JP2004124317A - Polyester-based nonwoven fabric and filter - Google Patents
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- JP2004124317A JP2004124317A JP2002291495A JP2002291495A JP2004124317A JP 2004124317 A JP2004124317 A JP 2004124317A JP 2002291495 A JP2002291495 A JP 2002291495A JP 2002291495 A JP2002291495 A JP 2002291495A JP 2004124317 A JP2004124317 A JP 2004124317A
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【０００１】
【発明の属する技術分野】
本発明は、剛性が高く遮蔽性やフィルター特性に優れた不織布に関する。特に濾過操作時の流体抵抗により変形することの小さいフィルターとして好適な複合不織布に関する。さらに、ダスト払い落とし性の良いフィルターに関する。そして、プリーツ加工されてのちカートリッジに使用されるフィルター関するものである。
【０００２】
【従来の技術】
ポリエチレンテレフタレートよりなる不織布は、機械的特性及び化学的特性に優れており、それぞれのポリエステルの特性に応じて、例えば土木・建築資材用や産業資材用の繊維に使用されている。
特に、代表的なポリエステルであるポリエチレンテレフタレートは、耐熱性、優れた強伸度特性、比較的安価な原料価格などの優位性から工業的に広く利用されている。
また、ポリエチレンテレフタレートと低密度ポリエチレンの２成分よりなる複合繊維を用いた長繊維不織布が特公平８−１４０６９号公報に開示されるごとく熱接着性不織布として用いられている。たとえば、ポリエステル系複合繊維不織布は、微多孔分離膜材などと貼り合わせて分離膜の支持体として用いられることも多い。膜材は、ポリプロピレンやポリテトラフルオロエチレンなどで構成される場合も多いが、これらの構成樹脂は非常に薄く剛性が低いために単独で用いることが困難であるため、補強材として積層されている。
【０００３】
これらの複合繊維不織布は、目付を大きく設定すると接点での接着強度が高くなり、その結果として剛性にすぐれるため構造材など高い剛性の必要な用途に用いられている。
【０００４】
通常、不織布の繊維径を太くするほど、およびまたは目付を大きくするほど不織布の剛性を高くすることが可能となるが、複合繊維でない不織布を熱接着により一体化をはかった場合には目付がおおよそ１５０〜１８０ｇ／ｍ＾２くらいより高い場合に熱伝導差の問題で層間剥離の問題を生じやすい。その対策として、繊維径が大きく目付も大きいポリエステル系の芯鞘型複合繊維をも使用されているが、それでも部分的にエンボス加工された部分がフィルムに近い状態に変化しており、フィルターとして用いた際に流体透過抵抗が大きくなり、送液ポンプやブロアなどの動力費が高くなるという問題が有った。また、剛性を高めるためにエンボス押さえ部面積が大きくなることが多く、場合によっては溝状の長いエンボスパターンをつけることもあるが、表面に凹凸があるためにフィルターを逆洗やパルス払い落としなどの手段によりフィルターを再生する際に、ダストなどのケーキ剥離性が低下するという問題点が有った。また、不織布の剛性が高くなるとシートの巻き出しが不安定になりやすいが、表面の凹部があることによりプリーターなどの加工機供給部との接触面積が小さくなりすぎるためか供給時にシートが滑って供給が不安定になるという問題が顕著となる場合も少なくなかった。また、太い繊維を用いた場合には濾過精度が高く設定しにくいという問題が有った。
【０００５】
【発明が解決しようとする課題】
本発明は、かかる問題点を鑑みて、剛性が高く、しかもフィルターとして用いた場合のフィルター性能が高くかつダストの剥離性が良い長繊維不織布およびそれを用いたフィルターを提供するものである。
【０００６】
【課題を解決するための手段】
かかる問題点を解決するために本発明は以下の手段をとる。
【０００７】
すなわち、本発明は、下記の構成からなる。
１．３層以上の積層不織布層よりなり、３点支持曲げ剛性が０．１０〜１．５０Ｎ／２ｃｍ、目付が１００〜３００ｇ／ｍ＾２、厚みが０．２〜０．７ｍｍであることを特徴とするポリエステル系不織布。
２．少なくとも、繊維径が７〜２０ミクロンの繊維よりなる目付が１０〜１５０ｇ／ｍ＾２の不織布Ａ層、繊維径が２０〜５０μｍの芯鞘型複合繊維を３０％以上含む目付が１５〜２００ｇ／ｍ＾２である不織布Ｂ層、目付が３０〜２００ｇ／ｍ＾２のポリエステル不織布Ｃ層からなる積層不織布であって、各層が積層一体化されてなることを特徴とする上記第１に記載のポリエステル系不織布。
３．少なくとも不織布Ａ層あるいはＣ層の何れか一方が長繊維不織布であることを特徴とする上記第２に記載のポリエステル系不織布。
４．芯鞘型複合繊維が、鞘成分の融点が１１０℃〜２５０℃のポリエステル、芯成分の融点が１８５℃〜３００℃のポリエステルであることを特徴とする上記第２に記載のポリエステル系不織布。
５．熱接着により積層一体化されていることを特徴とする上記第２に記載のポリエステル系不織布。
６．プリーツ加工されてなることを特徴とする上記第２に記載のポリエステル系不織布。
７．上記第１記載のポリエステル系不織布を用いてなることを特徴とするフィルタ−。
８．上記第２記載の不織布Ａ層とＣ層を構成する繊維の繊維径が異なり、かつ不織布の色が異なることを特徴とするフィルター。
９．不織布Ａおよび不織布Ｃ層が熱エンボスカレンダープレスにより外表面側に部分的に凹面の窪みを有することを特徴とする上記第７あるいは８に記載のフィルター。
１０．不織布がプリーツ加工されてなることを特徴とする上記第８に記載のフィルター。
【０００８】
以下に本発明の用件について詳細に説明する。
先ず、本発明に係る不織布は、３層以上の積層不織布により構成され、３点支持曲げ剛性が０．１０〜１．５０Ｎ／２ｃｍ、目付が１００〜３００ｇ／ｍ＾２、厚みが０．２〜０．７ｍｍであることが好ましい。
本発明に係る不織布は、比較的低い目付かつ薄い厚みであっても、３点支持曲げ剛性を上記範囲内とするには後述する不織布の積層一体化が好ましい態様である。剛性が上記範囲を下回ると、低いとプリーツ織りしてフィルターやフィルターの支持体に用いたり、構造体の一部として不織布を用いた場合にたわみなどの変形を生じやすくなるため好ましくない。また剛性が上記範囲を上回るっても大きな問題はないが剛性を高くするためには厚みを大きくとる必要が出てくるため、カートリッジのプリーツ折り込み本数が少なくなるためあまり好ましくはない。好ましくは、０．１５〜０．７０Ｎ／２ｃｍである。
また、フラジール通気度が３〜２０ｃｃ／ｃｍ＾２秒であることが望ましい。通気抵抗が上記範囲を下回ると被濾過流体を供給するポンプなどの動力費が高くなったり流体から受ける抗力でプリーツの山形状が変形したりするする問題が発生する場合がありあまり好ましくない。一方、剛性が上記範囲を上回ってもあまり問題はないが、発明者らの経験では濾過精度が低下する可能性が高く望ましくない場合が多かった。好ましくは５〜２０ｃｃ／ｃｍ＾２秒、特に好ましくは７〜１５ｃｃ／ｃｍ＾２秒である。フラジール通気度と５ｃｍ／秒の通気抵抗は以下の式でほぼ換算可能である。
５ｃｍ／秒の通気抵抗（ｍｍＡｑ）＝６３．５／フラジール通気度（ｃｃ／ｃｍ＾２秒）
【０００９】
本発明で用いられる不織布は、具体的には、下記の多層構造からなることが剛性を高くする目的から推奨される。
構成要素である不織布Ａ層は、目付が１０〜１５０ｇ／ｍ＾２の不織布であることが望ましい。また、厚みが０．２〜０．７ｍｍであることが好ましい。かかる条件をはずれて、目付が小さすぎたりあるいは厚みが薄すぎると所望の剛性を得ることが困難となる。目付が高すぎると通気度が小さくなりすぎてあまり好ましくない。また、厚みが厚いと剛性は高くなる場合も多いが、厚すぎると繊維相互の接着点数が減るために剛性が不足したりあるいは不織布が毛羽立ちやすくなるなどの問題を生じる場合があるためあまり好ましくない。フィルターカートリッジに織り込んで使用する場合は、厚みが厚すぎると折り込み面積が小さくなるため好ましくない場合もある。繊維径が７〜２０ミクロンの間にあることで、充填密度をあまり高く設定しないでも高い濾過精度を達成することが可能となる。繊維径が細すぎると摩耗などにより毛羽だちやすいという問題点が発現する。また、剛性を高くするために繊維径を太くするとフィルターとして用いた場合に充填率を高くしないと濾過精度が高く設定できなくなり、その結果流体透過抵抗が増加するという問題を生じる。本発明の複合不織布をフィルターとして用いる場合は、不織布Ａ層を濾過面とするサーフェース濾過材として用いられることが一般的であると考えられるので、細い繊維径であるほど濾過精度が高くなり、かつ表面が平滑化されやすくその結果ケーキ剥離性が良くなって濾過ライフも長くすることが可能となる。一方、捕集される粒子の凝集性が高い場合には繊維径をある程度太くすることも好ましく、繊維径が１０〜２０ミクロンの間にあることが好ましかった。
本発明のように複合構造をとらない場合は、濾過精度と濾過ライフの性能バランスを良くして、かつ剛性の高い不織布を得ることは極めて困難と考えられる。不織布Ａ層およびまたはＣ層が長繊維不織布であると、フィルターや遮蔽材として用いた場合に繊維の脱落の心配がないために特に好ましい。
【００１０】
また、不織布Ａ層の繊維はシートの長手方向中心線に沿ってプラスマイナス１５度の角度の範囲に主に配列していることが好ましい。繊維を主に長手方向に配列させることで不織布の剛性を高めることが可能となる。この範囲に配列する繊維本数の割合が２５％以上であれば（均一な繊維配列で有れば約１７％）主に配列していると見なすことができるが、好ましくは３０％以上、特に好ましくは５０％以上である。不織布剛性を高めるためには、繊維径が細いほど長手方向に繊維配向の割合が高いことが好ましい。繊維径が１５ミクロン以下である場合には、該方向への繊維配列が７０％以上、特に好ましくは８０％以上である。特に、横手方向に平行な折れ目をジグザグ状にいれてプリーツ折りして用いる場合にその曲げ剛性を高くする事が可能となり、水などの流体が透過するときの抵抗で不織布折れ曲がって隣接するシートが重なるために有効濾過面積が低下するという問題を防止することが容易となる。本不織布の構成繊維の融点は不織布Ｃ層の融点と同じであってもよいが、好ましくはそれより１０〜５０℃程度低くして、不織布張り合わせの過程で繊維の一部を融解させることで毛羽立ち防止をすることが可能であり特に好ましい。
【００１１】
本発明で用いられる不織布の構成要素である不織布Ｂ層は、鞘成分が融点が１１０℃から２５０℃の間にある低融点ポリエステルであり、芯成分が融点が１８０℃〜３００℃のポリエステルである芯鞘型複合繊維であることが望ましい。この構成により、本発明の目的である剛性の高い不織布およびそれを用いたフィルターを提供することが可能となる。不織布の形態は、長繊維不織布で有ればプロセス油剤を付与する必要がないため異物を無くすることが可能である。また、長繊維不織布はリントフリー性にもすぐれるため繊維の脱落が無いのでフィルターなどの用途に特に好適である。発明者らの検討の範囲では各ポリマーの融点が高いほど良好な剛性を得ることが可能であった。
【００１２】
鞘成分に用いるポリマーは、融点が１１０℃から２５０℃の間にある低融点ポリエステルであることが望ましい。融点が１１０℃以下であると、室温に於いても接着力が低下してしまったり、粘着性がでてブロッキングなどの問題が出るおそれがあるためあまり好ましくない。一方、融点が２５０℃より高くなると、接着加工温度が高くなり過ぎて接着対象物の表面温度が低いとすぐに固化が始まり接着性が低下したり操業性が悪くなる可能性があるためあまり好ましくない。ポリエステル系樹脂は、一般に異物の発生が少ないためフィルター関連用途への市場に特に好適である。用いる樹脂としては、ポリプロピレンテレフタレート、ポリブチレンテレフタレート、脂肪族ポリエステルあるいはブロック共重合ポリエステルおよびそれらのいずれかを基本骨格の一分とする共重合ポリマーなどが好適に利用できる。
【００１３】
また、芯成分のポリマーは、ポリエチレンテレフタレート、ポリプロピレンテレフタレート、ポリブチレンテレフタレート、ポリ乳酸あるいはそれらのいずれかを一部に含む共重合体であることが望ましい。これらのポリエステル系樹脂は、融点が１８０℃〜３００℃の間にあれば高温時の寸法安定性や機械的強度特性に優れるため特に好ましい。最近、自然成分由来やバイオテクノロジーで原料を得ることが可能となってきており、環境保全の観点からも特に好ましい。特に、液体フィルターなどとして形態安定性を樹脂されるときには、ポリエステル繊維のもつ高い剛性が有効になる。芯成分のポリマーは、鞘成分のポリマーの融点あるいは軟化点より少なくとも２０℃以上高い温度であることが、接着加工の操業性を考えると好ましい。融点の差が小さいと、加工温度のコントロールを厳密にする必要があるため高度な温度制御設備が必要になったり、加工速度が低速にせざるをえなくなりあまり好ましくない。
【００１４】
複合繊維の芯成分と鞘成分の重量比は２０：８０〜７０：３０程度であることが好ましく、さらに好ましくは３０：７０〜６０：４０の間であり、特に好ましくは４０：６０〜５５：４５の間である。接着成分である鞘成分が３０％より少ないと十分な接着力を得ることが難しくなる。一方、７０％を超えると、接着加工時の温度コントロールが難しくなったり、機械的強度特性が低くなりやすいなど問題を生じやすいので余り好ましくない。
【００１５】
また、該不織布Ｂ層を構成する主な繊維の繊維径が２０〜５０μｍの間にあることが望ましく、好ましくは２５〜５０μｍの間であり、特に好ましくは３０〜５０μｍである。繊維径が２０μｍより小さいと接着部面積が小さくなり、接着力が低下しやすくなりあまり好ましくない。一方、繊維径が５０μｍより大きくなると不織布の不織布の地合が斑が大きくなり好ましくない。また、スパンボンド法で該不織布を製造する場合には紡糸過程で糸切れを生じたり、繊維牽引のエジェクターに繊維が付着したり詰まったりするなどの問題点を生じやすく操業性に問題を生じることも少なくなかった。また、太すぎる繊維よりなる不織布は繊維量が少ないために地合の斑が目立ちやすく、物性のバラツキにつながる。繊維の少ないところは、不織布の剛性不足や不織布の接着強度の低下を招き好ましくない。不織布Ｂ層の繊維は、Ａ層とＢ層に挟まれているため繊維の脱落の可能性が低いことから短繊維であっても良い。
【００１６】
さらに、不織布Ｂ層の目付が１５〜２００ｇ／ｍ＾２の間であることが好ましい。また、目付が２００ｇ／ｍ＾２より大きいと熱エンボス加工を行うときに、エンボスロールでの伝熱性の問題から接着強度が低くなると言う問題を生じやすくあまり好ましくない。本発明の不織布を、分離膜支持体として利用した場合には、目付が１５〜７０ｇ／ｍ＾２の間であることが好ましい。目付が１５ｇ／ｍ＾２より小さいと先述の理由から適切な接着力を得ることが困難となったり、形態保持性が低下したりするためあまり好ましくない。一方、目付が７０ｇ／ｍ＾２より大きくても接着力が高くなることはあまり期待できず、分離膜の支持体として用いる際に、厚みや重量が大きくなって取り扱い性が低下したり、圧力損失が大きくなるという問題を生じやすく余り好ましくない。また、厚みが厚いとプリーツ型フィルターに用いる場合に織り込み襞折り数が少なくなり結果として有効濾過面積が少なくなる。
【００１７】
本発明で用いる不織布Ｃ層は、目付が３０〜２００ｇ／ｍ＾２のポリエステル不織布Ｃ層であることが望ましく、好ましくは４０〜１８０ｇ／ｍ＾２、特に好ましくは６０〜１８０ｇ／ｍ＾２である。不織布の製造方法は特に規定されないが、耐熱性が高くコストパフォーマンスにすぐれたポリエステル長繊維不織布を用いることができる。不織布Ｃ層は他の不織布に比べて厚みや目付が高い場合が多いので、熱カレンダー処理などで不織布相互を貼り合わせる際に伝熱不良を生じる恐れがある。その防止のためには、不織布Ｃ層をあらかじめ赤外線ヒータなどで予熱することも好ましい。電熱性を高くするために金属を表面に蒸着したり、カーボンなどを練り込んだりするのも好ましい形態の一つで有る。表裏の色を変えておくと使用時の間違い防止の効果も期待できて好ましい。また、不織布Ａ層〜Ｃ以外の不織布を、これらの間あるいは片面に貼り合わせて用いても良い。本発明の不織布をフィルターとして用いる際にＡ層とＣ層の不織布の繊維径を異なるように設定すると、表裏を入れ替えて使うと異なる精度のフィルターとして使用することが可能であり好ましい形態の一つであると考えられる。この際には、表裏の色を変えておくことが使用方法の間違い防ぐ上で好ましい。また、片側は白やグレーなどの淡い色にしておくと、襞織り数を数えるのを容易とするために襞数を表面に印字する場合に印字が鮮明であり好ましい。
【００１８】
本発明の不織布の積層方法は特に規定されないが、好ましい実施形態のひとつとして熱により不織布Ｂ層の鞘成分のみあるいは、これに不織布Ａ層の一部の繊維を溶融させて接着して分離膜として用いることも好ましい形態のひとつである。このとき、熱により不織布表面積の１５％以上の部分が鞘成分のみを溶融させて変形接着していることが好ましい。接着部分の面積が１５％以下だと接着力が弱く剥離しやすくなるのであまり好ましくない。また、圧力をかけすぎてフィルム化するとフィルターとして用いた場合の濾過対象流体による透過抵抗が上昇するためあまり好ましくない。本発明の不織布をフィルター用途に用いる場合は、不織布Ａおよび不織布Ｃ層が熱エンボスカレンダープレスにより外表面側に部分的に凹面の窪みを有することが好ましい。内面側に凹面の凹みを有するとパルスジェットや逆洗浄により濾過ダストの払い落としをした場合に内部にダストが残ってしまい、残量圧力損失が高くなり、その結果フィルターの洗浄再生サイクルタイムが短くなるため好ましくない。本発明の不織布と多孔膜の接着性を良くするためには、不織布が熱エンボス処理不織布で有る場合には、平滑面（プレーンロール）により積層することが、不織布Ａ層面の表面平滑性を向上させるために特に好ましい。フィルターとして用いる場合に、ケーキ剥離性を向上することが可能となり、工業用集塵フィルターや放電加工などのクーラントフィルターとして用いる場合に特に好適である。
【００１９】
本発明の複合不織布あるいはそれを一部に用いたフィルターは剛性が高いためにプリーツ加工されてのちカートリッジにされることが好ましい。積層加工していることで曲げ剛性を高く設定することが可能である。また、不織布Ｂ層が低融点成分を持つことで、プリーツ加工の成形性が良好となり、レシプロ加工はもとより従来のスパンボンド不織布では加工の難かしいといわれていた高速ロータリー方式の襞折り加工が可能となる。加工時の下面となる不織布層がエンボス加工によって処理されている場合はその面積が２５％以上であると不織布と加工機の支持体部との間で滑りを生じる問題が生じやすくあまり好ましくない。繊維径が太くなるほど該エンボス押さえ面積率が小さい方が好ましい。本発明者の経験ではエンボス部面積が７〜２５％の間にあることが特に好ましかった。
【００２０】
（繊維径）
走査型電子顕微鏡（ＳＥＭ）の拡大写真より、１００本以上の繊維を読み取り、その算術平均値を繊維径とした。
（目付）
ＪＩＳ−Ｌ−１９０６に準拠して評価する。
（曲げ剛性）
評価用試料片を幅２ｃｍ×長さ１０ｃｍの大きさに採取し、支持幅５ｃｍによる３点支持曲げ剛性を測定した。加圧子はＪＩＳ−Ｌ−１０９６ 曲げ反発性 Ｃ法（ループ圧縮法）で使用される形状とする。
（融点）
ＰＥＲＫＩＮ−ＥＬＭＥＲ社製 ＤＳＣ７を使用し、昇温速度２０℃／分で評価した。
（繊維配列）
画像処理プログラム（東洋紡績株式会社より発売中Ｉｍａｇｅ３２）によりフーリエ変換法により測定した。繊維の配列を長手方向に対してプラスマイナス９０度の範囲で３０度刻みで測定し、長手方向プラスマイナス１５度の範囲にある繊維の割合を測定した。画像処理装置がない場合は、−９０度から＋６０度の範囲で３０度刻みの角度で不織布を、２０ｃｍ長、５ｃｍ幅に切り出してのち引っ張り強度を測定して、それらの値の合計が１００になるように規格化したときの長手方向の値を採用しても大きな誤りがないと推定される。
（エアーフィルター性能）
大気塵を用いて５ｃｍ／ｓで濾過操作を行った時の直径５０ｍｍのサンプルの前後の粒子濃度をパーティクルカウンターにより測定して１〜２ミクロンの間の粒子径の捕集効率を求めた。また、通気抵抗を、精度測定時にマノメータによりフィルター前後の差圧を測定することにより求めた。
（フラジール通気度）ＪＩＳ Ｌ１０９６に準じて測定を行った。
（ダスト払い落とし性）有効濾過面積０．０４ｍ＾２（直径２２．６ｃｍ）の円形濾材にダスト濃度の３ｇ／ｍ＾３のガスを３ｍ／分で濾過を行い、１５０ｍｍＡｑになった時点で３ｋｇｆ／ｃｍ＾２でパルスで払い落としを行った。３０回以上払い落とすと払い落とし間隔の時間が行ってしてくることから、１００回払い落とした時点でのパルス払い落とし間隔を測定した。時間が短いほどフィルターの払い落とし性が良くないことになる。
【００２１】
【実施例】
（実施例１）
繊維径約１２ミクロン、目付２０ｇ／ｍ＾２のポリエチレンテレフタレートスパンボンド不織布（白色）を不織布Ａ層とした。繊維は４０％以上がシートの長手方向中心線に沿ってプラスマイナス１５度の角度の範囲に配列していた。イソフタル酸を導入した共重合ポリエステル（融点約１３０℃）を芯成分に、融点が約２７０℃のポリエチレンテレフタレートである繊維径が約４０μｍの芯鞘型複合繊維よりなるスパンボンド不織布Ｂ層（目付４０ｇ／ｍ＾２）を作成した。芯鞘比は重量ベースで５０：５０であった。不織布Ｃ層として繊維径１４ミクロン、目付１８０ｇ／ｍ＾２のポリエチレンテレフタレートスパンボンド不織布（東洋紡績株式会社製６Ａ８１ＡＤ：黒色）を不織布Ｃ層として、３枚の不織布をプレーンカレンダーにより１５０℃、設定線圧約５０ｋｇ／ｃｍ、速度１８ｍ／分で貼り合わせた。不織布ＡおよびＣは、エンボスロールによる凹部窪みが外表面側になるように配置した。不織布の曲げ剛性は０．８０Ｎ／２ｃｍであった。不織布Ａ層が上面になるようにしてロータリー方式の襞折り加工機で処理したところ問題なく処理することが可能であった。エアーフィルタ性能は、捕集効率が６２％、通気抵抗が５．２ｍｍＡｑとフィルター性能がすぐれていた。払い落とし間隔は３．１分と長く、払い落とし性は良好であった。表裏の色が違うので濾過面を間違えることがないと加工場で好評であった。
【００２２】
（実施例２）
不織布Ｂ層が、繊維径約３５ミクロンの芯鞘型短繊維（日本エステル株式会社製メルティー２０８０、芯部融点約２００℃）よりなる目付４０ｇ／ｍ＾２の不織布に変更した以外は実施例１と同じ方法にて積層不織布を作成した。不織布の曲げ剛性は０．５８Ｎ／２ｃｍであった。不織布Ａ層が上面になるようにしてロータリー方式の襞折り加工機で処理したところ問題なく処理することが可能であった。エアーフィルタ性能は、捕集効率が５９％、通気抵抗が５．７ｍｍＡｑとフィルター性能がすぐれていた。払い落とし間隔は３．２分と長く、払い落とし性は良好であった。
【００２３】
（比較例１）
繊維径が１７ミクロン、目付２５０ｇ／ｍ＾２のポリエチレンテレフタレートスパンボンド不織布をプレーンカレンダーにより２１０℃、設定線圧約８０ｋｇ／ｃｍ、速度３ｍ／分で貼り合わせた。繊維は約３８％がシートの長手方向中心線に沿ってプラスマイナス１５度の角度の範囲に配列していた。不織布を折り曲げたところ、簡単に層間剥離を生じて不織布の曲げ剛性は測定できず、襞折り加工機での処理ができなかった。エアーフィルタ性能は、捕集効率が５２％、通気抵抗が１３．０ｍｍＡｑと圧力損失が高い割に捕集効率が低く問題であった。
【００２４】
（比較例２）
実施例１で用いた不織布Ｂ層と同じ構成の複合繊維で繊維径が約２０ミクロン、目付約２５０ｇ／ｍ＾２のスパンボンド不織布をプレーンカレンダーにより１８０℃、設定線圧約５０ｋｇ／ｃｍ、速度１０ｍ／分で貼り合わせた。繊維は約２３％がシートの長手方向中心線に沿ってプラスマイナス１５度の角度の範囲に配列していた。ロータリー方式の襞折り加工機で処理したところ滑りを若干生じたがほぼ問題なく処理することが可能であった。不織布の曲げ剛性は０．３２Ｎ／２ｃｍであった。エアーフィルタ性能は、捕集効率が５５％、通気抵抗が１０．１ｍｍＡｑと圧力損失が高い割に捕集効率が低く問題であった。払い落とし間隔は２．３分と短く、払い落とし性はあまり良くなかった。
【００２５】
（比較例３）
比較例２で用いた目付２５０ｇ／ｍ＾２のスパンボンド不織布を熱エンボスカレンダー（押さえ部面積約５０％）により１８０℃、設定線圧約５０ｋｇ／ｃｍ、速度１５ｍ／分で貼り合わせた。ロータリー方式の襞折り加工機で処理したところ、不織布が機械機のシート供給部で滑って襞折りの間隔がそろわないため問題であった。不織布の曲げ剛性は０．４１Ｎ／２ｃｍであった。エアーフィルタ性能は、捕集効率が４９％、通気抵抗が９．７ｍｍＡｑと実施例１，２より性能が劣り問題であった。払い落とし間隔は１．７分と短く、払い落とし性はあまり良くなかった。
【００２６】
（比較例４）
繊維径約１８ミクロン、目付２０ｇ／ｍ＾２のポリエチレンテレフタレートスパンボンド不織布を不織布Ａ層とした。繊維は約２５％以上がシートの長手方向中心線に沿ってプラスマイナス１５度の角度の範囲に配列していた。イソフタル酸を導入した共重合ポリエステル（融点約１３０℃）を芯成分に、融点が約２７０℃のポリエチレンテレフタレートである繊維径が約１４μｍの芯鞘型複合繊維よりなるスパンボンド不織布Ｂ層（目付４０ｇ／ｍ＾２）を作成した。芯鞘比は重量ベースで５０：５０であった。不織布Ｃ層として繊維径１８ミクロン、目付１８０ｇ／ｍ＾２のポリエチレンテレフタレートスパンボンド不織布を不織布Ｃ層として、３枚の不織布をプレーンカレンダーにより１５０℃、設定線圧約５０ｋｇ／ｃｍ、速度１８ｍ／分で貼り合わせた。不織布ＡおよびＣは、エンボスロールによる凹部窪みが内側になるように配置した。不織布の曲げ剛性は０．５３Ｎ／２ｃｍであった。不織布Ａ層が上面になるようにしてロータリー方式の襞折り加工機で処理したところ問題なく処理することが可能であった。エアーフィルタ性能は、捕集効率が５７％と高かったが通気抵抗が８．４ｍｍＡｑと高く問題であった。払い落とし間隔は１．２分と短く、払い落とし性は悪かった。
【００２７】
【発明の効果】
本発明によれば、剛性が高く遮蔽性やフィルター特性に優れた不織布を得ることができる。特に濾過操作時の流体抵抗により変形することの小さいフィルターとして好適な複合不織布となる。さらに、ダスト払い落とし性の良いフィルターにとして使用しうる。また、プリーツ加工されてのちカートリッジ化して使用される高性能のフィルターを提供することを可能とした。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a nonwoven fabric having high rigidity and excellent shielding properties and filter characteristics. In particular, the present invention relates to a composite nonwoven fabric suitable as a filter that is less likely to be deformed by fluid resistance during a filtration operation. Further, the present invention relates to a filter having good dust removal properties. Further, the present invention relates to a filter used in a cartridge after being pleated.
[0002]
[Prior art]
Nonwoven fabrics made of polyethylene terephthalate have excellent mechanical properties and chemical properties, and are used in, for example, fibers for civil engineering and construction materials and industrial materials according to the properties of each polyester.
In particular, polyethylene terephthalate, which is a typical polyester, is widely used industrially because of its advantages such as heat resistance, excellent strength and elongation properties, and relatively inexpensive raw material prices.
A long-fiber nonwoven fabric using a composite fiber composed of two components, polyethylene terephthalate and low-density polyethylene, is used as a heat-bonding nonwoven fabric as disclosed in Japanese Patent Publication No. 8-14069. For example, a polyester-based composite fiber nonwoven fabric is often used as a support for a separation membrane by bonding it to a microporous separation membrane material or the like. The film material is often composed of polypropylene, polytetrafluoroethylene, or the like, but since these constituent resins are extremely thin and have low rigidity, it is difficult to use them alone, so they are laminated as a reinforcing material. .
[0003]
These composite fiber nonwoven fabrics are used for applications requiring high rigidity, such as structural materials, because when the basis weight is set large, the adhesive strength at the contact point increases, and as a result, the rigidity is excellent.
[0004]
In general, the larger the fiber diameter of the nonwoven fabric and / or the larger the basis weight, the higher the rigidity of the nonwoven fabric can be.However, when the nonwoven fabric which is not a composite fiber is integrated by heat bonding, the basis weight is approximately When it is higher than about 150 to 180 g / m @ 2, a problem of delamination tends to occur due to a difference in thermal conductivity. As a countermeasure, polyester core-sheath composite fibers with a large fiber diameter and a large basis weight are also used, but still the partially embossed part is changing to a state close to the film, and it is used as a filter. In such a case, there is a problem that the fluid permeation resistance increases and the power cost of a liquid feed pump, a blower, and the like increases. In addition, the area of the embossing retainer is often large to increase rigidity.In some cases, a long groove-shaped embossing pattern is used.However, due to the unevenness of the surface, the filter is backwashed or pulsed off. When the filter is regenerated by the above method, there is a problem that the cake peeling property of dust and the like is reduced. Also, when the rigidity of the nonwoven fabric increases, the unwinding of the sheet tends to be unstable, but the sheet may slip due to the concave portion on the surface, possibly because the contact area with the feeding unit of the processing machine such as the pleater becomes too small. In many cases, the problem of unstable supply became noticeable. In addition, when thick fibers are used, there is a problem that filtration accuracy is high and setting is difficult.
[0005]
[Problems to be solved by the invention]
In view of the above problems, the present invention provides a long-fiber nonwoven fabric having high rigidity, high filter performance when used as a filter, and good dust releasability, and a filter using the same.
[0006]
[Means for Solving the Problems]
To solve such a problem, the present invention takes the following measures.
[0007]
That is, the present invention has the following configurations.
1. It is composed of three or more laminated nonwoven fabric layers, has a three-point supporting flexural rigidity of 0.10 to 1.50 N / 2 cm, a basis weight of 100 to 300 g / m @ 2, and a thickness of 0.2 to 0.7 mm. A polyester nonwoven fabric characterized by the following.
2. At least a nonwoven fabric A layer having a basis weight of 10 to 150 g / m @ 2, which is composed of fibers having a fiber diameter of 7 to 20 microns, and a basis weight of 15 to 200 g /%, containing 30% or more of a core-sheath type composite fiber having a fiber diameter of 20 to 50 μm. 2. The laminated nonwoven fabric comprising a nonwoven fabric B layer having m ＾ 2 and a polyester nonwoven fabric C layer having a basis weight of 30 to 200 g / m ＾ 2, wherein each layer is laminated and integrated. Polyester non-woven fabric.
3. 3. The polyester-based nonwoven fabric according to the above item 2, wherein at least one of the nonwoven fabric A layer and the C layer is a long-fiber nonwoven fabric.
4. 3. The polyester-based nonwoven fabric according to the above item 2, wherein the core-sheath type conjugate fiber is a polyester whose sheath component has a melting point of 110 ° C to 250 ° C and a polyester whose core component has a melting point of 185 ° C to 300 ° C.
5. 3. The polyester-based nonwoven fabric according to the above item 2, wherein the polyester-based nonwoven fabric is laminated and integrated by thermal bonding.
6. 3. The polyester-based nonwoven fabric according to the above item 2, which is pleated.
7. A filter comprising the polyester-based nonwoven fabric according to the first aspect.
8. The filter according to the second aspect, wherein the fibers constituting the non-woven fabric A layer and the C layer have different fiber diameters and the non-woven fabrics have different colors.
9. The filter according to the above item 7 or 8, wherein the nonwoven fabric A and the nonwoven fabric C have a partially concave depression on the outer surface side by a hot emboss calender press.
10. 9. The filter according to the above item 8, wherein the nonwoven fabric is pleated.
[0008]
Hereinafter, the requirements of the present invention will be described in detail.
First, the nonwoven fabric according to the present invention is composed of three or more laminated nonwoven fabrics, has a three-point supporting flexural rigidity of 0.10 to 1.50 N / 2 cm, a basis weight of 100 to 300 g / m ／ 2, and a thickness of 0.2. It is preferably about 0.7 mm.
In the nonwoven fabric according to the present invention, lamination and integration of the nonwoven fabric described later is a preferable embodiment in order to keep the three-point bending rigidity within the above range even if the nonwoven fabric has a relatively low basis weight and a small thickness. If the rigidity is lower than the above range, it is not preferable if the rigidity is low because deformation such as bending tends to occur when pleated and used for a filter or a support of the filter or when a nonwoven fabric is used as a part of the structure. Although there is no major problem if the rigidity exceeds the above range, it is necessary to increase the thickness in order to increase the rigidity, so that the number of pleated folds of the cartridge is reduced. Preferably, it is 0.15 to 0.70 N / 2 cm.
It is desirable that the Frazier air permeability is 3 to 20 cc / cm @ 2 seconds. If the airflow resistance is lower than the above range, problems such as an increase in power cost of a pump for supplying a fluid to be filtered or deformation of a pleated mountain due to a drag received from the fluid may occur, which is not preferable. On the other hand, there is not much problem even if the stiffness exceeds the above range, but in the experience of the inventors, there is a high possibility that the filtration accuracy is reduced, which is not desirable in many cases. Preferably it is 5 to 20 cc / cm @ 2 seconds, particularly preferably 7 to 15 cc / cm @ 2 seconds. The Frazier air permeability and the airflow resistance of 5 cm / sec can be substantially converted by the following equation.
5 cm / sec airflow resistance (mmAq) = 63.5 / Fragile air permeability (cc / cm ＾ 2 sec)
[0009]
Specifically, it is recommended that the nonwoven fabric used in the present invention has the following multilayer structure for the purpose of increasing rigidity.
It is desirable that the nonwoven fabric A layer as a component is a nonwoven fabric having a basis weight of 10 to 150 g / m2. Further, the thickness is preferably 0.2 to 0.7 mm. If the condition is deviated and the basis weight is too small or the thickness is too small, it becomes difficult to obtain a desired rigidity. If the basis weight is too high, the air permeability becomes too small, which is not so preferable. In addition, when the thickness is large, the rigidity is often increased. However, when the thickness is too large, the rigidity is insufficient because the number of bonding points between the fibers is reduced, or a problem such as the nonwoven fabric is likely to be fluffed is not preferable. . In the case of being used by being woven into a filter cartridge, if the thickness is too large, the folded area becomes small, which may not be preferable. When the fiber diameter is between 7 and 20 microns, high filtration accuracy can be achieved without setting the packing density too high. If the fiber diameter is too small, there is a problem that fluff is likely to occur due to abrasion or the like. In addition, if the fiber diameter is increased to increase the rigidity, the filtration accuracy cannot be set high unless the filling rate is increased when the fiber is used as a filter. As a result, the fluid permeation resistance increases. When the composite nonwoven fabric of the present invention is used as a filter, it is generally considered to be used as a surface filtering material having the nonwoven fabric A layer as a filtration surface, so that the smaller the fiber diameter, the higher the filtration accuracy. In addition, the surface is easily smoothed, and as a result, the cake peeling property is improved and the filtration life can be extended. On the other hand, when the collected particles have high cohesiveness, it is preferable to increase the fiber diameter to some extent, and it is preferable that the fiber diameter is between 10 and 20 microns.
When a composite structure is not taken as in the present invention, it is considered to be extremely difficult to obtain a nonwoven fabric having a high rigidity with a good balance between filtration accuracy and filtration life. It is particularly preferable that the non-woven fabric layer A and / or C layer is a long-fiber non-woven fabric because there is no fear of the fibers falling off when used as a filter or a shielding material.
[0010]
Further, it is preferable that the fibers of the non-woven fabric A layer are mainly arranged in a range of an angle of ± 15 degrees along the center line in the longitudinal direction of the sheet. By arranging the fibers mainly in the longitudinal direction, the rigidity of the nonwoven fabric can be increased. If the ratio of the number of fibers arranged in this range is 25% or more (about 17% if the fiber arrangement is uniform), it can be considered that the fibers are mainly arranged, but preferably 30% or more, particularly preferably Is 50% or more. In order to increase the rigidity of the nonwoven fabric, it is preferable that the smaller the fiber diameter, the higher the ratio of fiber orientation in the longitudinal direction. When the fiber diameter is 15 microns or less, the fiber arrangement in this direction is 70% or more, particularly preferably 80% or more. In particular, when a fold parallel to the lateral direction is zigzag and pleated and used, the bending rigidity can be increased, and the nonwoven fabric bends due to resistance when a fluid such as water permeates and adjacent sheets are bent. It is easy to prevent the problem that the effective filtration area decreases due to the overlap. The melting point of the constituent fibers of the present nonwoven fabric may be the same as the melting point of the nonwoven fabric C layer, but is preferably lowered by about 10 to 50 ° C., and a part of the fibers is melted in the process of laminating the nonwoven fabric, so that the fibers are fluffed. It is particularly preferable because it can be prevented.
[0011]
The nonwoven fabric B layer, which is a component of the nonwoven fabric used in the present invention, is a low-melting polyester having a sheath component having a melting point of between 110 ° C and 250 ° C, and a polyester having a core component having a melting point of 180 ° C to 300 ° C. Desirably, it is a core-sheath composite fiber. With this configuration, it is possible to provide a highly rigid nonwoven fabric and a filter using the same, which are the objects of the present invention. As long as the nonwoven fabric is a long-fiber nonwoven fabric, it is not necessary to apply a process oil agent, so that it is possible to eliminate foreign matters. In addition, long-fiber nonwoven fabrics are particularly suitable for applications such as filters because they have excellent lint-free properties and do not fall off the fibers. Within the scope of the studies by the inventors, it was possible to obtain better rigidity as the melting point of each polymer was higher.
[0012]
The polymer used for the sheath component is desirably a low-melting polyester having a melting point between 110 ° C and 250 ° C. If the melting point is 110 ° C. or less, the adhesive strength is lowered even at room temperature, and there is a possibility that a problem such as blocking occurs due to tackiness, which is not preferable. On the other hand, when the melting point is higher than 250 ° C., the bonding temperature is too high, and solidification starts as soon as the surface temperature of the object to be bonded is low. Absent. Polyester-based resins are particularly suitable for the market for filter-related applications because they generally generate less foreign matter. As the resin to be used, polypropylene terephthalate, polybutylene terephthalate, aliphatic polyester or block copolymerized polyester, and a copolymer having any of them as a part of the basic skeleton can be suitably used.
[0013]
Further, the polymer of the core component is desirably polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polylactic acid or a copolymer partially containing any of them. It is particularly preferable that these polyester resins have a melting point of between 180 ° C. and 300 ° C. because of their excellent dimensional stability and mechanical strength at high temperatures. In recent years, it has become possible to obtain raw materials from natural components or biotechnology, which is particularly preferable from the viewpoint of environmental conservation. In particular, when the liquid filter or the like is made of a resin having form stability, the high rigidity of the polyester fiber is effective. The temperature of the polymer of the core component is preferably at least 20 ° C. higher than the melting point or softening point of the polymer of the sheath component in view of the operability of the bonding process. If the difference between the melting points is small, it is necessary to strictly control the processing temperature, so that sophisticated temperature control equipment is required and the processing speed must be reduced, which is not preferable.
[0014]
The weight ratio of the core component and the sheath component of the composite fiber is preferably about 20:80 to 70:30, more preferably between 30:70 to 60:40, and particularly preferably 40:60 to 55: It is between 45. If the sheath component, which is an adhesive component, is less than 30%, it is difficult to obtain a sufficient adhesive force. On the other hand, if it exceeds 70%, problems such as difficulty in controlling the temperature at the time of bonding and deterioration of mechanical strength characteristics are apt to occur, which is not preferable.
[0015]
The fiber diameter of the main fibers constituting the non-woven fabric B layer is desirably between 20 and 50 μm, preferably between 25 and 50 μm, and particularly preferably between 30 and 50 μm. If the fiber diameter is smaller than 20 μm, the area of the bonded portion becomes small, and the adhesive strength tends to decrease, which is not preferable. On the other hand, if the fiber diameter is larger than 50 μm, the formation of the nonwoven fabric becomes uneven, which is not preferable. In addition, when the nonwoven fabric is manufactured by the spun bond method, problems such as yarn breakage in the spinning process, and fibers adhering or clogging in the fiber pulling ejector are likely to occur, causing problems in operability. Not a few. Further, since the nonwoven fabric made of too thick fiber has a small amount of fiber, unevenness of the formation tends to be conspicuous, leading to variation in physical properties. Where the number of fibers is small, the rigidity of the nonwoven fabric is insufficient and the bonding strength of the nonwoven fabric is reduced, which is not preferable. The fibers of the non-woven fabric B layer may be short fibers because they are sandwiched between the layer A and the layer B and thus have a low possibility of falling off.
[0016]
Further, the basis weight of the nonwoven fabric B layer is preferably between 15 and 200 g / m @ 2. On the other hand, if the basis weight is larger than 200 g / m @ 2, a problem that the adhesive strength is reduced due to the problem of heat transfer in the embossing roll when performing the hot embossing is not preferable. When the nonwoven fabric of the present invention is used as a separation membrane support, the basis weight is preferably between 15 and 70 g / m @ 2. If the basis weight is less than 15 g / m ＾ 2, it is difficult to obtain an appropriate adhesive force or the shape retention is deteriorated for the above-mentioned reason, and it is not so preferable. On the other hand, even if the basis weight is larger than 70 g / m @ 2, it is not expected that the adhesive strength becomes high, and when used as a support for a separation membrane, the thickness and weight are increased and handleability is reduced, and pressure is reduced. The problem that the loss is increased tends to occur, which is not preferable. On the other hand, when the thickness is large, the number of weaving folds is reduced when used for a pleated filter, and as a result, the effective filtration area is reduced.
[0017]
The nonwoven fabric C layer used in the present invention is desirably a polyester nonwoven C layer having a basis weight of 30 to 200 g / mｇ2, preferably 40 to 180 g / m ＾ 2, particularly preferably 60 to 180 g / mｇ2. is there. The method for producing the nonwoven fabric is not particularly limited, but a polyester long-fiber nonwoven fabric having high heat resistance and excellent cost performance can be used. Since the nonwoven fabric C layer often has a higher thickness and basis weight than other nonwoven fabrics, there is a possibility that poor heat transfer may occur when the nonwoven fabrics are bonded to each other by heat calendering or the like. In order to prevent this, it is also preferable to preheat the nonwoven fabric C layer in advance with an infrared heater or the like. Evaporation of a metal on the surface or kneading of carbon or the like in order to enhance the electrothermal property is also one of the preferable modes. It is preferable to change the color of the front and back, since the effect of preventing mistakes during use can be expected. Further, non-woven fabrics other than the non-woven fabric layers A to C may be used by being bonded between them or on one side. When the non-woven fabric of the present invention is used as a filter, if the fiber diameter of the non-woven fabric of the A layer and the C layer is set to be different, it is possible to use the non-woven fabric of the present invention as a filter with different accuracy when used by exchanging the front and back sides. It is considered to be. In this case, it is preferable to change the color of the front and back sides in order to prevent erroneous use. Further, it is preferable that one side has a light color such as white or gray, because the number of folds is printed on the surface in order to facilitate counting the number of folds, which is preferable.
[0018]
Although the method for laminating the nonwoven fabric of the present invention is not particularly limited, as a preferred embodiment, only the sheath component of the nonwoven fabric B layer is heated, or a part of the fibers of the nonwoven fabric A layer is melted and bonded to the sheath component as a separation membrane. Use is also one of the preferred modes. At this time, it is preferable that 15% or more of the nonwoven fabric surface area is deformed and adhered by melting only the sheath component by heat. When the area of the bonding portion is 15% or less, the bonding strength is weak and the film is easily peeled, which is not preferable. Further, if the film is formed by applying too much pressure, the permeation resistance of the fluid to be filtered when used as a filter is undesirably increased. When the nonwoven fabric of the present invention is used for a filter, it is preferred that the nonwoven fabric A and the nonwoven fabric C have a partially concave depression on the outer surface side by a hot emboss calender press. If there is a concave dent on the inner side, dust is left inside when the dust is removed by pulse jet or back washing, and the residual pressure loss increases, resulting in a shorter filter regeneration cycle time. Is not preferred. In order to improve the adhesiveness between the nonwoven fabric of the present invention and the porous film, when the nonwoven fabric is a hot-embossed nonwoven fabric, laminating with a smooth surface (plain roll) improves the surface smoothness of the nonwoven fabric A layer surface. It is particularly preferred for When used as a filter, cake peelability can be improved, which is particularly suitable when used as a coolant filter for industrial dust collection filters or electric discharge machining.
[0019]
Since the composite nonwoven fabric of the present invention or a filter using the composite nonwoven fabric as a part thereof has high rigidity, it is preferable to form a cartridge after pleating. Bending rigidity can be set high by laminating. In addition, since the non-woven fabric B layer has a low melting point component, the formability of the pleating process is improved, and high-speed rotary fold folding, which is said to be difficult to process with conventional spunbonded non-woven fabrics, as well as reciprocating processing, is possible. It becomes. When the nonwoven fabric layer serving as the lower surface at the time of processing is processed by embossing, if the area is 25% or more, a problem of causing slippage between the nonwoven fabric and the support of the processing machine is apt to occur, which is not preferable. It is preferable that the larger the fiber diameter is, the smaller the embossing area ratio is. In the experience of the inventor, it was particularly preferred that the embossed area be between 7 and 25%.
[0020]
(Fiber diameter)
From an enlarged photograph of a scanning electron microscope (SEM), 100 or more fibers were read, and the arithmetic average value was defined as the fiber diameter.
(Weight)
It is evaluated according to JIS-L-1906.
(Bending rigidity)
An evaluation sample piece was sampled in a size of 2 cm in width × 10 cm in length, and three-point support bending rigidity at a support width of 5 cm was measured. The pressurizer has a shape used in JIS-L-1096 bending resilience C method (loop compression method).
(Melting point)
The evaluation was performed at a heating rate of 20 ° C./min using DSC7 manufactured by PERKIN-ELMER.
(Fiber array)
It was measured by a Fourier transform method using an image processing program (Image32 sold by Toyobo Co., Ltd.). The arrangement of the fibers was measured at intervals of 30 degrees within a range of ± 90 degrees with respect to the longitudinal direction, and the proportion of fibers within the range of ± 15 degrees in the longitudinal direction was measured. If there is no image processing device, the nonwoven fabric is cut into 20cm length and 5cm width at angles of 30 degrees in the range of -90 degrees to +60 degrees, and the tensile strength is measured. It is estimated that there is no great error even if the value in the longitudinal direction when standardized as follows is adopted.
(Air filter performance)
The particle concentration before and after the sample having a diameter of 50 mm when a filtration operation was performed at 5 cm / s using air dust was measured by a particle counter, and the collection efficiency of a particle diameter between 1 and 2 microns was obtained. In addition, the ventilation resistance was determined by measuring the differential pressure across the filter with a manometer at the time of accuracy measurement.
(Fragile air permeability) The measurement was performed according to JIS L1096.
(Dust removal property) A circular filter medium having an effective filtration area of 0.04 m 2 (diameter 22.6 cm) was filtered at a rate of 3 m / min with a gas having a dust concentration of 3 g / m 3 at a rate of 3 m / min. / Cm ＾ 2, and the pulse was used to wipe off. Since the time of the wiping-off interval increases when the wiping-off is performed 30 times or more, the pulse wiping-off interval at the time of the 100-wiring-off is measured. The shorter the time, the poorer the filter sweepability.
[0021]
【Example】
(Example 1)
A polyethylene terephthalate spunbonded nonwoven fabric (white) having a fiber diameter of about 12 microns and a basis weight of 20 g / m @ 2 was used as the nonwoven fabric A layer. More than 40% of the fibers were arranged in the range of plus or minus 15 degrees along the longitudinal center line of the sheet. A spunbond nonwoven fabric B layer (having a basis weight of 40 g) consisting of a core-sheath type composite fiber of polyethylene terephthalate having a melting point of about 270 ° C. and a fiber diameter of about 40 μm, using a copolymerized polyester (melting point of about 130 ° C.) into which isophthalic acid is introduced as a core component. / M ＾ 2). The core-sheath ratio was 50:50 on a weight basis. As a non-woven fabric C layer, a polyethylene terephthalate spunbond non-woven fabric (6A81AD manufactured by Toyobo Co., Ltd .: black) having a fiber diameter of 14 μm and a basis weight of 180 g / m 2 was used as a non-woven fabric C layer. Lamination was performed at a pressure of about 50 kg / cm and a speed of 18 m / min. The nonwoven fabrics A and C were arranged such that the recessed portion due to the embossing roll was on the outer surface side. The bending stiffness of the nonwoven fabric was 0.80 N / 2 cm. When processing was performed by a rotary fold folding machine with the nonwoven fabric A layer facing upward, processing was possible without any problem. As for the air filter performance, the trapping efficiency was 62%, and the airflow resistance was 5.2 mmAq, and the filter performance was excellent. The cleaning interval was as long as 3.1 minutes, and the cleaning performance was good. The color of the front and back was different, so it was popular at the processing plant that the filtration surface was not mistaken.
[0022]
(Example 2)
Example 1 except that the non-woven fabric B layer was changed to a non-woven fabric having a basis weight of 40 g / m @ 2 made of core-sheath short fibers having a fiber diameter of about 35 microns (Melty 2080 manufactured by Nippon Ester Co., Ltd., core melting point of about 200 ° C.). A laminated nonwoven fabric was prepared in the same manner as described above. The bending stiffness of the nonwoven fabric was 0.58 N / 2 cm. When processing was performed by a rotary fold folding machine with the nonwoven fabric A layer facing upward, processing was possible without any problem. Regarding the air filter performance, the trapping efficiency was 59%, and the airflow resistance was 5.7 mmAq, and the filter performance was excellent. The cleaning interval was as long as 3.2 minutes, and the cleaning performance was good.
[0023]
(Comparative Example 1)
A polyethylene terephthalate spunbonded nonwoven fabric having a fiber diameter of 17 microns and a basis weight of 250 g / m @ 2 was bonded by a plain calendar at 210 ° C., at a set linear pressure of about 80 kg / cm, and at a speed of 3 m / min. About 38% of the fibers were arranged in a range of plus or minus 15 degrees along the longitudinal centerline of the sheet. When the nonwoven fabric was bent, delamination occurred easily, so that the bending stiffness of the nonwoven fabric could not be measured, and the treatment with a folding machine could not be performed. Regarding the performance of the air filter, the trapping efficiency was low and the trapping efficiency was 13.0 mmAq.
[0024]
(Comparative Example 2)
A spunbonded nonwoven fabric having the same structure as the nonwoven fabric B layer used in Example 1 and having a fiber diameter of about 20 microns and a basis weight of about 250 g / m @ 2 was subjected to a plain calendar at 180 ° C., a set linear pressure of about 50 kg / cm, and a speed of 10 m. / Min. About 23% of the fibers were arranged in a range of plus or minus 15 degrees along the longitudinal centerline of the sheet. When processed with a rotary fold folding machine, slippage occurred slightly, but processing could be performed with almost no problem. The bending stiffness of the nonwoven fabric was 0.32 N / 2 cm. Regarding the performance of the air filter, the trapping efficiency was 55% and the ventilation resistance was 10.1 mmAq. The payoff interval was as short as 2.3 minutes and the payoff was not very good.
[0025]
(Comparative Example 3)
The spunbond nonwoven fabric having a basis weight of 250 g / m ＾ 2 used in Comparative Example 2 was bonded by a hot emboss calender (pressing portion area of about 50%) at 180 ° C., a set linear pressure of about 50 kg / cm, and a speed of 15 m / min. When processed with a rotary fold folding machine, there was a problem because the nonwoven fabric slipped in the sheet supply section of the machine and the intervals between the folds were not uniform. The bending stiffness of the nonwoven fabric was 0.41 N / 2 cm. Regarding the performance of the air filter, the trapping efficiency was 49% and the airflow resistance was 9.7 mmAq, which was inferior to those of the first and second examples. The payoff interval was as short as 1.7 minutes and the payoff was not very good.
[0026]
(Comparative Example 4)
A polyethylene terephthalate spunbonded nonwoven fabric having a fiber diameter of about 18 microns and a basis weight of 20 g / m @ 2 was used as the nonwoven fabric A layer. About 25% or more of the fibers were arranged in a range of plus or minus 15 degrees along the longitudinal center line of the sheet. A spunbond nonwoven B layer made of a core-sheath type conjugate fiber of polyethylene terephthalate having a melting point of about 270 ° C. and a fiber diameter of about 14 μm using a copolymer polyester (melting point of about 130 ° C.) into which isophthalic acid is introduced as a core component (basis weight: 40 g) / M ＾ 2). The core-sheath ratio was 50:50 on a weight basis. As a non-woven fabric C layer, a polyethylene terephthalate spunbond non-woven fabric having a fiber diameter of 18 μm and a basis weight of 180 g / m ／ 2 was used as a non-woven fabric C layer, and three non-woven fabrics were subjected to plain calendering at 150 ° C., a set linear pressure of about 50 kg / cm, and a speed of 18 m / min. Stuck together. The nonwoven fabrics A and C were arranged such that the depressions formed by the embossing rolls were inside. The bending stiffness of the nonwoven fabric was 0.53 N / 2 cm. When processing was performed by a rotary fold folding machine with the nonwoven fabric A layer facing upward, processing was possible without any problem. Regarding the air filter performance, the trapping efficiency was as high as 57%, but the airflow resistance was as high as 8.4 mmAq, which was a problem. The payoff interval was as short as 1.2 minutes, and the payoff was poor.
[0027]
【The invention's effect】
According to the present invention, a nonwoven fabric having high rigidity and excellent shielding properties and filter characteristics can be obtained. In particular, the composite nonwoven fabric is suitable as a filter that is less likely to be deformed due to fluid resistance during a filtration operation. Furthermore, it can be used as a filter with good dust removal properties. In addition, it has become possible to provide a high-performance filter that is pleated and then used as a cartridge.
Claims (10)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002291495A JP4131383B2 (en) | 2002-10-03 | 2002-10-03 | Polyester nonwoven fabric and filter |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002291495A JP4131383B2 (en) | 2002-10-03 | 2002-10-03 | Polyester nonwoven fabric and filter |
Publications (2)
| Publication Number | Publication Date |
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| JP2004124317A true JP2004124317A (en) | 2004-04-22 |
| JP4131383B2 JP4131383B2 (en) | 2008-08-13 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2002291495A Expired - Fee Related JP4131383B2 (en) | 2002-10-03 | 2002-10-03 | Polyester nonwoven fabric and filter |
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| JP (1) | JP4131383B2 (en) |
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006231168A (en) * | 2005-02-23 | 2006-09-07 | Nitto Denko Corp | Vent filter and enclosure equipped with it |
| JP2007107126A (en) * | 2005-10-12 | 2007-04-26 | Toyobo Co Ltd | Laminated non-woven fabric |
| JP2007125546A (en) * | 2005-10-04 | 2007-05-24 | Toray Ind Inc | Nonwoven fabric for filter |
| WO2007083370A1 (en) * | 2006-01-18 | 2007-07-26 | Nissei Bio Co., Ltd. | Filter for air conditioner capable of removing toxic substance |
| WO2007088824A1 (en) | 2006-02-01 | 2007-08-09 | Toray Industries, Inc. | Nonwoven fabric for filters and process for production of the same |
| JP2008114177A (en) * | 2006-11-07 | 2008-05-22 | Toray Ind Inc | Nonwoven fabric for air sucking filter |
| JP2009297656A (en) * | 2008-06-13 | 2009-12-24 | Mahle Filter Systems Japan Corp | Filter element |
| JP2012045815A (en) * | 2010-08-26 | 2012-03-08 | Asahi Kasei Fibers Corp | Composite film |
| JP2012152706A (en) * | 2011-01-27 | 2012-08-16 | Toyota Boshoku Corp | Filter medium and manufacturing method for the same |
| US8308833B2 (en) | 2005-10-04 | 2012-11-13 | Toray Industries, Inc. | Nonwoven fabric for filters |
| KR101242687B1 (en) * | 2008-12-24 | 2013-03-12 | 코오롱인더스트리 주식회사 | Polyester nonwoven fabrics and preparation method thereof |
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2002
- 2002-10-03 JP JP2002291495A patent/JP4131383B2/en not_active Expired - Fee Related
Cited By (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006231168A (en) * | 2005-02-23 | 2006-09-07 | Nitto Denko Corp | Vent filter and enclosure equipped with it |
| JP4702829B2 (en) * | 2005-02-23 | 2011-06-15 | 日東電工株式会社 | Vent filter and casing provided with the same |
| JP2007125546A (en) * | 2005-10-04 | 2007-05-24 | Toray Ind Inc | Nonwoven fabric for filter |
| US8308833B2 (en) | 2005-10-04 | 2012-11-13 | Toray Industries, Inc. | Nonwoven fabric for filters |
| JP2007107126A (en) * | 2005-10-12 | 2007-04-26 | Toyobo Co Ltd | Laminated non-woven fabric |
| JPWO2007083370A1 (en) * | 2006-01-18 | 2009-06-11 | 日生バイオ株式会社 | Air conditioner filter that can remove harmful substances |
| WO2007083370A1 (en) * | 2006-01-18 | 2007-07-26 | Nissei Bio Co., Ltd. | Filter for air conditioner capable of removing toxic substance |
| WO2007088824A1 (en) | 2006-02-01 | 2007-08-09 | Toray Industries, Inc. | Nonwoven fabric for filters and process for production of the same |
| US8187520B2 (en) | 2006-02-01 | 2012-05-29 | Toray Industries, Inc. | Nonwoven fabric for filters and method of producing the same |
| JP2008114177A (en) * | 2006-11-07 | 2008-05-22 | Toray Ind Inc | Nonwoven fabric for air sucking filter |
| JP4737039B2 (en) * | 2006-11-07 | 2011-07-27 | 東レ株式会社 | Filter nonwoven fabric for air intake |
| JP2009297656A (en) * | 2008-06-13 | 2009-12-24 | Mahle Filter Systems Japan Corp | Filter element |
| KR101242687B1 (en) * | 2008-12-24 | 2013-03-12 | 코오롱인더스트리 주식회사 | Polyester nonwoven fabrics and preparation method thereof |
| JP2012045815A (en) * | 2010-08-26 | 2012-03-08 | Asahi Kasei Fibers Corp | Composite film |
| JP2012152706A (en) * | 2011-01-27 | 2012-08-16 | Toyota Boshoku Corp | Filter medium and manufacturing method for the same |
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