JP3702922B2 - Heat resistant filter - Google Patents
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- JP3702922B2 JP3702922B2 JP35401696A JP35401696A JP3702922B2 JP 3702922 B2 JP3702922 B2 JP 3702922B2 JP 35401696 A JP35401696 A JP 35401696A JP 35401696 A JP35401696 A JP 35401696A JP 3702922 B2 JP3702922 B2 JP 3702922B2
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Description
【００１０】
【発明の属する技術分野】
本発明は、耐熱性フィルターに関する。さらに詳しくは、従来のフィルターが使用不可能であった酸化剤を含む高温流体、高温芳香族系流体を始めとする高温流体や、高溶解性流体の濾過に好適に使用でき、さらに耐圧性・形態保持性に優れ、かつ濾材の脱落が無く、優れた濾過精度を有するフィルターに関するものである。
【００１１】
【従来の技術】
近年、化学工業製品分野の高純度化が進んだことに伴い、製品の溶液中に含まれる粒子径0.2μｍ〜数ｍｍ程度の異物を取り除くための、繊維を素材とするフィルターの使用が急激にのびてきている。従来、このようなフィルターに使用される繊維の素材としてはポリオレフィン系繊維、ポリエステル系繊維などが多く使われてきた。
一般に繊維を素材とするフィルターは安価であり、構成繊維の繊維径を選択することによって自由に濾過精度を変更でき、繊維間の空隙部に多くの粒子を捕らえることができるために濾過ライフが長い、といったような長所を有している。しかしながら、そのフィルターの耐熱性や耐薬品性は、構成繊維の化学的特性に依存するため、これまでのポリオレフィン系繊維、ポリエステル系繊維などを素材とするフィルターでは高温溶液、高温酸性溶液、高温アルカリ溶液などの、溶解性、反応性の高い溶液によっては問題が生じることがあった。
【００１２】
一方、耐熱性、耐薬品性共に優れた繊維として、ガラス繊維、アラミド繊維、フッソ系繊維、ポリイミド繊維、ポリアリーレン繊維等が一般に知られている。このうち、アラミド繊維は、メタ系アラミド繊維でＵＬサーマルインデックス２００〜２２０℃の耐熱性を有し、パラ系アラミド繊維ではさらに耐熱性に優れているが、高温下ではアルカリ、酸による強度劣化が起こり、高温高湿下では加水分解するという欠点を持つ。また、テトラフルオロエチレン繊維は、ＵＬサーマルインデックス２６０℃の良好な耐熱性と優れた耐薬品性を有するが、強度が低いために加工性が悪く、加工された製品も一般に強度が低くなる。また、特公昭５２−３０６０９公報等で製法が示されるポリフェニレンスルフィド（以下ＰＰＳと略記する）繊維は、ＵＬサーマルインデックス１９０℃を有し、高温での耐アルカリ性、耐酸性に非常に優れており、高い繊維強度を持っている。
【００１３】
このように、これらの耐熱性繊維はそれぞれ短所と長所を併せ持っているが、いずれの繊維も一般の熱融着性繊維に比べて熱接着性が悪いため、従来の技術では、これを前述したようなフィルター、あるいは不織布に成形することが難しかった。
【００１４】
これらの耐熱性繊維を不織布に加工する方法として、これまでに提案されている方法の１つに、耐熱性短繊維のウェブに高圧水流加工やニードルパンチ加工を施して繊維間を交絡させる方法がある。この方法は耐熱性繊維を比較的容易に不織布化できるため、ＰＰＳ繊維にニードルパンチ加工を施して作られたバグフィルターが、ゴミ焼却炉高温排ガス用フィルターのように非常に耐薬品性、耐熱性を要求される分野で数多く用いられている。しかし、これらの方法で作られた不織布からなるフィルターは、繊維が単に機械的に交絡しているだけなので、交絡が不十分な場合には耐圧性や形態安定性が不十分であったり、構成繊維が下流側へ脱落する可能性があり、フィルターへの使用には問題があった。
また、特開平７ー３１３８２３号公報では、多数の小孔を有する筒体を芯として、その外周面にポリフェニレンスルフィド樹脂製の繊維を巻き付けた濾過材が提案されている。しかしながら、この様な糸巻き上のフィルターでは濾過精度に劣り、かつ濾過材が脱落し易いという欠点を有する。
【００１５】
【発明が解決しようとする課題】
本発明の目的は、優れた耐熱性、耐薬品性を有し、構成繊維の脱落がなく、かつ耐圧性と濾過精度にも優れたフィルターを提供するものであり、特に酸やアルカリ成分を含む高温流体等の従来のフィルターが使用不可能であった高温、高反応性、高溶解性流体の濾過に好適に使用できるフィルターを提供するものである。
【００１６】
【課題を解決するための手段】
本発明者らは、前記課題を解決するべく鋭意研究を重ねた結果、耐熱性繊維と熱融着性繊維からなる不織繊維集合体を熱処理し、成形することにより、耐熱性繊維本来の特性を損なうことなく繊維同士が強固に接着した、優れた耐圧性・形態安定性と濾過精度とを併せ持ち、かつ構成繊維の脱落のないフィルターが提供できることを知り、本発明を完成するに至った。
【００１７】
本発明は前記課題を解決するために以下の構成を有する。
（１）耐熱性繊維ウエブの両側若しくは片側に熱融着性繊維ウエブを重ね合わせ成形と同時に若しくは成形後に熱融着性繊維を加熱融着することにより得られる、耐熱性繊維が熱融着性繊維で熱接合された不織繊維集合体からなる耐熱性フィルター。
（２）耐熱性繊維ウエブの両側若しくは片側に熱融着性繊維からなる熱接合された不織布を重ね合わせ、成形と同時に若しくは成形後に熱融着性繊維を加熱融着することにより得られる、耐熱性繊維が熱融着性繊維で熱接合された不織繊維集合体からなる耐熱性フィルター。
（３）熱接合された耐熱性不織繊維集合体が巻回積層された（１）項若しくは（２）項に記載の耐熱性フィルター。
（４）耐熱性不織布をプリーツ状に折り曲げて両側面部を接着した濾過材の中央開口部に、多孔支持体を配して、その両端部が接着された（１）項若しくは（２）項に記載の耐熱性フィルター。
（５）耐熱性繊維が、延伸されたポリフェニレンスルフィド繊維である（１）項若しくは（２）項に記載の耐熱性フィルター。
（６）熱融着性繊維が、繊維長３〜３０ｍｍの熱可塑性繊維である（１）項若しくは（２）項に記載の耐熱性フィルター。
（７）熱融着性繊維が、メルトブロー法で得られた熱可塑性繊維である（１）項若しくは（２）項に記載の耐熱性フィルター。
（８）熱融着性繊維が、融点差１０℃以上を有する高融点樹脂と低融点樹脂との熱可塑性複合繊維である（１）項若しくは（２）項に記載の耐熱性フィルター。
（９）熱融着性繊維が、未延伸状態および／または半延伸状態のポリフェニレンスルフィド繊維である（１）項若しくは（２）項に記載の耐熱性フィルター。
（１０）熱融着性繊維が、ポリオレフィン系繊維、ポリエステル系繊維、ポリアミド系繊維の群から選ばれた少なくとも１種である（１）項若しくは（２）項に記載の耐熱性フィルター。
（１１）熱融着繊維の繊維径が、耐熱性繊維の繊維径以下である（１）項若しくは（２）項に記載の耐熱性フィルター。
（１２）耐熱性繊維ウェブの目付けが、１０〜１００ｇ／ｍ ２ である（１）項若しくは（２）項に記載の耐熱性フィルター。
【００１８】
【発明の実施の形態】
以下、本発明を詳細に説明する。本発明に係る耐熱性フィルターとは、耐熱性繊維が熱融着性繊維で熱接合された不織繊維集合体により構成されるものである。
【００１９】
本発明でいう耐熱性繊維とは、高温雰囲気中に長時間置いた後にも、顕著な表面劣化、強度低下等が生じることがない繊維であればいかなるものでも良い。例えば、延伸されたＰＰＳ繊維、アラミド繊維、ポリエーテルエーテルケトン繊維、ポリイミド繊維、ポリテトラフルオロエチレン繊維、ポリエステル繊維、６６ナイロン繊維、フェノール繊維、ガラス繊維、セラミックス繊維、金属繊維などである。しかし、本発明の耐熱性フィルターに利用される耐熱性繊維には、強度、耐薬品性、耐熱性及びコストや量産化を考えた場合、延伸されたＰＰＳ繊維が最も好適である。また、これらの耐熱性繊維の中に、通常使用される添加物、例えば顔料、カーボン、熱安定剤、紫外線吸収剤、滑剤等を、本発明の効果を妨げない範囲において、必要に応じて使用してもよい。
【００２０】
本発明において耐熱性繊維の原料として好適に利用されるＰＰＳとは、繰り返し単位として、ｐ−フェニレンスルフィド単位やｍ−フェニレンスルフィド単位などのフェニレンスルフィド単位を含有するポリマーを意味する。ｐ−フェニレンスルフィド単位を７０重量％以上、好ましくは９０重量％以上含む実質的に線状ポリマーが好ましい。その製造方法は、工業的にはｐ−ジハロベンゼンと硫化ナトリウムを反応させハロゲン元素をハロゲン化ナトリウムとして取り除くという方法が用いられることが多い。
また、本発明の主旨を逸脱しないかぎり、他の芳香族スルフィドとの共重合体や混合物であってもよい。また、これらの直線状重合体以外に分子中に２個より多いハロゲン原子の置換基を有するポリハロ芳香族化合物をｐ−ジハロベンゼンに対して、０．１〜５モル％添加した分岐型重合体も好適に使用できる。
【００２１】
また、耐熱性繊維の形状は、特に限定されるものではないが、ウェブへの加工性を考慮して、ステープルファイバーであることが好ましい。また、耐熱性繊維の断面は円形、扁平形、三角〜八角形等の角型、Ｔ字形、多葉形、中空断面形等任意の形状とすることができる。
本発明において耐熱性繊維の形状としてステープルファイバーを利用する場合、その単糸繊度、繊維長は特に限定されるわけではないが、カーディング法、エヤレイド法等でウェブ化することを考慮して、単糸繊度１〜１００デニール、繊維長３〜９０ｍｍであることが好ましい。
また、トウを直接開繊してウェブを作製してもよく、特開昭５７−１６９５４号公報に示されるような方法でスパンボンド法等を用いて直接不織布にしても良い。この方法は一般にステープルファイバーを利用する方法よりも高度な技術が必要であるが、製品は構成繊維の形状が長繊維であり、かつ繊維が相互に固着されているため繊維の脱落が起こらず好ましい。
【００２２】
次に、本発明において耐熱性繊維として好適に利用されるＰＰＳステープルファイバーの製造方法の例を述べる。
先ず、ＰＰＳペレットを通常の溶融紡糸工程により溶融紡糸する。すなわち、押出機により約３００〜３５０℃に溶融されたＰＰＳ樹脂をノズルから押し出し、空気、水、グリセリン等の媒体中で好ましくはガラス転移温度以下の温度で冷却し、ロールに巻取る。ロール巻き取り速度は、通常、１００〜１５００ｍ／分で巻取ることができる。
次に溶融紡糸によって得られたＰＰＳ未延伸糸を、供給ロールと引き取りロールとの間で自然延伸比以上で延伸する。延伸は、一段延伸でもよく、２段延伸以上の多段延伸で行ってもよい。延伸温度は通常、ＰＰＳのガラス転移温度すなわち９０℃付近から２７０℃までの範囲で可能である。延伸によりＰＰＳ繊維は、強度、耐熱性、耐薬品性などが付与される。
延伸した後、寸法安定性及び結晶化促進のために、必要に応じて融点以下で定長熱処理または弛緩熱処理を行ってもよい。この熱処理は、常法により行うことができ、特にその条件は限定されないが、例えば、２００〜２８０℃の乾熱雰囲気中、延伸比０．８〜１．２倍の条件下、１〜５０秒間熱処理を行う方法が挙げられる。
そして得られた延伸ＰＰＳ繊維にクリンプを付与した後、所定長に切断し、ステープルファイバーとする。
【００２３】
次に、耐熱性繊維をウェブまたは不織布とする方法について述べる。
耐熱性繊維の形状としてステープルファイバーを利用する場合、まず、カーディング法、エヤレイド法等を用いて必要な目付のウェブに加工する。このウェブの目付は、特に限定されるものではないが、１０〜１００ｇ／ｍ2の範囲のものが好ましい。１０ｇ／ｍ2未満であると、目付が小さすぎて均一なウェブを製造するのが困難であるばかりでなく、フィルターとした場合の利用価値も乏しい。一方、目付が１００ｇ／ｍ2を超えると熱融着性繊維との接着が不十分となり、耐熱性繊維の脱落が起こる場合がある。また、前記のように作製した耐熱性繊維ウェブを予めニードルパンチ法や高圧水流法等で不織布としておくと、繊維が三次元絡合されるので、目付が１００ｇ／ｍ2よりも厚くなっても繊維抜けが起こらず好ましい。ニードルパンチ法や高圧水流法は常法の方式を利用することができる。ニードルパンチ法を使う場合には、３０〜１５０ポイント／ｃｍ2でニードルパンチ加工することが好ましい。高圧水流法を使う場合には、例えば孔径が０．０５〜１．０ｍｍ、好ましくは０．１〜０．４ｍｍの噴射孔を多数配列した装置を用い、噴射圧力が２０〜１５０ｋｇ／ｃｍ2の高圧液体を前記噴射孔から噴射する。噴射孔の配列は、ウェブの進行方向と直交する方向に列状に配列する。この処理はウェブの片面あるいは両面のいずれに施してもよいが、特に片面処理の場合は、噴射孔を複数列に配列し、噴射圧力を前段階で低く後段階で高くして処理すると、均一で緻密な交絡形態と均一な地合を有する不織布を得ることができる。高圧流体としては、水あるいは温水を用いるのが一般的である。また、この工程は連続工程、別工程のいずれであってもよい。高圧流体処理を施した後は、例えば熱風乾燥機等の乾燥設備を用いて、ウェブを乾燥させる。
【００２４】
次に、本発明でいう熱融着性繊維とは、耐熱性繊維に比べて融点または軟化温度が低く、耐熱性繊維と熱融着性繊維との混合物または混繊物を加熱または加圧加熱した場合に耐熱性繊維と接着する。つまり耐熱性繊維同士の繊維接点を熱接合できる繊維であれば、特に限定されない。本発明の場合は特に熱融着性繊維を用いると不織繊維集合体または不織布とした場合に強度向上、形態保持性が良くなり好ましい。これら熱融着性繊維として、例えば、ＰＰＳ樹脂、ポリオレフィン系樹脂、ポリアミド系樹脂、ポリエステル系樹脂のいずれかの樹脂よりなる繊維等が挙げられる。尚、ここで用いられるＰＰＳ樹脂は未延伸又は半延伸状態の物をいい、この様な物は比較的低温で軟化し、熱圧着することが可能であるために熱融着性繊維として使用することができるのである。繊維の形態としては、特にメルトブロー不織布または繊維長３〜３０ｍｍの超短繊維が好適に用いられる。
【００２５】
本発明で用いられる熱融着性繊維は、融点差が１０℃以上の高融点樹脂と低融点樹脂を組み合わせた２種類以上の熱可塑性ポリマーからなる複合繊維であってもよい。本発明において融点とは、示差走査型熱量計によって得られる昇温示差熱曲線において極小値をとる温度をいう。熱融着性繊維としてそのような高融点樹脂と低融点樹脂からなる複合繊維を用いた場合、該複合繊維を含む不織繊維集合体を熱処理した場合でも高融点樹脂の融点以下の温度であれば該複合繊維が通常の熱融着性繊維のように繊維形態を失うことがないため、熱融着性繊維が繊維間空隙を埋めるといったようなフィルターの濾過能力の低下の原因となることがなく好ましい。その形状は、鞘芯型、並列型、偏芯鞘芯型、多層型、あるいは海島型とすることができる。また、熱可塑性ポリマーの組み合わせとしてはＰＰＳ樹脂、ポリエーテルエーテルケトン樹脂、ポリオレフィン系樹脂、ポリエステル系樹脂、ポリアミド系樹脂等を任意に組み合わせることができる。組み合わせの例として、ＰＰＳ樹脂／ ポリエーテルエーテルケトン樹脂、ＰＰＳ樹脂／ポリオレフィン樹脂、ＰＰＳ樹脂／ポリエステル樹脂、ＰＰＳ樹脂／ポリアミド樹脂、ポリエステル樹脂／ポリオレフィン樹脂、ポリオレフィン樹脂／ポリアミド樹脂などが利用可能である。
【００２６】
本発明において熱融着性繊維として超短繊維を用いる場合、その形状は繊維長３〜３０ｍｍ程度でエヤレイド法等によりウェブ化可能であれば特に限定されない。超短繊維は通常の溶融紡糸、延伸法により得ることができる。この超短繊維は、耐熱性繊維との混繊が容易でかつ３次元的方向にランダムに分級し、熱接合点を大きくする。このため不織布層内は、理想的なポーラス構造を有するので、フィルターとした場合に通気性、通水性に優れる。
【００２７】
本発明において熱融着性繊維としてメルトブロー不織布を用いる場合、通常のメルトブロー法が使用できる。すなわち、溶融紡糸しながら、両サイドから高速加熱気流を噴射して繊維を細化し、それをメッシュスクリーン上に捕集し不織布とする方法である。メルトブロー不織布の繊維は、多くの非結晶部分を含み、比較的低温でも軟化するため、接着成分として耐熱性繊維を接着させることができる。つまりメルトブロー不織布と耐熱性繊維とを、そのメルトブロー不織布を構成している繊維のガラス転移点以上で加圧加熱して非結晶部分を軟化させることで、耐熱性繊維の物性には影響は与えず接着し、耐熱性不織布にすることができる。また、メルトブロー法により紡糸された不織布は、一般に通常の溶融紡糸法により作られた繊維よりも構成繊維径が細いために、特に高精度のフィルターを製造する場合に好適に用いることが出来る。メルトブロー不織布の平均繊維径は特に限定されるものではないが、通常、１μｍ以上、好ましくは５μｍ以上、更に好ましくは８μｍ以上であり、通常耐熱性繊維を構成するステープルファイバーの繊維径以下であることが好ましい。耐熱性繊維よりも平均繊維径が大きいと繊維接着交点が少なく、十分な強度が得られにくい。一方、メルトブロー不織布の目付は、２０〜２００ｇ／ｍ2程度のものが好適に用いられる。
【００２８】
次に、前記で得られた耐熱性繊維ウェブまたは不織布を、熱融着性繊維で熱接合して、本発明の耐熱性フィルターを製造する方法について述べる。まず、前記で得られた耐熱性繊維ウェブの両側若しくは片側に熱融着性繊維ウエブを重ね合わせるか、耐熱性繊維ウエブの両側若しくは片側に熱融着性繊維からなる熱接合された不織布を重ね合わせる。熱融着性繊維を使う場合、耐熱性繊維不織布と熱融着性繊維不織布を各１枚ずつ積層したものでもよいし、複数枚交互に積層したものでもよい。不織布の代わりにウェブを使用しても良い。次に、この重ね合わせた物を熱接着あるいは加圧熱接着させて、耐熱性繊維を熱接合する。この処理には、公知の方法を利用することができる。例えば、表面平滑なロールで処理する場合、プレスは、加圧圧力１〜５０ｋｇ／ｃｍで行うことが必要である。加圧圧力が、１ｋｇ／ｃｍ未満の場合には、十分な強度が得られない。５０ｋｇ／ｃｍを超える場合には、空隙率が低くなりフィルターとして十分な通気性が得られないばかりではなく、耐熱性繊維そのものの強度劣化につながり好ましくない。
【００２９】
また、表面平滑なロールの一方をエンボスロールに変えて、エンボスロールのエンボスパターン部に存在する繊維同士を部分的に熱接着させる場合、エンボスロールの圧接面積率は、５％以上が好ましい。この圧接面積率が５％未満の場合、点状の融着区域が少なく機械的強度が低下し、良好な寸法安定性を得るのが困難となる。またエンボスパターンは圧接面積率が５％以上であれば、特に限定されるものではなく、丸型、楕円型、菱型、三角型、Ｔ字型、井型等任意の形状でよい。ロール温度は、熱融着性繊維のガラス転移点以上融点以下の温度範囲で熱接着すればよい。あらかじめホットエアー等で該不織布を予備加熱してもよい。
【００３０】
熱処理においては、例えば熱融着繊維に未延伸状態および／または半延伸状態のＰＰＳ繊維を使用する場合、ＰＰＳの融点に近い高温で熱処理を行うと、空隙率の低いペーパーライクなものとなり、フィルターに利用するのに適したものが得られにくい。このような場合、前記したメルトブロー法で紡糸して得られたＰＰＳ繊維は、未延伸状態および／または半延伸状態をなし、かなり低温（例えば９０〜９５℃位）で軟化しており、これをうまく利用することにより、耐熱性繊維を熱接合することができる。この結果、形態保持性に優れたものとなる。しかも、このような低温で熱接合された不織布は、空隙率が高く、嵩高性に飛んでいるので、フィルターの流量特性、濾過ライフに好影響を与える。熱融着性繊維が前記複合繊維の場合、低融点樹脂の融点以上、高融点樹脂の融点以下の温度で熱処理を行うと熱融着性繊維の高融点樹脂の成分が繊維として残存し、熱接合後の不織布強度向上に寄与し、空隙率と嵩高性にも優れたものが得られる。
【００３１】
次に、前記方法で作製した耐熱性不織布をフィルターの形状に成形する。フィルターの形状は特に限定される物ではなく、例えば筒状フィルター、バグフィルター、シート状フィルターとすることができる。しかし、本発明の実施態様としては筒状フィルターがもっとも好ましい。
【００３２】
筒状フィルターに成形する方法には公知の方法を用いることができる。その方法の１つに、前記耐熱性不織布を多孔支持体に巻き付ける方法が挙げられる。巻き付ける方法は、単に多孔支持体に巻き付けても良く、加熱しながら１〜５０ｋｇ／ｃｍ程度の適当な加圧圧力をかけて巻き付けても良い。また、多孔支持体の材質や形状は特に限定されるものではないが、当初の目的を達成するため、前記耐熱性不織布よりも耐熱性、耐薬品性にすぐれ、かつ変形することがないよう十分な強度を持つものが望ましい。例えばＰＰＳ、ポリテトラフルオロエチレン、ポリエステル、フェノール樹脂などの樹脂を加工した射出成型品、セラミックスやステンレス等の金属を加工したもの等を挙げることができる。また、濾過精度は耐熱性不織布の構成繊維径や空隙率を変えることによって任意のものに設定できる。さらに、耐熱性不織布の繊維径や空隙率をフィルターの上流側から下流側にかけて変化させることによって濾過ライフを延ばすことも可能である。
【００３３】
また、前記の耐熱性繊維ウェブ若しくは不織布と熱融着性繊維ウェブ若しくは不織布を後者を前者の両側若しくは片側に重ね合わせ、特公昭５６−４３１３９のようにサクションドライヤー法、熱風乾燥装置あるいは熱ロール法等の公知の方法で加熱しながら、１〜５０ｋｇ／ｃｍの加圧圧力をかけて芯棒に巻き付けて筒状フィルターとしても良い。この場合には多孔支持体が不要であるため、フィルターを使用後廃棄する場合に多孔支持体を処理する必要がなくなる。この場合も、前記のような構成繊維径や空隙率を変えることにより濾過精度や濾過ライフの調節が可能である。
【００３４】
また、別のフィルターへの加工方法として、前記方法で作製した耐熱性不織布をプリーツ状に折り曲げて筒状フィルターとすることもできる。
この製造法の１例をあげるが、特にこの方法に限定されるものではない。まず、前記の耐熱性不織布を１枚あるいは数枚積層してプリーツ状に折り畳み、両側面部を超音波、高周波等の熱シール法によって完全に溶着させる。この時、補強あるいは有効濾過面積増大のために、耐熱性不織布と適当なスペーサーとを交互に積層して折り畳んでもよい。このスペーサーの形状は特に限定されるものではなく、編物、ネット、パンチングシートなど種々のものを用いることが出来る。また、積層する耐熱性不織布の繊維径を変化させたり、密度勾配を付与することにより、濾過精度の変化やフィルターの交換寿命の延長を計ることもできる。次に多孔支持体を内部に入れ、両端をエンドキャップで接着する。接着には加熱溶融法を使用しても良く、ホットメルトなどのバインダーで接着しても良い。必要によってはフィルターエレメントの保護のために外層に多孔網筒を使用しても良い。これらのスペーサー、エンドキャップ、バインダー、多孔網筒等の材料や形状は特に限定されるものではないが、本発明の効果を損なうことがないよう、いずれの材質も耐熱性不織布と同程度以上の耐熱性、耐薬品性を持つことが望ましい。
【００３５】
【実施例】
以下、実施例により本発明をより具体的に説明するが、本発明はこれにより限定されるものではない。本実施例における不織布、筒状フィルターの物性値等の定義と測定方法は以下の通りである。
（濾過精度）
循環式濾過性能試験機のハウジングにフィルター１本（２５０ｍｍ）を取り付け、５０リットル用水槽からポンプで通水循環する。流量を毎分３０リットルに調節後、水槽に試験粉体として基礎物性用標準粉体であるＡＣコース・テストダスト（ＡＣＣＴＤと略す。中位径：２７〜３１μｍ）を６０ｍｇ／分で連続添加し、添加開始から５分後に原液と濾液を採取し、それぞれの液に含まれる粒子の粒度分布を光遮断式粒子検出器を用いて計測する。この粒度分布測定結果を用いて、フィルターが捕集した粒子の個数の割合を捕集効率として算出し、９９．９％捕集した粒径をフィルターの濾過精度とした。
【００３６】
（濾過ライフ及び耐圧強度）
前記、循環式濾過性能試験器のハウジングにフィルター１本（２５０ｍｍ）を取り付け、流量３０リットル／分で通水循環する。ここに、ＡＣＣＴＤを４００ｍｇ／分で連続添加し、フィルターの１次側と２次側で圧力を測定して圧力損失の変化を記録する。フィルターの圧力損失が２ｋｇ／ｃｍ2に達するまでのケーキの添加量を濾過ライフとした。
引き続き、粉体の添加を行い、フィルターの圧力損失が１０ｋｇ／ｃｍ2に達するか、もしくはフィルターが変形した時点での圧力損失を耐圧強度とした。
（耐熱性および耐薬品性）
循環式濾過性能試験機のハウジングにフィルター１本（２５０ｍｍ）を取り付け、試験流体を流量３０リットル／分、入口圧０．５ｋｇ／ｃｍ2の条件で６０分間通液循環した。その後、冷却、乾燥して外観観察、外径変化測定、および構成繊維表面の電子顕微鏡観察を行った。試験流体として、９５℃の３０重量％硫酸水溶液（溶液１）、９５℃の３０重量％水酸化ナトリウム水溶液（溶液２）を使用した。
【００３７】
実施例１
（耐熱性繊維ウェブ）
ＰＰＳ樹脂（メルトフローレイト（以下ＭＦＲと略す）：５０ｇ／１０分、３１０℃、２．１６ｋｇ荷重）を、１４０℃で２時間予備乾燥した後、シリンダー径３０ｍｍ押出機にて、紡糸温度３２０℃、巻取速度８００ｍ／ｍｉｎにて紡糸した。得られた未延伸糸を９０℃で３倍に延伸し、ついで１６０℃で１．２倍に二段延伸し、最後に２２０℃で弛緩熱処理を行い、３デニール（繊維径１８μｍ）、カット長５１ｍｍのＰＰＳ繊維を得た。得られたステープルファイバーをカードにて目付５０ｇ／ｍ2のウェブに加工した。
（熱融着性繊維ウェブ）
熱融着性繊維としてＰＰＳ（ＭＦＲ：１３０ｇ／１０分、３１０℃、２．１６ｋｇ荷重）を、メルトブロー法によって、平均繊維径が約１０μｍ、目付２７ｇ／ｍ2のメルトブローウェブを作製した。
（本発明のフィルターの作製）
これら得られた耐熱性繊維ウェブを熱融着性繊維ウェブで挟み、サクションバンドドライヤーを用いて、９０℃で加熱しながら加圧圧力１０ｋｇ／ｃｍをかけてＰＰＳ樹脂製多孔射出成形体に巻き取った後、２５０ｍｍの長さに切断し、外径６５ｍｍ、内径３０ｍｍ、長さ２５０ｍｍの中空円筒状フィルターを得た。このフィルターの濾過精度、濾過ライフ、耐圧強度、耐熱性、耐薬品性を評価した。
フィルターの製造条件及びその性能の評価結果はそれぞれ表１及び表２に示した。以下の実施例及び比較例でも同様である。
【００３８】
【表１】
【表２】
実施例２
実施例１で作製した耐熱性繊維ウェブを同じく実施例１で使用した熱融着性繊維ウェブで挟み、加工温度９０℃、加圧圧力１０ｋｇ／ｃｍの条件でカレンダー加工を行い、耐熱性不織布とした。この耐熱性不織布１枚をプリーツ状に折り畳み、両側面部を超音波法によって完全に溶着させ、次にＰＰＳ性多孔支持体を内部に入れ、両端に加熱溶融法を使用してエンドキャップを接着して中空円筒状フィルターを得た。このフィルターの濾過精度、濾過ライフ、耐圧強度、耐熱性、耐薬品性を評価した。
【００４１】
実施例３
耐熱性繊維として、単糸繊度２デニール、繊維長７６ｍｍのポリ−ｍ−フェニレンイソフタルアミド（コーネックス、帝人（株）製）をカードにて目付５０ｇ／ｍ2のウェブを作製した。得られたウェブを実施例１で作製した熱融着性繊維ウェブで挟み、実施例１と同条件で成形を行い、中空円筒状フィルターを得た。このフィルターの濾過精度、濾過ライフ、耐圧強度、耐熱性、耐薬品性を評価した。
【００４２】
実施例４
熱融着性繊維としてポリプロピレン（ＰＰと略す。ＭＦＲ：１６ｇ／１０分、２３０℃、２．１６ｋｇ荷重）をメルトブロー法によって、平均繊維径が約１０μｍ、目付２３ｇ／ｍ2のメルトブロー不織布を作製した。
得られたＰＰメルトブロー不織布で実施例１で作製した耐熱性繊維ウェブを挟み、１６０℃、加圧圧力１０ｋｇ／ｃｍの条件でＰＰＳ樹脂製多孔射出成形体に巻き取った後、２５０ｍｍの長さに切断し、外径６５ｍｍ、内径３０ｍｍ、長さ２５０ｍｍの中空円筒状フィルターを得た。このフィルターの濾過精度、濾過ライフ、耐圧強度、耐熱性、耐薬品性を評価した。
【００４３】
実施例５
実施例１で得られた耐熱性繊維ウェブを、８０メッシュの平織ネット上に置いて、ノズル径０．１ｍｍ、ピッチ１ｍｍのノズルプレートから、水圧２０ｋｇ／ｃｍ2で予備処理した後、４０ｋｇ／ｃｍ2の高水圧で３回処理し、次いでこの交絡したトウウェブを反転させ、同様のノズルプレートから４０ｋｇ／ｃｍ2の高水圧で３回処理し、三次元結合させた。次に、この不織布を乾燥して、目付４８ｇ／ｍ2のウォータージェット（以後ＷＪ）加工耐熱性繊維不織布を得た。この不織布上に、実施例１で得られた熱融着性繊維ウェブを乗せ、実施例１と同条件で成形を行い、中空円筒状フィルターを得た。このフィルターの濾過精度、濾過ライフ、耐圧強度、耐熱性、耐薬品性を評価した。
【００４４】
実施例６
熱融着性繊維としてＰＰ（ＭＦＲ：１６ｇ／１０分、２３０℃、２．１６ｋｇ荷重）を芯成分とし、高密度ポリエチレン（ＰＥと略す。ＭＩ：１６ｇ／１０分、１９０℃）を鞘成分として、メルトブロー法によって、平均繊維径が約１０μｍ、目付２６ｇ／ｍ2の複合メルトブロー不織布を作製した。
得られた複合メルトブロー不織布で実施例５で作製したＷＪ加工耐熱性繊維不織布を挟み、１３０℃、加圧圧力１０ｋｇ／ｃｍの条件でＰＰＳ樹脂製多孔射出成形体に巻き取った後、２５０ｍｍの長さに切断し、外径６５ｍｍ、内径３０ｍｍ、長さ２５０ｍｍの中空円筒状フィルターを得た。このフィルターの濾過精度、濾過ライフ、耐圧強度、耐熱性、耐薬品性を評価した。
【００４５】
実施例７
熱融着性繊維として、ＰＰＳ樹脂（ＭＦＲ：５０ｇ／１０分、３１０℃、２．１６ｋｇ荷重）を、１４０℃で２時間予備乾燥した後、シリンダー径３０ｍｍ押出機にて、紡糸温度３２０℃、巻取速度８００ｍ／ｍｉｎにて紡糸した。得られた繊維は、繊維径１８μｍ、カット長５ｍｍの低配向短繊維とした。実施例１で得られたＰＰＳ繊維ウェブをエヤレイド不織布加工機に供給し、前記低配向ＰＰＳ短繊維をエヤレイド加工機によってＰＰＳ繊維ウェブ上に、堆積させた。なおこの短繊維ウェブの目付は、２４ｇ／ｍ2とした。このＰＰＳ繊維と熱融着性短繊維の混繊物をサクションバンドドライヤーを用いて、９０℃で加熱しながら加圧圧力１０ｋｇ／ｃｍをかけて金属製の芯棒に巻き取った後、冷却し芯棒を抜き取り、２５０ｍｍの長さに切断し、外径６５ｍｍ、内径３０ｍｍ、長さ２５０ｍｍの中空円筒状フィルターを得た。このフィルターの濾過精度、濾過ライフ、耐圧強度、耐熱性、耐薬品性を評価した。
【００４６】
実施例８
熱融着性繊維として、芯成分に極限粘度［η］が０．６５のポリエチレンテレフタレート（ＰＥＴと略す）と鞘成分にＰＰ（ ＭＦＲ：１６ｇ／１０分、２３０℃、２．１６ｋｇ荷重）の鞘芯複合型繊維を溶融紡糸装置を用いて紡糸、延伸し、繊度２デニール、カット長５ｍｍの短繊維とした。実施例１で得られたＰＰＳ繊維ウェブをエヤレイド不織布加工機に供給し、前記複合短繊維をエヤレイド加工機によってＰＰＳ繊維ウェブ上に、堆積させた。なおこの短繊維ウェブの目付は、２３ｇ／ｍ2とした。このＰＰＳ繊維と熱融着性短繊維の混繊物を１６０℃の熱風乾燥機を通し、加圧圧力１０ｋｇ／ｃｍをかけて金属製の芯棒に巻き取った後、冷却し芯棒を抜き取り、２５０ｍｍの長さに切断し、外径６５ｍｍ、内径３０ｍｍ、長さ２５０ｍｍの中空円筒状フィルターを得た。このフィルターの濾過精度、濾過ライフ、耐圧強度、耐熱性、耐薬品性を評価した。
【００４７】
実施例９
熱融着性繊維不織布として、ＰＰＳ（ＭＦＲ：１３０ｇ／１０分、３１０℃、２．１６ｋｇ荷重）をメルトブロー法によって平均繊維径が約２０μｍ、目付２０ｇ／ｍ2とした不織布を作製した。実施例５で得た耐熱性繊維不織布の上に熱融着性繊維不織布を乗せ、１６０℃の熱風乾燥機を通し、加圧圧力１０ｋｇ／ｃｍをかけて金属製の芯棒に巻き取った後、冷却し芯棒を抜き取り、２５０ｍｍの長さに切断し、外径６５ｍｍ、内径３０ｍｍ、長さ２５０ｍｍの中空円筒状フィルターを得た。このフィルターの濾過精度、濾過ライフ、耐圧強度、耐熱性、耐薬品性を評価した。
【００４９】
比較例１
実施例５で作製したウォーターニードル加工耐熱性繊維不織布のみを実施例１と同条件で成形を行ったが、耐熱性繊維同士の接着はなく、フィルターとして使用することができなかった。
【００５０】
比較例２
熱融着性繊維としてＰＥＴ（融点２５３℃）を芯成分とし、共重合ポリエステル（融点１９５℃）を鞘成分とする繊維径２２μｍ、カット長５１ｍｍの複合熱融着性繊維を使用し、カードにて目付５０ｇ／ｍ2のウェブを作製した。そのウェブを２００℃で加熱しながら加圧圧力１０ｋｇ／ｃｍをかけてＰＥＴ樹脂製多孔射出成形体に巻き取った後、２５０ｍｍの長さに切断し、外径６０ｍｍ、内径３０ｍｍ、長さ２５０ｍｍの中空円筒状フィルターを得た。このフィルターの濾過精度、濾過ライフ、耐圧強度、耐熱性、耐薬品性を評価した。
【００５１】
比較例３
熱融着性繊維としてＰＰ（ＭＦＲ：１６ｇ／１０分、２３０℃、２．１６ｋｇ荷重）を芯成分とし、高密度ＰＥ（ＭＦＲ：１６ｇ／１０分、１９０℃、２．１６ｋｇ荷重）を鞘成分とする繊維径２２μｍ、カット長５１ｍｍの複合熱融着性繊維を使用し、カードにて目付５０ｇ／ｍ2のウェブを作製した。そのウェブを１３０℃で加熱しながら加圧圧力１０ｋｇ／ｃｍをかけてＰＥ樹脂製多孔射出成形体に巻き取った後、２５０ｍｍの長さに切断し、外径６０ｍｍ、内径３０ｍｍ、長さ２５０ｍｍの中空円筒状フィルターを得た。このフィルターの濾過精度、濾過ライフ、耐圧強度、耐熱性、耐薬品性を評価した。
【００５２】
実施例１と比較例２を比較すると、濾過精度、ライフ、耐圧強度は同程度であるが、実施例１の方が高温アルカリ溶液である溶液２に対する耐熱・耐薬品性で優っている。また、実施例１と比較例３を比較すると、濾過精度、ライフ、耐圧強度は同程度であるが、実施例１の方が高温酸性溶液である溶液１、高温アルカリ性溶液である溶液２の何れに対しても耐熱・耐薬品性で優っている。
以上、熱融着性繊維については未延伸／半延伸ＰＰＳ繊維、ポリオレフィン繊維、ポリエステル繊維について評価したが、未延伸／半延伸ポリアミド繊維についても同様の効果が得られる。
【００５３】
【発明の効果】
本発明の耐熱性フィルターは、耐熱性繊維が強固に熱接合されているため、濾材の脱落が無く、耐熱性、耐薬品性、及び耐圧性が要求されるような分野に好適に使用することができる。このため、使用時には十分な耐圧強度と優れた濾過精度を発揮する。
また、構成繊維径や空隙率を変えることにより、さまざまな濾過精度や寿命を持つフィルターを設計することも可能である。[0010]
BACKGROUND OF THE INVENTION
The present invention relates to a heat resistant filter. More specifically, it can be suitably used for filtration of high-temperature fluids including oxidants, high-temperature aromatic fluids, and high-solubility fluids that contain oxidants, which cannot be used with conventional filters. The present invention relates to a filter having excellent shape retention and no filter material falling off and having excellent filtration accuracy.
[0011]
[Prior art]
In recent years, with the progress of high purity in the chemical industry field, the use of fiber-based filters to remove foreign substances with a particle size of about 0.2 μm to several mm contained in product solutions has been rapidly increasing. It is growing. Conventionally, polyolefin fibers, polyester fibers, and the like have been frequently used as the fiber materials used in such filters.
In general, a filter made of fiber is inexpensive, the filtration accuracy can be freely changed by selecting the fiber diameter of the constituent fibers, and many particles can be trapped in the gaps between the fibers, resulting in a long filtration life. , And so on. However, since the heat resistance and chemical resistance of the filter depend on the chemical properties of the constituent fibers, high-temperature solutions, high-temperature acidic solutions, and high-temperature alkalis have been used in filters made from conventional polyolefin fibers and polyester fibers. Problems may arise depending on highly soluble and reactive solutions such as solutions.
[0012]
On the other hand, glass fibers, aramid fibers, fluorine-based fibers, polyimide fibers, polyarylene fibers and the like are generally known as fibers excellent in both heat resistance and chemical resistance. Among them, the aramid fiber is a meta-aramid fiber and has a heat resistance of UL thermal index of 200 to 220 ° C., and the para-aramid fiber is more excellent in heat resistance. However, the strength is deteriorated by alkali and acid at high temperatures. It has the disadvantage of hydrolyzing under high temperature and high humidity. Tetrafluoroethylene fiber has good heat resistance of UL thermal index of 260 ° C. and excellent chemical resistance, but has low workability due to low strength, and processed products generally have low strength. Further, a polyphenylene sulfide (hereinafter abbreviated as PPS) fiber whose production method is disclosed in JP-B-52-30609 has a UL thermal index of 190 ° C., and is extremely excellent in alkali resistance and acid resistance at high temperatures. Has high fiber strength.
[0013]
As described above, these heat-resistant fibers have both disadvantages and advantages. However, since each fiber has poor thermal adhesiveness as compared with a general heat-fusible fiber, the conventional technique described above. It was difficult to form such a filter or nonwoven fabric.
[0014]
As a method for processing these heat-resistant fibers into a nonwoven fabric, one of the methods proposed so far is a method in which a web of heat-resistant short fibers is subjected to high-pressure water flow processing or needle punching to entangle the fibers. is there. This method makes it relatively easy to fabricate heat resistant fibers, so bag filters made by needle punching PPS fibers are extremely chemical and heat resistant like high temperature exhaust gas filters for garbage incinerators. It is used in many fields where it is required. However, filters made of non-woven fabric made by these methods are only mechanically entangled with fibers, so if the entanglement is insufficient, pressure resistance and form stability are insufficient, There is a possibility that the fibers fall off downstream, and there is a problem in using the filter.
Japanese Patent Application Laid-Open No. 7-313823 proposes a filter medium in which a cylindrical body having a large number of small holes is used as a core, and a fiber made of polyphenylene sulfide resin is wound around the outer peripheral surface thereof. However, such a filter on a spool has the disadvantages that the filtration accuracy is inferior and the filter medium easily drops off.
[0015]
[Problems to be solved by the invention]
An object of the present invention is to provide a filter having excellent heat resistance and chemical resistance, having no falling off of constituent fibers, and excellent in pressure resistance and filtration accuracy, and particularly includes an acid or alkali component. It is an object of the present invention to provide a filter that can be suitably used for filtration of a high temperature, high reactivity, highly soluble fluid, which cannot be used with a conventional filter such as a high temperature fluid.
[0016]
[Means for Solving the Problems]
As a result of intensive research to solve the above problems, the present inventors have heat treated and molded a non-woven fiber assembly composed of heat-resistant fibers and heat-fusible fibers, and thus have inherent properties of heat-resistant fibers. The present invention has been completed by knowing that it is possible to provide a filter in which fibers are firmly bonded to each other without impairing the properties, having excellent pressure resistance, form stability, and filtration accuracy, and without losing constituent fibers.
[0017]
In order to solve the above problems, the present invention has the following configuration.
(1)Obtained by heating and fusing the heat-fusible fiber simultaneously with or after molding the heat-fusible fiber web on both sides or one side of the heat-resistant fiber web,A heat-resistant filter comprising a non-woven fiber assembly in which heat-resistant fibers are thermally bonded with heat-fusible fibers.
(2)A heat-resistant fiber obtained by superimposing a heat-bonded nonwoven fabric made of heat-fusible fibers on both sides or one side of a heat-resistant fiber web and heat-sealing the heat-fusible fibers simultaneously with or after the molding, Consists of non-woven fiber assemblies thermally bonded with heat-fusible fibersHeat resistant filter.
(3)Item (1) or (2), wherein the heat-bonded heat-resistant nonwoven fiber assembly is wound and laminatedHeat resistant filter.
(4)Item (1) or (2), wherein the porous support is disposed in the central opening of the filter medium in which the heat-resistant non-woven fabric is folded into a pleat shape and the both side surfaces are adhered, and both ends thereof are adhered.Heat resistant filter.
(5)Item (1) or (2), wherein the heat resistant fiber is a stretched polyphenylene sulfide fiber.Heat resistant filter.
(6)Item (1) or (2), wherein the heat-fusible fiber is a thermoplastic fiber having a fiber length of 3 to 30 mm.Heat resistant filter.
(7)Item (1) or (2), wherein the heat-fusible fiber is a thermoplastic fiber obtained by a melt blow method.Heat resistant filter.
(8)Item (1) or (2), wherein the heat-fusible fiber is a thermoplastic composite fiber of a high-melting point resin and a low-melting point resin having a melting point difference of 10 ° C. or more.Heat resistant filter.
(9)The heat-fusible fiber is an unstretched and / or semi-stretched polyphenylene sulfide fiber according to (1) or (2)Heat resistant filter.
(10)The heat-fusible fiber is at least one selected from the group of polyolefin fibers, polyester fibers, and polyamide fibers, according to item (1) or (2)Heat resistant filter.
(11)The fiber diameter of the heat-sealing fiber is equal to or less than the fiber diameter of the heat-resistant fiber, as described in (1) or (2)Heat resistant filter.
(12) The basis weight of the heat resistant fiber web is 10 to 100 g / m. 2 As described in (1) or (2)Heat resistant filter.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail. The heat-resistant filter according to the present invention is composed of a nonwoven fiber assembly in which heat-resistant fibers are thermally bonded with heat-fusible fibers.
[0019]
The heat-resistant fiber referred to in the present invention may be any fiber as long as it does not cause remarkable surface deterioration, strength reduction, etc. even after being placed in a high temperature atmosphere for a long time. For example, stretched PPS fibers, aramid fibers, polyether ether ketone fibers, polyimide fibers, polytetrafluoroethylene fibers, polyester fibers, 66 nylon fibers, phenol fibers, glass fibers, ceramic fibers, metal fibers, and the like. However, a stretched PPS fiber is most suitable for the heat resistant fiber used in the heat resistant filter of the present invention in view of strength, chemical resistance, heat resistance, cost and mass production. Further, in these heat-resistant fibers, commonly used additives such as pigments, carbon, heat stabilizers, ultraviolet absorbers, lubricants, etc. are used as necessary within the range that does not interfere with the effects of the present invention. May be.
[0020]
PPS suitably used as a raw material for heat-resistant fibers in the present invention means a polymer containing phenylene sulfide units such as p-phenylene sulfide units and m-phenylene sulfide units as repeating units. A substantially linear polymer containing 70% by weight or more, preferably 90% by weight or more of p-phenylene sulfide units is preferred. As the production method, industrially, a method in which p-dihalobenzene and sodium sulfide are reacted to remove a halogen element as sodium halide is often used.
Moreover, unless it deviates from the main point of this invention, the copolymer and mixture with another aromatic sulfide may be sufficient. In addition to these linear polymers, there are also branched polymers in which 0.1 to 5 mol% of a polyhaloaromatic compound having a substituent of more than 2 halogen atoms in the molecule is added to p-dihalobenzene. It can be suitably used.
[0021]
The shape of the heat-resistant fiber is not particularly limited, but is preferably a staple fiber in consideration of processability to the web. The cross section of the heat resistant fiber may be any shape such as a circle, a flat shape, a square shape such as a triangle to an octagon, a T shape, a multileaf shape, and a hollow cross sectional shape.
When using staple fibers as the heat-resistant fiber shape in the present invention, the single yarn fineness and fiber length are not particularly limited, but considering that the web is formed by the carding method, the airlaid method, etc. It is preferable that the single yarn fineness is 1 to 100 denier and the fiber length is 3 to 90 mm.
Alternatively, the tow may be directly opened to produce a web, or a non-woven fabric may be formed directly using a spunbond method or the like by a method as disclosed in Japanese Patent Application Laid-Open No. 57-16954. This method generally requires a higher level of technology than the method using staple fibers, but the product is preferable because the shape of the constituent fibers is long fibers and the fibers are fixed to each other so that the fibers do not fall off. .
[0022]
Next, the example of the manufacturing method of the PPS staple fiber used suitably as a heat resistant fiber in this invention is described.
First, PPS pellets are melt-spun by a normal melt-spinning process. That is, a PPS resin melted at about 300 to 350 ° C. is extruded from a nozzle by an extruder, cooled in a medium such as air, water, or glycerin, preferably at a temperature not higher than the glass transition temperature, and wound on a roll. The roll can be wound at a roll winding speed of usually 100 to 1500 m / min.
Next, the PPS undrawn yarn obtained by melt spinning is drawn at a natural drawing ratio or higher between the supply roll and the take-up roll. The stretching may be a single-stage stretching or a multi-stage stretching of two or more stages. The stretching temperature is usually possible in the range of the glass transition temperature of PPS, that is, from about 90 ° C. to 270 ° C. The PPS fiber is given strength, heat resistance, chemical resistance and the like by stretching.
After stretching, for the purpose of dimensional stability and crystallization promotion, a constant length heat treatment or a relaxation heat treatment may be performed at a melting point or lower as required. This heat treatment can be performed by a conventional method, and the conditions are not particularly limited. For example, in a dry heat atmosphere at 200 to 280 ° C., for 1 to 50 seconds under a stretch ratio of 0.8 to 1.2 times. A method of performing heat treatment can be mentioned.
And after giving a crimp to the obtained extending | stretching PPS fiber, it cut | disconnects to predetermined length and is set as a staple fiber.
[0023]
Next, a method for forming a heat resistant fiber into a web or a nonwoven fabric will be described.
When using staple fiber as the shape of the heat resistant fiber, first, it is processed into a required basis weight web using a carding method, an air raid method or the like. The basis weight of the web is not particularly limited, but is 10 to 100 g / m.2The thing of the range of is preferable. 10 g / m2If it is less, the basis weight is too small and it is difficult to produce a uniform web, and the utility value when used as a filter is poor. On the other hand, the basis weight is 100 g / m2If it exceeds 1, adhesion to the heat-fusible fiber becomes insufficient, and the heat-resistant fiber may fall off. In addition, when the heat-resistant fiber web produced as described above is made into a nonwoven fabric in advance by a needle punch method or a high-pressure water flow method, the fibers are three-dimensionally entangled, so that the basis weight is 100 g / m.2Even if it becomes thicker than this, it is preferable because no fiber loss occurs. Conventional methods can be used for the needle punch method and the high-pressure water flow method. 30 to 150 points / cm when using the needle punch method2It is preferable to perform needle punching. When using the high-pressure water flow method, for example, an apparatus in which a large number of injection holes having a hole diameter of 0.05 to 1.0 mm, preferably 0.1 to 0.4 mm are arranged, and the injection pressure is 20 to 150 kg / cm.2The high-pressure liquid is ejected from the ejection hole. The arrangement of the injection holes is arranged in a row in a direction orthogonal to the traveling direction of the web. This treatment may be performed on either one side or both sides of the web, but in the case of single-sided treatment, it is uniform if the injection holes are arranged in a plurality of rows and the injection pressure is increased in the previous stage and increased in the later stage. A non-woven fabric having a dense entangled form and a uniform texture can be obtained. As the high-pressure fluid, water or warm water is generally used. Moreover, this process may be either a continuous process or a separate process. After performing the high-pressure fluid treatment, the web is dried using a drying facility such as a hot air dryer.
[0024]
Next, the heat-fusible fiber referred to in the present invention has a melting point or a softening temperature lower than that of the heat-resistant fiber, and heats or pressurizes a mixture or fiber mixture of the heat-resistant fiber and the heat-fusible fiber. When bonded, heat-resistant fibers are bonded. That is, it is not particularly limited as long as it is a fiber that can thermally bond a fiber contact between heat resistant fibers. In the case of the present invention, it is particularly preferable to use a heat-fusible fiber because the strength is improved and the shape retention is improved when a non-woven fiber aggregate or nonwoven fabric is used. Examples of these heat-fusible fibers include fibers made of any one of PPS resin, polyolefin resin, polyamide resin, and polyester resin. The PPS resin used here refers to an unstretched or semi-stretched material, and such a material is softened at a relatively low temperature and can be thermocompression bonded, so that it is used as a heat-fusible fiber. It can be done. As the form of the fiber, a melt blown nonwoven fabric or an ultrashort fiber having a fiber length of 3 to 30 mm is particularly preferably used.
[0025]
The heat-fusible fiber used in the present invention may be a composite fiber composed of two or more types of thermoplastic polymers in which a high melting point resin having a melting point difference of 10 ° C. or more and a low melting point resin are combined. In this invention, melting | fusing point means the temperature which takes the minimum value in the temperature rising differential heat curve obtained by a differential scanning calorimeter. When a composite fiber composed of such a high-melting resin and a low-melting resin is used as the heat-fusible fiber, even if the nonwoven fiber assembly containing the composite fiber is heat-treated, it should be at a temperature lower than the melting point of the high-melting resin. For example, since the composite fiber does not lose its fiber form like a normal heat-fusible fiber, the heat-fusible fiber may cause a decrease in the filtration ability of the filter such as filling the inter-fiber gap. Less preferred. The shape may be a sheath core type, a parallel type, an eccentric sheath core type, a multilayer type, or a sea island type. Further, as a combination of thermoplastic polymers, a PPS resin, a polyether ether ketone resin, a polyolefin resin, a polyester resin, a polyamide resin, and the like can be arbitrarily combined. Examples of combinations that can be used include PPS resin / polyether ether ketone resin, PPS resin / polyolefin resin, PPS resin / polyester resin, PPS resin / polyamide resin, polyester resin / polyolefin resin, polyolefin resin / polyamide resin, and the like.
[0026]
In the present invention, when an ultrashort fiber is used as the heat-fusible fiber, the shape is not particularly limited as long as the fiber length is about 3 to 30 mm and a web can be formed by the air raid method or the like. Ultrashort fibers can be obtained by ordinary melt spinning and drawing methods. These ultrashort fibers are easy to mix with heat-resistant fibers and are randomly classified in a three-dimensional direction to increase the thermal bonding point. For this reason, since the inside of a nonwoven fabric layer has an ideal porous structure, when it is set as a filter, it is excellent in air permeability and water permeability.
[0027]
In the present invention, when a melt blown nonwoven fabric is used as the heat-fusible fiber, a normal melt blow method can be used. In other words, while melt spinning, a high-speed heated air stream is jetted from both sides to make the fibers finer and collect them on a mesh screen to make a nonwoven fabric. The fiber of the melt blown nonwoven fabric contains many amorphous parts and softens even at a relatively low temperature. Therefore, the heat resistant fiber can be bonded as an adhesive component. In other words, the melt-blown nonwoven fabric and heat-resistant fiber are heated under pressure above the glass transition point of the fiber constituting the melt-blown nonwoven fabric to soften the amorphous part without affecting the physical properties of the heat-resistant fiber. It can be bonded to make a heat-resistant nonwoven fabric. Moreover, since the nonwoven fabric spun by the melt-blowing method generally has a smaller fiber diameter than fibers produced by the usual melt-spinning method, it can be suitably used particularly when a highly accurate filter is produced. The average fiber diameter of the melt blown nonwoven fabric is not particularly limited, but is usually 1 μm or more, preferably 5 μm or more, more preferably 8 μm or more, and is usually equal to or less than the fiber diameter of staple fibers constituting the heat-resistant fiber. Is preferred. When the average fiber diameter is larger than that of the heat-resistant fiber, there are few fiber bonding intersections, and it is difficult to obtain sufficient strength. On the other hand, the basis weight of the melt blown nonwoven fabric is 20 to 200 g / m.2Those having a degree are preferably used.
[0028]
Next, a method for producing the heat-resistant filter of the present invention by thermally bonding the heat-resistant fiber web or nonwoven fabric obtained above with heat-fusible fibers will be described. First, the heat-resistant fiber web obtained aboveHeat-sealable fiber webs are stacked on both sides or one side of the fabric, or heat-bonded nonwoven fabric made of heat-sealable fibers is stacked on both sides or one side of the heat-resistant fiber webThe When using heat-fusible fibers, the heat-resistant fiber nonwoven fabric and the heat-fusible fiber nonwoven fabric may be laminated one by one, or a plurality of sheets may be laminated alternately. If you use a web instead of a non-woven fabricgood. Then thisSuperimposedThe object is thermally bonded or pressurized and thermally bonded to heat-resistant fibers. A known method can be used for this processing. For example, when processing with a roll having a smooth surface, it is necessary to perform pressing at a pressure of 1 to 50 kg / cm. When the pressure is less than 1 kg / cm, sufficient strength cannot be obtained. When it exceeds 50 kg / cm, not only does the porosity become low and sufficient air permeability as a filter cannot be obtained, but the strength of the heat resistant fiber itself is deteriorated, which is not preferable.
[0029]
In addition, when one of the surface smooth rolls is changed to an embossing roll and the fibers existing in the embossing pattern portion of the embossing roll are partially thermally bonded, the pressure contact area ratio of the embossing roll is preferably 5% or more. When the pressure contact area ratio is less than 5%, there are few dotted fusion areas, the mechanical strength is lowered, and it becomes difficult to obtain good dimensional stability. The embossed pattern is not particularly limited as long as the pressure contact area ratio is 5% or more, and may be any shape such as a round shape, an elliptical shape, a rhombus shape, a triangular shape, a T shape, and a well shape. The roll temperature may be heat-bonded in a temperature range from the glass transition point to the melting point of the heat-fusible fiber. The nonwoven fabric may be preheated with hot air or the like in advance.
[0030]
In heat treatment, for example, when unstretched and / or semi-stretched PPS fibers are used as the heat-bonding fibers, if heat treatment is performed at a high temperature close to the melting point of PPS, it becomes a paper-like one with a low porosity. It is difficult to obtain a product suitable for use. In such a case, the PPS fiber obtained by spinning by the melt blow method described above is in an unstretched state and / or a semi-stretched state, and is softened at a considerably low temperature (for example, about 90 to 95 ° C.). By making good use, heat resistant fibers can be thermally bonded. As a result, the form retainability is excellent. Moreover, the nonwoven fabric heat-bonded at such a low temperature has a high porosity and is voluminous, and thus has a positive effect on the flow characteristics of the filter and the filtration life. When the heat-fusible fiber is the above-mentioned composite fiber, when the heat treatment is performed at a temperature not lower than the melting point of the low-melting resin and not higher than the melting point of the high-melting resin, the components of the high-melting resin of the heat-fusible fiber remain as fibers. It contributes to improving the strength of the nonwoven fabric after bonding, and is excellent in porosity and bulkiness.
[0031]
Next, the heat-resistant nonwoven fabric produced by the above method is formed into a filter shape. The shape of the filter is not particularly limited, and for example, a cylindrical filter, a bag filter, or a sheet filter can be used. However, a cylindrical filter is most preferred as an embodiment of the present invention.
[0032]
A known method can be used as a method for forming the cylindrical filter. One of the methods includes a method of winding the heat-resistant nonwoven fabric around a porous support. As a method of winding, it may be simply wound around the porous support, or may be wound by applying an appropriate pressure of about 1 to 50 kg / cm while heating. In addition, the material and shape of the porous support are not particularly limited. However, in order to achieve the initial purpose, the porous support is superior in heat resistance and chemical resistance than the heat resistant nonwoven fabric, and is not sufficiently deformed. What has a sufficient strength is desirable. For example, an injection molded product obtained by processing a resin such as PPS, polytetrafluoroethylene, polyester, or phenol resin, or a product obtained by processing a metal such as ceramics or stainless steel can be used. The filtration accuracy can be set arbitrarily by changing the constituent fiber diameter and the porosity of the heat-resistant nonwoven fabric. Furthermore, it is possible to extend the filtration life by changing the fiber diameter and porosity of the heat-resistant nonwoven fabric from the upstream side to the downstream side of the filter.
[0033]
Further, the heat-resistant fiber web or nonwoven fabric and the heat-fusible fiber web or nonwoven fabric are overlapped on both sides or one side of the former, and a suction dryer method, a hot air drying device or a hot roll method as disclosed in Japanese Patent Publication No. 56-43139. While being heated by a known method such as, a cylindrical filter may be formed by applying a pressure of 1 to 50 kg / cm and winding it around a core rod. In this case, since the porous support is unnecessary, it is not necessary to treat the porous support when the filter is discarded after use. Also in this case, the filtration accuracy and the filtration life can be adjusted by changing the constituent fiber diameter and the porosity as described above.
[0034]
Further, as another method of processing into a filter, the heat resistant nonwoven fabric produced by the above method can be folded into a pleated shape to form a cylindrical filter.
Although an example of this manufacturing method is given, it is not particularly limited to this method. First, one or several of the above heat-resistant nonwoven fabrics are laminated and folded into a pleat shape, and both side portions are completely welded by a heat sealing method such as ultrasonic wave and high frequency. At this time, in order to reinforce or increase the effective filtration area, heat-resistant nonwoven fabrics and appropriate spacers may be alternately laminated and folded. The shape of the spacer is not particularly limited, and various types such as a knitted fabric, a net, and a punching sheet can be used. Further, by changing the fiber diameter of the heat-resistant non-woven fabric to be laminated or imparting a density gradient, it is possible to change the filtration accuracy and extend the replacement life of the filter. Next, the porous support is put inside, and both ends are bonded with end caps. For the bonding, a heat melting method may be used, or bonding with a binder such as hot melt may be used. If necessary, a porous mesh tube may be used as the outer layer for protecting the filter element. The materials and shapes of these spacers, end caps, binders, perforated net cylinders, etc. are not particularly limited, but any material should be at least as high as the heat-resistant nonwoven fabric so as not to impair the effects of the present invention. It is desirable to have heat resistance and chemical resistance.
[0035]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, this invention is not limited by this. The definitions and measurement methods of physical properties of the nonwoven fabric and the cylindrical filter in this example are as follows.
(Filtration accuracy)
A filter (250 mm) is attached to the housing of the circulating filtration performance tester, and water is circulated by a pump from a 50 liter water tank. After adjusting the flow rate to 30 liters per minute, AC course test dust (ACCTD, abbreviated as medium diameter: 27-31 μm), which is a standard powder for basic physical properties, is continuously added to the water tank at 60 mg / min. After 5 minutes from the start of addition, the stock solution and the filtrate are collected, and the particle size distribution of the particles contained in each solution is measured using a light blocking particle detector. Using this particle size distribution measurement result, the ratio of the number of particles collected by the filter was calculated as the collection efficiency, and the particle size collected by 99.9% was taken as the filtration accuracy of the filter.
[0036]
(Filtration life and pressure resistance)
One filter (250 mm) is attached to the housing of the circulating filtration performance tester, and water is circulated at a flow rate of 30 liters / minute. Here, ACCTD is continuously added at 400 mg / min, the pressure is measured on the primary side and the secondary side of the filter, and the change in pressure loss is recorded. The pressure loss of the filter is 2kg / cm2The amount of cake added until reaching the value was defined as the filtration life.
Subsequently, powder is added and the pressure loss of the filter is 10 kg / cm.2The pressure loss at the time when the pressure reached or the filter was deformed was defined as the pressure resistance.
(Heat resistance and chemical resistance)
A filter (250 mm) is attached to the housing of the circulating filtration performance tester, the test fluid is supplied at a flow rate of 30 liters / minute, and the inlet pressure is 0.5 kg / cm.2The solution was circulated for 60 minutes under the following conditions. Then, it cooled and dried and performed appearance observation, outer diameter change measurement, and electron microscope observation of the constituent fiber surface. As test fluids, a 30 wt% aqueous sulfuric acid solution (solution 1) at 95 ° C. and a 30 wt% aqueous sodium hydroxide solution (solution 2) at 95 ° C. were used.
[0037]
Example 1
(Heat resistant fiber web)
PPS resin (melt flow rate (hereinafter abbreviated as MFR): 50 g / 10 min, 310 ° C., 2.16 kg load) was pre-dried at 140 ° C. for 2 hours, and then a spinning temperature of 320 ° C. with a 30 mm cylinder extruder. Spinning was performed at a winding speed of 800 m / min. The undrawn yarn obtained was stretched 3 times at 90 ° C, then double-stretched 1.2 times at 160 ° C, and finally subjected to relaxation heat treatment at 220 ° C, 3 denier (fiber diameter 18 µm), cut length A 51 mm PPS fiber was obtained. The obtained staple fiber is 50 g / m in weight with a card.2Processed into a web.
(Heat-bondable fiber web)
PPS (MFR: 130 g / 10 min, 310 ° C., 2.16 kg load) is used as the heat-fusible fiber, the average fiber diameter is about 10 μm, and the basis weight is 27 g / m.2A melt blow web was prepared.
(Preparation of the filter of the present invention)
These obtained heat-resistant fiber webs are sandwiched between heat-fusible fiber webs and wound around a PPS resin porous injection molded article by applying a pressure of 10 kg / cm while heating at 90 ° C. using a suction band dryer. After that, it was cut into a length of 250 mm to obtain a hollow cylindrical filter having an outer diameter of 65 mm, an inner diameter of 30 mm, and a length of 250 mm. The filter was evaluated for filtration accuracy, filtration life, pressure strength, heat resistance, and chemical resistance.
The production conditions of the filter and the evaluation results of its performance are shown in Table 1 and Table 2, respectively. The same applies to the following examples and comparative examples.
[0038]
[Table 1]
[Table 2]
Example 2
The heat-resistant fiber web produced in Example 1 was sandwiched between the heat-fusible fiber webs used in Example 1 and calendered under the conditions of a processing temperature of 90 ° C. and a pressure of 10 kg / cm. did. This heat-resistant nonwoven fabric is folded into a pleat shape, and both sides are completely welded by ultrasonic method. Next, a PPS porous support is put inside, and end caps are bonded to both ends using a heat melting method. Thus, a hollow cylindrical filter was obtained. The filter was evaluated for filtration accuracy, filtration life, pressure strength, heat resistance, and chemical resistance.
[0041]
Example 3
As a heat-resistant fiber, poly-m-phenyleneisophthalamide (conex, manufactured by Teijin Ltd.) having a single yarn fineness of 2 denier and a fiber length of 76 mm is used as a card with a weight of 50 g / m.2The web was made. The obtained web was sandwiched between the heat-fusible fiber webs produced in Example 1 and molded under the same conditions as in Example 1 to obtain a hollow cylindrical filter. The filter was evaluated for filtration accuracy, filtration life, pressure strength, heat resistance, and chemical resistance.
[0042]
Example 4
Polypropylene (abbreviated as PP. MFR: 16 g / 10 min, 230 ° C., 2.16 kg load) as a heat-fusible fiber is melt blown to an average fiber diameter of about 10 μm and a basis weight of 23 g / m.2A melt blown nonwoven fabric was prepared.
The heat resistant fiber web produced in Example 1 was sandwiched between the obtained PP melt blown nonwoven fabric, wound on a PPS resin porous injection molded body under the conditions of 160 ° C. and a pressure of 10 kg / cm, and then 250 mm long. A hollow cylindrical filter having an outer diameter of 65 mm, an inner diameter of 30 mm, and a length of 250 mm was obtained by cutting. The filter was evaluated for filtration accuracy, filtration life, pressure strength, heat resistance, and chemical resistance.
[0043]
Example 5
The heat resistant fiber web obtained in Example 1 was placed on a plain mesh net of 80 mesh, and a water pressure of 20 kg / cm from a nozzle plate having a nozzle diameter of 0.1 mm and a pitch of 1 mm.240kg / cm after pretreatment with23 times at a high water pressure, and then the entangled tow web was inverted and 40 kg / cm from a similar nozzle plate2Were treated three times at a high water pressure and three-dimensionally coupled. Next, the nonwoven fabric is dried to have a basis weight of 48 g / m.2Water-jet (hereinafter WJ) processed heat resistant fiber nonwoven fabric was obtained. On this nonwoven fabric, the heat-fusible fiber web obtained in Example 1 was placed and molded under the same conditions as in Example 1 to obtain a hollow cylindrical filter. The filter was evaluated for filtration accuracy, filtration life, pressure strength, heat resistance, and chemical resistance.
[0044]
Example 6
PP (MFR: 16 g / 10 min, 230 ° C., 2.16 kg load) is used as the heat-fusible fiber, and high-density polyethylene (abbreviated as PE. MI: 16 g / 10 min, 190 ° C.) is used as the sheath component. The average fiber diameter is about 10 μm and the basis weight is 26 g / m by the melt blow method.2A composite meltblown nonwoven fabric was prepared.
The WJ-processed heat-resistant fiber nonwoven fabric produced in Example 5 was sandwiched between the obtained composite meltblown nonwoven fabric, wound on a PPS resin porous injection molded body under the conditions of 130 ° C. and a pressure of 10 kg / cm, and then a length of 250 mm A hollow cylindrical filter having an outer diameter of 65 mm, an inner diameter of 30 mm, and a length of 250 mm was obtained. The filter was evaluated for filtration accuracy, filtration life, pressure strength, heat resistance, and chemical resistance.
[0045]
Example 7
As a heat-fusible fiber, PPS resin (MFR: 50 g / 10 min, 310 ° C., 2.16 kg load) was pre-dried at 140 ° C. for 2 hours, and then a spinning temperature of 320 ° C. with a cylinder diameter 30 mm extruder. Spinning was performed at a winding speed of 800 m / min. The obtained fiber was a low orientation short fiber having a fiber diameter of 18 μm and a cut length of 5 mm. The PPS fiber web obtained in Example 1 was supplied to an airlaid nonwoven fabric processing machine, and the low-oriented PPS short fibers were deposited on the PPS fiber web by an airlaid processing machine. The basis weight of this short fiber web is 24 g / m.2It was. The mixture of PPS fibers and heat-fusible short fibers is wound on a metal core rod by applying a pressure of 10 kg / cm while heating at 90 ° C. using a suction band dryer, and then cooled. The core rod was extracted and cut into a length of 250 mm to obtain a hollow cylindrical filter having an outer diameter of 65 mm, an inner diameter of 30 mm, and a length of 250 mm. The filter was evaluated for filtration accuracy, filtration life, pressure strength, heat resistance, and chemical resistance.
[0046]
Example 8
As the heat-fusible fiber, the core component is polyethylene terephthalate (abbreviated as PET) having an intrinsic viscosity [η] of 0.65 and the sheath component is PP (MFR: 16 g / 10 min, 230 ° C., 2.16 kg load). The core composite type fiber was spun and drawn using a melt spinning apparatus to obtain a short fiber having a fineness of 2 denier and a cut length of 5 mm. The PPS fiber web obtained in Example 1 was supplied to an airlaid nonwoven fabric processing machine, and the composite short fibers were deposited on the PPS fiber web by an airlaid processing machine. The basis weight of this short fiber web is 23 g / m.2It was. This mixed fiber of PPS fiber and heat-fusible short fiber is passed through a hot air drier at 160 ° C., wound around a metal core rod under a pressure of 10 kg / cm, then cooled and extracted. A hollow cylindrical filter having an outer diameter of 65 mm, an inner diameter of 30 mm, and a length of 250 mm was obtained. The filter was evaluated for filtration accuracy, filtration life, pressure strength, heat resistance, and chemical resistance.
[0047]
Example 9
As a heat-fusible fiber nonwoven fabric, an average fiber diameter of PPS (MFR: 130 g / 10 min, 310 ° C., 2.16 kg load) is about 20 μm, and a basis weight is 20 g / m.2A non-woven fabric was prepared. After placing the heat-fusible fiber non-woven fabric on the heat-resistant fiber non-woven fabric obtained in Example 5, passing it through a hot air dryer at 160 ° C. and applying a pressure of 10 kg / cm and winding it on a metal core rod After cooling, the core rod was extracted and cut into a length of 250 mm to obtain a hollow cylindrical filter having an outer diameter of 65 mm, an inner diameter of 30 mm, and a length of 250 mm. The filter was evaluated for filtration accuracy, filtration life, pressure strength, heat resistance, and chemical resistance.
[0049]
Comparative Example 1
Only the water-needle processed heat-resistant fiber nonwoven fabric produced in Example 5 was molded under the same conditions as in Example 1, but the heat-resistant fibers were not bonded to each other and could not be used as a filter.
[0050]
Comparative Example 2
As a heat-fusible fiber, a composite heat-fusible fiber having a fiber diameter of 22 μm and a cut length of 51 mm having PET (melting point 253 ° C.) as a core component and copolymer polyester (melting point 195 ° C.) as a sheath component is used for a card. 50g / m2The web was made. The web was heated at 200 ° C. under a pressure of 10 kg / cm and wound on a PET resin porous injection molded article, cut into a length of 250 mm, an outer diameter of 60 mm, an inner diameter of 30 mm, and a length of 250 mm. A hollow cylindrical filter was obtained. The filter was evaluated for filtration accuracy, filtration life, pressure strength, heat resistance, and chemical resistance.
[0051]
Comparative Example 3
PP (MFR: 16 g / 10 min, 230 ° C., 2.16 kg load) as the core component, and high density PE (MFR: 16 g / 10 min, 190 ° C., 2.16 kg load) as the sheath component A composite heat-fusible fiber having a fiber diameter of 22 μm and a cut length of 51 mm is used, and the basis weight is 50 g / m by card.2The web was made. The web was heated at 130 ° C. under a pressure of 10 kg / cm and wound on a PE resin porous injection molded article, cut into a length of 250 mm, an outer diameter of 60 mm, an inner diameter of 30 mm, and a length of 250 mm. A hollow cylindrical filter was obtained. The filter was evaluated for filtration accuracy, filtration life, pressure strength, heat resistance, and chemical resistance.
[0052]
When Example 1 and Comparative Example 2 are compared, the filtration accuracy, life, and pressure resistance are similar, but Example 1 is superior in heat resistance and chemical resistance to the solution 2 that is a high-temperature alkaline solution. Further, when Example 1 and Comparative Example 3 are compared, the filtration accuracy, life, and pressure strength are comparable, but Example 1 is either solution 1 that is a high-temperature acidic solution or solution 2 that is a high-temperature alkaline solution. It also excels in heat and chemical resistance.
As described above, the heat-fusible fiber was evaluated for unstretched / semi-stretched PPS fiber, polyolefin fiber, and polyester fiber, but the same effect can be obtained for unstretched / semi-stretched polyamide fiber.
[0053]
【The invention's effect】
The heat-resistant filter of the present invention is suitably used in fields where heat-resistant fibers are firmly heat-bonded, so that the filter medium does not fall off and heat resistance, chemical resistance, and pressure resistance are required. Can do. For this reason, sufficient pressure resistance and excellent filtration accuracy are exhibited during use.
It is also possible to design filters having various filtration accuracy and life by changing the constituent fiber diameter and porosity.
Claims (12)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP35401696A JP3702922B2 (en) | 1996-10-17 | 1996-12-18 | Heat resistant filter |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29580596 | 1996-10-17 | ||
| JP8-295805 | 1996-10-17 | ||
| JP35401696A JP3702922B2 (en) | 1996-10-17 | 1996-12-18 | Heat resistant filter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH10174822A JPH10174822A (en) | 1998-06-30 |
| JP3702922B2 true JP3702922B2 (en) | 2005-10-05 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP35401696A Expired - Lifetime JP3702922B2 (en) | 1996-10-17 | 1996-12-18 | Heat resistant filter |
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| Country | Link |
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| JP (1) | JP3702922B2 (en) |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000117027A (en) * | 1998-08-10 | 2000-04-25 | Toray Ind Inc | Filter fabric for collecting dust and bag filter |
| WO2000009790A1 (en) * | 1998-08-10 | 2000-02-24 | Toray Industries, Inc. | Dust collecting filter cloth and bag filter |
| KR100875842B1 (en) | 1999-03-30 | 2008-12-24 | 칫소가부시키가이샤 | Filter cartridge |
| DE60026420T8 (en) * | 1999-10-28 | 2006-12-07 | Toray Industries, Inc. | Heat-resistant material and filter made from it |
| JP4556263B2 (en) * | 1999-11-11 | 2010-10-06 | チッソ株式会社 | Pleated net laminate |
| US20020092423A1 (en) * | 2000-09-05 | 2002-07-18 | Gillingham Gary R. | Methods for filtering air for a gas turbine system |
| US6943207B2 (en) * | 2002-09-13 | 2005-09-13 | H.B. Fuller Licensing & Financing Inc. | Smoke suppressant hot melt adhesive composition |
| JP2009155764A (en) * | 2007-12-27 | 2009-07-16 | Toyobo Co Ltd | Long fiber nonwoven fabric and process for producing the same |
| KR101057818B1 (en) | 2010-09-27 | 2011-08-19 | 비엔케이(주) | A functional filter and manufacturing method thereof |
| JP6102141B2 (en) * | 2012-09-21 | 2017-03-29 | 東レ株式会社 | Polyphenylene sulfide fiber nonwoven fabric |
| US9155982B2 (en) * | 2013-05-10 | 2015-10-13 | Pall Corporation | Poss-modified support element |
-
1996
- 1996-12-18 JP JP35401696A patent/JP3702922B2/en not_active Expired - Lifetime
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| JPH10174822A (en) | 1998-06-30 |
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