JP4128665B2 - Manufacturing method of non-woven fabric for thermoforming - Google Patents
Manufacturing method of non-woven fabric for thermoforming Download PDFInfo
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- JP4128665B2 JP4128665B2 JP23514298A JP23514298A JP4128665B2 JP 4128665 B2 JP4128665 B2 JP 4128665B2 JP 23514298 A JP23514298 A JP 23514298A JP 23514298 A JP23514298 A JP 23514298A JP 4128665 B2 JP4128665 B2 JP 4128665B2
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Description
【０００１】
【発明の属する技術分野】
本発明は、構成繊維の潜在延伸性を利用することによって、所定の型に熱成型しやすい不織布の製造方法に関するものである。
【０００２】
【従来の技術】
不織布よりなる衛生マスクや濾過材は、一定の型に成型されていることが多い。例えば、不織布よりなる衛生マスクは、それを着用したままで、話やすいようにするため、中央部が凹部となるように成型し、唇等がマスク本体と接触しないようにされている。また、濾過材は、濾過面積を増加させるために、多数の折り目を設けること（プリーツ加工）が行われている。特に、コーヒー用濾過材（コーヒー用フィルター）においては、漏斗の形に合致する形状に成型することが行われている。
【０００３】
従来より、成型用不織布としては、延伸熱可塑性短繊維よりなるニードルパンチ不織布が用いられている。このニードルパンチ不織布は、延伸熱可塑性短繊維相互間が絡合されたもので、フェルト状の比較的厚みの厚いもの（目付１００ｇ／ｍ2程度以上）である。このようなニードルパンチ不織布を成型すると、延伸熱可塑性短繊維相互間の絡合点が移動し、構造的に変形する。従って、その変形度が大きくなると、ニードルパンチ不織布の厚みが薄くなり、更に変形度が過大になると、孔が開いてしまうということもあった。
【０００４】
また、成型用不織布として、融点又は軟化点の低い未延伸ポリエステル短繊維と、この未延伸ポリエステル短繊維よりも融点又は軟化点の高い延伸ポリエステル短繊維とを混合してなるものも提案されている（特開平６−１０２５５号公報）。この成型用不織布は、未延伸ポリエステル短繊維の溶融又は軟化によって、延伸ポリエステル短繊維相互間が結合されたものである。そして、成型前に、予め未延伸ポリエステル短繊維を再度、溶融又は軟化させた後、成型用金型内で成型するというものである。このような成型は、延伸ポリエステル短繊維相互間の結合の解除及び再結合を伴うものであり、得られた成型不織布の引張強力等の機械的物性が変化しやすいということがあった。
【０００５】
【発明が解決しようとする課題】
本発明は、従来の方法と異なり、不織布を構成する短繊維として、潜在延伸性を有する未延伸ポリエステル短繊維を採用し、この未延伸ポリエステル短繊維自体を伸長することによって所定の形状に成型しうる熱成型用不織布を提供しようというものである。
【０００６】
特開平６−１０２５５号公報に記載されているように、未延伸ポリエステル短繊維は、不織布を構成する同種の延伸短繊維相互間を結合するための結合材として用いられている。これは、未延伸短繊維の融点が、同種の延伸短繊維のそれに比べて、低いからである。一方、未延伸ポリエステル短繊維は、その製造方法にもよるが、潜在延伸性を持つことがある。しかし、この潜在延伸性を利用した不織布については、従来より、何らの提案もされていない。これは、未延伸ポリエステル短繊維が潜在延伸性を持っていたとしても、不織布製造工程において、その潜在延伸性が破壊されることが多いからである。例えば、未延伸ポリエステル短繊維を結合材として用い、加熱して溶融又は軟化させてしまうと、その潜在延伸性は破壊されてしまうからである。また、未延伸ポリエステル短繊維を構成繊維とする繊維ウェブを作成した後、接着樹脂等の結合剤を付与し、この結合剤を硬化させるために加熱処理を行うと、未延伸ポリエステル短繊維の潜在延伸性は破壊されてしまうからである。
【０００７】
【課題を解決するための手段】
そこで、本発明は、潜在延伸性を有する未延伸ポリエステル短繊維を含む繊維ウェブに、高圧柱状水流を施すことによって、該未延伸ポリエステル短繊維相互間を緊密に絡合させた後、該高圧柱状水流により該繊維ウェブに付与された水を、１３０℃以下の温度で乾燥除去することにより、該未延伸ポリエステル短繊維の潜在延伸性が破壊されないようにして不織布を得、不織布の構成繊維である未延伸ポリエステル短繊維に潜在延伸性を維持させようというものである。そして、この潜在延伸性を利用して、所望の形状に熱成型しやすくしようというものである。
【０００８】
まず、本発明に用いる潜在延伸性を有する未延伸ポリエステル短繊維について説明する。一般に、ポリエステル短繊維は、溶融紡糸した後、加熱下で延伸することにより、結晶化及び配向を促進させて製造されている。このようにして、引張強力の高い延伸ポリエステル短繊維が得られるのであり、短繊維不織布製造用の構成繊維は、その殆どが延伸ポリエステル短繊維である。一方、溶融紡糸した後、加熱下で延伸することなく得られたポリエステル短繊維は、未延伸ポリエステル短繊維と呼ばれ、不織布製造用の構成繊維としては、殆ど用いられていない。しかし、この未延伸ポリエステル短繊維は、その融点が同種の延伸ポリエステル短繊維に比べて低いので、構成繊維である延伸ポリエステル短繊維相互間を結合するための結合材として用いられていることは、前記したとおりである。
【０００９】
このような未延伸ポリエステル短繊維は、その製造条件により、潜在延伸性を持つものとすることができる。例えば、ポリエステルを原料として、未延伸ポリエステル短繊維を得るには、溶融紡糸後、急冷することによって、結晶化を促進させずに巻き取り、その後、所望の繊維長に裁断することによって、潜在延伸性の未延伸ポリエステル短繊維を得ることができる。溶融紡糸後、冷却を徐々に行うと、結晶化が促進され、未延伸ポリエステル短繊維短繊維であっても、潜在延伸性が少なくなる場合があるので、好ましくない。
【００１０】
本発明で用いる未延伸ポリエステル短繊維の潜在延伸性の程度は、その伸長度が２倍〜６倍程度であるのが好ましい。ここで言う伸長度とは、当初の未延伸ポリエステル短繊維の長さをＬ0とし、これを伸長させて破断に到った時点における短繊維の長さをＬ1としたとき、（Ｌ1／Ｌ0）で表されるものである。伸長度が２倍未満であると、熱成型時において、深絞りした箇所が存在すると、その箇所で十分に伸長せず、所望の形状に成型しにくくなる。また、伸長度が６倍を超えても差し支えないが、一般的に、上記した製造方法では、製造しにくい。なお、熱成型時に深絞りがなされない場合には、伸長度が２倍未満であっても良く、また伸長度が２倍以上のものであっても、現実の成型時には、２倍未満しか伸長しない場合があることは、言うまでもない。
【００１１】
本発明で用いる未延伸ポリエステル短繊維の繊度は、１〜１０デニール程度であり、特に１〜３デニール程度であるのが好ましい。繊度が１デニール未満の未延伸ポリエステル短繊維は、一般的に製造しにくい。繊度が１０デニールを超える未延伸ポリエステル短繊維は、繊維径が太いため、得られる不織布の地合や風合いが低下する傾向がある。また、未延伸ポリエステル短繊維の繊維長は、２０〜１００ｍｍ程度であり、特に３０〜５０ｍｍ程度であるのが好ましい。繊維長が２０ｍｍ未満であると、不織布に十分な強力を与えにくくなる。即ち、本発明において、未延伸ポリエステル短繊維は、不織布の構成繊維として用いられるものであるため、繊維長が短いと、構成繊維相互間の絡合が不十分になり、高強力の不織布が得られにくくなるのである。また、繊維長が１００ｍｍを超えると、未延伸ポリエステル短繊維相互間の絡合が不十分となり、高強力の不織布が得られにくくなる。即ち、高圧柱状水流による構成繊維相互間の絡合は、構成繊維の自由端の運動によって促進されるため、繊維長が長すぎると、自由端の割合が少なくなり、このため、絡合が十分に促進されないのである。
【００１２】
本発明においては、この未延伸ポリエステル短繊維を構成繊維として繊維ウェブを作成する。繊維ウェブは、未延伸ポリエステル短繊維１００重量％で構成されていても良いが、他種短繊維が混合されていても良い。他種短繊維としては、レーヨン短繊維や綿繊維等を採用することができる。他種短繊維を混合するときであっても、未延伸ポリエステル短繊維の含有割合は５０重量％以上であり、他種短繊維の含有割合は５０重量％以下であるのが好ましい。未延伸ポリエステル短繊維の含有割合が５０重量％未満であると、伸長する構成繊維の割合が少なくなり、成型時に、所望の形状に成型しにくくなる。本発明において、他種短繊維を混合するときは、未延伸ポリエステル短繊維６０〜９０重量％とレーヨン短繊維４０〜１０重量％の割合で混合するのが好ましい。この程度のレーヨン短繊維の存在によって、吸水性に優れた不織布とすることができ、吸水・吸液性を必要とする用途に用いることができるからである。また、本発明においては、未延伸ポリエステル短繊維５０重量％以上と延伸ポリエステル短繊維５０重量％以下の割合で混合することも好ましいことである。この場合、ポリエステル製の熱成型用不織布でありながら、レギュラータイプのポリエステル短繊維である延伸ポリエステル短繊維が混入されているので、耐熱性や耐候性に優れるからである。
【００１３】
繊維ウェブの目付は、５０〜３００ｇ／ｍ2程度であるのが好ましい。この目付が５０ｇ／ｍ2未満であると、単位面積当たりの繊維量が少なく、後の工程で、未延伸ポリエステル短繊維等の構成繊維相互間を絡合しにくくなる。また、得られる不織布の目付も少なく、これを成型すると、全体的に薄くなりすぎて孔が開く恐れもある。一方、目付が３００ｇ／ｍ2を超えると、単位面積当たりの繊維量が多くて、高圧柱状水流のエネルギーでは、構成繊維相互間を絡合しにくくなる。
【００１４】
繊維ウェブを作成した後、この繊維ウェブに、高圧柱状水流を施す。この高圧柱状水流によって、繊維ウェブ中の未延伸ポリエステル短繊維は、相互に緊密に絡合する。このように、未延伸ポリエステル短繊維相互間が緊密に絡合するのは、繊維ウェブ中において、未延伸ポリエステル短繊維が未結合の状態となっており、高圧柱状水流の付与によって、各未延伸ポリエステル短繊維の自由端が運動し、相互に絡み合うからである。ここで、高圧柱状水流とは、微細な直径のノズル孔を通して高圧で水を噴出させて得られるものである。具体的には、直径０．０１〜０．３ｍｍ程度のノズルを用いて、圧力１０〜２００ｋｇ／ｃｍ2で水を噴出させて得られるものである。
【００１５】
絡合を終えた繊維ウェブは、高圧柱状水流による水を多量に含んでいるため、乾燥工程に導入される。ここで留意すべき点は、未延伸ポリエステル短繊維の潜在延伸性が破壊されない温度、具体的には、１３０℃以下の温度で乾燥することである。これより高い温度で乾燥すると、未延伸ポリエステル短繊維の潜在延伸性が破壊されてしまい、成型時に、未延伸ポリエステル短繊維の十分な伸長が得られなくなる恐れがある。以上のような乾燥工程を経て、本発明に係る熱成型用不織布が得られる。
【００１６】
以上のようにして得られた熱成型用不織布は、以下の如き方法で熱成型する。即ち、熱成型用不織布を熱型に導入して、その熱型に合致した形状に成型されるのである。本発明で留意すべき点は、熱成型用不織布を熱型に導入する前に、未延伸ポリエステル繊維を可塑化させるために予熱しない点にある。一般に、不織布を熱成型する場合、不織布の構成繊維或いは構成繊維相互間を結合している結合材を可塑化させるために予熱し、その後、金型等の成型型に導入することが行われている。しかし、本発明においては、このような可塑化のための予熱は施さない。仮に、本発明で得られた熱成型用不織布を予熱すると、不織布中の未延伸ポリエステル短繊維の潜在延伸性が破壊されてしまうからである。以上の説明から明らかなとおり、本発明で言う予熱とは、未延伸ポリエステル短繊維の潜在延伸性が破壊される程度の温度で行う加熱を言い、その以下の温度における加熱は、予熱の概念に含まれない。例えば、未延伸ポリエステル短繊維を含む熱成型用不織布を、１００℃前後の温度に加熱しても、未延伸ポリエステル短繊維の潜在延伸性は破壊されない。従って、この程度の加熱は、本発明においては予熱とは言わない。
【００１７】
成型時に用いる熱型は、一般的に高温加熱されている。具体的には、１５０℃〜４００℃程度、特に２００〜３００℃程度に加熱されている。熱成型用不織布は、この熱型に導入され、直ちに加圧等の手段によって、熱型の形状に成型される。加圧等の手段は、熱型に導入されて直ちに行われるため、熱成型用不織布は熱型の温度に到るまで昇温していない。従って、熱成型用不織布の変形時には、未延伸ポリエステル短繊維の潜在延伸性が破壊されておらず、その形状に応じて伸長する。その後、変形した熱成型用不織布は、熱型の温度近傍に昇温し、熱固定されるのである。この際、未延伸ポリエステル短繊維が軟化又は溶融し、短繊維相互間が固着する場合もある。このような固着は、得られた成型体の引張強力等の機械的物性が向上するので、好ましいものである。
【００１８】
また、本発明により得られた熱成型用不織布は、熱型を用いることなしに熱成型することも可能である。例えば、加熱雰囲気中に導入した後、折り畳む等の変形を施しただけで、所望の形状に熱成型することも可能である。
【００１９】
以上のようにして得られた成型体は、衛生マスクや濾過材（コーヒー用フィルターや空調用フィルター）として好適に用いられる。また、その他に、自動車用内装材等の種々の用途にも用いられる。
【００２０】
【実施例】
実施例１
繊度２．２デニール，繊維長４５ｍｍの未延伸ポリエステル短繊維７０重量％と、繊度１．５デニール，繊維長４５ｍｍのレーヨン短繊維３０重量％と均一に混合した後、カード法で開繊及び集積して、目付１００ｇ／ｍ2の繊維ウェブを得た。この繊維ウェブを平板上に載置し、ノズル径０．１２ｍｍのノズルを用いて、圧力１００ｋｇ／ｃｍ2で、柱状水流を繊維ウェブ全体に亙って均一に付与した。なお、ノズルは、その先端が繊維ウェブの上方１０ｃｍの位置になるように配設した。この処理によって、繊維ウェブ中の各短繊維相互間は、緊密に絡合した。その後、１００℃の雰囲気温度に保たれた乾燥機に導入し、含有水を蒸発させて、熱成型用不織布を得た。
【００２１】
この熱成型用不織布を、２４０℃に加熱された凹型上に導入し、直ちに、２４０℃に加熱された凸型で凹型内に加圧した。この結果、碗型の成型体が得られた。なお、未延伸ポリエステル短繊維は、この成型によって、成型箇所にもよるが、成型の程度が大きい箇所で、概ね１．４〜１．７倍程度の伸長度で伸長せしめられていた。
【００２２】
実施例２
繊維ウェブとして、繊度２．７デニール，繊維長３８ｍｍの未延伸ポリエステル短繊維１００重量％よりなるものを用いる他は、実施例１と同様の方法で、熱成型用不織布を得た。この熱成型用不織布を、実施例１と同様の方法で熱成型したところ、良好に成型された成型体が得られた。
【００２３】
【作用】
本発明に係る製造方法は、潜在延伸性を有する未延伸ポリエステル短繊維を原料とし、この未延伸ポリエステル短繊維の潜在延伸性が破壊されないような条件を採用しながら、即ち、高温下にさらすことなく、高圧柱状水流を施すことにより、熱成型用不織布を得るというものである。従って、得られた熱成型用不織布中の未延伸ポリエステル短繊維は、概ね、当初の潜在延伸性を有しており、外力を与えたときに、良好に伸長する。
【００２４】
【発明の効果】
従って、本発明に係る製造方法で得られた熱成型用不織布は、構成繊維である潜在延伸性を有する未延伸ポリエステル短繊維が伸長しやすく、容易に所望の形状に成型することができるという効果を奏する。また、この熱成型用不織布は、構造的にも変形するが、主として構成繊維の伸長による変形であるため、変形度を大きくしても、孔が開きにくく、不良品の成型体の発生を少なくすることができるという効果も奏する。更に、成型前の構成繊維相互間の緊密な絡合は、成型後も、概ね、そのままに維持されているため、成型体の引張強力等の機械的物性が低下することも防止しうるという効果を奏する。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a non-woven fabric that is easily thermoformed into a predetermined mold by utilizing the latent stretchability of constituent fibers.
[0002]
[Prior art]
Sanitary masks and filter media made of nonwoven fabric are often molded into a fixed mold. For example, a sanitary mask made of non-woven fabric is molded so that the center portion is a concave portion so that it is easy to talk while wearing it so that the lips and the like do not contact the mask body. In order to increase the filtration area, the filter medium is provided with a large number of folds (pleating). In particular, in the filter material for coffee (coffee filter), it is molded into a shape that matches the shape of the funnel.
[0003]
Conventionally, as a nonwoven fabric for molding, a needle punched nonwoven fabric made of drawn thermoplastic short fibers has been used. This needle punched nonwoven fabric is entangled between stretched thermoplastic short fibers, and is a felt-like one having a relatively large thickness (a basis weight of about 100 g / m 2 or more). When such a needle punched nonwoven fabric is molded, the entanglement points between the stretched thermoplastic short fibers move and structurally deform. Therefore, when the degree of deformation increases, the thickness of the needle punched nonwoven fabric decreases, and when the degree of deformation becomes excessive, holes may open.
[0004]
Further, as a non-woven fabric for molding, a non-stretched polyester short fiber having a low melting point or softening point and a stretched polyester short fiber having a higher melting point or softening point than the unstretched polyester short fiber have been proposed. (Japanese Patent Laid-Open No. 6-10255). This nonwoven fabric for molding is obtained by bonding stretched polyester staple fibers to each other by melting or softening unstretched polyester staple fibers. Then, before molding, unstretched polyester short fibers are melted or softened again in advance, and then molded in a molding die. Such molding involves release and recombination of the bonds between the stretched polyester short fibers, and mechanical properties such as tensile strength of the resulting molded nonwoven fabric are likely to change.
[0005]
[Problems to be solved by the invention]
Unlike conventional methods, the present invention employs unstretched polyester staple fibers having latent stretchability as the staple fibers constituting the nonwoven fabric, and the unstretched polyester staple fibers themselves are stretched to be molded into a predetermined shape. It is intended to provide a thermoforming non-woven fabric.
[0006]
As described in JP-A-6-10255, unstretched polyester short fibers are used as a binding material for bonding between the same kinds of stretched short fibers constituting a nonwoven fabric. This is because the melting point of undrawn short fibers is lower than that of the same kind of drawn short fibers. On the other hand, unstretched polyester short fibers may have latent stretchability depending on the production method. However, no proposals have been made for non-woven fabrics utilizing this latent stretchability. This is because even if the unstretched polyester short fiber has latent stretchability, the latent stretchability is often destroyed in the nonwoven fabric manufacturing process. For example, if unstretched polyester short fibers are used as a binder and heated to melt or soften, the latent stretchability is destroyed. Further, after creating a fibrous web as a constituent fibers undrawn polyester staple fibers imparts a binder such as an adhesive resin, the heat treatment is performed to cure the binder, the potential of the undrawn polyester staple fibers This is because the stretchability is destroyed.
[0007]
[Means for Solving the Problems]
Therefore, the present invention, after applying a high-pressure columnar water flow to a fiber web containing unstretched polyester short fibers having latent stretchability , the unstretched polyester short fibers are intertwined closely, and then the high-pressure columnar The water imparted to the fiber web by a water flow is dried and removed at a temperature of 130 ° C. or less to obtain a nonwoven fabric so that the latent stretchability of the unstretched polyester short fibers is not destroyed , and is a constituent fiber of the nonwoven fabric. The unstretched polyester short fiber is intended to maintain latent stretchability. And it is going to make it easy to thermo-form to a desired shape using this latent stretchability.
[0008]
First, the unstretched polyester staple fiber having latent stretchability used in the present invention will be described. In general, polyester short fibers are produced by melt spinning and then stretching under heating to promote crystallization and orientation. Thus, stretched polyester staple fibers having high tensile strength can be obtained, and most of the constituent fibers for producing the staple fiber nonwoven fabric are stretched polyester staple fibers. On the other hand, polyester short fibers obtained after melt spinning without stretching under heating are called unstretched polyester short fibers and are hardly used as constituent fibers for producing nonwoven fabrics. However, since this unstretched polyester short fiber has a lower melting point than that of the same type of stretched polyester short fiber, it is used as a binder for bonding between stretched polyester short fibers that are constituent fibers. As described above.
[0009]
Such unstretched polyester short fibers can have latent stretchability depending on the production conditions. For example, in order to obtain an unstretched polyester short fiber using polyester as a raw material, latent melt is obtained by winding it without promoting crystallization by quenching after melt spinning, and then cutting to a desired fiber length. Unstretched polyester short fibers can be obtained. If the cooling is gradually performed after melt spinning, crystallization is promoted, and even if it is an unstretched polyester short fiber short fiber, latent stretchability may be reduced, which is not preferable.
[0010]
The degree of latent stretchability of the unstretched polyester short fibers used in the present invention is preferably about 2-6 times. The degree of elongation referred to here means that when the length of the initial unstretched polyester short fiber is L 0, and the length of the short fiber at the time when the short fiber is broken to L 1 is L 1 (L 1 / L 0 ). When the degree of elongation is less than 2 times, if there is a deep-drawn portion at the time of thermoforming, the portion does not expand sufficiently and it is difficult to mold into a desired shape. Moreover, although the extension degree may exceed 6 times, it is generally difficult to manufacture with the above manufacturing method. If deep drawing is not performed at the time of thermoforming, the degree of elongation may be less than 2 times, and even if the degree of extension is 2 times or more, it will only be less than 2 times during actual molding. Needless to say, there are times when you don't.
[0011]
The fineness of the unstretched polyester short fiber used in the present invention is about 1 to 10 denier, and preferably about 1 to 3 denier. Unstretched polyester staple fibers having a fineness of less than 1 denier are generally difficult to produce. Unstretched polyester short fibers having a fineness exceeding 10 denier have a large fiber diameter, so that the texture and texture of the resulting nonwoven fabric tend to be lowered. Moreover, the fiber length of the unstretched polyester short fiber is about 20-100 mm, and it is especially preferable that it is about 30-50 mm. When the fiber length is less than 20 mm, it becomes difficult to give sufficient strength to the nonwoven fabric. That is, in the present invention, unstretched polyester short fibers are used as constituent fibers of the nonwoven fabric. Therefore, when the fiber length is short, the entanglement between the constituent fibers becomes insufficient, and a high-strength nonwoven fabric is obtained. It becomes difficult to be done. On the other hand, when the fiber length exceeds 100 mm, entanglement between unstretched polyester short fibers becomes insufficient, and it becomes difficult to obtain a high-strength nonwoven fabric. That is, the entanglement between the constituent fibers due to the high-pressure columnar water flow is promoted by the movement of the free ends of the constituent fibers. Therefore, if the fiber length is too long, the ratio of the free ends decreases, and therefore the entanglement is sufficient. It is not promoted by
[0012]
In the present invention, a fiber web is formed using the unstretched polyester short fibers as constituent fibers. The fiber web may be composed of 100% by weight of unstretched polyester short fibers, but other types of short fibers may be mixed. As other types of short fibers, rayon short fibers, cotton fibers and the like can be employed. Even when other types of short fibers are mixed, the content of unstretched polyester short fibers is preferably 50% by weight or more, and the content of other types of short fibers is preferably 50% by weight or less. When the content ratio of the unstretched polyester short fibers is less than 50% by weight, the ratio of the constituent fibers to be stretched decreases, and it becomes difficult to mold into a desired shape at the time of molding. In the present invention, when mixing other types of short fibers, it is preferable to mix them in a ratio of 60 to 90% by weight of unstretched polyester short fibers and 40 to 10% by weight of rayon short fibers. This is because the presence of rayon short fibers of this level can make a nonwoven fabric excellent in water absorption and can be used for applications requiring water absorption and liquid absorption. Moreover, in this invention, it is also preferable to mix in the ratio of 50 weight% or more of unstretched polyester staple fibers, and 50 weight% or less of stretched polyester staple fibers. In this case, the stretched polyester staple fiber, which is a regular polyester staple fiber, is mixed while being a non-woven fabric for thermoforming made of polyester, so that it is excellent in heat resistance and weather resistance.
[0013]
Basis weight of the fibrous web is preferably about 50~300g / m 2. When the basis weight is less than 50 g / m 2 , the amount of fibers per unit area is small, and it becomes difficult to entangle the constituent fibers such as unstretched polyester short fibers in a later step. Moreover, there is little fabric weight of the obtained nonwoven fabric, and when this is shape | molded, there exists a possibility that it may become thin too much and a hole may open. On the other hand, if the basis weight exceeds 300 g / m 2 , the amount of fibers per unit area is large, and the energy of the high-pressure columnar water stream makes it difficult to entangle the constituent fibers.
[0014]
After creating the fiber web, the fiber web is subjected to high pressure columnar water flow. This high-pressure columnar water stream causes the unstretched polyester staple fibers in the fiber web to be intertwined closely with each other. In this way, the unstretched polyester short fibers are intertwined in close contact with each other because the unstretched polyester short fibers are in an unbonded state in the fiber web, and each unstretched by the application of high-pressure columnar water flow. This is because the free ends of the polyester short fibers move and entangle with each other. Here, the high-pressure columnar water flow is obtained by jetting water at a high pressure through a nozzle hole having a fine diameter. Specifically, it is obtained by ejecting water at a pressure of 10 to 200 kg / cm 2 using a nozzle having a diameter of about 0.01 to 0.3 mm.
[0015]
The fiber web that has been entangled contains a large amount of water from the high-pressure columnar water stream, and is therefore introduced into the drying process. It should be noted here is the temperature at which the potential stretching of undrawn polyester staple fibers is not destroyed, in particular, it is dried at 130 ° C. or lower. If it is dried at a temperature higher than this, the latent stretchability of the unstretched polyester short fibers is destroyed, and there is a possibility that sufficient elongation of the unstretched polyester short fibers cannot be obtained at the time of molding. The non-woven fabric for thermoforming according to the present invention is obtained through the drying process as described above.
[0016]
The thermoforming nonwoven fabric obtained as described above is thermoformed by the following method. That is, a non-woven fabric for thermoforming is introduced into a thermal mold and molded into a shape that matches the thermal mold. The point to be noted in the present invention is that the non-stretched polyester fiber is not preheated before it is introduced into the thermal mold before the thermoforming nonwoven fabric is introduced. In general, when a nonwoven fabric is thermoformed, it is preheated in order to plasticize the constituent fibers of the nonwoven fabric or the binding material that joins the constituent fibers, and then introduced into a mold such as a mold. Yes. However, in the present invention, such preheating for plasticization is not performed. This is because, if the thermoforming nonwoven fabric obtained in the present invention is preheated, the latent stretchability of the unstretched polyester short fibers in the nonwoven fabric is destroyed. As is clear from the above description, the preheating referred to in the present invention refers to heating performed at a temperature at which the latent stretchability of the unstretched polyester short fibers is destroyed, and heating at temperatures below that is the concept of preheating. Not included. For example, even if a thermoforming nonwoven fabric containing unstretched polyester short fibers is heated to a temperature of around 100 ° C., the latent stretchability of the unstretched polyester short fibers is not destroyed. Therefore, this level of heating is not preheating in the present invention.
[0017]
The thermal mold used at the time of molding is generally heated at a high temperature. Specifically, it is heated to about 150 ° C. to 400 ° C., particularly about 200 to 300 ° C. The non-woven fabric for thermoforming is introduced into this heat mold and immediately molded into a heat mold shape by means such as pressurization. Since the means such as pressurization are performed immediately after being introduced into the thermal mold, the temperature of the nonwoven fabric for thermoforming is not increased until reaching the temperature of the thermal mold. Therefore, at the time of deformation of the non-woven fabric for thermoforming, the latent stretchability of the unstretched polyester short fibers is not destroyed and stretches according to the shape. Thereafter, the deformed non-woven fabric for thermoforming is heated to a temperature close to the temperature of the heat mold and is heat-set. At this time, the unstretched polyester short fibers may be softened or melted, and the short fibers may be fixed to each other. Such fixing is preferable because mechanical properties such as tensile strength of the obtained molded body are improved.
[0018]
Moreover, the non-woven fabric for thermoforming obtained by the present invention can be thermoformed without using a heat mold. For example, after being introduced into a heated atmosphere, it can be thermoformed into a desired shape simply by performing a deformation such as folding.
[0019]
The molded body obtained as described above is suitably used as a sanitary mask or a filter medium (coffee filter or air conditioning filter). In addition, it is also used for various applications such as automobile interior materials.
[0020]
【Example】
Example 1
After uniformly mixing with 70% by weight of unstretched polyester short fibers with a fineness of 2.2 denier and a fiber length of 45 mm and 30% by weight of short rayon fibers with a fineness of 1.5 denier and a fiber length of 45 mm, the fibers are opened and collected by the card method. Thus, a fiber web having a basis weight of 100 g / m 2 was obtained. This fiber web was placed on a flat plate, and a columnar water stream was uniformly applied over the entire fiber web at a pressure of 100 kg / cm 2 using a nozzle having a nozzle diameter of 0.12 mm. In addition, the nozzle was arrange | positioned so that the front-end | tip may become a position of 10 cm above a fiber web. By this treatment, the short fibers in the fiber web were intertwined closely. Then, it introduce | transduced into the dryer maintained at 100 degreeC atmospheric temperature, the contained water was evaporated, and the nonwoven fabric for thermoforming was obtained.
[0021]
This nonwoven fabric for thermoforming was introduced onto a concave mold heated to 240 ° C., and immediately pressed into the concave mold with a convex mold heated to 240 ° C. As a result, a bowl-shaped molded body was obtained. Note that the unstretched polyester short fibers were stretched at a stretch degree of about 1.4 to 1.7 times at locations where the degree of molding was large, depending on the molding location.
[0022]
Example 2
A nonwoven fabric for thermoforming was obtained in the same manner as in Example 1, except that the fiber web was made of 100% by weight of unstretched polyester short fibers having a fineness of 2.7 denier and a fiber length of 38 mm. When this non-woven fabric for thermoforming was thermoformed in the same manner as in Example 1, a well-formed molded body was obtained.
[0023]
[Action]
The production method according to the present invention uses unstretched polyester short fibers having latent stretchability as raw materials, and is subjected to conditions under which the latent stretchability of the unstretched polyester short fibers is not destroyed, that is, exposed to a high temperature. However, a nonwoven fabric for thermoforming is obtained by applying a high-pressure columnar water flow. Therefore, the unstretched polyester staple fibers in the obtained non-woven fabric for thermoforming generally have the initial latent stretchability and extend well when an external force is applied.
[0024]
【The invention's effect】
Therefore, the nonwoven fabric for thermoforming obtained by the production method according to the present invention has the effect that unstretched polyester short fibers having latent stretchability, which are constituent fibers, are easily stretched and can be easily molded into a desired shape. Play. In addition, although this non-woven fabric for thermoforming is structurally deformed, it is mainly deformed by the elongation of the constituent fibers, so even if the degree of deformation is increased, it is difficult to open holes and the generation of defective molded products is reduced. There is also an effect that it can be done. Furthermore, since the close entanglement between the constituent fibers before molding is generally maintained as it is after molding, it is possible to prevent mechanical properties such as tensile strength of the molded body from being lowered. Play.
Claims (4)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23514298A JP4128665B2 (en) | 1998-08-21 | 1998-08-21 | Manufacturing method of non-woven fabric for thermoforming |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23514298A JP4128665B2 (en) | 1998-08-21 | 1998-08-21 | Manufacturing method of non-woven fabric for thermoforming |
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| Publication Number | Publication Date |
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| JP2000073266A JP2000073266A (en) | 2000-03-07 |
| JP4128665B2 true JP4128665B2 (en) | 2008-07-30 |
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| JP23514298A Expired - Lifetime JP4128665B2 (en) | 1998-08-21 | 1998-08-21 | Manufacturing method of non-woven fabric for thermoforming |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104862879A (en) * | 2015-06-04 | 2015-08-26 | 福建省三达纤维股份有限公司 | Production method for anti-static non-woven fabric |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2013119672A (en) * | 2011-12-06 | 2013-06-17 | Nippon Ester Co Ltd | Method for producing molded article |
| JP6782941B2 (en) * | 2016-10-07 | 2020-11-11 | 山中産業株式会社 | Biodegradable non-woven fabric, biodegradable beverage extraction filter using this, and biodegradable beverage extraction capsule using this beverage extraction filter |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA1327343C (en) * | 1987-08-28 | 1994-03-01 | Gates Formed-Fibre Products, Inc. | Semirigid luggage shell and method for its production |
| JPH0228409U (en) * | 1988-08-16 | 1990-02-23 | ||
| JP3081731B2 (en) * | 1993-07-05 | 2000-08-28 | 日本バイリーン株式会社 | Skin material for automobile interior, automobile interior material and manufacturing method thereof |
| JPH0787848A (en) * | 1993-09-27 | 1995-04-04 | Japan Vilene Co Ltd | Pot for plant and its production |
| JPH08170262A (en) * | 1994-12-16 | 1996-07-02 | Asahi Chem Ind Co Ltd | Material for mask |
| JP3769674B2 (en) * | 1995-11-30 | 2006-04-26 | 日本バイリーン株式会社 | Electretized mask |
| JPH101855A (en) * | 1996-04-15 | 1998-01-06 | Unitika Ltd | Biodegradable short fiber nonwoven fabric and its production |
| JP3657700B2 (en) * | 1996-06-18 | 2005-06-08 | 新日本石油化学株式会社 | Method for producing high-quality nonwoven fabric |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104862879A (en) * | 2015-06-04 | 2015-08-26 | 福建省三达纤维股份有限公司 | Production method for anti-static non-woven fabric |
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