JP4409126B2 - Method for producing activated carbon sheet and activated carbon sheet - Google Patents
Method for producing activated carbon sheet and activated carbon sheet Download PDFInfo
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Description
【０００１】
【発明の属する技術分野】
本発明は、湿潤時の強度に優れると共に、活性炭素が本来持つ吸着活性、触媒活性を阻害することなく、高い効率で有害物質を除去することができるケミカルフィルター用活性炭素シートの製造方法に関するものである。
【０００２】
【従来の技術】
活性炭は、ピッチ、コールタール、レーヨン（木材）、ＰＡＮ等を由来として、炭素前駆体となる原材料を数百℃の温度で炭素化、さらに賦活することにより製造される。炭素化は不活性ガス雰囲気中で原材料を熱分解することによって行われ、由来する原料により、液相炭化法、固相炭化法、気相炭化法等が適宜用いられる。炭素化後、賦活することにより多数の細孔とそれに相当する比表面積をもつ活性炭が得られる。賦活法は、ガス化賦活（物理的賦活）法と薬品賦活（化学的賦活）法に大別され、活性炭は、これら賦活方法を単独あるいは複数組み合わせて製造されるものである。
【０００３】
活性炭はその多孔性構造により強力な吸着作用を示すほか、触媒作用等も示し、様々な用途に活用されている。例えば吸着作用を応用した例としては、浄水器、ダイオキシン等の排ガス処理、脱臭、たばこフィルター等が挙げられる。また触媒作用を応用した例としては、アルコールの塩素化反応、アルコールの脱水反応等が挙げられる。
活性炭の形状は、粉末、粒状、繊維状等さまざまな形状の活性炭が製造される。これらの活性炭は、その形状のまま使用される場合もあるし、シート状等、様々な形状に成形した後、使用される場合もある。特にシート状に成形した場合、その後の製品加工が行いやすくなるため、活性炭シートへの期待は、年々高まってきている。
【０００４】
活性炭をシート化するための方法は、様々な方法が提案されている。例えば特開昭５３−０３５７１２号公報には木材パルプ、麻、ラミー等の天然繊維またはこれと化学繊維との混合物からなる保持繊維を水中で攪拌しながら活性炭４０〜７０％を添加したスラリーにアニオン性高分子を０．０１〜１．０％添加し、更にカチオン性高分子を０．１〜１．０％添加した後、抄紙する方法が提案されている。また、特開昭５５−０７５９１１号公報には、湿潤紙料繊維に粉末活性炭を加えて叩解した後、▲１▼カチオン系凝集剤を加えて混合、その後アニオン系凝集剤を混合し抄紙する。または、▲２▼カチオン系凝集剤を加えて混合後抄紙し、アニオン系凝集剤で処理する方法が提案されている。これらの方法は、シート形成時（抄紙時）に活性炭のフロックを形成させ、活性炭の定着率を向上させる方法であるが、粒子状活性炭（粉末活性炭や粒状活性炭）を使用しているため、活性炭が脱落しやすく、製品加工しにくいものであった。
【０００５】
成形したシートからの活性炭の脱落を防止するために、粉末状活性炭に代えて繊維状活性炭（活性炭素繊維）を使用する方法も提案されている。例えば特開昭６２−１５５９１４号公報では、フィブリル化結合剤繊維、活性炭素繊維、サブミクロン寸法のガラス繊維を混抄した活性炭フィルターが提案されている。この提案では、フィブリル化結合剤繊維として木材パルプや茎皮繊維、種子繊維等を使用することで、そのフィブリル化結合剤繊維の水素結合力によりシート強力を得ようとするものである。さらに活性炭が繊維状であるため、粒子状活性炭を使用した場合に比べて使用時の活性炭脱落が低くなるというものである。しかしながら、シートの結合力をフィブリル化結合剤繊維の水素結合力のみに頼ることとなるため、活性炭素繊維の保持力は十分ではなく、依然として活性炭の脱落が生じてしまう。また、フィブリル化結合剤繊維はセルロース繊維であるため、耐薬品性に劣るばかりでなく、活性炭素繊維シートを湿潤した場合にも大幅に強度が低下し、使用しにくいものとなってしまった。
【０００６】
また、特開平２−２４０９０８では不織布製造技術により活性炭素繊維と熱融着繊維(熱融着性合成繊維)のシートを作ることが提案されている。これは、熱融着繊維によって活性炭素繊維が接着しているため、活性炭素繊維が容易に脱落することなく、対薬品性、湿潤時の強度および湿潤時の強度の低下に優れているが、一般的に用いられる熱融着繊維を使用しているために、比表面積が小さくなってしまう。
【０００７】
【発明が解決しようとする課題】
本発明者らは、これらの問題点に鑑み、活性炭シートを構成する材料を鋭意研究し、一般的に用いられる熱融着性合成繊維には紡糸油剤などの薬剤が塗布されており、これらの薬剤がシート形成の際に熱融着性合成繊維の表面から離脱して活性炭素の細孔に吸着し細孔をふさいでしまうため、比表面積が小さくなってフィルターとしての吸着性能を低下させてしまうという問題点を見出した。そして、材料として活性炭と薬剤が付着していない特定の熱融着性繊維とを組み合わせてシート成形することで、活性炭が本来持つ吸着活性、触媒活性等を阻害することなく、高い効率で有害物質を除去することができることを見出し、本発明を完成するに至った。
【０００８】
したがって、本発明の目的は、耐薬品性に優れ、湿潤時の強度の低下が小さく、使用時の活性炭の脱落が少ない活性炭シートであると共に、活性炭が本来持つ吸着活性、触媒活性を極力阻害することなく、高い効率で有害物質を除去することができるケミカルフィルター用シートを提供することである。
【０００９】
本発明の第１は、活性炭素繊維と熱融着性合成繊維とを主構成要素として混合し、該熱融着性合成繊維の一部を溶融させて、これらの構成要素間を接着させることにより、活性炭シートを形成する製造方法において、紡糸して得られた該熱融着性合成繊維を、エアーレイ法による不織布製造工程におけるシート形成工程（ウェブ形成工程と接着工程を合わせてシート形成工程と称する）に導入する前に、水または有機溶剤等の洗浄剤で洗浄して、付着している紡糸油剤等の薬剤を除去して、紡糸油剤等の薬剤の残量が、熱融着性合成繊維を基準として（熱融着性合成繊維の質量を１００％として）０．１質量％以下とする工程を具備することを特徴とするケミカルフィルター用活性炭シートの製造方法である。
更に好ましくは、前記紡糸用油剤等の薬剤の残量が、熱融着性合成繊維を基準として０．０５質量％以下である。
ここで、前記熱融着性合成繊維に付着している紡糸油剤等の薬剤残量は、ＪＩＳ Ｌ １０１５：１９９９に規定されているメタノール抽出法による溶剤抽出分の測定方法に依って測定するものとする。
【００１０】
本発明においては熱融着性合成繊維を用いているため活性炭の脱落が少なく、活性炭としては、活性炭素繊維、粒状活性炭、粉末状活性炭があるが、特に活性炭素繊維は脱落しにくく好適であり、本発明においてはこれを使用する。
また、本発明の活性炭シートは、活性炭素繊維と熱融着性合成繊維以外の構成要素を含んでいても構わない。
【００１３】
本発明の第２は、前記シート形成工程において、界面活性剤、分散剤等の薬剤を使用しないことを特徴とする第１の発明に記載したケミカルフィルター用活性炭シートの製造方法である。
【００１８】
本発明の第３は、本発明の第１または第２に記載された方法で製造されたことを特徴とするケミカルフィルター用活性炭シートである。
【００１９】
【発明の実施の形態】
本発明においては、活性炭素繊維と熱融着性合成繊維を準備する。活性炭素繊維は、従来公知の方法で得られた様々な繊維を使用することが出来る。例えばレーヨン系繊維、アクリル系繊維、ピッチ系繊維、フェノール樹脂系繊維等を出発原料として、炭素化、賦活化して得られる。なお、本発明において用いる活性炭とは、活性炭素繊維を意味する。また、マンガン、マグネシウム、コバルトなどの触媒を担持した活性炭であっても良い。
【００２０】
熱融着性合成繊維も、従来公知の様々な繊維を使用することが出来る。例えばポリオレフィン系熱融着性繊維、ポリエステル系熱融着性繊維、ポリアミド系熱融着性繊維等を使用することが出来るし、繊維の外側のみまたは外側の一部分が熱溶融可能な複合成分型熱融着性繊維等を用いることが出来る。複合成分型熱融着性繊維の例としては、ポリエチレン／低融点ポリエチレン芯鞘複合繊維、ポリプロピレン／ポリエチレン芯鞘複合繊維、ポリエステル／ポリエチレン芯鞘複合繊維、ポリエステル／低融点ポリエステル芯鞘複合繊維が挙げられる。また、三井化学製「商品名ＳＷＰ」に代表されるポリプロピレン／ポリビニルアルコール、ポリエチレン／ポリビニルアルコールの複合繊維、等も挙げることができる。
【００２１】
本発明でもっとも重要な点の一つは、シート形成工程で使用する熱融着性合成繊維として、これに付着している紡糸油剤等の薬剤残量が所定量以下のものを用いることである。紡糸油剤は、繊維−繊維間、繊維−金属間（場合によっては合成樹脂製品）の摩擦係数を低減し加工性を向上させるため繊維製造工程の紡糸工程において付与されたり、またチョップ状に切断された繊維に付与される。この紡糸油剤を付与することで、紡糸工程における静電気などを防止できたり、また、熱融着繊維を実際に使用する際の後加工性の向上も期待できる。このように油剤は様々な場面で使用されるものであり、１種類あるいは複数種類の成分を組み合わせて使用されている。紡糸油剤としては、例えば親水化剤などの界面活性剤やシリコン系処理剤、アミン系処理剤などが用いられている。
【００２２】
本発明では、熱融着性合成繊維製造時に紡糸油剤等の薬剤を全く使用しないで製造した熱融着性合成繊維、または紡糸油剤等の薬剤の使用量を従来より減らして紡糸したり後工程で除去したりして、これらの薬剤の残量を所定量以下(熱融着性合成繊維を基準として０．１％以下)にした熱融着性合成繊維を用いて活性炭シートの形成を行う。また、除去する方法として、従来公知の紡糸油剤等の薬剤を使用して紡糸した熱融着性合成繊維、または紡糸油剤等の薬剤の使用量を減らして紡糸した熱融着性合成繊維を、後工程で、水、温水または有機溶剤等の洗浄剤で洗浄し、該熱融着性合成繊維表面に付着した紡糸油剤等の薬剤を除去して使用することができる。この場合、洗浄工程は、熱融着性合成繊維の製造者が紡糸工程に連続して設けてもよいし、活性炭シートの製造者がシート形成工程の前に設けてもよく、洗浄者は限定されない。
【００２３】
これら熱融着性合成繊維の入手方法は、薬剤の残量を所定量以下にしたものを入手して使用しても良いし、活性炭シートの製造者が熱融着性合成繊維に付着している薬剤等を洗浄して薬剤の残量を所望の量以下にして使用しても良い。また、所望にあわせて両方の方法を組み合わせて用いても良い。一般には、製造工程で紡糸油剤等の薬剤を全く使用していない熱融着性合成繊維の入手は難しいため、紡糸油剤等の薬剤の残量を所定量以下にした熱融着性合成繊維を入手するか、紡糸油剤等の薬剤を使用して製造された熱融着性合成繊維を入手し、水、温水または有機溶剤等の洗浄剤で洗浄して使用する方法を用いることが、繊維の製造が容易であり好ましい。
【００２４】
紡糸油剤等の薬剤を使用して製造された熱融着性合成繊維を洗浄する洗浄剤は、水、温水または有機溶剤等を単独あるいは複数種類を適宜組合せて使用することができるが、温水あるいはエチルアルコール、イソプロピルアルコール等のアルコール類が安全性、洗浄効果の両面から好適に使用できる。
【００２５】
洗浄剤による洗浄方法は、従来公知の方法を適宜選択して使用することが出来る。一例としては、洗浄液中に熱融着性合成繊維を浴したのち、熱融着性合成繊維を分離、ろ過して洗浄する方法がある。この際、洗浄液浴中に該熱融着性合成繊維を静置しても良いし、洗浄液浴中で該熱融着性合成繊維を攪拌しても良い。洗浄液浴は、油剤が除去できるまで複数回繰り返して行うことができ、各段階の洗浄液浴に使用する洗浄液の種類は１種類のものを使用しても良いし、複数種類混合したり各段階毎に変更しても良い。１回あたりの洗浄剤浴の時間は、所望に応じ適宜設定できる。熱融着性合成繊維は、洗浄剤浴から分離・ろ過した後、乾燥して使用する。
【００２６】
通常販売されている熱融着性合成繊維に付着している紡糸油剤等の薬剤の残量は、熱融着性合成繊維を基準として(熱融着性合成繊維の質量を１００％として)、０．４〜１．０質量％程度であるが、本発明においては、前述の洗浄等の方法により、シート形成工程においてこの比率が０．１質量％以下の熱融着性合成繊維を用いる。この比率は更に好ましくは０．０５質量％以下である。この紡糸油剤等の薬剤の残量比率は、小さい程、薬剤がシート形成の際に熱融着性合成繊維の表面から離脱して活性炭の細孔に吸着して細孔をふさいでしまうことが少なくなるため好ましいが、この比率をあまりにも小さくすることは、洗浄に要する労力や費用が高くなる等の製造コストの問題が生じるため得策ではない。したがって、０．１質量％以下、更には０．０５質量％以下に出来れば充分と言える。尚、熱融着性合成繊維に付着している紡糸油剤等の薬剤の残量は、ＪＩＳ Ｌ １０１５：１９９９に規定されている、メタノール抽出法による溶剤抽出分の測定方法に依って測定するものとする。
【００２７】
活性炭素繊維と熱融着性合成繊維は、所望の配合に混合して、従来公知のウェブ形成方法である、空気中で原料を分散させてフォーミングする所謂エアーレイ法（代表的な製造プロセスとしてはＪ＆Ｊ法、Ｋ−Ｃ法、本州法等が挙げられ、本法はキノクロス法ともいう）を用いてシート化される。
形成されたウェブは、従来公知の熱処理装置により、熱融着性合成繊維の一部を溶融し、該熱融着性合成繊維間および該活性炭素繊維間を接着することで、活性炭シートを得る。熱処理の方法も特に限定されるものではないが、例えば次に挙げる熱処理装置を挙げることが出来る。すなわち、スルーエアー型乾燥機、ヤンキー型乾燥機、多筒ドラム型乾燥機等の乾燥装置、あるいは、熱カレンダー装置、熱エンボス装置等のカレンダー装置等である。
【００２８】
本発明で重要な点の第二は、ウェブ形成工程および接着工程（あわせてシート形成工程と呼ぶ）においても、界面活性剤、分散剤等の薬剤を使用しないことである。
熱融着性合成繊維表面に処理される紡糸油剤等の薬剤、あるいはシート形成工程で使用される界面活性剤、分散剤等の薬剤は、シート形成工程において、あるいは使用時に繊維表面から離脱し、活性炭素繊維等の活性炭の細孔に吸着されやすいため、このような薬剤を使用したままシートを形成し、使用すると、活性炭シートを構成する活性炭素繊維等の活性炭の細孔をふさいでしまい、活性炭が本来持つ吸着活性、触媒活性等の活性を阻害してしまうのである。活性炭がもつ活性が阻害された場合、活性炭シートの吸着能力、触媒能力等の機能が低下し、そのシートを応用した製品の性能を低いものとしてしまうのである。
【００２９】
本発明においては、活性炭シートの吸着能力、触媒能力等の機能低下の評価方法として、シート形成前の活性炭(活性炭素繊維等)と形成した活性炭シートの比表面積を後述のＢＥＴ法のガス連続流動法により測定し、更に後述の式により比表面積低下率を算出して、これにより評価した。当然、比表面積低下率は低い方が好ましく、上述の通り、紡糸油剤等の薬剤の残量が少ないほど比表面積低下率は低くなる。但し、活性炭の細孔を塞いでしまうのは紡糸油剤等の薬剤のみでなく、溶融した熱融着性合成繊維も活性炭表面に付着して細孔を塞いでしまうので、熱融着性合成繊維をどの程度溶融させるかによってもこの数値は変動することになり、活性炭の配合比率が高い程この数値は高くなる傾向になる。
活性炭の配合比率が４０％以上の場合を例にとると、比表面積低下率が概ね３０％以下であれば、活性炭素繊維の活性の低下は小さく好ましいと言える。
【００３０】
本発明においては、紡糸油剤等の薬剤を使用して製造された熱融着性合成繊維を入手して活性炭シートを製造する場合、水、温水または有機溶剤等の洗浄剤で洗浄してからシート形成に使用する方法について説明したが、洗浄効率を重視しなければ、活性炭シートを製造した後に、水、温水または有機溶剤等の洗浄剤で洗浄する方法を用いることも勿論可能である。
【００３１】
【実施例】
以下、実施例によって本発明を具体的に説明するが、本発明はこれらの実施例に限定されるものではない。
【００３２】
<実施例１> 比表面積１５００ｍ２／ｇの活性炭素繊維（アドール社製、商品名：Ａ−１５、繊維長：公称３ｍｍ、３．３ｄｔｅｘ）と接着温度１３５℃のポリプロピレン／ポリエチレン芯鞘型複合熱融着性繊維（チッソ社製、商品名：ＥＳＣ８７１、繊維長５ｍｍ、１．７ｄｔｅｘ）を用意した。該熱融着性合成繊維をエチルアルコールに１０分間浴しながら攪拌した後、ろ過し該熱融着性合成繊維を取り出す操作を、エチルアルコールを毎回新しいものに代えながら３回繰り返した後、乾燥し、紡糸油剤を除去した熱融着性合成繊維を得た。
該活性炭素繊維６０質量％、該熱融着性合成繊維４０質量％を均一に混合した後、キノクロス法によるエアーレイ不織布製造装置を使用して、目付１５０ｇ／ｍ２のウェブを得た。すなわち、該活性炭素繊維と該熱融着性合成繊維を空気中で混合、解繊（繊維を分離状態でときほぐすこと）して、マットフォーマーに送ってウェブを形成し、ウェブを温度１３８℃のスルーエアードライヤーを通過させ、プレスすることによって活性炭素繊維シート(活性炭シートの一形態)を得た。
【００３３】
<実施例２> 比表面積１５００ｍ２／ｇの活性炭素繊維（アドール社製、商品名：Ａ−１５）と接着温度１３５℃のポリプロピレン／ポリエチレン芯鞘型複合熱融着性繊維（チッソ社製、商品名：ＥＳＣ８７１）を用意した。該熱融着性合成繊維を温度８０℃のイオン交換水に３０分間浴しながら攪拌した後、ろ過し該熱融着性合成繊維を取り出す操作を、イオン交換水を毎回新しいものに代えながら３回繰り返した後、乾燥し、紡糸油剤を除去した熱融着性合成繊維を得た。
該活性炭素繊維６０質量％、該熱融着性合成繊維４０質量％を均一に混合した後、キノクロス法によるエアーレイ不織布製造装置を使用して、目付１５０ｇ／ｍ２のウェブを得た。すなわち、該活性炭素繊維と該熱融着性合成繊維を空気中で混合、解繊（繊維を分離状態でときほぐすこと）して、マットフォーマーに送ってウェブを形成し、ウェブを温度１３８℃のスルーエアードライヤーを通過させ、プレスすることによって活性炭素繊維シート(活性炭シートの一形態)を得た。
【００３４】
<実施例３> 比表面積１５００ｍ２／ｇの活性炭素繊維（アドール社製、商品名：Ａ−１５）と接着温度１３５℃のポリプロピレン／ポリエチレン芯鞘型複合熱融着性繊維（チッソ社製、商品名：ＥＳＣ８７１）を用意した。該熱融着性合成繊維を温度８０℃のイオン交換水に３０分間浴しながら攪拌した後、ろ過し該熱融着性合成繊維を取り出す操作を、イオン交換水を毎回新しいものに代えながら３回繰り返した後、乾燥し、紡糸油剤を除去した熱融着性合成繊維を得た。
該活性炭素繊維４０質量％、該熱融着性合成繊維６０質量％を均一に混合した後、キノクロス法によるエアーレイ不織布製造装置を使用して、目付１５０ｇ／ｍ２のウェブを得た。すなわち、該活性炭素繊維と該熱融着性合成繊維を空気中で混合、解繊（繊維を分離状態でときほぐすこと）して、マットフォーマーに送ってウェブを形成し、ウェブを温度１３８℃のスルーエアードライヤーを通過させ、プレスすることによって活性炭素繊維シートを得た。
【００３５】
<比較例１> 比表面積１５００ｍ２／ｇの活性炭素繊維（アドール社製、商品名：Ａ−１５、繊維長：公称３ｍｍ、３．３ｄｔｅｘ）と接着温度１３５℃のポリプロピレン／ポリエチレン芯鞘型複合熱融着性繊維（チッソ社製、商品名：ＥＳＣ８７１、繊維長５ｍｍ、１．７ｄｔｅｘ）を用意した。
該活性炭素繊維６０質量％、該熱融着性合成繊維４０質量％を均一に混合した後、キノクロス法によるエアーレイ不織布製造装置を使用して、目付１５０g/ｍ２のウェブを得た。すなわち、該活性炭素繊維と該熱融着性合成繊維を空気中で混合、解繊（繊維を分離状態でときほぐすこと）して、マットフォーマーに送ってウェブを形成し、ウェブを温度１３８℃のスルーエアードライヤーを通過させ、活性炭素繊維シートを得た。
比較例１は、実施例１において、該熱融着性合成繊維を洗浄しないで使用した例である。
【００３６】
<比較例２> 比表面積１５００ｍ２／ｇの活性炭素繊維（アドール社製、商品名：Ａ−１５）と接着温度１３５℃のポリプロピレン／ポリエチレン芯鞘型複合熱融着性繊維（チッソ社製、商品名：ＥＳＣ８７１）を用意した。
該活性炭素繊維４０質量％、該熱融着性合成繊維６０質量％を均一に混合した後、キノクロス法によるエアーレイ不織布製造装置を使用して、目付１５０g/ｍ２のウェブを得た。すなわち、該活性炭素繊維と該熱融着性合成繊維を空気中で混合、解繊（繊維を分離状態でときほぐすこと）して、マットフォーマーに送ってウェブを形成し、ウェブを温度１３８℃のスルーエアードライヤーを通過させ、活性炭素繊維シートを得た。
比較例２は、実施例３において、該熱融着性合成繊維を洗浄しないで使用した例である。
【００３７】
実施例１〜３、比較例１〜２で得られた活性炭シートを下記の方法で試験し、その品質を評価した。結果は表1、表２に示すとおりである。
【００３８】
試験方法
(１)引張強さ ： ＪＩＳ Ｐ ８１１３：１９９８に準じてＭＤ方向の引張強さを測定した。
(２)活性炭シート形成に用いる熱融着性合成繊維に付着している紡糸油剤等の薬剤残量 ： ＪＩＳ Ｌ １０１５：１９９９ の８．２２ (ａ)項に規定されている、メタノール抽出法による溶剤抽出分の測定方法に依って測定した。
【００３９】
(３)比表面積 ： (株)堀場製作所製の連続流動式表面積計(ＳＡ−６２００ シリーズ)を用いて、ＢＥＴ法のガス連続流動法により、活性炭素繊維と活性炭素繊維シート (活性炭シート)の比表面積を測定した。
この装置は連続で混合ガスが流れている経路の途中に試料をおき、試料通過時に吸着／脱着により減少／増加したガス量を混合ガスの成分の変化として測定するものである。本装置では、試料を入れたセルを液体窒素に漬けて吸着を完了させた後、セルを室温に戻して試料から脱着した際のＮ２ガス量の増加量から、吸着量を求める。詳細は、(株) 堀場製作所の連続流動式表面積計ＳＡ−６２００ シリーズの取扱説明書(第２版 １９９５年９月)による。
試料は、一測定につき、約０．０５ｇ程度使用し、１１０℃で３０分間加熱することにより、脱ガス処理を行った。
本測定における比表面積は、相対圧Ｐ／Ｐ０＝０．２９４ (Ｎ２ ３０％、Ｈｅ ７０％の混合ガス使用）で吸着した窒素量から算出したものである。
装置には、吸着量から算出して測定される試料の全表面積が表示され、
比表面積は、この全表面積を試料の質量で除算することによって求めた。
【００４０】
(４)比表面積低下率 ： 熱融着性合成繊維の比表面積は活性炭に比べて極めて小さいことからゼロと仮定し、下式により活性炭素シートに加工したことによる比表面積の低下率を求めた。
比表面積低下率(％)＝１００−１００×Ａ／(Ｂ×Ｃ)
但し、Ａ：活性炭シートの比表面積(ｍ２／ｇ)
Ｂ：活性炭の比表面積(ｍ２／ｇ)
Ｃ：活性炭の配合率(無次元)
【００４１】
【表１】
【表２】
実施例１〜３で使用した熱融着性合成繊維の紡糸油剤残量は、０．０３〜０．０４質量％と小さいため、得られた活性炭素繊維シート(活性炭シート)は比表面積低下率が５．６％（実施例１）、８．９％（実施例２）、１８．３(実施例３)と低い値であり、シート形成による活性の低下がほとんどないことが分かる。一方、比較例１〜２で用いた熱融着性合成繊維は洗浄していないので紡糸油剤残量が０．５質量％と大きいため、得られた活性炭素繊維シートの比表面積低下率は４６．７％(比較例１)、４８．３％(比較例２)と高く、活性炭の活性が大幅に低下してしまっており、吸着性能、触媒性能等の機能が十分に得られない可能性が示唆されている。
【００４４】
【発明の効果】
以上説明したように、本発明にかかる活性炭シートは、耐薬品性に優れ、湿潤時の強度の低下が小さく、使用時の活性炭の脱落が少ないシートであると共に、活性炭が本来持つ吸着活性、触媒活性を阻害することなく、高い効率で有害物質を除去することができ、本発明はケミカルフィルターに好適な活性炭シートを提供するという効果を奏する。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing an activated carbon sheet for a chemical filter, which has excellent strength when wet and can remove harmful substances with high efficiency without impairing the adsorption activity and catalytic activity inherent in activated carbon. It is.
[0002]
[Prior art]
Activated carbon is produced by carbonizing and further activating a raw material to be a carbon precursor from a pitch, coal tar, rayon (wood), PAN or the like at a temperature of several hundred degrees Celsius. Carbonization is performed by thermally decomposing the raw material in an inert gas atmosphere, and a liquid phase carbonization method, a solid phase carbonization method, a gas phase carbonization method, or the like is appropriately used depending on the raw material derived. After carbonization, activated carbon having a large number of pores and a specific surface area corresponding thereto is obtained by activation. Activation methods are roughly classified into gasification activation (physical activation) methods and chemical activation (chemical activation) methods, and activated carbon is produced by combining these activation methods singly or in combination.
[0003]
Activated carbon exhibits a strong adsorption action due to its porous structure, and also exhibits a catalytic action and the like, and is used in various applications. For example, examples of application of the adsorption action include water purifiers, exhaust gas treatment such as dioxins, deodorization, tobacco filters and the like. Examples of applying the catalytic action include alcohol chlorination reaction, alcohol dehydration reaction and the like.
The activated carbon is produced in various shapes such as powder, granule, and fiber. These activated carbons may be used as they are, or may be used after being formed into various shapes such as sheets. In particular, when it is formed into a sheet, it becomes easier to process the product thereafter, so the expectation for the activated carbon sheet is increasing year by year.
[0004]
Various methods for forming activated carbon into a sheet have been proposed. For example, Japanese Patent Application Laid-Open No. 53-035712 discloses an anion in a slurry in which 40 to 70% of activated carbon is added to a holding fiber made of a natural fiber such as wood pulp, hemp, ramie, or a mixture of this and a chemical fiber while stirring in water. A method has been proposed in which 0.01 to 1.0% of a cationic polymer is added and 0.1 to 1.0% of a cationic polymer is further added, and then paper is made. In JP-A-55-075911, powdered activated carbon is added to a wet paper fiber and beaten, and then (1) a cationic flocculant is added and mixed, and then an anionic flocculant is mixed to make paper. Alternatively, (2) a method is proposed in which a cationic flocculant is added and mixed to make paper, and then treated with an anionic flocculant. These methods are methods for forming activated carbon flocs at the time of sheet formation (paper making) and improving the fixing rate of activated carbon. However, activated carbon is used because it uses particulate activated carbon (powder activated carbon or granular activated carbon). Was easy to drop off and difficult to process the product.
[0005]
In order to prevent the activated carbon from dropping from the molded sheet, a method of using fibrous activated carbon (activated carbon fiber) instead of powdered activated carbon has been proposed. For example, Japanese Patent Application Laid-Open No. 62-155914 proposes an activated carbon filter in which fibrillated binder fibers, activated carbon fibers, and submicron size glass fibers are mixed. In this proposal, wood pulp, stem bark fiber, seed fiber, or the like is used as the fibrillated binder fiber to obtain sheet strength by the hydrogen bonding force of the fibrillated binder fiber. Furthermore, since activated carbon is fibrous, activated carbon omission at the time of use becomes lower than when particulate activated carbon is used. However, since the bonding strength of the sheet depends only on the hydrogen bonding strength of the fibrillated binder fibers, the retention strength of the activated carbon fibers is not sufficient, and the activated carbon still falls off. Further, since the fibrillated binder fiber is a cellulose fiber, not only is it poor in chemical resistance, but also when the activated carbon fiber sheet is wetted, the strength is greatly reduced, making it difficult to use.
[0006]
Japanese Patent Laid-Open No. 2-240908 proposes making a sheet of activated carbon fiber and heat-fusible fiber (heat-fusible synthetic fiber) by a nonwoven fabric manufacturing technique. This is because the activated carbon fibers are bonded by heat-bonding fibers, and the activated carbon fibers do not easily fall off, and are excellent in chemical resistance, strength when wet, and reduction in strength when wet. Since a commonly used heat-sealing fiber is used, the specific surface area becomes small.
[0007]
[Problems to be solved by the invention]
In view of these problems, the present inventors have intensively studied the materials constituting the activated carbon sheet, and generally used heat-fusible synthetic fibers are coated with a chemical such as a spinning oil agent. Since the chemicals are separated from the surface of the heat-fusible synthetic fiber during sheet formation and adsorb to the pores of the activated carbon to block the pores, the specific surface area is reduced, reducing the adsorption performance as a filter. I found the problem of end. And, by combining the activated carbon and the specific heat-fusible fiber with no chemicals attached as a material, the sheet can be molded to prevent harmful substances with high efficiency without hindering the inherent adsorption activity and catalytic activity of the activated carbon. Has been found to be able to be removed, and the present invention has been completed.
[0008]
Accordingly, an object of the present invention is an activated carbon sheet that has excellent chemical resistance, a small decrease in strength when wet, and a small fall of activated carbon during use, and inhibits the adsorption activity and catalytic activity inherent to activated carbon as much as possible. It is an object of the present invention to provide a chemical filter sheet that can remove harmful substances with high efficiency.
[0009]
In the first aspect of the present invention, activated carbon fibers and heat-fusible synthetic fibers are mixed as main components, and a part of the heat-fusible synthetic fibers is melted to bond these components. In the manufacturing method of forming an activated carbon sheet, the heat- fusible synthetic fiber obtained by spinning is formed into a sheet forming step (sheet forming step by combining the web forming step and the bonding step) in the nonwoven fabric manufacturing step by the airlay method. Before being introduced into the water), it is washed with a cleaning agent such as water or an organic solvent to remove the adhering agent such as spinning oil, and the remaining amount of the agent such as spinning oil is the heat-fusible synthetic. A method for producing an activated carbon sheet for a chemical filter, comprising a step of setting the amount to 0.1% by mass or less based on fibers (assuming the mass of the heat-fusible synthetic fiber is 100%).
More preferably, the remaining amount of the agent such as the spinning oil is 0.05% by mass or less based on the heat-fusible synthetic fiber.
Here, the remaining amount of chemicals such as spinning oil adhering to the heat-fusible synthetic fiber is measured by a method for measuring a solvent extract by a methanol extraction method defined in JIS L 1015: 1999. And
[0010]
Less dropping of the activated carbon due to the use of thermal adhesive synthetic fibers in the present invention, the activated carbon, activated carbon fiber, granular activated carbon, there is a powdered activated carbon, suitably der particular activated carbon fibers are less likely to fall off Therefore, this is used in the present invention .
Further, the activated carbon sheet of the present invention may also contain components other than the activated carbon-containing fibers and thermally fusible synthetic fiber.
[0013]
2nd of this invention is a manufacturing method of the activated carbon sheet for chemical filters as described in 1st invention which does not use chemical | medical agents, such as surfactant and a dispersing agent, in the said sheet | seat formation process.
[0018]
A third aspect of the present invention is an activated carbon sheet for chemical filters, which is produced by the method described in the first or second aspect of the present invention.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, to prepare the activated carbon textiles and heat fusible synthetic fibers. As the activated carbon fiber, various fibers obtained by a conventionally known method can be used. For example, it is obtained by carbonization and activation using rayon fibers, acrylic fibers, pitch fibers, phenol resin fibers and the like as starting materials. Note that the activated carbon used in the present invention means activated carbon fiber. Moreover, the activated carbon which carry | supported catalysts, such as manganese, magnesium, cobalt, may be sufficient.
[0020]
Various conventionally known fibers can also be used as the heat-fusible synthetic fiber. For example, polyolefin-based heat-fusible fibers, polyester-based heat-fusible fibers, polyamide-based heat-fusible fibers, and the like can be used. A fusible fiber or the like can be used. Examples of the composite component type heat-fusible fiber include polyethylene / low melting point polyethylene core / sheath composite fiber, polypropylene / polyethylene core / sheath composite fiber, polyester / polyethylene core / sheath composite fiber, and polyester / low melting point polyester core / sheath composite fiber. It is done. In addition, polypropylene / polyvinyl alcohol, polyethylene / polyvinyl alcohol composite fiber represented by “trade name SWP” manufactured by Mitsui Chemicals, and the like can be mentioned.
[0021]
One of the most important points in the present invention is to use a heat-sealable synthetic fiber used in the sheet forming step, with a remaining amount of chemicals such as a spinning oil adhering to the predetermined amount or less. . The spinning oil is applied in the spinning process of the fiber manufacturing process to reduce the friction coefficient between the fibers and fibers and between the fibers and metals (in some cases, synthetic resin products) and to improve the workability, and is also cut into chops. Added to the fiber. By applying this spinning oil, it is possible to prevent static electricity and the like in the spinning process, and it is also expected to improve post-processability when the heat-bonded fiber is actually used. As described above, the oil agent is used in various situations, and is used in combination of one kind or plural kinds of components. As the spinning oil agent, for example, a surfactant such as a hydrophilizing agent, a silicon-based treating agent, an amine-based treating agent, or the like is used.
[0022]
In the present invention, the heat fusible synthetic fiber produced without using any chemicals such as spinning oil or the like during the production of the heat fusible synthetic fiber, or the amount of chemicals such as the spinning oil used is reduced compared to the conventional method, and spinning is performed. The activated carbon sheet is formed using a heat-fusible synthetic fiber whose residual amount is less than a predetermined amount (0.1% or less based on the heat-fusable synthetic fiber). . In addition, as a method of removing, a heat-fusible synthetic fiber spun using a conventionally known agent such as a spinning oil, or a heat-fusible synthetic fiber spun by reducing the amount of the agent used such as a spinning oil, In a subsequent step, the composition can be used after washing with a cleaning agent such as water, warm water or an organic solvent to remove a chemical such as a spinning oil adhering to the surface of the heat-fusible synthetic fiber. In this case, the washing process may be provided continuously by the manufacturer of the heat-fusible synthetic fiber in the spinning process, or the manufacturer of the activated carbon sheet may be provided before the sheet forming process, and the washing person is limited. Not.
[0023]
The method for obtaining these heat-fusible synthetic fibers may be obtained by using a medicine whose residual amount is a predetermined amount or less, or the activated carbon sheet manufacturer adheres to the heat-fusible synthetic fibers. The remaining medicine may be used by cleaning the remaining medicine or the like to a desired amount or less. Moreover, you may use combining both methods as desired. In general, since it is difficult to obtain heat-fusible synthetic fibers that do not use any chemicals such as spinning oil in the manufacturing process, it is necessary to use heat-fusible synthetic fibers that have a remaining amount of chemicals such as spinning oil or less. It is possible to obtain a heat-fusible synthetic fiber obtained by using a chemical such as a spinning oil or the like, and use a method in which the fiber is washed with a cleaning agent such as water, warm water or an organic solvent. Manufacture is easy and preferable.
[0024]
The cleaning agent for cleaning the heat-fusible synthetic fiber manufactured using a chemical such as a spinning oil can be water, hot water, an organic solvent, or the like, which can be used alone or in combination of a plurality of types. Alcohols such as ethyl alcohol and isopropyl alcohol can be preferably used from the viewpoint of safety and cleaning effect.
[0025]
As a cleaning method using a cleaning agent, a conventionally known method can be appropriately selected and used. As an example, there is a method in which a heat-fusable synthetic fiber is bathed in a cleaning solution, and then the heat-fusible synthetic fiber is separated, filtered and washed. At this time, the heat-fusible synthetic fiber may be allowed to stand in the washing liquid bath, or the heat-fusible synthetic fiber may be stirred in the washing liquid bath. The cleaning liquid bath can be repeated a plurality of times until the oil agent can be removed, and one type of cleaning liquid can be used in each stage of the cleaning liquid bath, or a plurality of types can be mixed or mixed at each stage. You may change to The time of the cleaning agent bath per time can be appropriately set as desired. The heat-fusible synthetic fiber is used after being separated and filtered from the cleaning agent bath and then dried.
[0026]
The remaining amount of the agent such as spinning oil adhering to the heat-fusible synthetic fiber that is usually sold is based on the heat-fusible synthetic fiber (the mass of the heat-fusible synthetic fiber is 100%) Although the order of 0.4 to 1.0 mass%, in the present invention, by a method such as washing of the foregoing, this ratio Ru with heat-sealable synthetic fibers of 0.1 wt% in the sheet forming process . This ratio is more preferably 0.05% by mass or less. The smaller the remaining ratio of the agent such as the spinning oil agent, the more the agent is detached from the surface of the heat-fusible synthetic fiber during sheet formation, and adsorbs to the pores of the activated carbon to block the pores. Although it is preferable because it is reduced, it is not a good idea to make this ratio too small because it causes manufacturing cost problems such as increased labor and cost for cleaning. Therefore, it can be said that it is sufficient if it can be made 0.1% by mass or less, and further 0.05% by mass or less. In addition, the remaining amount of chemicals such as spinning oil adhering to the heat-fusible synthetic fiber is measured by the method for measuring the amount of solvent extracted by the methanol extraction method specified in JIS L 1015: 1999. And
[0027]
Activated carbon fibers and thermally fusible synthetic fiber is mixed to the desired composition, a conventionally known web forming method, by dispersing the raw material in the air called airlaid method where you forming (representative production processes J & J method as, K-C method, Honshu method, and the like, this method is sheeted using also referred) and Kinocloth method.
The formed web is obtained by melting a part of the heat-fusible synthetic fibers and bonding the heat-fusible synthetic fibers and the activated carbon fibers by a conventionally known heat treatment apparatus to obtain an activated carbon sheet. . The heat treatment method is not particularly limited, and examples thereof include the following heat treatment apparatuses. That is, a drying device such as a through-air dryer, a Yankee dryer, a multi-cylinder drum dryer, or a calendar device such as a heat calendar device or a heat emboss device.
[0028]
The second important point in the present invention is that no chemicals such as surfactants and dispersants are used in the web forming step and the bonding step (also referred to as sheet forming step).
Agents such as spinning oil agent treated on the surface of the heat-fusible synthetic fiber, or surfactants and dispersants used in the sheet forming process are released from the fiber surface in the sheet forming process or during use. Since it is easily adsorbed to the pores of activated carbon such as activated carbon fibers, forming a sheet while using such a chemical, if used, it will block the pores of activated carbon such as activated carbon fibers constituting the activated carbon sheet, The activity such as adsorption activity and catalytic activity inherent to the activated carbon is inhibited. When the activity of the activated carbon is inhibited, functions such as the adsorption ability and catalytic ability of the activated carbon sheet are lowered, and the performance of the product to which the sheet is applied is lowered.
[0029]
In the present invention, the specific surface area of the activated carbon sheet (active carbon fiber etc.) and the formed activated carbon sheet before the sheet formation is evaluated as a method for evaluating the functional deterioration of the activated carbon sheet, such as adsorption ability and catalytic ability. The specific surface area reduction rate was calculated by the method described later, and further evaluated. Naturally, it is preferable that the specific surface area decrease rate is low. As described above, the specific surface area decrease rate decreases as the remaining amount of the chemical such as the spinning oil decreases. However, it is not only the chemicals such as spinning oil that block the pores of the activated carbon, but also the fused heat-fusible synthetic fibers adhere to the activated carbon surface and block the pores. This value varies depending on how much is melted, and this value tends to increase as the blending ratio of activated carbon increases.
Taking the case where the blending ratio of the activated carbon is 40% or more as an example, if the specific surface area reduction rate is approximately 30% or less, it can be said that the decrease in the activity of the activated carbon fiber is small and preferable.
[0030]
In the present invention, when a heat-fusible synthetic fiber manufactured using a chemical such as a spinning oil is obtained and an activated carbon sheet is manufactured, the sheet is washed with a cleaning agent such as water, warm water, or an organic solvent. Although the method used for formation has been described, it is of course possible to use a method of cleaning with a cleaning agent such as water, warm water or an organic solvent after the activated carbon sheet is manufactured unless importance is placed on the cleaning efficiency.
[0031]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples.
[0032]
<Example 1> Activated carbon fiber having a specific surface area of 1500 m 2 / g (manufactured by Ador, trade name: A-15, fiber length: nominally 3 mm, 3.3 dtex) and a polypropylene / polyethylene core-sheath type composite having an adhesion temperature of 135 ° C. A heat-fusible fiber (manufactured by Chisso Corporation, trade name: ESC871, fiber length 5 mm, 1.7 dtex) was prepared. After stirring the heat-fusible synthetic fiber in ethyl alcohol for 10 minutes while bathing, the operation of filtering and taking out the heat-fusible synthetic fiber was repeated three times while replacing the ethyl alcohol with a new one each time, followed by drying. Thus, a heat-fusible synthetic fiber from which the spinning oil was removed was obtained.
After 60% by mass of the activated carbon fiber and 40% by mass of the heat-fusible synthetic fiber were uniformly mixed, a web having a basis weight of 150 g / m 2 was obtained using an airlay nonwoven fabric manufacturing apparatus by a kino cloth method. That is, the activated carbon fiber and the heat-fusible synthetic fiber are mixed in air, defibrated (fibers are loosened when separated), and sent to a mat former to form a web. The web is heated to a temperature of 138 ° C. The activated carbon fiber sheet (one form of activated carbon sheet) was obtained by passing through a through air dryer and pressing.
[0033]
<Example 2> Activated carbon fiber having a specific surface area of 1500 m 2 / g (manufactured by Adol Co., Ltd., trade name: A-15) and polypropylene / polyethylene core-sheath composite heat-fusible fiber (manufactured by Chisso Corporation) having an adhesion temperature of 135 ° C. Product name: ESC871) was prepared. The operation of stirring the heat-fusible synthetic fiber in ion-exchanged water at a temperature of 80 ° C. for 30 minutes and then filtering to take out the heat-fusible synthetic fiber is performed while replacing the ion-exchanged water with a new one every time. After repeating the process, it was dried to obtain a heat-fusible synthetic fiber from which the spinning oil was removed.
After 60% by mass of the activated carbon fiber and 40% by mass of the heat-fusible synthetic fiber were uniformly mixed, a web having a basis weight of 150 g / m 2 was obtained using an airlay nonwoven fabric manufacturing apparatus by a kino cloth method. That is, the activated carbon fiber and the heat-fusible synthetic fiber are mixed in air, defibrated (fibers are loosened when separated), and sent to a mat former to form a web. The web is heated to a temperature of 138 ° C. The activated carbon fiber sheet (one form of activated carbon sheet) was obtained by passing through a through air dryer and pressing.
[0034]
<Example 3> Activated carbon fiber having a specific surface area of 1500 m 2 / g (manufactured by Adol Co., Ltd., trade name: A-15) and polypropylene / polyethylene core-sheath type composite heat-fusible fiber having a bonding temperature of 135 ° C. (manufactured by Chisso Corporation) Product name: ESC871) was prepared. The operation of stirring the heat-fusible synthetic fiber in ion-exchanged water at a temperature of 80 ° C. for 30 minutes and then filtering to take out the heat-fusible synthetic fiber is performed while replacing the ion-exchanged water with a new one every time. After repeating the process, it was dried to obtain a heat-fusible synthetic fiber from which the spinning oil was removed.
After 40% by mass of the activated carbon fiber and 60% by mass of the heat-fusible synthetic fiber were uniformly mixed, a web having a basis weight of 150 g / m 2 was obtained using an airlay nonwoven fabric manufacturing apparatus by a kino cloth method. That is, the activated carbon fiber and the heat-fusible synthetic fiber are mixed in air, defibrated (fibers are loosened when separated), and sent to a mat former to form a web. The web is heated to a temperature of 138 ° C. The activated carbon fiber sheet was obtained by passing through a through air dryer and pressing.
[0035]
<Comparative Example 1> Activated carbon fiber having a specific surface area of 1500 m 2 / g (manufactured by Ador, trade name: A-15, fiber length: nominally 3 mm, 3.3 dtex) and a polypropylene / polyethylene core-sheath type composite having an adhesion temperature of 135 ° C. A heat-fusible fiber (manufactured by Chisso Corporation, trade name: ESC871, fiber length 5 mm, 1.7 dtex) was prepared.
After 60% by mass of the activated carbon fiber and 40% by mass of the heat-fusible synthetic fiber were uniformly mixed, a web having a basis weight of 150 g / m 2 was obtained using an airlay nonwoven fabric manufacturing apparatus using a kino cloth method. That is, the activated carbon fiber and the heat-fusible synthetic fiber are mixed in air, defibrated (fibers are loosened when separated), and sent to a mat former to form a web. The web is heated to a temperature of 138 ° C. The activated carbon fiber sheet was obtained.
Comparative Example 1 is an example of using the heat-fusible synthetic fiber in Example 1 without washing.
[0036]
<Comparative Example 2> Activated carbon fiber having a specific surface area of 1500 m 2 / g (manufactured by Adol, trade name: A-15) and polypropylene / polyethylene core-sheath type composite heat-fusible fiber having a bonding temperature of 135 ° C. (manufactured by Chisso Corporation) Product name: ESC871) was prepared.
After 40% by mass of the activated carbon fiber and 60% by mass of the heat-fusible synthetic fiber were uniformly mixed, a web having a basis weight of 150 g / m 2 was obtained using an airlay nonwoven fabric manufacturing apparatus by a kino cloth method. That is, the activated carbon fiber and the heat-fusible synthetic fiber are mixed in air, defibrated (fibers are loosened when separated), and sent to a mat former to form a web. The web is heated to a temperature of 138 ° C. The activated carbon fiber sheet was obtained.
Comparative Example 2 is an example in which the heat-fusible synthetic fiber was used without washing in Example 3.
[0037]
The activated carbon sheets obtained in Examples 1 to 3 and Comparative Examples 1 and 2 were tested by the following method to evaluate the quality. The results are as shown in Tables 1 and 2.
[0038]
Test method
(1) Tensile strength: The tensile strength in the MD direction was measured according to JIS P 8113: 1998.
(2) Remaining amount of chemicals such as spinning oil adhering to the heat-fusible synthetic fiber used for forming the activated carbon sheet: according to the methanol extraction method defined in 8.22 (a) of JIS L 1015: 1999 It measured according to the measuring method of solvent extract.
[0039]
(3) Specific surface area: Using a continuous flow surface area meter (SA-6200 series) manufactured by HORIBA, Ltd., the activated carbon fiber and activated carbon fiber sheet (activated carbon sheet) can be obtained by the continuous gas flow method of the BET method. The specific surface area was measured.
In this apparatus, a sample is placed in the middle of a path through which a mixed gas flows, and the amount of gas decreased / increased by adsorption / desorption when passing through the sample is measured as a change in the component of the mixed gas. In this apparatus, after the cell containing the sample is immersed in liquid nitrogen to complete the adsorption, the adsorption amount is obtained from the increase in the amount of N 2 gas when the cell is returned to room temperature and desorbed from the sample. For details, refer to the instruction manual (2nd edition, September 1995) of the continuous flow type surface area meter SA-6200 series manufactured by HORIBA, Ltd.
The sample was degassed by using about 0.05 g per measurement and heating at 110 ° C. for 30 minutes.
The specific surface area in this measurement is calculated from the amount of nitrogen adsorbed at a relative pressure P / P 0 = 0.294 (using a mixed gas of 30% N 2 and 70% He).
The device displays the total surface area of the sample as measured from the amount of adsorption,
The specific surface area was determined by dividing this total surface area by the mass of the sample.
[0040]
(4) Specific surface area reduction rate: Since the specific surface area of the heat-fusible synthetic fiber is extremely small compared to activated carbon, it was assumed to be zero, and the specific surface area reduction rate obtained by processing into an activated carbon sheet was calculated by the following formula. .
Specific surface area reduction rate (%) = 100-100 × A / (B × C)
However, A: Specific surface area of activated carbon sheet (m 2 / g)
B: Specific surface area of activated carbon (m 2 / g)
C: Mixing ratio of activated carbon (dimensionless)
[0041]
[Table 1]
[Table 2]
Since the remaining amount of the spinning oil of the heat-fusible synthetic fiber used in Examples 1 to 3 is as small as 0.03 to 0.04% by mass, the obtained activated carbon fiber sheet (activated carbon sheet) has a specific surface area reduction rate. Are 5.6% (Example 1), 8.9% (Example 2), and 18.3 (Example 3), indicating that there is almost no decrease in activity due to sheet formation. On the other hand, since the heat-fusible synthetic fibers used in Comparative Examples 1 and 2 were not washed, the remaining amount of the spinning oil was as large as 0.5% by mass, and the specific surface area reduction rate of the obtained activated carbon fiber sheets was 46. .7% (Comparative Example 1) and 48.3% (Comparative Example 2) are high, and the activity of the activated carbon has greatly decreased, and the functions such as adsorption performance and catalyst performance may not be sufficiently obtained. Has been suggested.
[0044]
【The invention's effect】
As described above, the activated carbon sheet according to the present invention is a sheet having excellent chemical resistance, a small decrease in strength when wet, and a small amount of falling off of activated carbon during use. A harmful substance can be removed with high efficiency without inhibiting the activity, and the present invention has an effect of providing an activated carbon sheet suitable for a chemical filter.
Claims (3)
紡糸して得られた該熱融着性合成繊維を、エアーレイ法による不織布製造工程におけるシート形成工程に導入する前に、水または有機溶剤からなる洗浄剤で洗浄して、付着している紡糸油剤を含む薬剤を除去して、紡糸油剤を含む薬剤の残量が熱融着性合成繊維を基準として０．１質量％以下とする工程を具備することを特徴とするケミカルフィルター用活性炭シートの製造方法。An active carbon fiber and heat-fusible synthetic fibers mixed as principal components, by melting part of the heat fusible synthetic fibers, by adhering between these components, to form an activated carbon sheet In the method
The heat-fusible synthetic fiber obtained by spinning is washed with a cleaning agent made of water or an organic solvent before being introduced into the sheet forming step in the non-woven fabric manufacturing step by the airlay method, and the attached spinning oil agent A step of removing the chemical containing the chemical, and the step of adjusting the residual amount of the chemical containing the spinning oil to 0.1% by mass or less based on the heat-fusible synthetic fiber, Method.
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| JP6054865B2 (en) * | 2010-07-07 | 2016-12-27 | スリーエム イノベイティブ プロパティズ カンパニー | Patterned airlaid nonwoven fibrous webs and methods for making and using them |
| CN102808288B (en) * | 2012-08-09 | 2015-05-20 | 深圳市中纺滤材无纺布有限公司 | Production method of active carbon three-component melt-blown non-woven fabric |
| DE102013106457B3 (en) * | 2013-06-20 | 2014-09-04 | Grimm-Schirp Gs Technologie Gmbh | Carbon fiber random web production process and three-dimensional nonwoven production process as well as carbon fiber random web manufacturing arrangement and nonwoven fabric |
| CN104963084A (en) * | 2015-06-06 | 2015-10-07 | 浙江金三发非织造布有限公司 | SMS stereoscopic protection enclosure waterproof non-woven cloth |
| JP7204026B1 (en) | 2022-03-31 | 2023-01-13 | 大阪ガスケミカル株式会社 | NONWOVEN FABRIC AND METHOD FOR MANUFACTURING SAME, METHOD FOR COLLECTING ORGANIC SOLVENT USING SAME, AND ORGANIC SOLVENT COLLECTION APPARATUS |
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