JP3705413B2 - Composite nonwoven fabric and method for producing the same - Google Patents
Composite nonwoven fabric and method for producing the same Download PDFInfo
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Description
【０００１】
【発明の属する技術分野】
本発明は、柔らかな風合いと緻密な構造とをあわせ持つ不織布に関する。更に詳しくは、軽量で薄く形態安定性に優れ、かつ吸音および制振特性に優れた複合不織布に関する。また、濾過精度が高くかつライフも長いフィルターに好適な複合不織布に関する。さらに、防護衣やバクテリアバリアなどの特性に優れた複合不織布に関する。
【０００２】
【従来の技術】
従来、極細繊維を含む不織布は優れた吸音特性やフィルター性、遮蔽性などのすぐれた特性があり多くの用途に利用されてきたが、強度が弱かったり、形態安定性が悪いなどの問題があり、その改善のために別の不織布と積層複合化して用いられてきた。この際に不織布を積層一体化する方法としては、スプレーや転写などでバインダーとなる樹脂を付与する方法や熱融着繊維などを使用する方法がある。しかしながら、これらの方法では、乾燥あるいは樹脂の融解接着の目的で熱処理を行うことが必要であり、環境汚染の問題や省エネルギーの観点からあまり好ましいことではない。また、バインダー樹脂が不織布間の界面で皮膜を形成し、通気性や通液性が低下するなどの問題もあった。
一方、極細繊維不織布と長繊維不織布を積層一体化する方法として、スパンボンド不織布の間にメルトブローン不織布を積層して熱エンボス法で接合する方法が知られている。しかしながら、これらの長繊維不織布どうしを接合一体化した不織布は、ボリューム感に欠け、硬い風合いとなり用途が制限されてしまうという問題点があった。
【０００３】
【発明が解決しようとする課題】
本発明は、柔らかな風合いで、かつ緻密な構造を持つ複合不織布を安価に提供することを目的とする。
【０００４】
【課題を解決するための手段】
本発明は、かかる問題を解決するために以下の手段をとる。
第一の発明は、繊維径が６ミクロン以下の極細繊維を含有する目付が３０〜２００ｇ／ｍ2のメルトブローン不織布と、繊維径が７〜４０ミクロンで目付が５０〜２０００ｇ／ｍ2の短繊維不織布とがこれらの繊維の交絡により一体化されていることを特徴とする複合不織布である。
【０００５】
第２の発明は、繊維径が６ミクロン以下の極細繊維を含有する目付が３０〜２００ｇ／ｍ2のメルトブローン不織布と、繊維径が７〜４０ミクロンで目付が５０〜２０００ｇ／ｍ2の短繊維不織布とを流体交絡法またはニードルパンチ法のいずれかにより一体化する事を特徴とする複合不織布の製造方法である。
【０００６】
【発明の実施の形態】
以下に本発明を詳細に説明する。
本発明における複合不織布は、少なくとも２種以上の不織布が接合一体化されていることが必要である。通気性などをコントロールするために極細繊維を含む不織布層にフィルムなどを積層する事も望ましい形態のひとつである。また、織布や編物と複合化するのも用途により好ましい。さらに、該複合不織布の外側に色や模様のついた意匠性のある表層不織布を貼り付けても良く、車両内装材や建築用途の防音材として好適に用いることが可能である。
【０００７】
本発明における極細繊維メルトブローン不織布は、繊維径が６ミクロン以下の極細繊維を重量で１０％以上含有されていることが好ましい。不織布全体が極細繊維のみで構成されていてもよいが、含有率が低すぎると極細繊維特性による効果が得られにくい。極細繊維の繊維径は５ミクロン以下がより好ましく、特に好ましくは、０．５〜４ミクロンであり、最も好ましくは１．５〜３ミクロン前後である。メルトブロー法により得られる不織布は、繊維がランダムに配列することが可能でフィルター性能や吸音性能を高くすることができる上に、生産コストが安いため好ましい。
【０００８】
メルトブローン不織布は強度が弱いので、スパンボンド不織布など補強用不織布と接合した不織布を用いたり、積層工程で同時に３層以上の不織布を積層するのも好ましい。この際、耐摩耗性にすぐれたスパンボンド不織布が使用時に表層側にくるように設置することが好ましい。メルトブローン不織布とスパンボンド不織布のエンボス加工積層不織布はＳ／Ｍ／ＳやＳ／Ｍなどの名称で呼ばれ市販されておりこれらを用いるのも好ましい（Ｓはスパンボンド不織布を、Ｍはメルトブローン不織布を表す）。
【０００９】
また、分割繊維あるいは海島型繊維のメルトブローン極細繊維を用いるのも好ましい形態の一つである。分割繊維は予め分割しておいても良いし、積層加工の際に分割を同時に行っても良い。
【００１０】
本発明におけるメルトブローン極細繊維不織布は、目付が３０〜２００ｇ／ｍ2不織布であることが好ましい。目付が、３０ｇ／ｍ2より小さくなると、極細繊維の持つ遮蔽性、フィルター性能、柔らかさ、吸音性などの効果があまり期待できず好ましくない。一方、目付が２００ｇ／ｍ2を超えると、短繊維不織布との複合化する際に皺が入ったり、接合力が弱いという問題が生じる場合がありあまり好ましくない。また、目付をあまり大きくしすぎても目的とする遮蔽性、フィルター性能、柔らかさ、吸音性などの改善効果があまり変わらず、コスト削減や軽量化などの観点からあまり好ましくない。
【００１１】
メルトブローン極細繊維不織布を構成する素材としては、特に限定はされないが、ポリエステルあるいはポリオレフィンがリサイクル性などの観点から特に好ましい。好ましくは、メルトブローン極細繊維不織布に積層される短繊維不織布と同じ素材であることがリサイクルしやすく特に好ましい。一方、複数の素材よりなる繊維が混合されていても実用上は問題はない。
【００１２】
次に、メルトブローン極細繊維不織布と積層される短繊維不織布は、繊維径が７〜４０ミクロンであることが好ましく、特に好ましくは７〜２０ミクロンである。繊維径が７ミクロンより細いと、カード機からの紡出性など、生産性の点であまり好ましくない。また、繊維径が７ミクロンより大幅に小さいと、本発明による積層効果が小さくなる。また、不織布が毛羽立ちやすいなど別の問題を生じる場合がある。繊維径が４０ミクロンより太いと、吸音性能やフィルター性能などの目的とする特性に対する寄与が小さくなりあまり好ましくない。この理由は明らかではないが、メルトブローン極細繊維不織布との特性差が大きすぎるためではないかと推定できる。
【００１３】
本発明において、短繊維の不織布を極細繊維を含む不織布と積層することにより、メルトブローン極細繊維不織布が形態安定性が低く（へたりやすかったり、毛羽立ちやすい）、嵩高性の維持に問題を生じやすいという欠点を改善したり、高いクッション性を得るなどの効果が発揮される。また、フィルターとして用いる際に、濾過ライフやダストあるいは粉塵などの保持量が長くなるなどの効果を得ることができる。
【００１４】
該短繊維不織布の目付は、５０〜２０００ｇ／ｍ2の短繊維不織布である。目付が５０ｇ／ｍ2より小さいと積層効果が小さく不織布の嵩高性や柔らかい風合いの点であまり好ましくない。一方、２０００ｇ／ｍ2より大きい目付であると厚みが大きくなりすぎてスペースをとるため用途が限定されてしまうため好ましくない。
【００１５】
短繊維の長さは３８〜１５０ｍｍが好ましく、特に好ましくは５０〜１００ｍｍである。複合不織布を吸音材として用いる場合、繊維長が長いほど優れた吸音率を示すが、繊維長が長すぎるとカードからの紡出性が悪くなり好ましくない。短繊維は単一成分でも良いが、２種類以上の混合物や複数成分の複合繊維でも良い。不織布の堅さを調整するために重量分率で３０％程度以下であればさらに太い繊維を混合しても特性はあまり変化しない。太い繊維が多すぎると不織布風合いが硬くなりすぎるなどの問題を生じやすくあまり好ましくない。融点の異なる熱融着性繊維を用いることも寸法安定性を改善する観点から好ましい。
【００１６】
短繊維不織布の重量ベースの充填密度は、嵩高性の観点から０．００５〜０．３ｇ／ｃｍ3であることが好ましい。充填密度が小さすぎると形態安定性が悪くなりあまり好ましくない。充填密度が０．３ｇ／ｃｍ3より大きいと嵩高性が悪く本発明の目的を満足することが難しくなる。
【００１７】
本発明における不織布の積層一体化方法は、流体交絡法あるいはニードルパンチ法のいずれかにより一体化する。ニードルパンチ法は不織布加工方法として一般的に実施されている方法が採用でき、例えば、日本繊維機械学会不織布研究会編集の「不織布の基礎と応用」などで解説されている方法である。前記のメルトブローン不織布と短繊維不織布とをニードルパンチ法を用いて複合化すると、メルトブローン極細繊維不織布に穴が開いて、吸音性能やフィルター性能などが低下してしまうことが一般的には、予想されるが、意外なことに本発明においては、そのような欠点の発現がない。
【００１８】
ニードルパンチ加工を行う際には、３８番手より細いニードル（針）を用いることが好ましく、特に好ましくは４０〜４２番手である。ニードルは、短繊維不織布側から入り、メルトブローン極細繊維を含有する不織布の外側に、短繊維のループを生じさせることが好ましい。メルトブローン極細繊維不織布は、繊維が他の物に引っかかったり、それにより切断されたりして毛羽立ちやすいが、短繊維のループは、メルトブローン不織布の表面毛羽立ちを防止したり、クッション層になって、メルトブローン不織布層にかかる外力を緩和することで破壊の防止に役立つ効果がある。
【００１９】
また、別の不織布やフィルムなどと積層する際に、短繊維のループと積層相手の第３の素材を接着することで、曲げや引っ張りなどの外力がかかったときにメルトブローン不織布が破壊されるのを防止することが可能となる。適切なループの大きさを形成するために、ニードルパンチの針深度は１５ｍｍ以下であることが好ましい。針深度が１５ｍｍを超えると、メルトブローン極細繊維不織布を針および短繊維が貫通するときの衝撃で該不織布が破れたり、貫通した後の針穴が大きくなりすぎることが多くなりあまり好ましくない。針深度は、ニードルのバーブの位置にもよるが５ｍｍ以上であることが、不織布の交絡を増やして剥離を防止する上で好ましい。
【００２０】
刺孔密度は３０〜２００本／ｃｍ2であることが好ましい。刺孔密度が３０本／ｃｍ2より小さいと不織布の剥離の問題が生じやすく、２５０本／ｃｍ2より大きいと刺孔による開口総面積が大きすぎたり、メルトブローン極細繊維不織布の破れや破壊を生じやすくあまり好ましくない。
【００２１】
次に、流体交絡法は、流体を作用させることで繊維の交絡を生じさせる方法であり、水流交絡法が一般的である。水流交絡法では、一般的に、水流の跡が筋状に残りやすいことが知られており、このために嵩高の不織布とメルトブローン極細繊維不織布との積層手段として水流交絡法を用いる事は一般的ではなかったが、本発明者は、短繊維不織布の目付が３００ｇ／ｍ2以下と小さい際には、特に短繊維不織布の柔らかい風合いをあまり損なうことなく積層加工が可能であることを見出したのである。
【００２２】
【実施例】
以下に本発明を実施例をあげて説明する。なお、評価方法は、以下の方法によった。
（平均繊維径）：走査型電子顕微鏡写真を適当な倍率でとり、繊維側面を２０本以上測定して、その平均値から求めた。極細繊維不織布がメルトブロー法の場合は、繊維径のバラツキが大きいため１００本以上を測定して平均値を採用した。
【００２３】
（目付および充填密度）：不織布を２０ｃｍ角に切り出してその重量を測定した値を１ｍ2あたりに換算して目付とした。充填密度は、不織布の目付を２０ｇ／ｃｍ2の荷重下での厚みで割った値を求めて、ｇ／ｃｍ3に単位換算して求めた。
【００２４】
（剥離）：複合した不織布を手で９０度前後折り曲げる動作を２０回繰り返して、剥離が生じるかどうかを目視で評価した。
【００２５】
（吸音率）：ＪＩＳ Ａ−１４０５に従って、垂直入射法吸音率を求めた。代表値として１０００Ｈｚと２０００Ｈｚの値の平均値を用いた。
【００２６】
実施例１
平均繊維径３ミクロン、目付１００ｇ／ｍ2のポリプロピレン製メルトブローン不織布の上に、平均繊維径１４ミクロン、繊維長５１ｍｍ、捲縮数12個／インチの短繊維よりなる目付２５０ｇ／ｍ2、充填密度０．０６ｇ／ｃｍ3のポリエチレンテレフタレート製ニードルパンチ不織布を重ねて、４０番手のニードルを用いて、刺孔密度５０本／ｃｍ2、針深度１０ｍｍでニードルパンチ積層加工を実施した。この複合不織布を２０回程度折り曲げても剥離の問題は生じず、吸音率も６８％と高く良好であった。
【００２７】
実施例２
平均繊維径１４ミクロン、目付２０ｇ／ｍ2のポリエチレンテレフタレート製スパンボンドン不織布の上に平均繊維径３ミクロン、目付１００ｇ／ｍ2のポリエチレンテレフタレート製メルトブローン不織布を重ね、さらにその上に平均繊維径１４ミクロン、繊維長５１ｍｍ、捲縮数12個／インチの短繊維よりなる目付２５０ｇ／ｍ2、充填密度０．０６ｇ／ｃｍ3のポリエチレンテレフタレート製ニードルパンチ不織布を重ねて、４０番手のニードルを用いて、刺孔密度５０本／ｃｍ2、針深度１０ｍｍでニードルパンチ積層加工を実施した。この複合不織布を２０回程度折り曲げても剥離の問題は生じず、吸音率も７１％と高く良好であった。
【００２８】
実施例３
平均繊維径３ミクロン、目付５０ｇ／ｍ2のポリエチレンテレフタレート製メルトブローン不織布の下に、平均繊維径１４ミクロン、繊維長５１ｍｍ、捲縮数12個／インチの短繊維よりなる目付２５０ｇ／ｍ2、充填密度０．０６ｇ／ｃｍ３のポリエチレンテレフタレート製ニードルパンチ不織布をセットして、直径０．１ｍｍ、孔ピッチ１ｍｍ、孔列数２列のプレートを用いて水圧３０ｋｇｆ／ｃｍ2で水流交絡積層加工を２度実施した。この時のノズルと不織布の間の距離はほぼ１インチあった。この複合不織布を２０回程度折り曲げても剥離の問題は生じず、吸音率も５９％と高く良好であった。
【００２９】
比較例１
実施例１で用いた２種の不織布を、アクリル系樹脂バインダーを１５ｇ／ｍ2塗布することで不織布を複合化した。複合不織布を折り曲げても初期の剥離の問題は生じなかったが、繰り返すと部分的な剥離を生じて問題であった。メルトブローン不織布構成繊維の接着が弱く、内部で破壊を生じたと考えらる。吸音率は７０％と高く実施例１と同等で良好であった。吸音率は実施例１より若干高いが、樹脂の付着分の効果も考慮すると、ニードルパンチによる刺孔の跡による差はなく、吸音率の測定誤差程度と考えられる。
【００３０】
比較例２
平均繊維径３ミクロン、目付１５ｇ／ｍ2のポリプロピレン製メルトブローン不織布の上に、平均繊維径１４ミクロン、繊維長５１ｍｍ、捲縮数12個／インチの短繊維よりなる目付２５０ｇ／ｍ2、充填密度０．０６ｇ／ｃｍ3のポリエチレンテレフタレート製ニードルパンチ不織布を重ねて、３２番手のニードルを用いて、刺孔密度５０本／ｃｍ2、針深度１８ｍｍでニードルパンチ積層加工を実施した。積層不織布１ｍ2あたりに５〜２０程度のメルトブロー不織布が針穴近傍で破れが発生しており問題であった。複合不織布を折り曲げても剥離の問題は生じなかったが、破れの箇所が増加して問題であった。破れのない箇所の吸音率を測定したが、２８％と低く問題であった。
【００３１】
比較例３
平均繊維径１４ミクロン、繊維長５１ｍｍ、捲縮数12個／インチの短繊維よりなる目付５００ｇ／ｍ2のポリエチレンテレフタレート製短繊維ウエッブを４０番手のニードルを用いて、表と裏の両方からそれぞれ刺孔密度３０本／ｃｍ2、針深度１０ｍｍでニードルパンチ加工して、充填密度０．０５ｇ／ｃｍ3嵩高不織布を得た。吸音率を測定したが、２１％と低く問題であった。
【００３２】
【発明の効果】
本発明により、柔らかな風合いで、かつ緻密な構造を持つ複合不織布を提供することが可能となる。特に、軽量で薄い吸音および制振特性にすぐれた不織布あるいは、濾過精度が高くかつライフも長いフィルターに好適な不織布、あるいは防護衣やバクテリアバリアなどの特性に優れた不織布として産業上の広い用途で好適に使用される。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a nonwoven fabric having both a soft texture and a dense structure. More specifically, the present invention relates to a composite nonwoven fabric that is lightweight, thin, excellent in form stability, and excellent in sound absorption and vibration damping characteristics. The present invention also relates to a composite nonwoven fabric suitable for a filter having high filtration accuracy and a long life. Furthermore, it is related with the composite nonwoven fabric excellent in characteristics, such as a protective clothing and a bacteria barrier.
[0002]
[Prior art]
Conventionally, nonwoven fabrics containing ultrafine fibers have been used in many applications with excellent sound absorption properties, filter properties, shielding properties, etc., but there are problems such as low strength and poor shape stability. In order to improve this, it has been used by being laminated with another nonwoven fabric. In this case, as a method of laminating and integrating the nonwoven fabrics, there are a method of applying a resin as a binder by spraying or transfer, a method of using a heat-bonding fiber, or the like. However, these methods require heat treatment for the purpose of drying or melting and bonding the resin, and are not so preferable from the viewpoint of environmental pollution and energy saving. In addition, there is a problem that the binder resin forms a film at the interface between the nonwoven fabrics, and the air permeability and liquid permeability are lowered.
On the other hand, as a method of laminating and integrating an ultrafine fiber nonwoven fabric and a long fiber nonwoven fabric, a method of laminating a melt blown nonwoven fabric between spunbond nonwoven fabrics and joining them by a hot embossing method is known. However, the nonwoven fabric obtained by joining and integrating these long-fiber nonwoven fabrics has a problem that it lacks volume, has a hard texture, and has limited applications.
[0003]
[Problems to be solved by the invention]
An object of the present invention is to provide a composite nonwoven fabric having a soft texture and a dense structure at low cost.
[0004]
[Means for Solving the Problems]
The present invention takes the following means in order to solve this problem.
The first invention is a melt-blown nonwoven fabric having a basis weight of 30 to 200 g / m 2 containing ultrafine fibers having a fiber diameter of 6 microns or less, and short fibers having a fiber diameter of 7 to 40 microns and a basis weight of 50 to 2000 g / m 2 The composite nonwoven fabric is characterized in that the nonwoven fabric is integrated by entanglement of these fibers.
[0005]
The second invention is a melt blown nonwoven fabric having a basis weight of 30 to 200 g / m 2 containing ultrafine fibers having a fiber diameter of 6 microns or less, and short fibers having a fiber diameter of 7 to 40 microns and a basis weight of 50 to 2000 g / m 2 . A method for producing a composite nonwoven fabric, wherein the nonwoven fabric is integrated by either a fluid entanglement method or a needle punch method.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is described in detail below.
The composite nonwoven fabric in the present invention requires that at least two kinds of nonwoven fabrics are joined and integrated. In order to control air permeability and the like, it is also a desirable form to laminate a film or the like on a nonwoven fabric layer containing ultrafine fibers. Further, it is also preferable to make a composite with a woven fabric or a knitted fabric depending on the application. Furthermore, a surface layer nonwoven fabric having a design or color having a color or pattern may be attached to the outside of the composite nonwoven fabric, and can be suitably used as a vehicle interior material or a soundproofing material for architectural use.
[0007]
The ultrafine fiber melt blown nonwoven fabric according to the present invention preferably contains 10% or more by weight of ultrafine fibers having a fiber diameter of 6 microns or less. The entire nonwoven fabric may be composed of only ultrafine fibers, but if the content is too low, it is difficult to obtain the effect of the ultrafine fiber characteristics. The fiber diameter of the ultrafine fiber is more preferably 5 microns or less, particularly preferably 0.5 to 4 microns, and most preferably about 1.5 to 3 microns. Nonwoven fabrics obtained by the melt blow method are preferable because fibers can be arranged at random, filter performance and sound absorption performance can be enhanced, and production costs are low.
[0008]
Since the melt-blown nonwoven fabric has low strength, it is also preferable to use a nonwoven fabric joined to a reinforcing nonwoven fabric such as a spunbond nonwoven fabric, or to laminate three or more nonwoven fabrics simultaneously in the lamination step. At this time, it is preferable to install the spunbonded nonwoven fabric having excellent wear resistance so that it is on the surface layer side during use. Embossed laminated nonwoven fabrics of meltblown nonwoven fabric and spunbond nonwoven fabric are called and marketed under names such as S / M / S and S / M (S is a spunbond nonwoven fabric and M is a meltblown nonwoven fabric). Represent).
[0009]
In addition, it is one of preferred modes to use meltblown ultrafine fibers of split fibers or sea-island type fibers. The split fibers may be split in advance, or may be split simultaneously during the lamination process.
[0010]
The melt blown ultrafine fiber nonwoven fabric in the present invention is preferably a nonwoven fabric having a basis weight of 30 to 200 g / m 2 . If the basis weight is smaller than 30 g / m 2 , the effects such as shielding properties, filter performance, softness, and sound absorption properties of the ultrafine fibers cannot be expected so much, which is not preferable. On the other hand, when the basis weight exceeds 200 g / m 2 , there may be a problem that wrinkles may occur when the composite with the short fiber nonwoven fabric is formed, or the bonding strength is weak. Further, even if the basis weight is too large, the intended effects of improving shielding properties, filter performance, softness, sound absorption, etc. do not change so much, which is not preferable from the viewpoint of cost reduction and weight reduction.
[0011]
The material constituting the melt blown ultrafine fiber nonwoven fabric is not particularly limited, but polyester or polyolefin is particularly preferable from the viewpoint of recyclability. Preferably, the same material as the short fiber nonwoven fabric laminated on the melt blown ultrafine fiber nonwoven fabric is particularly preferable because it is easy to recycle. On the other hand, even if fibers made of a plurality of materials are mixed, there is no practical problem.
[0012]
Next, the short fiber nonwoven fabric laminated with the melt blown ultrafine fiber nonwoven fabric preferably has a fiber diameter of 7 to 40 microns, particularly preferably 7 to 20 microns. If the fiber diameter is thinner than 7 microns, it is not preferable in terms of productivity such as spinning from a card machine. Also, if the fiber diameter is much smaller than 7 microns, the lamination effect according to the present invention will be reduced. In addition, other problems may occur, such as the non-woven fabric being easily fluffed. If the fiber diameter is larger than 40 microns, the contribution to desired properties such as sound absorption performance and filter performance is reduced, which is not preferable. The reason for this is not clear, but it can be estimated that the characteristic difference from the meltblown ultrafine fiber nonwoven fabric is too large.
[0013]
In the present invention, by laminating a nonwoven fabric of short fibers with a nonwoven fabric containing ultrafine fibers, the meltblown ultrafine fiber nonwoven fabric has low form stability (easy to sag and easily fluff), and is likely to cause problems in maintaining bulkiness. The effect of improving a fault and obtaining high cushioning properties is exhibited. In addition, when used as a filter, it is possible to obtain effects such as an increased filtration life and retention amount of dust or dust.
[0014]
Basis weight of the short fiber nonwoven fabric, a short fiber nonwoven fabric of 50 to 2000 g / m 2. When the basis weight is less than 50 g / m 2 , the lamination effect is small, which is not preferable in terms of bulkiness and soft texture of the nonwoven fabric. On the other hand, if the basis weight is larger than 2000 g / m 2 , the thickness becomes too large and takes up space, which limits the application.
[0015]
The length of the short fiber is preferably 38 to 150 mm, particularly preferably 50 to 100 mm. When a composite nonwoven fabric is used as the sound absorbing material, the longer the fiber length, the better the sound absorption rate. However, if the fiber length is too long, the spinning property from the card is deteriorated. The short fiber may be a single component, but may be a mixture of two or more types or a multicomponent composite fiber. If the weight fraction is about 30% or less in order to adjust the stiffness of the nonwoven fabric, the characteristics do not change much even if thicker fibers are mixed. If there are too many thick fibers, problems such as the feeling of the nonwoven fabric becoming too hard are likely to occur, which is not preferable. It is also preferable to use heat-fusible fibers having different melting points from the viewpoint of improving dimensional stability.
[0016]
The weight-based packing density of the short fiber nonwoven fabric is preferably 0.005 to 0.3 g / cm 3 from the viewpoint of bulkiness. When the packing density is too small, the form stability is deteriorated, which is not preferable. When the packing density is larger than 0.3 g / cm 3 , the bulkiness is poor and it is difficult to satisfy the object of the present invention.
[0017]
In the present invention, the nonwoven fabric is laminated and integrated by either the fluid entanglement method or the needle punch method. For the needle punch method, a method generally used as a nonwoven fabric processing method can be adopted. For example, the needle punch method is a method described in “Basics and Applications of Nonwoven Fabrics” edited by the Nonwoven Fabric Research Society of the Japan Textile Machinery Society. It is generally expected that when the melt blown nonwoven fabric and the short fiber nonwoven fabric are combined using the needle punch method, a hole is opened in the melt blown ultrafine fiber nonwoven fabric, resulting in a decrease in sound absorption performance or filter performance. Surprisingly, however, the present invention does not exhibit such defects.
[0018]
When performing needle punching, it is preferable to use a needle (needle) thinner than 38th, particularly preferably 40-42. It is preferable that the needle enters from the short fiber nonwoven fabric side and causes a short fiber loop to be formed on the outside of the nonwoven fabric containing the meltblown ultrafine fibers. Melt blown ultra-fine fiber nonwoven fabric is prone to fluff when fibers get caught or cut by other objects, but short fiber loops prevent surface fluff of the melt-blown nonwoven fabric or become a cushion layer, melt-blown nonwoven fabric It has the effect of helping to prevent destruction by alleviating the external force applied to the layer.
[0019]
Also, when laminating with another non-woven fabric or film, the melt-blown non-woven fabric is destroyed when an external force such as bending or pulling is applied by bonding the loop of the short fiber and the third material to be laminated. Can be prevented. In order to form an appropriate loop size, the needle depth of the needle punch is preferably 15 mm or less. When the needle depth exceeds 15 mm, the nonwoven fabric is often broken by the impact when the needle and the short fiber penetrate the melt blown ultrafine fiber nonwoven fabric, or the needle hole after penetrating is often too large. The needle depth is preferably 5 mm or more, although it depends on the position of the needle barb, in order to prevent the peeling by increasing the entanglement of the nonwoven fabric.
[0020]
The puncture density is preferably 30 to 200 / cm 2 . If the piercing hole density is less than 30 / cm 2, the problem of peeling of the nonwoven fabric is likely to occur. If the piercing hole density is greater than 250 / cm 2, the total opening area of the piercing holes is too large, and the meltblown ultrafine fiber nonwoven fabric is torn or broken. It is easy and not very desirable.
[0021]
Next, the fluid entanglement method is a method of causing fiber entanglement by applying a fluid, and the hydroentanglement method is general. In the hydroentanglement method, it is generally known that traces of the water flow are likely to remain in a streak pattern. For this reason, it is common to use the hydroentanglement method as a means of laminating a bulky nonwoven fabric and a meltblown ultrafine fiber nonwoven fabric. However, the present inventor has found that when the basis weight of the short fiber nonwoven fabric is as small as 300 g / m 2 or less, lamination processing is possible without particularly damaging the soft texture of the short fiber nonwoven fabric. is there.
[0022]
【Example】
The present invention will be described below with reference to examples. In addition, the evaluation method was based on the following method.
(Average fiber diameter): A scanning electron micrograph was taken at an appropriate magnification, 20 or more fiber side surfaces were measured, and the average value was obtained from the average value. When the ultrafine fiber nonwoven fabric was melt blown, the fiber diameter variation was large, so 100 or more were measured and the average value was adopted.
[0023]
(Weight and packing density): A value obtained by cutting a nonwoven fabric into 20 cm square and measuring its weight was converted to 1 m 2 to obtain a basis weight. The packing density was obtained by calculating the unit of g / cm 3 by obtaining a value obtained by dividing the basis weight of the nonwoven fabric by the thickness under a load of 20 g / cm 2 .
[0024]
(Peeling): The operation of bending the composite nonwoven fabric by 90 degrees by hand was repeated 20 times, and whether or not peeling occurred was visually evaluated.
[0025]
(Sound Absorption Rate): A normal incidence method sound absorption rate was determined in accordance with JIS A-1405. The average value of 1000 Hz and 2000 Hz was used as a representative value.
[0026]
Example 1
The average fiber diameter of 3 microns, on a polypropylene meltblown nonwoven fabric having a basis weight of 100 g / m 2, average fiber diameter of 14 microns, fiber length 51 mm, basis weight 250 g / m 2 consisting of staple fibers of crimp number of 12 or / inch, a filling density A needle punch nonwoven fabric made of polyethylene terephthalate of 0.06 g / cm 3 was stacked, and needle punch lamination processing was carried out using a 40th needle at a puncture density of 50 / cm 2 and a needle depth of 10 mm. Even if this composite nonwoven fabric was bent about 20 times, no problem of peeling occurred, and the sound absorption rate was as high as 68%, which was good.
[0027]
Example 2
An average fiber diameter of 3 microns and a polyethylene terephthalate meltblown nonwoven fabric with a basis weight of 100 g / m 2 are laminated on a polyethylene terephthalate spunbonded nonwoven fabric having an average fiber diameter of 14 microns and a basis weight of 20 g / m 2 . A needle punched nonwoven fabric made of polyethylene terephthalate with a basis weight of 250 g / m 2 and a packing density of 0.06 g / cm 3 made of short fibers with a fiber length of 51 mm and 12 crimps / inch is piled up, and pierced using a 40th needle. Needle punch lamination was performed at a hole density of 50 / cm 2 and a needle depth of 10 mm. Even if this composite nonwoven fabric was bent about 20 times, no problem of peeling occurred, and the sound absorption rate was as high as 71%, which was good.
[0028]
Example 3
The average fiber diameter of 3 microns, below the polyethylene terephthalate melt blown nonwoven fabric having a mass per unit area of 50 g / m 2, average fiber diameter of 14 microns, fiber length 51 mm, basis weight 250 g / m 2 consisting of staple fibers of crimp number of 12 or / inch, filling A polyethylene terephthalate needle punched nonwoven fabric with a density of 0.06 g / cm3 is set, and hydroentangled lamination is performed twice at a water pressure of 30 kgf / cm 2 using a plate having a diameter of 0.1 mm, a hole pitch of 1 mm, and a number of holes of 2 rows. Carried out. At this time, the distance between the nozzle and the nonwoven fabric was approximately 1 inch. Even if this composite nonwoven fabric was bent about 20 times, no problem of peeling occurred, and the sound absorption rate was as high as 59%, which was good.
[0029]
Comparative Example 1
The nonwoven fabric was compounded by applying 15 g / m 2 of an acrylic resin binder to the two types of nonwoven fabric used in Example 1. Even if the composite nonwoven fabric was bent, the problem of initial peeling did not occur. However, when it was repeated, partial peeling occurred, which was a problem. It is considered that the melt-blown non-woven fabric was weakly bonded and caused to break inside. The sound absorption coefficient was as high as 70%, which was the same as that of Example 1 and was good. Although the sound absorption rate is slightly higher than that in Example 1, there is no difference due to the puncture mark by the needle punch, considering the effect of the resin adhering part, and it is considered to be about the measurement error of the sound absorption rate.
[0030]
Comparative Example 2
The average fiber diameter of 3 microns, on a polypropylene meltblown nonwoven fabric having a basis weight of 15 g / m 2, average fiber diameter of 14 microns, fiber length 51 mm, basis weight 250 g / m 2 consisting of staple fibers of crimp number of 12 or / inch, a filling density A needle punch nonwoven fabric made of polyethylene terephthalate at 0.06 g / cm 3 was stacked, and needle punch lamination processing was carried out using a 32nd needle with a needle hole density of 50 / cm 2 and a needle depth of 18 mm. The melt blown nonwoven fabric of about 5 to 20 per 1 m 2 of the laminated nonwoven fabric was broken in the vicinity of the needle hole, which was a problem. Even if the composite nonwoven fabric was bent, the problem of peeling did not occur, but the number of breaks increased and was a problem. The sound absorptivity of the unbreakable portion was measured, but it was a problem as low as 28%.
[0031]
Comparative Example 3
A short fiber web made of polyethylene terephthalate with a basis weight of 500 g / m 2 consisting of short fibers with an average fiber diameter of 14 microns, a fiber length of 51 mm, and a crimped number of 12 pieces / inch is used from both the front and back sides using a 40th needle. Needle punching was performed at a puncture density of 30 / cm 2 and a needle depth of 10 mm to obtain a bulky nonwoven fabric with a packing density of 0.05 g / cm 3 . Although the sound absorption coefficient was measured, it was a problem as low as 21%.
[0032]
【The invention's effect】
According to the present invention, it is possible to provide a composite nonwoven fabric having a soft texture and a dense structure. Especially for a wide range of industrial applications as a lightweight, thin non-woven fabric with excellent sound absorption and damping properties, a non-woven fabric suitable for filters with high filtration accuracy and long life, or a non-woven fabric with excellent properties such as protective clothing and bacterial barriers. It is preferably used.
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| JP2000094183A JP3705413B2 (en) | 2000-03-30 | 2000-03-30 | Composite nonwoven fabric and method for producing the same |
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| JP2000094183A JP3705413B2 (en) | 2000-03-30 | 2000-03-30 | Composite nonwoven fabric and method for producing the same |
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| JP3705413B2 true JP3705413B2 (en) | 2005-10-12 |
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Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
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| JP3972296B2 (en) * | 2002-06-18 | 2007-09-05 | 東洋紡績株式会社 | Sound absorbing material and vehicle interior material |
| JP3968648B2 (en) * | 2002-06-18 | 2007-08-29 | 東洋紡績株式会社 | Sound absorbing material |
| JP4798948B2 (en) * | 2003-12-24 | 2011-10-19 | トヨタ紡織株式会社 | Automotive interior materials |
| US20080274658A1 (en) * | 2007-05-02 | 2008-11-06 | Simmonds Glen E | Needlepunched nanoweb structures |
| US10259190B2 (en) * | 2015-03-31 | 2019-04-16 | Freudenberg Performance Materials Lp | Moldable composite mat |
| JP6614919B2 (en) * | 2015-10-30 | 2019-12-04 | タイガースポリマー株式会社 | Method for producing nonwoven filter material |
| CN108866830A (en) * | 2018-08-24 | 2018-11-23 | 芜湖跃飞新型吸音材料股份有限公司 | A kind of two-component car bra acoustical cotton and preparation method thereof |
| CN108950862B (en) * | 2018-08-24 | 2021-04-16 | 芜湖跃飞新型吸音材料股份有限公司 | Multi-component sandwich type sound-absorbing cotton for automobile and preparation method thereof |
| JPWO2020137605A1 (en) * | 2018-12-28 | 2021-11-18 | クラレクラフレックス株式会社 | Fiber structure and its uses |
| JPWO2021010178A1 (en) * | 2019-07-16 | 2021-01-21 | ||
| JPWO2023282088A1 (en) * | 2021-07-07 | 2023-01-12 |
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| JPS5936757A (en) * | 1982-08-19 | 1984-02-29 | 株式会社クラレ | Laminate nonwoven fabric and production thereof |
| JP3632876B2 (en) * | 1997-01-27 | 2005-03-23 | 日産自動車株式会社 | Sound insulation structure |
| JP3415400B2 (en) * | 1997-08-18 | 2003-06-09 | ユニチカ株式会社 | Sound absorbing material |
| JP2000008260A (en) * | 1998-06-16 | 2000-01-11 | Asahi Chem Ind Co Ltd | Sound-absorbing material |
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