when parallel to the fiber bundle sheet-like material in which a large number of acrylic fiber bundles that are heat treated fiber bundles are aligned, it is caused by the wind in the flameproofing furnace. The heat removal effect of the heat storage of the heat-treated fiber bundle cannot be obtained, and smoke due to poor heat removal tends to occur.
[0030]
Also, when the wind direction is perpendicular to the fiber bundle sheet material in which a large number of acrylic fiber bundles that are heat-treated fiber bundles are aligned, the wind speed exceeds 1.5 m / sec, or the wind direction is covered. When a large number of acrylic fiber bundles that are heat treated fiber bundles are made parallel to a bundle of fiber bundle sheets, if the wind speed exceeds 5 m / sec, the fiber bundles caused by wind in the flameproofing furnace The fluttering of the fiber increases, and a single yarn breakage occurs due to contact between adjacent fiber bundles on a surface parallel to the bottom surface of the flameproofing furnace, so that flameproof fiber with a lot of fluff is easily obtained.
[0031]
Furthermore, if the process tension of the acrylic fiber bundle running in the flameproofing furnace consisting of a hot air circulation type convection heating furnace is less than 0.5 g / tex, single yarn breakage due to fluttering of the heat-treated fiber bundle, Fusion between single yarns due to contact between adjacent fiber bundles in a plane parallel to the bottom surface is likely to occur, and the fiber bundle shape regulated by a roller may not be maintained. On the other hand, if it is higher than 2.5 g / tex, not only the process tension is easily broken, but also the durability of the heat-treated fiber bundle against physical contact at the entrance and exit of the flameproofing furnace is weakened.
[0032]
In the method of the present invention in which a heat-treated fiber bundle made of an acrylic fiber bundle is continuously heat-treated to make flame-resistant fibers, as means for regulating the travel path of the heat-treated fiber bundle and toe width, for example, a guide is used. Although it can be used and is not subject to any restrictions, it is most preferred to use a grooved roller. The cross-sectional shape of the groove of this groove roller may be either a flat bottom type as shown in FIG. 1, a round bottom type as shown in FIG. 2, or a wave bottom type as shown in FIG. It is determined appropriately in consideration of the total fineness of the heat-treated fiber bundle and problems in the production of the roller.
[0033]
【Example】
Hereinafter, the concrete structure of the continuous heat processing method of the acrylic fiber bundle of this invention is demonstrated based on an Example.
The heat-treated fiber bundle and the flameproofing furnace used in each example and comparative example are as follows.
Heat-treated fiber bundle: Acrylic fiber bundle of 0.13 single yarn tex made of acrylic copolymer fiber containing 96 mol% of acrylonitrile
Flameproofing furnace: Hot air circulation type convection heating furnace
[0034]
Example 1
4 and 5, the effective furnace length L 1 : 10m, effective furnace width L 2 1 m, wind direction in the furnace: perpendicular to the fiber bundle sheet, furnace temperature: 230 ° C., wind speed in the furnace: 0.6 m / sec. The flame-resistant fiber 3 was obtained by performing a continuous heat treatment in which the fiber bundle sheet-like material 2 formed of 120 heat-treated fiber bundles S was run over 3 reciprocating halves. At this time, the surface occupation ratio of the fiber bundle sheet-like material introduced into the flameproofing furnace with respect to the bottom surface of the flameproofing furnace is 43%.
[0035]
In the continuous heat treatment of the acrylic fiber bundle, the width of the fiber bundle S to be heat-treated introduced into the flameproofing furnace 1 is regulated to 3.6 mm by the
[0036]
During the above-described continuous heat treatment step for the acrylic fiber bundle, smoke was not generated due to runaway reaction, and stable continuous operation was possible. Also, there is no breakage of single yarn due to contact between adjacent fiber bundles in the flameproofing furnace, fusion between single yarns, contamination of the fiber surface, etc. A flame-resistant fiber with a small amount was obtained. The degree of increase in flame resistance density of acrylic fiber by this continuous heat treatment is 0.06 g / cm. Three / 17 min. Met.
[0037]
Example 2
Effective furnace length: 14 m, effective furnace width: 1 m, wind direction in the furnace: perpendicular to the fiber bundle sheet, furnace temperature: 240 ° C., wind speed in the furnace: 1.0 m / sec. Flame-resistant fibers were obtained by performing continuous heat treatment of acrylic fiber bundles through a fiber bundle sheet-like material consisting of 200 heat-treated fiber bundles having 12,000 filaments. The area ratio of the fiber bundle sheet to be introduced into the flameproofing furnace with respect to the bottom face of the flameproofing furnace at this time is 40%.
[0038]
In the above-mentioned continuous heat treatment of the acrylic fiber bundle, the width of the fiber bundle to be heat treated per groove is regulated to 2.0 mm and the pitch between the fiber bundles is regulated to 5.0 mm by the groove roller, and the inside of the flameproofing furnace The process tension of the acrylic fiber bundle running on the machine was 0.8 g / tex (1.2 kg per one).
[0039]
During the above-described continuous heat treatment step for the acrylic fiber bundle, smoke was not generated due to runaway reaction, and stable continuous operation was possible. In addition, there is no breakage of single yarn due to contact between adjacent fiber bundles, fusion between single yarns, contamination of the fiber surface, etc., and there are few flame-resistant fibers and single yarn treatment spots in the width direction of the fiber bundle sheet. was gotten. The degree of increase in flame resistance density of acrylic fiber by this continuous heat treatment is 0.06 g / cm. Three / 15 min. Met.
[0040]
Example 3
Effective furnace length: 10 m, effective furnace width: 1 m, wind direction in the furnace: perpendicular to the fiber bundle sheet, furnace temperature: 220 ° C., wind speed in the furnace: 0.5 m / sec. Flame-resistant fibers were obtained by continuous heat treatment of acrylic fiber bundles through a fiber bundle sheet-like material comprising 60 heat-treated fiber bundles having a filament number of 72,000. At this time, the surface occupation ratio of the fiber bundle sheet-like material introduced into the flameproofing furnace with respect to the bottom surface of the flameproofing furnace is 48%.
[0041]
In the above-mentioned continuous heat treatment of the acrylic fiber bundle, the width of the fiber bundle to be heat treated per groove is regulated to 8.0 mm and the pitch between the fiber bundles is controlled to 16.0 mm by the groove roller, and the inside of the flameproofing furnace The process tension of the acrylic fiber bundle traveling on the road was set to 1.4 g / tex (12 kg per one).
[0042]
During the above-described continuous heat treatment step for the acrylic fiber bundle, smoke was not generated due to runaway reaction, and stable continuous operation was possible. In addition, there is no breakage of single yarn due to contact between adjacent fiber bundles, fusion between single yarns, contamination of the fiber surface, etc., and there are few flame-resistant fibers and single yarn treatment spots in the width direction of the fiber bundle sheet. was gotten. The degree of increase in flame resistance density of acrylic fiber by this continuous heat treatment is 0.06 g / cm. Three / 24 min. Met.
[0043]
Example 4
Effective furnace length: 14 m, effective furnace width: 1.5 m, wind direction in the furnace: parallel to the fiber bundle sheet, furnace temperature: 220 ° C., furnace air velocity: 2.8 m / sec The acrylic fiber bundle was subjected to continuous heat treatment through a fiber bundle sheet-like material comprising 90 heat-treated fiber bundles having a filament number of 72,000 to obtain flame-resistant fibers. At this time, the surface occupation ratio of the fiber bundle sheet-like material introduced into the flameproofing furnace with respect to the bottom surface of the flameproofing furnace is 48%.
[0044]
In the above-mentioned continuous heat treatment of the acrylic fiber bundle, the width of the fiber bundle to be heat treated per groove is regulated to 8.0 mm and the pitch between the fiber bundles is controlled to 16.0 mm by the groove roller, and the inside of the flameproofing furnace The process tension of the acrylic fiber bundle traveling on the road was 1.0 g / tex (9 kg per one).
[0045]
During the above-described continuous heat treatment step for the acrylic fiber bundle, smoke was not generated due to runaway reaction, and stable continuous operation was possible. In addition, flame resistant fibers free from breakage of single yarn due to contact between adjacent fiber bundles, fusion between single yarns, contamination of the fiber surface, and the like were obtained. In addition, although some single yarn treatment spots were confirmed, the treatment spots in the width direction of the fiber bundle sheet were small, and the flame-resistant fibers were sufficiently satisfactory. The degree of increase in flame resistance density of acrylic fiber by this continuous heat treatment is 0.06 g / cm. Three / 20 min. Met.
[0046]
Example 5
Effective furnace length: 14 m, effective furnace width: 1.5 m, wind direction in the furnace: parallel to the fiber bundle sheet, furnace temperature: 215 ° C., furnace wind speed: 2.8 m / sec Inside, the acrylic fiber bundle was subjected to continuous heat treatment through a fiber bundle sheet-like material composed of 90 heat-treated fiber bundles having a filament number of 72,000 to obtain flame-resistant fibers. The area ratio of the fiber bundle sheet to be introduced into the flameproofing furnace with respect to the bottom surface of the flameproofing furnace at this time is 56%.
[0047]
In the above-mentioned continuous heat treatment of the acrylic fiber bundle, the width of the fiber bundle to be heat treated per one is regulated to 10.5 mm and the pitch between the fiber bundles is regulated to 17.0 mm by a flat roller and a comb guide. The process tension of the acrylic fiber bundle running in the flameproofing furnace was 1.4 g / tex (2 kg per one).
[0048]
During the above-described continuous heat treatment step for the acrylic fiber bundle, smoke was not generated due to runaway reaction, and stable continuous operation was possible. In addition, flame resistant fibers free from breakage of single yarn due to contact between adjacent fiber bundles, fusion between single yarns, contamination of the fiber surface, and the like were obtained. In addition, although some single yarn treatment spots were confirmed, the treatment spots in the width direction of the fiber bundle sheet were small, and the flame-resistant fibers were sufficiently satisfactory. The degree of increase in flame resistance density of acrylic fiber by this continuous heat treatment is 0.06 g / cm. Three / 27 min. Met.
[0049]
Comparative Example 1
Effective furnace length: 10 m, effective furnace width: 1 m, wind direction in the furnace: perpendicular to the fiber bundle sheet, furnace temperature: 230 ° C., furnace wind speed: 0.6 m / sec in a flameproof furnace The acrylic fiber bundle was subjected to continuous heat treatment through a fiber bundle sheet-like material comprising 50 heat-treated fiber bundles having 36,000 filaments. The area ratio of the fiber bundle sheet to be introduced into the flameproofing furnace with respect to the bottom face of the flameproofing furnace at this time is 30%.
[0050]
In the above-mentioned continuous heat treatment of the acrylic fiber bundle, the width of the fiber bundle to be heat treated per groove is regulated to 6.0 mm and the pitch between the fiber bundles is regulated to 14.0 mm by the groove roller, and the inside of the flameproofing furnace The process tension of the acrylic fiber bundle running on the road was 1.4 g / tex (6 kg per one).
[0051]
During the above-described continuous heat treatment step for the acrylic fiber bundle, smoke was not generated due to runaway reaction, and stable continuous operation was possible. In addition, there is no breakage of single yarn due to contact between adjacent fiber bundles, fusion between single yarns, contamination of the fiber surface, etc., and there are few flame-resistant fibers and single yarn treatment spots in the width direction of the fiber bundle sheet. was gotten. The degree of increase in flame resistance density of acrylic fiber by this continuous heat treatment is 0.06 g / cm. Three / 17 min. Thus, it was impossible to cover the decrease in the surface occupancy ratio of the fiber bundle sheet to be introduced into the flameproofing furnace with respect to the bottom surface of the flameproofing furnace with the increase in the flameproofing density of the acrylic fiber.
[0052]
Comparative Example 2
Effective furnace length: 10 m, effective furnace width: 1 m, wind direction in the furnace: perpendicular to the fiber bundle sheet, furnace temperature: 230 ° C., furnace wind speed: 0.6 m / sec in a flameproof furnace The acrylic fiber bundle was continuously heat-treated through a fiber bundle sheet-like material comprising 120 heat-treated fiber bundles having 36,000 filaments. At this time, the surface occupation ratio of the fiber bundle sheet-like material introduced into the flameproofing furnace with respect to the bottom surface of the flameproofing furnace is 72%.
[0053]
In the above-mentioned continuous heat treatment of the acrylic fiber bundle, the width of the fiber bundle to be heat treated per groove is regulated to 6.0 mm and the pitch between the fiber bundles is regulated to 8.0 mm by the groove roller, and the inside of the flameproofing furnace The process tension of the acrylic fiber bundle running on the road was 1.4 g / tex (6 kg per one).
[0054]
During the above-mentioned continuous heat treatment of the acrylic fiber bundle, single yarn breakage frequently occurs due to contact between adjacent fiber bundles on a surface parallel to the bottom surface of the flameproofing furnace, and the single yarn treatment spots in the fiber bundle As a result, a flame-resistant fiber with a large amount was obtained. The degree of increase in flame resistance density of acrylic fiber by this continuous heat treatment is 0.06 g / cm. Three / 17 min. And the process stability was very poor.
[0055]
Comparative Example 3
Effective furnace length: 14 m, effective furnace width: 1 m, wind direction in the furnace: perpendicular to the fiber bundle sheet, furnace temperature: 240 ° C., wind speed in the furnace: 1.0 m / sec. The acrylic fiber bundle was subjected to continuous heat treatment through a fiber bundle sheet-like material composed of 200 heat-treated fiber bundles having 12,000 filaments. The area ratio of the fiber bundle sheet to be introduced into the flameproofing furnace with respect to the bottom face of the flameproofing furnace at this time is 40%.
[0056]
In the above-mentioned continuous heat treatment of the acrylic fiber bundle, the width of the fiber bundle to be heat treated per groove is regulated to 2.0 mm and the pitch between the fiber bundles is regulated to 5.0 mm by the groove roller, and the inside of the flameproofing furnace The process tension of the acrylic fiber bundle traveling on the road was set to 0.3 g / tex (0.5 kg per one).
[0057]
During the continuous heat treatment step for the acrylic fiber bundle, bundle breakage occurred due to contact between adjacent fiber bundles on a surface parallel to the bottom surface of the flameproofing furnace. The degree of increase in flame resistance density of acrylic fiber by this continuous heat treatment is 0.06 g / cm. Three / 15 min. And the process stability was very poor.
[0058]
Comparative Example 4
Effective furnace length: 14 m, effective furnace width: 1 m, wind direction in the furnace: perpendicular to the fiber bundle sheet, furnace temperature: 240 ° C., furnace wind speed: 2.0 m / sec in a flameproof furnace The acrylic fiber bundle was subjected to continuous heat treatment through a fiber bundle sheet-like material composed of 200 heat-treated fiber bundles having 12,000 filaments. The area ratio of the fiber bundle sheet to be introduced into the flameproofing furnace with respect to the bottom face of the flameproofing furnace at this time is 40%.
[0059]
In the above-mentioned continuous heat treatment of the acrylic fiber bundle, the width of the fiber bundle to be heat treated per groove is regulated to 2.0 mm and the pitch between the fiber bundles is regulated to 5.0 mm by the groove roller, and the inside of the flameproofing furnace The process tension of the acrylic fiber bundle traveling on the road was set to 0.3 g / tex (0.5 kg per one).
[0060]
During the continuous heat treatment process of the acrylic fiber bundle, smoke did not occur due to a runaway reaction, but the flutter of the fiber bundle consisting of wind in the flameproofing furnace was large and parallel to the bottom of the flameproofing furnace. Single yarn breakage was caused by contact between adjacent fiber bundles on the surface, and flame-resistant fibers with a lot of fluff were obtained. The degree of increase in flame resistance density of acrylic fiber by this continuous heat treatment is 0.06 g / cm. Three / 15 min. Met.
[0061]
Comparative Example 5
Effective furnace length: 14 m, effective furnace width: 1.5 m, wind direction in the furnace: parallel to the fiber bundle sheet, furnace temperature: 215 ° C., furnace wind speed: 1.0 m / sec Inside, a continuous heat treatment of the acrylic fiber bundle was performed through a fiber bundle sheet-like material comprising 90 heat-treated fiber bundles having 72,000 filaments. The area ratio of the fiber bundle sheet to be introduced into the flameproofing furnace with respect to the bottom surface of the flameproofing furnace at this time is 56%.
[0062]
In the above-mentioned continuous heat treatment of the acrylic fiber bundle, the width of the fiber bundle to be heat treated per one is regulated to 10.5 mm and the pitch between the fiber bundles is regulated to 17.0 mm by a flat roller and a comb guide. The process tension of the acrylic fiber bundle running in the flameproofing furnace was set to 1.4 g / tex (2.0 kg per one).
[0063]
During the continuous heat treatment process for the acrylic fiber bundle, smoke was generated due to poor heat removal. The degree of increase in flame resistance density of acrylic fiber by this heat treatment is 0.06 g / cm. Three / 27 min. Met.
[0064]
The table occupancy ratio of the fiber bundle sheet to be introduced into the flameproofing furnace with respect to the bottom face of the flameproofing furnace in the above examples and comparative examples, process productivity, and visual properties of the obtained flameproofing fiber are collectively shown. It is shown in 1.
[0065]
[Table 1]
【The invention's effect】
According to the continuous heat treatment method for an acrylic fiber bundle of the present invention, it is possible to efficiently produce high-quality flame-resistant fibers, so that it becomes possible to produce high-quality carbon fibers at a high production rate. For this reason, the cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a cut end view showing a schematic shape of a groove of a flat bottom groove roll.
FIG. 2 is a cut end view showing a schematic shape of a groove of a round bottom groove roll.
FIG. 3 is a cut end view showing a schematic shape of a wave bottom groove roll.
FIG. 4 is a schematic longitudinal sectional view of a flameproofing furnace showing a state of a fiber bundle sheet traveling in the flameproofing furnace.
5 is a schematic cross-sectional view taken along line XY of the flameproofing furnace of FIG. 4;
[Explanation of symbols]
1. Flame proofing furnace
2. Fiber bundle sheet
3. Flame resistant fiber
4 .... Groove roller
S ... Fiber bundle to be heat treated
L 1 ... Effective furnace length
L 2 ... Effective furnace width
Claims (3)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33609598A JP4017772B2 (en) | 1998-11-26 | 1998-11-26 | Continuous heat treatment method for acrylic fiber bundles |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33609598A JP4017772B2 (en) | 1998-11-26 | 1998-11-26 | Continuous heat treatment method for acrylic fiber bundles |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2000160435A JP2000160435A (en) | 2000-06-13 |
| JP4017772B2 true JP4017772B2 (en) | 2007-12-05 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP33609598A Expired - Lifetime JP4017772B2 (en) | 1998-11-26 | 1998-11-26 | Continuous heat treatment method for acrylic fiber bundles |
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| JP (1) | JP4017772B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102767058A (en) * | 2012-07-03 | 2012-11-07 | 镇江奥立特机械制造有限公司 | Driving roller of carbon fiber softening machine |
| US20210310158A1 (en) * | 2018-11-26 | 2021-10-07 | Toray Industries, Inc. | Method for producing flame-proof fiber bundle, and method for producing carbon fiber bundle |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5087267B2 (en) * | 2006-12-15 | 2012-12-05 | 三菱レイヨン株式会社 | Flameproofing method for carbon fiber precursor |
| JP5556994B2 (en) * | 2009-12-21 | 2014-07-23 | 三菱レイヨン株式会社 | Method for producing flame resistant fiber |
| JP7354840B2 (en) | 2018-09-28 | 2023-10-03 | 東レ株式会社 | Method for producing flame-resistant fiber bundles and method for producing carbon fiber bundles |
| JP6729819B1 (en) * | 2018-11-12 | 2020-07-22 | 東レ株式会社 | Method for producing flame resistant fiber bundle and carbon fiber bundle, and flame resistant furnace |
| JP6680417B1 (en) * | 2018-11-26 | 2020-04-15 | 東レ株式会社 | Method for producing flame-resistant fiber bundle and method for producing carbon fiber bundle |
| CN115279958B (en) * | 2020-03-18 | 2024-04-16 | 东丽株式会社 | Flame-retardant fiber bundle, method for producing carbon fiber bundle, and flame-retardant furnace |
-
1998
- 1998-11-26 JP JP33609598A patent/JP4017772B2/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102767058A (en) * | 2012-07-03 | 2012-11-07 | 镇江奥立特机械制造有限公司 | Driving roller of carbon fiber softening machine |
| US20210310158A1 (en) * | 2018-11-26 | 2021-10-07 | Toray Industries, Inc. | Method for producing flame-proof fiber bundle, and method for producing carbon fiber bundle |
| US12012671B2 (en) * | 2018-11-26 | 2024-06-18 | Toray Industries, Inc. | Method for producing flame-proof fiber bundle, and method for producing carbon fiber bundle |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2000160435A (en) | 2000-06-13 |
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