JP4117915B2

JP4117915B2 - Biodegradable nonwoven fabric and method for producing the same

Info

Publication number: JP4117915B2
Application number: JP05111696A
Authority: JP
Inventors: 孝一長岡; 文夫松岡; 直次一瀬; 安広米沢; 恵子迫田
Original assignee: Unitika Ltd
Current assignee: Unitika Ltd
Priority date: 1995-03-08
Filing date: 1996-03-08
Publication date: 2008-07-16
Anticipated expiration: 2016-03-08
Also published as: JPH0978428A

Description

【０００１】
【発明の属する技術分野】
本発明は、医療・衛生材料、生活資材あるいは一般産業資材など、幅広い用途に用いられる生分解性不織布およびその製造方法に関するものである。
【０００２】
【従来の技術】
生分解性不織布としては、例えば、コットン、麻、羊毛、レーヨン、キチン、アルギン酸等のような天然繊維由来の生分解性不織布が知られている。しかし、これらの生分解性不織布は一般的に親水性であり、優れた吸水性を有するものであるが、反面、これらの不織布は湿潤環境下での強力や寸法安定性の低下が著しく、一部の用途への展開には限界があった。さらに、これらの不織布は非熱可塑性であることから、熱成形性を有さず加工性に劣るものであった。
【０００３】
これらの問題を解決する生分解性不織布としては、特開平５−９３３１８号公報または特開平５−１９５４０７号公報に生分解性を有する熱可塑性重合体を用いた不織布が開示されている。しかし、これらにおいては、紡出糸条の冷却性および可紡性に劣るためスパンボンド法による製造は困難であり、しかも全融タイプとなるので得られた不織布の機械的特性および柔軟性に劣るものであった。これは、一般的に生分解性を有する重合体の融点および結晶化温度が低く、しかも結晶化速度が遅いことに起因する。すなわち、溶融紡出後の冷却、牽引細化、捕集、堆積工程において、糸条間で密着が発生するために充分な開繊を行なうことができないため、得られる不織布の地合いを損なうこととなり、また生分解速度の制御も困難である等の問題を生じることとなる。
【０００４】
また、従来の、一成分のみから構成される単一型、単一中空型等の繊維横断面をもつ長繊維は、スパンボンド法による不織布の製造に際し、融点および結晶化温度の比較的高い生分解性を有する重合体を用いて紡出糸条の冷却性および開繊性を重視すると、得られる不織布の生分解性能に劣ることとなる。逆に、生分解性能を重視し融点および結晶化温度の比較的低い生分解性を有する重合体を用いると、紡出糸条の冷却性および開繊性が劣ることとなる。しかも、従来の方法では、生分解性能の制御は、適用する重合体の種類および繊度、複合比および繊維の配向度などを変更することにより幾分かは可能ではあるが、微妙な制御は不可能であった。
【０００５】
さらに、前述のような生分解性熱可塑性重合体を用いた長繊維単独で形成された不織布は、機械的特性には優れるものの、吸湿性、吸水性に劣り、用途が限定されるものであった。これを改善する方法としては、吸水性に優れる天然繊維等を積層することが考えられるが、生分解性熱可塑性重合体からなる長繊維不織ウエブと天然繊維からなる不織ウエブとを積層して部分熱融着を施す場合に、従来適用されているエンボスロールを用いた熱圧接装置によると、両ウエブ間の接着力が弱く、得られる積層不織布は到底使用に耐えるものではなかった。
【０００６】
【発明が解決しようとする課題】
本発明は、このような問題を解決するもので、生分解性能が制御可能であるとともに不織布の地合いおよび機械的特性、紡出糸条の冷却性および可紡性に優れ、かつ熱接着機能を有し、さらに必要に応じて吸水性をも発揮しうる生分解性不織布およびこれらの製造方法を提供しようとするものである。
【０００７】
【課題を解決するための手段】
この課題を解決するため本発明は、以下の構成を要旨とするものである。
（１）複合長繊維からなる長繊維不織ウエブが部分的に熱圧接されて所定の形態が保持されてなる不織布であって、前記複合長繊維が生分解性を有する第１の脂肪族ポリエステルからなる高融点成分とこの高融点成分よりも融点の低い生分解性を有する第２の脂肪族ポリエステルからなる低融点成分とから形成される環状均等配列型複合長繊維であり、この環状均等配列型複合長繊維の繊維横断面において高融点成分および低融点成分が繊維横断面の周方向の一定範囲ずつを交互に占め、かつ繊維横断面に中空部を有し、かつ前記両成分が繊維横断面において均等な面積を有する３〜２０個のセグメントにそれぞれ分割されており、しかも高融点成分および低融点成分が繊維軸方向に連続するとともに繊維表面ならびに中空部に露出しており、前記複合長繊維の単糸繊度が１．５〜１０デニールであることを特徴とする生分解性不織布。
（２）複合長繊維からなる長繊維不織ウエブと天然繊維からなる天然繊維不織ウエブとが積層され部分的な圧接により一体化されてなる積層不織布であって、前記複合長繊維が生分解性を有する第１の脂肪族ポリエステルからなる高融点成分とこの高融点成分よりも融点の低い生分解性を有する第２の脂肪族ポリエステルからなる低融点成分とから形成される環状均等配列型複合長繊維であり、この環状均等配列型複合長繊維の繊維横断面において高融点成分および低融点成分が繊維横断面の周方向の一定範囲ずつを交互に占め、かつ繊維横断面に中空部を有し、かつ前記両成分が繊維横断面において均等な面積を有する３〜２０個のセグメントにそれぞれ分割されており、しかも高融点成分および低融点成分が繊維軸方向に連続するとともに繊維表面ならびに中空部に露出しており、前記複合長繊維の単糸繊度が１．５〜１０デニールであることを特徴とする生分解性不織布。
（３）複合長繊維からなる長繊維不織ウエブが部分的に熱圧接されて所定の形態が保持されてなる不織布の製造方法であって、前記複合長繊維を生分解性を有する第１の脂肪族ポリエステルからなる高融点成分とこの高融点成分よりも融点の低い生分解性を有する第２の脂肪族ポリエステルからなる低融点成分とを用いて形成し、繊維横断面において高融点成分および低融点成分が繊維横断面の周方向の一定範囲ずつを交互に占め、かつ繊維横断面に中空部を有し、前記両成分が繊維横断面において均等な面積を有する３〜２０個のセグメントにそれぞれ分割されており、しかも高融点成分および低融点成分が繊維軸方向に連続するとともに繊維表面ならびに中空部に露出するような環状均等配列型複合長繊維を溶融紡糸し、この環状均等配列型複合長繊維を牽引速度２０００ｍ／分以上で牽引細化した後、前記複合長繊維の単糸繊度が１．５〜１０デニールである長繊維不織ウエブとなし、この長繊維不織ウエブを熱圧接装置により部分的に熱圧接させることを特徴とする生分解性不織布の製造方法。
（４）複合長繊維からなる長繊維不織ウエブと天然繊維からなる天然繊維不織ウエブとを積層して部分的に圧接することにより一体化されてなる積層不織布の製造方法であって、前記複合長繊維を生分解性を有する第１の脂肪族ポリエステルからなる高融点成分とこの高融点成分よりも融点の低い生分解性を有する第２の脂肪族ポリエステルからなる低融点成分とを用いて形成し、繊維横断面において高融点成分および低融点成分が繊維横断面の周方向の一定範囲ずつを交互に占め、かつ繊維横断面に中空部を有し、前記両成分が繊維横断面において均等な面積を有する３〜２０個のセグメントにそれぞれ分割されており、しかも高融点成分および低融点成分が繊維軸方向に連続するとともに繊維表面ならびに中空部に露出するような環状均等配列型複合長繊維を溶融紡糸し、この環状均等配列型複合長繊維を牽引速度２０００ｍ／分以上で牽引細化した後、前記複合長繊維の単糸繊度が１．５〜１０デニールである長繊維不織ウエブとなし、この長繊維不織ウエブに常法にて別途作成した天然繊維の不織ウエブを積層した後に、超音波融着処理を施して両不織ウエブを部分的に融着させ一体化することを特徴とする生分解性不織布の製造方法。
【０００８】
本発明によれば、長繊維の繊維横断面において、高融点成分と低融点成分とが複数に分かれた状態で配置されており、しかもこの高融点成分と低融点成分とが繊維軸方向に連続するとともに繊維表面および中空部に露出していることから、生分解性能には劣るが冷却性および開繊性に優れる高融点成分を細分化するとともに、冷却性および開繊性には劣るが生分解性能に優れる低融点成分を細分化することができる。これにより、冷却性、開繊性および生分解性能のいずれにも優れる不織布を得ることができるのである。しかも、高融点成分および低融点成分はいずれも各々均等に分かれた状態で配置されていることにより、紡出糸条の冷却性、開繊性に優れる高融点成分および生分解性能に優れる低融点成分は繊維表面においてバランス良く配置され、紡出糸条の冷却性、開繊性および生分解性能を偏りなく均一に付与することができるのである。
【０００９】
また、本発明の生分解性不織布のうち、長繊維不織ウエブと天然繊維不織ウエブとを積層した積層不織布は、天然繊維によって吸水性を発揮させるとともに、湿潤時の機械的強力に劣るという天然繊維の特性を長繊維不織ウエブによって補強するものである。しかも、長繊維不織ウエブは脂肪族ポリエステル系重合体から構成され、天然繊維不織ウエブはコットン等の分解性素材から構成されるため、本発明の積層不織布の構成素材は全て自然環境下で分解し得るものである。
【００１０】
【発明の実施の形態】
まず、本発明の生分解性不織布のうち、長繊維不織ウエブが部分的に熱圧接されて所定の形態を保持してなる長繊維不織布について説明する。
【００１１】
本発明に適用される長繊維は、生分解性を有する脂肪族ポリエステル２成分により形成される。すなわち、本発明に適用される長繊維は、高融点成分の脂肪族ポリエステルと低融点成分の脂肪族ポリエステルとで構成された複合長繊維である。一般に、高融点成分は、紡出糸条の冷却性および開繊性には優れるものの、結晶化度が高いため生分解性能には劣り、逆に、低融点成分は、紡出糸条の冷却性および開繊性には劣るものの、結晶化度が低いため生分解性能には優れる。例えば、繊維横断面が高融点成分単相の場合には、製糸性および不織布化には優れるものの、目標とする生分解性能を得ることができない。一方、繊維横断面が低融点成分単相の場合には、紡出糸条の冷却性に劣り不織布すら得ることができない。本発明によれば、繊維横断面において、生分解性能には劣るが冷却性および開繊性に優れる高融点成分を細分化するとともに、冷却性および開繊性には劣るが生分解性能に優れる低融点成分を細分化し、細分化した両成分を円周方向に交互に配列させることにより、冷却性、開繊性および生分解性能のいずれにも優れる不織布を得ることができるのである。
【００１２】
従って、本発明における長繊維では、高融点成分と低融点成分との融点差を５℃以上とすることが好ましく、さらに好ましくは１０℃以上とするのが良い。高融点成分と低融点成分との融点差が５℃未満であると、繊維横断面が単相の場合のような全融タイプに近づくため、次工程における不織布の部分熱圧接において低融点成分のみならず高融点成分であっても熱的なダメージを生じることとなり、得られる不織布は機械的特性と柔軟性とを伴せ持つことができないものとなる。
【００１３】
まず、本発明における環状均等配列型複合長繊維を形成する脂肪族ポリエステルについて説明する。高融点成分はポリブチレンサクシネートであることが好ましい。低融点成分は、ブチレンサクシネートを主繰り返し単位とし、これに他の脂肪族ポリエステルを構成する繰り返し単位要素を共重合させたものであることが好ましい。前記ブチレンサクシネ−トに共重合せしめる他の脂肪族ポリエステルとしては、例えば、ポリグリコール酸やポリ乳酸のようなポリ（α−ヒドロキシ酸）またはこれらを構成する繰り返し単位要素による共重合体が挙げられる。また、ポリ（ε−カプロラクトン）、ポリ（β−プロピオラクトン）のようなポリ（ω−ヒドロキシアルカノエート）が、さらに、ポリ−３−ヒドロキシプロピオネート、ポリ−３−ヒドロキシブチレート、ポリ−３−ヒドロキシカプロエート、ポリ−３−ヒドロキシヘプタノエート、ポリ−３−ヒドロキシオクタノエートのようなポリ（β−ヒドロキシアルカノエート）およびこれらを構成する繰り返し単位要素とポリ−３−ヒドロキシバリレートやポリ−４−ヒドロキシブチレートを構成する繰り返し単位要素との共重合体が挙げられる。またジオールとジカルボン酸の縮重合体からなるものとして、例えば、ポリエチレンオキサレート、ポリエチレンサクシネート、ポリエチレンアジペート、ポリエチレンアゼテート、ポリブチレンオキサレート、ポリブチレンアジペート、ポリブチレンセバケート、ポリヘキサメチレンセバケート、ポリネオペンチルオキサレートまたはこれらを構成する繰り返し単位要素による共重合体が挙げられる。以上の脂肪族ポリエステルのなかで、ポリエチレンサクシネートならびにポリブチレンアジペートが、製糸性および生分解性能に優れるなどの理由により、特に好適に用いられる。
【００１４】
前記低融点成分を構成する共重合体においては、ブチレンサクシネートの共重合量比が７０〜９０モル％であることが好ましい。ブチレンサクシネートの共重合量比が７０モル％未満であると、生分解性能には優れるものの、紡出糸条の冷却性および開繊性に劣り、目的とする長繊維ひいては不織布が得られないこととなる。逆に、９０モル％を超えると、冷却性および開繊性には優れるものの、生分解性能に劣り本発明の目的とするものではない。
【００１５】
本発明で適用する重合体のメルトフロレート値（以降、ＭＦＲ値と記す）は、高融点成分が２０〜７０ｇ／１０分であり、低融点成分が１５〜５０ｇ／１０分であることが好ましい。但し、本発明におけるＭＦＲ値は、ＡＳＴＭ−Ｄ−１２３８（Ｅ）記載の方法に準じて測定したものである。高融点成分のＭＦＲ値が２０ｇ／１０分未満および／または低融点成分のＭＦＲ値が１５ｇ／１０分未満であると、あまりにも高粘度であるため、紡出糸条の細化がスムーズに行われず操業性を損なう結果となり、しかも得られる繊維は太繊度で均斉度に劣るものとなる。逆に、高融点成分のＭＦＲ値が７０ｇ／１０分および／または低融点成分のＭＦＲ値が５０ｇ／１０分を超えると、あまりにも低粘度であるため、複合断面が不安定となるばかりか、紡糸工程において糸切れが発生し操業性を損なうとともに、得られる不織布の機械的特性が劣る結果となる。これらの理由により、高融点成分のＭＦＲ値は２５〜６５ｇ／１０分、低融点成分のＭＦＲ値は１８〜４５ｇ／１０分であることがさらに好ましい。
【００１６】
また、高融点成分の粘度は低融点成分の粘度より低い方が好ましい。一般に、熱可塑性樹脂の複合紡糸においては、低粘度成分が高粘度成分を被覆する傾向がある。すなわち、本発明においては、生分解性能には劣るものの紡出糸条の冷却性に優れる高融点成分を低粘度にすることにより、繊維表面における低融点成分の露出比率を減少させ、紡出糸条の密着を防止しさらに開繊性を良化させるとともに、両成分の楔状形態を安定化できるのである。
【００１７】
本発明において、高融点成分および低融点成分に適用される脂肪族ポリエステルは、数平均分子量が約２０，０００以上、好ましくは４０，０００以上、さらに好ましくは６０，０００以上のものが、製糸性および得られる糸条の特性の点で良い。また、重合度を高めるために少量のジイソシアネートやテトラカルボン酸二無水物などで鎖延長したものでも良い。
【００１８】
本発明において適用される長繊維においては、その構成成分のうちの少なくとも低融点成分中に結晶核剤が添加されていることが好ましい。結晶核剤を添加することにより、溶融紡出後に固化しにくい結晶性の低い重合体であっても、紡出糸条間に密着が発生するのを防止することができる。また、結晶核剤は、重合工程あるいは溶融工程で添加するが、その際、得られる糸の機械的性能および均斉度を向上させるため、できる限り均一分散させておくことが好ましい。
【００１９】
結晶核剤としては、粉末状の無機物で、かつ溶融液に溶解したりするものでなければ特に制限をうけないが、タルク、炭酸カルシウム、酸化チタン、窒化ホウ素、シリカゲル、酸化マグネシウムなどが通常用いられ、これらの中でも特に、タルクまたは酸化チタンまたはこれらの混合物が好適に用いられる。
【００２０】
結晶核剤としての無機粉末の平均粒径は５μｍ以下であるのが好ましい。平均粒径が５μｍを超えると、繊度のより細かな繊維が得られにくくなる傾向が生じたり、あるいは吐出孔を複数備えている紡糸口金内の濾過フィルターに目詰まりが発生しやすくなり、紡糸操業性が低下する傾向が生じる。これら理由により、結晶核剤としての無機粉末の平均粒径は５μｍ以下、好ましくは４μｍ以下、さらに好ましくは３μｍ以下が良い。
【００２１】
結晶核剤としての無機粉末の嵩比容は、２〜１０ｃｃ／ｇであるのが好ましく、３〜８ｃｃ／ｇであるのがより好ましい。なお、嵩比容は、単位重量当りの無機粉末の体積のことである。嵩比容が大きくなればなるほど、無機粉末の表面積が大きくなり、結晶核剤としての効果を増大させることになる。無機粉末の嵩比容が２ｃｃ／ｇ未満であると、結晶核剤としての効果が低減し、そのために結晶核剤の添加量（重合体中への含有量）を多くしなければならず、得られる長繊維ひいては不織布の機械的強度は低下する。また、嵩比容が１０ｃｃ／ｇを超える無機粉末の製造は困難であり、このような無機粉末を得ようとすると、無機粉末のコストが高騰し、ひいては得られる長繊維のコストも高騰する結果となる。
【００２２】
また、結晶核剤は、高融点成分中への結晶核剤の添加量をＱA （重量％）とし、低融点成分中への結晶核剤の添加量をＱB （重量％）としたときに、（１）式および（２）式を満足するように添加されていることが好ましい。
[(ΔＴA ＋ΔＴB)／100]−2 ／3 ≦ＱA ＋ＱB ≦[(ΔＴA ＋ΔＴB)／100]＋４…（１）
ＱA ≦ＱB …（２）
但し、ΔＴA ＝高融点成分の融点−高融点成分の結晶化温度≧３５
ΔＴB ＝低融点成分の融点−低融点成分の結晶化温度≧３５
結晶核剤の全添加量ＱA ＋ＱB （重量％）が（１）式で定義された上限を超えると、紡出糸条の冷却効果は高いものの、製糸性が低下するとともに得られた長繊維ひいては不織布の機械的性能が劣り好ましくない。逆に、結晶核剤の全添加量ＱA ＋ＱB （重量％）が（１）式で定義された下限より低くなると、紡出糸条の冷却性が低下して紡出糸条間に密着が発生し、目標とする不織布を得ることが困難となる。また、高融点成分中への結晶核剤の添加量ＱA （重量％）が、低融点成分中への結晶核剤の添加量ＱB （重量％）よりも多くなると、高融点成分の冷却性はさらに向上するが、低融点成分の冷却性が低くなり、これによって紡出糸条間に密着が発生しやすくなるため好ましくない。
【００２３】
ところで、（１）式において、ΔＴは各成分の融点と結晶化温度との差であるが、製糸工程においては、このΔＴが小さいほうが紡出糸条の冷却性は向上する。本発明の重合体において、ΔＴは通常３５以上と大きくなるが、結晶核剤を添加することにより効果的に紡出糸条の冷却を促進することができるのである。
【００２４】
なお、本発明において適用される熱可塑性重合体に、必要に応じて、例えば艶消し剤、顔料、光安定剤、耐候剤、酸化防止剤などの各種添加剤を本発明の効果を損なわない範囲内で添加することができる。
【００２５】
次に、本発明に適用される複合長繊維の繊維横断面形状について説明する。
本発明の環状均等配列型複合断面においては、高融点成分と低融点成分とが周方向の一定範囲ずつを交互に占め、かつ繊維横断面に中空部を有し、しかも高融点成分および低融点成分が繊維軸方向に連続するとともに繊維表面ならびに中空部に露出しており、前記両成分は繊維横断面においてそれぞれ均等な面積を有するセグメントに分割されていることが必要である。高融点成分と低融点成分とが交互に配列されていることにより、例えば、低融点成分が冷却性および開繊性に劣る重合体であっても、隣接する高融点成分により紡出糸条の冷却性および開繊性を向上できるのである。また、高融点成分が生分解性能に劣る重合体であっても隣接する低融点成分の生分解性能が優れるため、経時的に低融点成分が分解すると高融点成分が繊度が極細い楔状の薄片として取り残される状態となり、不織布としての生分解性能には優れる結果となるのである。また、繊維横断面に中空部を有することにより、紡出糸条の冷却性を向上させ、さらに、生分解速度を促進させることができる。すなわち、低融点成分の分解が進行すると中空部が有るために高融点成分が弧状の薄片として取り残される状態となり生分解速度が促進するのである。さらに、高融点成分および低融点成分のいずれもが繊維軸方向に連続していることが、繊維横断面の安定性、製糸性および繊維の機械的特性を高めるために必要である。また、前記両成分のいずれもが繊維表面ならびに中空部に露出していることが、紡出糸条の冷却性、開繊性および生分解性能の促進、制御のために必要である。たとえば低融点成分が繊維横断面の中空部まで貫通していない場合には、高融点成分が弧状になるのに時間を要するため生分解性能には劣る結果となる。さらに、高融点成分と低融点成分とがそれぞれ均等な面積を有するセグメントに配列されていることにより、紡出糸条の冷却性、開繊性に優れる高融点成分および生分解性能に優れる低融点成分は繊維表面においてバランス良く配置されるので、紡出糸条の冷却性、開繊性および生分解性能を偏りなく均一に付与することができる。
【００２６】
本発明に適用される複合長繊維の繊維横断面において、高融点成分／低融点成分の複合比が１／３〜３／１（重量比）であることが好ましい。複合比がこの範囲を外れると紡出糸条の冷却性、開繊性および生分解性能の全てを併せて満足することができず、さらに、繊維横断面形状の不安定さを誘発するため好ましくない。たとえば、高融点成分／低融点成分の複合比が１／３を超えると、生分解性能には優れるものの、紡出糸条の冷却性、開繊性には劣る結果となる。逆に、高融点成分／低融点成分の複合比が３／１を超えると、紡出糸条の冷却性、開繊性には優れるものの、生分解性能には劣る結果となる。低融点成分が生分解性能に劣る重合体であれば、高融点成分の複合比を上げることにより生分解速度を促進させることができる。この理由により、高融点成分／低融点成分の複合比は、さらに好ましくは１／２〜２／１（重量比）が良い。
【００２７】
また、本発明に適用される複合長繊維の繊維横断面において、中空率は５〜３０％であることが好ましい。ここで、中空率とは、図１に示すように、繊維横断面における糸の直径を（Ａ）、中空部の直径を（ａ）としたとき、次式で示される値である。
【００２８】
中空率（％）＝（ａ² ／Ａ² ）×１００
中空率が５％未満であると、冷却性および生分解速度の促進には不充分であり、逆に、中空率が３０％を超えると、製糸段階において中空部がパンクしたり高速製糸性に劣ることとなり好ましくない。この理由により、中空率は、さらに好ましくは１０〜２５％が良い。
【００２９】
本発明に適用される複合長繊維の繊維横断面において、高融点成分、低融点成分の各セグメント数が３〜２０であることが必要である。ここで、セグメント数とは、繊維横断面において、高融点成分、低融点成分それぞれが配列されて占める最小構成単位の存在数である。各セグメント数が３未満であると、紡出糸条の冷却性および開繊性に劣るとともに生分解性能にも劣る結果となる。逆に、各セグメント数が２０を超えると、紡糸口金における開孔数が減少し生産性に劣るとともに、安定した複合断面が得られないこととなる。従って、低融点成分が紡出糸条の冷却性および開繊性に劣る重合体であり、セグメント数が３未満であれば、セグメントが大きすぎるため冷却性および開繊性を改良することは困難となる。また、高融点成分が生分解性能に劣る重合体であれば、セグメント数を増加させ高融点成分を細分化することにより、生分解速度を促進させることができる。この理由により、各セグメント数は、さらに好ましくは６〜１６が良い。
【００３０】
本発明に適用される複合長繊維の単糸繊度は１．５〜１０デニールであることが必要である。１．５デニール未満であると、紡糸口金の複雑化、製糸工程における糸切れの増大、生産量の低下および繊維横断面形状の不安定さなどが発生する。逆に、１０デニールを超えると紡出糸条の冷却性に劣るとともに生分解性能にも劣る結果となる。この理由により、さらに好ましくは２〜８デニールが良い。
【００３１】
本発明の生分解性不織布は、生分解性能を異にする高融点成分および低融点成分で構成された環状均等配列型複合長繊維より形成されるので、両成分の複合比、両成分の各セグメント数、中空率、単糸繊度を適宜組み合わせることにより、要求する紡出糸条の冷却性、開繊性および生分解性能を発揮することができ、しかも生分解性能を微妙に制御することができる。
【００３２】
次に、本発明の生分解性不織布のうち、前記の長繊維不織ウエブに天然繊維不織ウエブを積層して超音波融着により一体化された積層不織布について説明する。
【００３３】
本発明に適用される天然繊維は、生分解性を有するものであれば特に制限はないが、特に、コットン、ラミー、短繊維状に裁断されたシルク繊維等が好適に用いられる。ここで、コットンとしては、晒し加工の施されていないコーマ糸、晒し加工の施された晒し綿、または織物・編み物から得られた反毛等が挙げられる。
【００３４】
本発明における天然繊維不織ウエブは、前記天然繊維を単独または複数組み合わせて作成されるウエブであり、カード機の進行方向に配列したパラレルウエブ、パラレルウエブのクロスレイドされたウエブ、ランダムに配列したランダムウエブあるいは中程度に配列したセミランダムウエブのいずれであっても良く、使用用途によって適宜選択することができる。特に、衣料用途に用いる場合には、不織布としての強力において、縦／横強力比が概ね１／１となるカードウエブを使用するのが好ましい。
【００３５】
天然繊維不織ウエブを積層する場合、天然繊維不織ウエブと長繊維不織ウエブとの積層比率は１０／９０〜９０／１０（重量％）であることが好ましい。天然繊維が１０重量％未満であると、積層不織布の機械的特性には優れるものの、吸湿性、吸水性を充分に向上させることができず、天然繊維を積層した目的を達成することができないため好ましくない。逆に、天然繊維が９０重量％を超えると、吸湿性、吸水性には優れるものの、機械的特性を損なうこととなり好ましくない。これらの理由により、天然繊維不織ウエブと長繊維不織ウエブとの積層比率は２０／８０〜８０／２０（重量％）であることがさらに好ましい。
【００３６】
積層された長繊維不織ウエブと天然繊維不織ウエブとの一体化は、超音波融着処理によって行われる。この超音波融着処理は後述の超音波融着装置を用いて部分的な融着区域を形成するものであり、融着区域における複合長繊維を熱融解させて天然繊維の内部に埋没させることにより、長繊維不織ウエブと天然繊維不織ウエブとが融着される。これにより、長繊維不織ウエブと熱接着性を有しない天然繊維とを実用に耐えうるだけの接着力で一体化することができる。
【００３７】
次に、本発明の生分解性不織布の製造方法について説明する。
まず、本発明の生分解性不織布のうち、長繊維不織ウエブが部分的に熱圧接されて所定の形態を保持してなる長繊維不織布についての製造方法を説明する。
【００３８】
本発明の生分解性不織布の製造は、通常の複合紡糸装置を用いて行なうことができる。前述したところの生分解性を有する脂肪族ポリエステルすなわち高融点成分としてポリブチレンサクシネート、低融点成分としてブチレンサクシネートの共重合量比が７０〜９０モル％であるブチレンサクシネートを主繰り返し単位とした共重合ポリエステルを好適材料とし、これを別々に溶融し、高融点成分／低融点成分の複合比が１／３〜３／１（重量比）となるように個別に計量した後、前述の両成分の各セグメント数、中空率、単糸繊度を満足する繊維横断面構造を形成可能な環状均等配列型複合紡糸口金より吐出した紡出糸条を公知の冷却装置にて冷却する。次いで、エアーサッカーを用いて目標繊度となるよう牽引細化して引き取られる。牽引細化した複合長繊維は公知の開繊器具にて開繊せしめた後、スクリーンコンベアなどの移動式捕集面上に開繊堆積させて長繊維不織ウエブとする。その後、この長繊維不織ウエブを熱圧接装置を用い部分的に熱圧接して生分解性不織布が得られるのである。
【００３９】
本発明の生分解性不織布の製造方法においては、用いる重合体、特に低融点成分を構成する重合体に前述の結晶核剤を添加することにより、紡出糸条の密着を防止し、冷却性、開繊性を向上させることができる。
【００４０】
溶融紡糸において、紡糸温度は、用いる脂肪族ポリエステルによって異なるものの、少なくとも重合体のＭＦＲ値と繊維形成性すなわち製糸性とを勘案すれば適宜設定することができる。通常は、紡糸温度を重合体の融点より少なくとも４０℃高い温度とし、特に１２０〜３００℃とするのが好ましい。紡糸温度が１２０℃未満であると、未溶融物が発生したり、重合体の溶融粘度が高過ぎるため溶融押出機を用いて重合体を押出すことが困難となり、逆に、紡糸温度が３００℃を超えると、重合体が熱分解をし始めるため、いずれも好ましくない。
【００４１】
牽引細化については、牽引速度は２０００ｍ／分以上であることが必要であり、特に２５００ｍ／分以上とすると不織布の寸法安定性が向上するため好適である。牽引速度が２０００ｍ／分未満であると、糸条の配向が不十分なため糸条が密着するとともに開繊性も悪化し、目標とする不織布が得られないこととなる。
【００４２】
長繊維不織ウエブに部分的な熱圧接処理を施し所定の形態を保持させるに際しては、加熱されたエンボスロールと表面が平滑な金属ロールとを用いて長繊維間に点状融着区域を形成する方法、あるいは超音波融着装置を用いパターンロール上で超音波による高周波を印加してパターン部の長繊維間に点状融着区域を形成する方法が採用される。
【００４３】
前記部分的な熱圧接とは、構成繊維間において、低融点成分同士が熱圧接されることでウエブの形態を保持し、少なくとも高融点成分同士は融着されず構成繊維同士の完全融着を防止し得るような熱圧接をいい、このような部分的熱圧接とすることにより、所定の不織布形態を保持しつつ生分解性能および柔軟性を発揮させることができる。
【００４４】
部分的熱圧接により形成された圧接領域は、長繊維不織ウエブの全表面積に対して特定の領域を有するものであり、具体的には、個々の熱圧接領域は丸型，楕円型，菱型，三角型，Ｔ字型，井型など任意の形状であって良いが、０．０７〜１．５ｍｍ² の面積を有し、その密度すなわち圧接点密度が１０〜１２０点／ｃｍ² 、好ましくは２０〜６０点／ｃｍ² であるのが良い。圧接点密度が１０点／ｃｍ² 未満であると得られる不織布の機械的特性や寸法安定性が向上せず、逆に、圧接点密度が１２０点／ｃｍ² を超えると柔軟性と嵩高性が向上せず、いずれも好ましくない。また、ウエブの全表面積に対する全熱圧接領域の面積の比すなわち圧接面積率は３〜４０％好ましくは４〜３０％であるのが良い。この圧接面積率が３％未満であると得られる不織布の寸法安定性に劣り好ましくない。逆に、圧接面積率が４０％を超えると、得られた不織布の柔軟性および嵩高性を損なうとともに、生分解性能にも劣ることとなるため好ましくない。
【００４５】
加熱されたエンボスロールを用いる場合、ロールの表面温度すなわち加工温度は低融点成分の融点以下の温度としなければならない。低融点成分の融点を超えると、熱圧接装置に重合体が固着し操業性を著しく損なうばかりか、不織布の風合いが硬くなり柔軟な不織布が得られない。さらに好ましくは、加工温度は、低融点成分の融点を（Ｔｍ）℃としたとき、（Ｔｍ−２５）℃〜（Ｔｍ）℃の範囲にあることが良い。加工温度が（Ｔｍ−２５）℃未満であると得られる不織布の機械的機能および毛羽立防止性が劣る結果となり好ましくない。
【００４６】
超音波融着装置を用いる場合、周波数が約２０ｋＨｚの通常ホーンと呼称される超音波発振器と、円周上に点状または帯状に凸状突起部を具備するパターンロールとからなる装置が採用される。前記超音波発振器の下部に前記パターンロールが配設され、長繊維不織ウエブを超音波発振器とパターンロールとの間に通すことにより部分的に熱融着することができる。このパターンロールに配設される凸状突起部１列あるいは複数列であってもよく、また、その配設が複数列の場合には、並列あるいは千鳥型のいずれの配列でも良い。
【００４７】
なお、部分的な熱圧接処理は、連続工程あるいは別工程のいずれで行っても良い。また、熱圧接処理については、前述の加熱されたエンボスロールあるいは超音波融着装置のいずれを選択しても良いが、不織布の使用用途に応じ、特に柔軟性が要求される医療・衛生材料や拭き取り布などの一般生活関連材としては、超音波融着装置を用いると、優れた性能を有する不織布を得ることができる。
【００４８】
次に、本発明の生分解性不織布のうち、長繊維不織ウエブと天然繊維不織ウエブとを積層した積層不織布を得る方法について説明する。
前記と同様にして移動式補集面上に開繊堆積させた長繊維不織ウエブに、常法により別途作成した天然繊維を積層し、これに超音波融着処理を施して一体化させて積層不織布を得る。
【００４９】
超音波融着処理を施すに際しては、前述の部分的熱圧接処理の場合と同様の超音波融着装置が好適に用いられ、ロールの加圧には空気圧が使用され、ホーンがロールに接する線圧は１．０〜５０ｋｇ／ｃｍの範囲とすることが好ましい。線圧が１．０ｋｇ／ｃｍ未満であると、積層不織布の厚みに対し押し圧が不足となり積層体の剥離強力が小さくなり好ましくない。逆に、線圧が５０ｋｇ／ｃｍを超えると、融着部分に対して圧力が掛かり過ぎるため、融着部分のフイルム化により同様に接着強力の低下を招き好ましくない。
【００５０】
本発明においては、移動式補集面上に開繊堆積させた長繊維不織ウエブと天然繊維不織ウエブとを積層する前に予め、長繊維不織ウエブに仮熱圧接処理または熱風接着処理または三次元交絡処理を公知の方法により施しておくことが好ましい。これにより、長繊維不織ウエブと天然繊維不織ウエブとを積層する際に、長繊維織ウエブの形態を予備的に保持することができる。
【００５１】
本発明の生分解性不織布の目付けは、使用目的により選択されるため特に限定されるものではないが、一般的には１０〜１５０ｇ／ｍ² の範囲が好ましく、より好ましくは１５〜７０ｇ／ｍ² の範囲である。目付けが１０ｇ／ｍ² 未満では柔軟性および生分解速度には優れるものの機械的強力に劣り実用的ではない。逆に、目付けが１５０ｇ／ｍ² を超えると、不織布が硬い風合いのものとなり、柔軟性に劣るものとなる。
【００５２】
【実施例】
次に、実施例に基づき本発明を具体的に説明するが、本発明は、これらの実施例によって何ら限定されるものではない。
【００５３】
実施例において、各物性値の測定を次の方法により実施した。
・メルトフローレート値（ｇ／１０分）；ＡＳＴＭ−Ｄ−１２３８（Ｅ）に記載の方法に準じて温度１９０℃で測定した。（以降、ＭＦＲ値と記す）
【００５４】
・融点（℃）；パーキンエルマ社製示差走査型熱量計ＤＳＣ−２型を用い、試料重量を５ｍｇ、昇温速度を２０℃／分として測定して得た融解吸熱曲線の極値を与える温度を融点（℃）とした。
【００５５】
，結晶化温度（℃）；パーキンエルマ社製示差走査型熱量計ＤＳＣ−２型を用い、試料重量を５ｍｇ、降温速度を２０℃／分として測定して得た固化発熱曲線の極値を与える温度を結晶化温度（℃）とした。
【００５６】
・中空率（％）；日本光学社製光学顕微鏡を用い、糸横断面写真を撮影し、図１に示す如く、糸の直径（Ａ）および中空部３の直径（ａ）を求め、次式より中空率を求めた。
【００５７】
中空率（％）＝（ａ² ／Ａ² ）×１００
【００５８】
・冷却性；紡出糸条を目視して下記の４段階にて評価した。
◎；密着糸が認められない。
○；密着糸がわずかではあるが認められる。
△；密着糸があり、繊維が一部集束している。
×；大部分が密着し、開繊不可能である。
【００５９】
・開繊性；開繊器具より吐出した紡出糸条にて形成された長繊維不織ウエブを、目視にて下記の４段階にて評価した。
◎；構成繊維が分繊され、密着糸および収束糸が全く認められない。
○；密着糸および収束糸がわずかではあるが認められる。
△；密着糸および収束糸があり、開繊性がやや不良である。
×；構成繊維の大部分が密着し、開繊性が不良である。
【００６０】
・目付け（ｇ／ｍ² ）；標準状態の試料から試料長が１０ｃｍ、試料幅が１０ｃｍの試料片１０点を作成し平衡水分にした後、各試料片の重量（ｇ）を秤量し、得られた値の平均値を単位面積当たりに換算し、目付け（ｇ／ｍ² ）とした。
【００６１】
・不織布の強力（ｋｇ／５ｃｍ幅）；ＪＩＳ−Ｌ−１０９６Ａに記載の方法に準じて測定した。すなわち、試料長が２０ｃｍ、試料幅が５ｃｍの試料片１０点を作成し、試料片毎に不織布の縦方向について、定速伸張型引張り試験機（東洋ボールドウイン社製テンシロンＵＴＭ−４−１−１００）を用いて、引張り速度１０ｃｍ／分で伸張し、得られた切断時荷重値の平均値を強力（ｋｇ／５ｃｍ幅）とした。
【００６２】
・不織布の圧縮剛軟度（ｇ）；試料長が１０ｃｍ、試料幅が５ｃｍの試料片５点を作成し、各試料片毎に横方向に曲げて円筒状物とし、各々その端部を接合したものを圧縮剛軟度測定試料とした。次いで、各測定試料毎にその軸方向について、定速伸長型引長試験機（東洋ボールドウイン社製テンシロンＵＴＭ−４−１−１００）を用い、圧縮速度５ｃｍ／分で圧縮し、得られた最大荷重値（ｇ）の平均値を圧縮剛軟度（ｇ）とした。なお、この圧縮剛軟度とは、値が小さいほど柔軟性が優れることを意味するものである。
【００６３】
・生分解性能；不織布を土中に埋設し、６ヶ月後に取り出し、不織布がその形態を保持していない場合、あるいは、その形態を保持していても強力が埋設前の強力初期値に対して５０％以下に低下している場合、生分解性能が良好（；○）であるとし、強力が埋設前の強力初期値に対して７５％以下に低下している場合、生分解性能が良好（；△）であるとし、強力が埋設前の強力初期値に対して７５％を超える場合、生分解性能が不良（；×）であると評価した。
【００６４】
・層間剥離強力（ｇ／５ｃｍ幅）：試料長が１５ｃｍ、試料幅が５ｃｍの試料片計３点を準備し、各試料毎に不織布の経方向について、定速伸張型引張試験機（東洋ボールウィン社製テンシロンＵＴＭ−４−−１−１００）を用いて、積層不織布における、長繊維不織ウエブの端部と天然繊維不織ウエブの端部とを上下チャックにて把持し、剥離速度５ｃｍ／にて５ｃｍ長を強制的に剥離させて得られた荷重値の平均値を層間剥離を（ｇ／５ｃｍ幅）とした。
【００６５】
・吸水性（ｍｍ）：ＪＩＳ−Ｌ−１０９６に記載のバイレック法に準じて測定した。すなわち、試料長が２０ｃｍ、試料幅が２．５ｃｍの試料片５点を作成し、各試料片を２０±２℃の水を入れた水槽上の一定の高さに支えた水平棒上にピンで留めて吊す。試料片の下端を一線に並べて水平棒を下げ、試料片の下端の１ｃｍがちょうど水に浸かるようにする。１０分間放置後の水の上昇した高さ（ｍｍ）を測り、その平均値を吸水性（ｍｍ）とした。
【００６６】
実施例１
高融点成分として、ＭＦＲ値が４０ｇ／１０分で融点１１４℃、結晶化温度７５℃のポリブチレンサクシネートを、低融点成分として、ＭＦＲ値が３０ｇ／１０分で融点１０２℃、結晶化温度５２℃のブチレンサクシネート／エチレンサクシネート＝８５／１５（モル％）の共重合ポリエステルを用いて、環状均等配列型複合長繊維よりなる不織布を製造した。
【００６７】
すなわち、前記２成分を、高融点成分／低融点成分の複合比が１／１（重量比）となるように個別に計量した後、個別のエクストルーダ型溶融押出し機を用いて温度１８０℃で溶融し、図１に示すような繊維横断面（両成分各セグメント数＝６）となる紡糸口金を用い、単孔吐出量１．８ｇ／分で環状均等配列型複合長繊維を溶融紡出した。この紡出糸条を公知の冷却装置にて冷却した後、口金の下方に設置したエアーサッカーを用いて、牽引速度が４０５０ｍ／分で牽引細化して引き取った。次いで、公知の開繊器具にて開繊し、移動するスクリーンコンベア上に単糸繊度４．０デニール（高融点成分セグメント繊度＝０．３３デニール、低融点成分セグメント繊度＝０．３３デニール）、中空率が２０．３％の複合長繊維からなる長繊維不織ウエブとして開繊堆積させた。この長繊維不織ウエブを熱エンボスロールからなる熱圧接装置にて熱圧接して目付けが３０ｇ／ｍ² の生分解性不織布を得た。熱圧接条件としては、面積が０．６ｍｍ² の彫刻模様で圧接点密度が２０点／ｃｍ² 、圧接面積率が１５％で配設された熱エンボスロールと表面が平滑な金属ロールとを用い、加工温度を９５℃とした。操業性および不織布物性、生分解性能を表１に示す。
【００６８】
実施例２
低融点成分としてＭＦＲ値が２５ｇ／１０分で融点９４℃、結晶化温度４８℃のブチレンサクシネート／ブチレンアジペート＝８０／２０（モル％）の共重合ポリエステルを用い、高融点成分／低融点成分の複合比が３／１（重量比）とすること以外は実施例１と同一条件下にて、環状均等配列型複合長繊維を溶融紡出した。この紡出糸条を公知の冷却装置にて冷却した後、エアーサッカーを用いて、牽引速度が４０００ｍ／分で牽引細化して引き取った。次いで、公知の開繊器具にて開繊し、移動するスクリーンコンベア上に単糸繊度４．１デニール（高融点成分セグメント繊度＝０．５１デニール、低融点成分セグメント繊度＝０．１７デニール）、中空率が２１．２％の複合長繊維からなる長繊維不織ウエブとして開繊堆積させた。この長繊維不織ウエブを熱エンボスロールからなる熱圧接装置にて熱圧接して目付けが３０ｇ／ｍ² の生分解性不織布を得た。熱圧接条件は、加工温度を８７℃とすること以外は実施例１と同一条件で実施した。操業性および不織布物性、生分解性能を表１に示す。
【００６９】
実施例３
低融点成分としてＭＦＲ値が２０ｇ／１０分で融点８２℃、結晶化温度２５℃のブチレンサクシネート／エチレンサクシネート＝７０／３０（モル％）の共重合ポリエステルを用い、高融点成分／低融点成分の複合比が３／１（重量比）とすること以外は実施例１と同一条件下にて、環状均等配列型複合長繊維を溶融紡出した。この紡出糸条を公知の冷却装置にて冷却した後、エアーサッカーを用いて、牽引速度が３２００ｍ／分で牽引細化して引き取った。次いで、公知の開繊器具にて開繊し、移動するスクリーンコンベア上に単糸繊度５．１デニール（高融点成分セグメント繊度＝０．６４デニール、低融点成分セグメント繊度＝０．２１デニール）、中空率が２２．６％の複合長繊維からなる長繊維不織ウエブとして開繊堆積させた。この長繊維不織ウエブを熱エンボスロールからなる熱圧接装置にて熱圧接して、目付けが３０ｇ／ｍ² の生分解性不織布を得た。熱圧接条件は、加工温度を７５℃とすること以外は実施例１と同一条件で実施した。操業性および不織布物性、生分解性能を表１に示す。
【００７０】
実施例４
低融点成分としてＭＦＲ値が３０ｇ／１０分で融点１０６℃、結晶化温度５８℃のブチレンサクシネート／エチレンサクシネート＝９０／１０（モル％）の共重合ポリエステルを用い、高融点成分／低融点成分の複合比が１／２（重量比）とすること以外は実施例１と同一条件下にて、環状均等配列型複合長繊維を溶融紡出した。この紡出糸条を公知の冷却装置にて冷却した後、エアーサッカーを用いて、牽引速度が４２００ｍ／分で牽引細化して引き取った。次いで、公知の開繊器具にて開繊し、移動するスクリーンコンベア上に単糸繊度３．９デニール（高融点成分セグメント繊度＝０．２１デニール、低融点成分セグメント繊度＝０．４３デニール）、中空率が２０．５％の複合長繊維からなる長繊維不織ウエブとして開繊堆積させた。この長繊維不織ウエブを熱エンボスロールからなる熱圧接装置にて熱圧接して、目付けが３０ｇ／ｍ² の生分解性不織布を得た。熱圧接条件は、加工温度を９９℃とすること以外は実施例１と同一条件で実施した。操業性および不織布物性、生分解性能を表１に示す。
【００７１】
実施例５
実施例１と同一の２成分を原料とし、高融点成分および低融点成分の各セグメント数が３である繊維横断面となるような紡糸口金を用いること以外は実施例１と同一条件下にて、環状均等配列型複合長繊維を溶融紡出した。この紡出糸条を公知の冷却装置にて冷却した後、エアーサッカーを用いて牽引速度が４０００ｍ／分で牽引細化して引き取った。次いで、公知の開繊器具にて開繊し、移動するスクリーンコンベア上に単糸繊度４．１デニール（高融点成分セグメント繊度＝０．６８デニール、低融点成分セグメント繊度＝０．６８デニール）、中空率が２０．０％の複合長繊維からなる長繊維不織ウエブとして開繊堆積させた。この長繊維不織ウエブを熱エンボスロールからなる熱圧接装置にて熱圧接して、目付けが３０ｇ／ｍ² の生分解性不織布を得た。熱圧接条件は、実施例１と同一条件で実施した。操業性および不織布物性、生分解性能を表１に示す。
【００７２】
実施例６
実施例１と同一の２成分を原料とし、高融点成分および低融点成分の各セグメント数が１８である繊維横断面となるような紡糸口金を用いること以外は実施例１と同一条件下にて、環状均等配列型複合長繊維を溶融紡出した。この紡出糸条を公知の冷却装置にて冷却した後、エアーサッカーを用いて牽引速度が３７５０ｍ／分で牽引細化して引き取った。次いで、公知の開繊器具にて開繊し、移動するスクリーンコンベア上に単糸繊度４．３デニール（高融点成分セグメント繊度＝０．１２デニール、低融点成分セグメント繊度＝０．１２デニール）、中空率が１６．８％の複合長繊維からなる長繊維不織ウエブとして開繊堆積させた。この長繊維不織ウエブを熱エンボスロールからなる熱圧接装置にて熱圧接して、目付けが３０ｇ／ｍ² の生分解性不織布を得た。熱圧接条件は、実施例１と同一条件で実施した。操業性および不織布物性、生分解性能を表１に示す。
【００７３】
実施例７
実施例１と同一の２成分を原料とし、高融点成分／低融点成分の複合比が１／３（重量比）となるように個別に計量した後、単孔吐出量を０．７２ｇ／分とすること以外は実施例１と同一条件下にて、環状均等配列型複合長繊維を溶融紡出した。この紡出糸条を公知の冷却装置にて冷却した後、エアーサッカーを用いて牽引速度が３６００ｍ／分で牽引細化して引き取った。次いで、公知の開繊器具にて開繊し、移動するスクリーンコンベア上に単糸繊度１．８デニール（高融点成分セグメント繊度＝０．０８デニール、低融点成分セグメント繊度＝０．２３デニール）、中空率が１８．２％の複合長繊維からなる長繊維不織ウエブとして開繊堆積させた。この長繊維不織ウエブを熱エンボスロールからなる熱圧接装置にて熱圧接して、目付けが３０ｇ／ｍ² の生分解性不織布を得た。熱圧接条件は、実施例１と同一条件で実施した。操業性および不織布物性、生分解性能を表２に示す。
【００７４】
実施例８
実施例１と同一の２成分を原料とし、高融点成分／低融点成分の複合比が３／１（重量比）となるように個別に計量した後、単孔吐出量を３．５ｇ／分とすること以外は実施例１と同一条件下にて、環状均等配列型複合長繊維を溶融紡出した。この紡出糸条を公知の冷却装置にて冷却した後、エアーサッカーを用いて、牽引速度が４５００ｍ／分で牽引細化して引き取った。次いで公知の開繊器具にて開繊し、移動するスクリーンコンベア上に単糸繊度７．０デニール（高融点成分セグメント繊度＝０．８８デニール、低融点成分セグメント繊度＝０．２９デニール）、中空率が２３．５％の複合長繊維からなる長繊維不織ウエブとして開繊堆積させた。この長繊維不織ウエブを熱エンボスロールからなる熱圧接装置にて熱圧接して、目付けが３０ｇ／ｍ² の生分解性不織布を得た。熱圧接条件は、実施例１と同一条件で実施した。操業性および不織布物性、生分解性能を表２に示す。
【００７５】
実施例９
実施例１と同一の２成分を原料とし、高融点成分／低融点成分の複合比を１／４（重量比）とすること以外は実施例１と同一条件下にて、環状均等配列型複合長繊維を溶融紡出した。この紡出糸条を公知の冷却装置にて冷却した後、エアーサッカーを用いて牽引速度が３８００ｍ／分で牽引細化して引き取った。次いで、公知の開繊器具にて開繊し、移動するスクリーンコンベア上に単糸繊度４．３デニール（高融点成分セグメント繊度＝０．１４デニール、低融点成分セグメント繊度＝０．５７デニール）、中空率が２１．９％の複合長繊維からなる長繊維不織ウエブとして開繊堆積させた。操業性を表２に示す。
【００７６】
実施例１０
実施例１と同一の２成分を原料とし、高融点成分／低融点成分の複合比を４／１（重量比）とすること以外は実施例１と同一条件下にて、環状均等配列型複合長繊維を溶融紡出した。この紡出糸条を公知の冷却装置にて冷却した後、エアーサッカーを用いて牽引速度が４３５０ｍ／分で牽引細化して引き取った。次いで、公知の開繊器具にて開繊し、移動するスクリーンコンベア上に単糸繊度３．７デニール（高融点成分セグメント繊度＝０．４９デニール、低融点成分セグメント繊度＝０．１２デニール）、中空率が１９．６％の複合長繊維からなる長繊維不織ウエブとして開繊堆積させた。この長繊維不織ウエブを熱エンボスロールからなる熱圧接装置にて熱圧接して、目付けが３０ｇ／ｍ² の生分解性不織布を得た。熱圧接条件は、実施例１と同一条件で実施した。操業性および不織布物性、生分解性能を表２に示す。
【００７７】
実施例１１
実施例１と同一の２成分を原料とし、紡糸温度を２５０℃とし、単孔吐出量を０．７２ｇ／分とすること以外は実施例１と同一条件下にて、環状均等配列型複合長繊維を溶融紡出した。この紡出糸条を公知の冷却装置にて冷却した後、エアーサッカーを用いて、牽引速度が３８００ｍ／分で牽引細化して引き取った。次いで公知の開繊器具にて開繊し、移動するスクリーンコンベア上に単糸繊度１．７デニール（高融点成分セグメント繊度＝０．１４デニール、低融点成分セグメント繊度＝０．１４デニール）、中空率が５．０％の複合長繊維からなる長繊維不織ウエブとして開繊堆積させた。この長繊維不織ウエブを熱エンボスロールからなる熱圧接装置にて熱圧接して、目付けが３０ｇ／ｍ² の生分解性不織布を得た。熱圧接条件は、実施例１と同一条件で実施した。操業性および不織布物性、生分解性能を表３に示す。
【００７８】
実施例１２
実施例１と同一の２成分を原料とし、紡糸温度を１６０℃とし、単孔吐出量を３．５ｇ／分とすること以外は実施例１と同一条件下にて、環状均等配列型複合長繊維を溶融紡出した。この紡出糸条を公知の冷却装置にて冷却した後、エアーサッカーを用いて、牽引速度が３２００ｍ／分で牽引細化して引き取った。次いで公知の開繊器具にて開繊し、移動するスクリーンコンベア上に単糸繊度９．８デニール（高融点成分セグメント繊度＝０．８２デニール、低融点成分セグメント繊度＝０．８２デニール）、中空率が３０．０％の複合長繊維からなる長繊維不織ウエブとして開繊堆積させた。この長繊維不織ウエブを熱エンボスロールからなる熱圧接装置にて熱圧接して、目付けが３０ｇ／ｍ² の生分解性不織布を得た。熱圧接条件は、実施例１と同一条件で実施した。操業性および不織布物性、生分解性能を表３に示す。
【００７９】
実施例１３
高融点成分としてＭＦＲ値が１８ｇ／１０分で融点１１４℃、結晶化温度７５℃のポリブチレンサクシネートを、低融点成分としてＭＦＲ値が１０ｇ／１０分で融点１０２℃、結晶化温度５２℃のブチレンサクシネート／エチレンサクシネート＝８５／１５（モル％）の共重合ポリエステルを用い、紡糸温度を１６０℃とし、単孔吐出量を３．０ｇ／分とすること以外は実施例１と同一条件下にて、環状均等配列型複合長繊維を溶融紡出した。この紡出糸条を公知の冷却装置にて冷却した後、エアーサッカーを用いて、牽引速度が２９００ｍ／分で牽引細化して引き取った。次いで、公知の開繊器具にて開繊し、移動するスクリーンコンベア上に単糸繊度９．３デニール（高融点成分セグメント繊度＝０．７８デニール、低融点成分セグメント繊度＝０．７８デニール）、中空率が３５．０％の複合長繊維からなる長繊維不織ウエブとして開繊堆積させた。操業性を表３に示す。
【００８０】
実施例１４
実施例１と同一条件下にて、環状均等配列型複合長繊維を溶融紡出した。この紡出糸条を公知の冷却装置にて冷却した後、エアーサッカーを用いて、牽引速度が２０００ｍ／分で牽引細化して引き取った。次いで、公知の開繊器具にて開繊し、移動するスクリーンコンベア上に単糸繊度８．１デニール（高融点成分セグメント繊度＝０．６８デニール、低融点成分セグメント繊度＝０．６８デニール）、中空率が１９．６％の複合長繊維からなる長繊維不織ウエブとして開繊堆積させた。この長繊維不織ウエブを熱エンボスロールからなる熱圧接装置にて熱圧接して、目付けが３０ｇ／ｍ² の生分解性不織布を得た。熱圧接条件は、実施例１と同一条件で実施した。操業性および不織布物性、生分解性能を表３に示す。
【００８１】
実施例１５
実施例１と同一条件下にて、環状均等配列型複合長繊維を溶融紡出、次いで、牽引細化、開繊し、単糸繊度４．０デニール（高融点成分セグメント繊度＝０．３３デニール、低融点成分セグメント繊度＝０．３３デニール）、中空率が２０．３％の複合長繊維からなる長繊維不織ウエブとして開繊堆積させた。この長繊維不織ウエブを超音波融着装置にて熱圧接して、目付けが３０ｇ／ｍ² の生分解性不織布を得た。超音波融着条件は、面積が０．６ｍｍ² の彫刻模様で圧接点密度が２０点／ｃｍ² 、圧接面積率が１５％で配設されたロールを用い、周波数を１９．１５ｋＨｚとした。操業性および不織布物性、生分解性能を表３に示す。
【００８２】
実施例１６
実施例１と同一条件下にて、環状均等配列型複合長繊維を溶融紡出、次いで、牽引細化、開繊し、単糸繊度４．０デニール（高融点成分セグメント繊度＝０．３３デニール、低融点成分セグメント繊度＝０．３３デニール）、中空率が２０．３％の複合長繊維からなる長繊維不織ウエブとして開繊堆積させた。この長繊維不織ウエブを熱エンボスロールからなる熱圧接装置にて熱圧接して、目付けが３０ｇ／ｍ² の生分解性不織布を得た。熱圧接条件は、加工温度を６７℃とした以外は実施例１と同一条件で実施した。操業性および不織布物性、生分解性能を表４に示す。
【００８３】
実施例１７
実施例１と同一条件下にて、環状均等配列型複合長繊維を溶融紡出、次いで牽引細化、開繊し、単糸繊度４．０デニール（高融点成分セグメント繊度＝０．３３デニール、低融点成分セグメント繊度＝０．３３デニール）、中空率が２０．３％の複合長繊維からなる長繊維不織ウエブとして開繊堆積させた。この長繊維不織ウエブを熱エンボスロールからなる熱圧接装置にて熱圧接して、目付けが３０ｇ／ｍ² の生分解性不織布を得た。熱圧接条件は、加工温度を７７℃とした以外は実施例１と同一条件で実施した。操業性および不織布物性、生分解性能を表４に示す。
【００８４】
実施例１８
実施例１と同一条件下にて、環状均等配列型複合長繊維を溶融紡出、次いで、牽引細化、開繊し、単糸繊度４．０デニール（高融点成分セグメント繊度＝０．３３デニール、低融点成分セグメント繊度＝０．３３デニール）、中空率が２０．３％の複合長繊維からなる長繊維不織ウエブとして開繊堆積させた。この長繊維不織ウエブを熱エンボスロールからなる熱圧接装置にて熱圧接して、目付けが３０ｇ／ｍ² の生分解性不織布を得た。熱圧接条件は、加工温度を１０２℃とした以外は実施例１と同一条件で実施した。操業性および不織布物性、生分解性能を表４に示す。
【００８５】
実施例１９
実施例１と同一の重合体を用い、これに結晶核剤を添加したこと以外は実施例１と同一条件下にて、長繊維不織布を得た。すなわち、結晶核剤として、平均粒径が１．０μｍのタルク／酸化チタン＝１／１（重量比）を２０重量％含有させたマスターバッチを高融点成分重合体および低融点成分重合体ベースであらかじめ作成し、このマスターバッチとそれに対応する重合体とをそれぞれブレンドして、高融点成分に添加する結晶核剤が０．２重量％、低融点成分に添加する結晶核剤が１．０重量％となるようにして原料としたこと以外は実施例１と同様にして生分解性不織布を得た。操業性および不織布物性、生分解性能を表４に示す。
【００８６】
実施例２０
低融点成分としてＭＦＲ値が２５ｇ／１０分で融点６３℃、結晶化温度２２℃のブチレンサクシネート／エチレンサクシネート＝６０／４０（モル％）の共重合ポリエステルを用い、実施例１９と同一条件下にて結晶核剤を添加したこと以外は実施例１と同様にして、環状均等配列型複合長繊維を溶融紡出した。この紡出糸条を公知の冷却装置にて冷却した後、エアーサッカーを用いて、牽引速度が３８５０ｍ／分で牽引細化して引き取った。次いで、公知の開繊器具にて開繊し、移動するスクリーンコンベア上に単糸繊度４．２デニール（高融点成分セグメント繊度＝０．３５デニール、低融点成分セグメント繊度＝０．３５デニール）、中空率が２０．８％の複合長繊維からなる長繊維不織ウエブとして開繊堆積させた。操業性を表４に示す。
【００８７】
実施例２１
実施例１と同一の２成分を原料とし、紡糸温度を２８０℃とし、単孔吐出量を０．５５ｇ／分とし、実施例１９と同一条件下にて結晶核剤を添加したこと以外は実施例１と同様にして、環状均等配列型複合長繊維を溶融紡出した。この紡出糸条を公知の冷却装置にて冷却した後、エアーサッカーを用いて、牽引速度が２９００ｍ／分で牽引細化して引き取った。次いで公知の開繊器具にて開繊し、移動するスクリーンコンベア上に単糸繊度１．７デニール（高融点成分セグメント繊度＝０．１４デニール、低融点成分セグメント繊度＝０．１４デニール）、中空率が２．０％の複合長繊維からなる長繊維不織ウエブとして開繊堆積させた。操業性を表４に示す。
【００８８】
実施例２２
実施例１と同一条件下にて、環状均等配列型複合長繊維からなる長繊維不織ウエブを得、これに天然繊維からなる不織ウエブを積層した積層不織布を得た。すなわち、移動式補集面上に開繊堆積させた長繊維不織ウエブに、予めエンボスロールからなる熱圧接装置にて仮熱圧接を施した。熱圧接条件としては、面積が０．６ｍｍ² の彫刻模様で圧接点密度が２０点／ｃｍ² 、圧接面積率が１５％で配設されたエンボスロールと表面が平滑な金属ロールとを用い、加工温度を５５℃とした。
【００８９】
一方、天然繊維からなる不織ウエブとして、木綿の晒し綿を用い、ランダムカード機により目付けが２５ｇ／ｍ² のカードウエブを作成した。
次いで、仮熱圧接処理を施した前述の長繊維不織ウエブに晒し綿よりなる天然繊維不織ウエブを積層し、超音波融着装置にて融着処理を施し、目付けが５０ｇ／ｍ² の積層不織布を得た。融着処理条件としては、周波数１９．７ｋＨｚ、面積が０．４ｃｍ² の彫刻模様が施されたロールには凸部が配設され、凸部の圧接面積率１５％、線圧２．０ｋｇ／ｃｍで実施した。操業性および不織布物性、生分解性能を表５に示す。
【００９０】
実施例２３
実施例２２と同一の長繊維不織ウエブおよび天然繊維不織ウエブを用い、長繊維不織ウエブの目付けを１０ｇ／ｍ² とし、天然繊維不織ウエブの目付けを４０ｇ／ｍ² としたこと以外、実施例２２と同一条件下にて目付けが５０ｇ／ｍ² の積層不織布を得た。操業性および不織布物性、生分解性能を表５に示す。
【００９１】
実施例２４
実施例２２と同一の長繊維不織ウエブおよび天然繊維不織ウエブを用い、長繊維不織ウエブの目付けを４０ｇ／ｍ² とし、天然繊維不織ウエブの目付けを１０ｇ／ｍ² としたこと以外、実施例２２と同一条件下にて目付けが５０ｇ／ｍ² の積層不織布を得た。操業性および不織布物性、生分解性能を表５に示す。
【００９２】
比較例１
実施例１と同一の高融点成分を単独で用い、繊維横断面が単相型になる紡糸口金を用いること以外は実施例１と同一条件下にて、単相型長繊維を溶融紡出した。この紡出糸条を公知の冷却装置にて冷却した後、エアーサッカーを用いて牽引速度が４５００ｍ／分で牽引細化して引き取った。次いで、公知の開繊器具にて開繊し、移動するスクリーンコンベア上に単糸繊度３．６デニールの長繊維からなる長繊維不織ウエブとして開繊堆積させた。この長繊維不織ウエブを熱エンボスロールからなる熱圧接装置にて熱圧接して、目付けが３０ｇ／ｍ² の生分解性不織布を得た。熱圧接条件は、加工温度を１０７℃とすること以外は実施例１と同一条件で実施した。操業性および不織布物性、生分解性能を表５に示す。
【００９３】
比較例２
実施例１と同一の２成分を用い、繊維横断面が芯鞘型になる紡糸口金を用いて芯部が高融点成分に、鞘部が低融点成分になり、かつ２成分の複合比が１／１（重合比）になるようにすること以外、実施例１と同一条件下にて、芯鞘型複合長繊維を溶融紡出した。この紡出糸条を公知の冷却装置にて冷却した後、エアーサッカーを用いて牽引速度が４４００ｍ／分で牽引細化して引き取った。次いで、公知の開繊器具にて開繊し、移動するスクリーンコンベア上に単糸繊度３．７デニールの長繊維からなる長繊維不織ウエブとして開繊堆積させた。操業性を表５に示す。
【００９４】
比較例３
実施例１と同一の条件下にて、環状均等配列型複合長繊維を溶融紡出した。この紡出糸条を公知の冷却装置にて冷却した後、エアーサッカーを用いて、牽引速度が１８００ｍ／分で牽引細化して引き取った。次いで、公知の開繊器具にて開繊し、移動するスクリーンコンベア上に単糸繊度９．０デニール（高融点成分セグメント繊度＝０．７５デニール、低融点成分セグメント繊度＝０．７５デニール）、中空率が２０．３％の複合長繊維からなる長繊維不織ウエブとして開繊堆積させた。操業性を表５に示す。
【００９５】
比較例４
実施例１６と同一の目付けが２５ｇ／ｍ² の長繊維不織ウエブと目付けが２５ｇ／ｍ² の晒し綿よりなる天然繊維不織ウエブとを積層し、熱エンボスローラーにて熱融着加工を行い、目付けが５０ｇ／ｍ² の積層不織布を得た。熱融着加工条件としては、ロールには彫刻部面積０．４ｃｍ² の彫刻模様が施された凸部が配設され、凸部の圧接面積率１５％、線圧５０ｋｇ／ｃｍ、加工温度９０℃で実施した。その結果を表５に示す。
【００９６】
【表１】

【００９７】
【表２】

【００９８】
【表３】

【００９９】
【表４】

【０１００】
【表５】

【０１０１】
表１から明らかなように、実施例１は、低融点成分としてブチレンサクシネート／エチレンサクシネート共重合ポリエステルを用いた本発明の環状均等配列型複合長繊維を適用しているので、紡出糸条の冷却性、可紡性、および開繊性も良好であり、機械的性能にも優れるものであった。また、この不織布は良好な生分解性能を有することが認められた。
【０１０２】
実施例２は、低融点成分としてブチレンサクシネート／ブチレンアジペート共重合ポリエステルを用いた本発明の環状均等配列型複合長繊維を適用しているので、紡出糸条の冷却性、可紡性、および開繊性も良好であり、機械的性能にも優れるものであった。また、この不織布は良好な生分解性能を有することが認められた。
【０１０３】
実施例３は、低融点成分として用いるブチレンサクシネート／エチレンサクシネート共重合ポリエステルのブチレンサクシネート共重合量比が実施例１よりも低いにもかかわらず、本発明の環状均等配列型複合長繊維を適用し、かつ高融点成分の複合比を上げブチレンサクシネートを多くしたので、紡出糸条の冷却性、可紡性、および開繊性も良好であり、機械的性能にも優れるものであった。また、この不織布は良好な生分解性能を有することが認められた。
【０１０４】
実施例４は、低融点成分として用いるブチレンサクシネート／エチレンサクシネート共重合ポリエステルのブチレンサクシネート共重合量比が実施例１よりも高いにもかかわらず、本発明の環状均等配列型複合長繊維を適用し、かつ低融点成分の複合比を上げブチレンサクシネート／エチレンサクシネートを多くしたので、紡出糸条の冷却性、可紡性、および開繊性も良好であり、機械的性能にも優れるものであった。また、この不織布は良好な生分解性能を有することが認められた。
【０１０５】
実施例５は、両成分の各セグメント数が実施例１よりも少ないにもかかわらず、本発明の環状均等配列型複合長繊維を適用しているので、紡出糸条の冷却性、可紡性、および開繊性も良好であり、機械的性能にも優れるものであった。また、この不織布は良好な生分解性能を有することが認められた。
【０１０６】
実施例６は、両成分の各セグメント数が実施例１よりも多いにもかかわらず、本発明の環状均等配列型複合長繊維を適用しているので、紡出糸条の冷却性、可紡性、および開繊性も良好であり、機械的性能にも優れるものであった。また、この不織布は非常に良好な生分解性能を有することが認められた。
【０１０７】
表２から明らかなように、実施例７は、低融点成分の複合比を上げたが、繊度を細くし、本発明の環状均等配列型複合長繊維を適用しているので、紡出糸条の冷却性、可紡性、および開繊性も良好であり、機械的性能にも優れるものであった。また、生分解性能は実施例１で得られた不織布よりさらに良好な結果が得られた。
【０１０８】
実施例８は、高融点成分の複合比を上げたが、繊度を太くし、本発明の環状均等配列型複合長繊維を適用しているので、紡出糸条の冷却性、可紡性、および開繊性も良好であり、機械的性能にも優れるものであった。また、生分解性能は、高融点成分を低融点成分で細分化しているので良好な結果が得られた。
【０１０９】
実施例９は、実施例７よりもさらに低融点成分を多くしたため、低融点成分の繊維表面における露出部分が多くなり、紡出糸条の冷却性に劣り操業性の面ではあまり好ましくなかった。
【０１１０】
実施例１０は、実施例８よりもさらに低融点成分を少なくしたため、低融点成分の繊維表面における露出部分が少なくなるので、得られた不織布の生分解性能には若干劣るものの、紡出糸条の冷却性、可紡性および開線性も良好であり、機械的性能にも優れるものであった。
【０１１１】
表３から明らかなように、実施例１１は、紡糸温度を上げ、かつ単孔吐出量を下げて、中空率を実施例１よりも低くしたにもかかわらず、本発明の環状均等配列型複合長繊維を適用しているので、紡出糸条の冷却性、可紡性、および開繊性も良好であり、機械的性能にも優れるものであった。また、この不織布は良好な生分解性能を有することが認められた。
【０１１２】
実施例１２は、紡糸温度を下げ、、かつ単孔吐出量を上げて中空率を実施例１よりも高くしたにもかかわらず、本発明の環状均等配列型複合長繊維を適用しているので、紡出糸条の冷却性、可紡性、および開繊性も良好であり、繊度が太くやや柔軟性に欠けるものの機械的性能にも優れるものであった。また、この不織布は良好な生分解性能を有することが認められた。
【０１１３】
実施例１３は、高融点成分および低融点成分を高粘度とし、紡糸温度を下げ、かつ単孔吐出量を上げたため、中空率が高く、紡糸工程において紡出糸条の中空部がパンクし易い傾向となり、操業性の面ではあまり好ましくなかった。
【０１１４】
実施例１４は、牽引速度が実施例１よりも遅くしたにもかかわらず、本発明の環状均等配列型複合長繊維を適用しているので、紡出糸条の冷却性、可紡性は良好であった。開繊性および柔軟性にはやや劣るものの機械的特性に優れるものであった。また、この不織布は良好な生分解性能を有することが認められた。
【０１１５】
実施例１５は、実施例１で得られた長繊維不織ウエブを、超音波融着装置を用い熱圧接しているので、不織布物性において若干機械的性能に劣るものの柔軟性に優れる不織布が得られた。
【０１１６】
表４から明らかなように、実施例１６は、熱圧接工程における加工温度が低いので、柔軟性には優れるものの、機械的特性に劣り、また毛羽が発生し易いものであった。また、この不織布は良好な生分解性能を有することが認められた。
【０１１７】
実施例１７は、熱圧接工程における加工温度を低くしたにもかかわらず、本発明の環状均等配列型複合長繊維を適用しているので、機械的特性にはやや劣るものの、特に柔軟性には優れるものであった。また、この不織布は良好な生分解性能を有することが認められた。
【０１１８】
実施例１８は、熱圧接工程における加工温度を高くしたにもかかわらず、本発明の環状均等配列型複合長繊維を適用しているので、柔軟性には劣るものの、機械的特性には優れるものであった。また、この不織布は良好な生分解性能を有することが認められた。
【０１１９】
実施例１９は、結晶核剤を添加したので、紡出糸条の各単繊維の冷却性が均一となり、かつ糸条の冷却性が向上するので、製糸性もさらに良好となった。また、この不織布は機械的特性および生分解性能にも優れるものであった。
【０１２０】
実施例２０は、低融点成分として実施例１よりもさらに融点の低い重合体を用いたため、結晶核剤の効果が大きく寄与するものの、紡出糸条の冷却性および開繊性にはやや劣る結果であった。
【０１２１】
実施例２１は、紡糸温度を上げ、かつ単孔吐出量を下げて繊度を細くしたため、中空率が低くなったが、結晶核剤を添加しているので、紡出糸条の冷却性および開繊性には大きな問題がないことが判った。
【０１２２】
表５から明らかなように、実施例２２は、天然繊維からなる不織ウエブを積層した本発明の生分解性不織布であるので、天然繊維により優れた吸水性を具備するとともに、複合長繊維により優れた機械的特性を具備し、かつ複合長繊維が天然繊維と同程度の生分解速度を有しているため、積層不織布としても生分解性能に優れる不織布であることが認められた。
【０１２３】
実施例２３は、実施例２２よりも天然繊維不織ウエブの積層比率が多いため、得られた不織布はさらに吸水性に優れるとともに、複合長繊維が天然繊維と同程度の生分解速度を有しているため、生分解性能にも優れるものであった。また、長繊維不織ウエブが少ないために、不織布の強力についてはやや低いが、実用的な機械的特性を有するものであった。
【０１２４】
実施例２４は、実施例２２よりも天然繊維不織ウエブの積層比率が少ないため、吸水性についてはやや劣るが、実用的な機械的特性を有する積層不織布となり、しかも複合長繊維が天然繊維と同程度の生分解速度を有しているため、生分解性能にも優れるものであった。
【０１２５】
これに対して、表５から明らかなように、比較例１は、実施例１と同一の高融点成分を用いたものの、繊維横断面が本発明範囲外である単相型であるので、不織布の機械的性能には優れるものの、不織布を６ヶ月間土中に埋設し、その後に掘り出して観察したところ不織布形態を維持しており、不織布の強力も埋設前の強力初期値に対して９１％であり、生分解性能には著しく劣るものであった。
【０１２６】
比較例２は、実施例１と同一の原料を用いたものの、繊維横断面が本発明の範囲外である芯鞘型であるので、紡出糸条が密着し、さらに開繊性も不良であり目標とした不織布を得ることができなかった。
【０１２７】
比較例３は、牽引速度が低く本発明の範囲外であるので、紡出糸条の牽引張力が低く、冷却性および開繊性が不良であり、目標とした不織布を得ることができなかった。
【０１２８】
比較例４は、天然繊維不織ウエブと長繊維不織ウエブとの積層不織布であるが、両ウエブの一体化を熱エンボスロールからなる熱圧接装置にて行ったので、天然繊維不織ウエブがローラーに取られ熱圧接固定ができず、天然繊維不織ウエブと長繊維不織ウエブとの一体化された積層不織布を得ることができなかった。
【０１２９】
【発明の効果】
本発明によれば、生分解性能が制御可能であるとともに不織布の地合いおよび機械的特性、紡出糸条の冷却性および可紡性に優れ、かつ熱接着機能を有し、さらに必要に応じて吸水性をも発揮しうる生分解性不織布およびこれらの製造方法を提供することができる。
【０１３０】
本発明の不織布は、おむつや生理用品などの医療・衛生材料素材、使い捨ておしぼりやワイピングクロスなどの拭き取り布、使い捨て包装材、家庭・業務用の生ごみ捕集用袋その他廃棄物処理材などの生活関連用素材、あるいは、農業・園芸・土木用に代表される産業用資材の各素材として好適である。しかもこの不織布は、生分解性を有するので、その使用後に完全に分解消失するため、自然環境保護の観点からも有益であり、あるいは、例えば堆肥化して肥料とするなど再利用を図ることもできるため資源の再利用の観点からも有益である。
【図面の簡単な説明】
【図１】本発明の環状均等配列型複合長繊維の繊維横断面のモデル図である。
【符号の説明】
１高融点成分
２低融点成分
３中空部
４環状均等配列型複合長繊維[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a biodegradable nonwoven fabric used for a wide range of uses such as medical / hygiene materials, daily life materials, or general industrial materials, and a method for producing the same.
[0002]
[Prior art]
As biodegradable nonwoven fabrics, for example, biodegradable nonwoven fabrics derived from natural fibers such as cotton, hemp, wool, rayon, chitin, alginic acid and the like are known. However, these biodegradable nonwoven fabrics are generally hydrophilic and have excellent water absorption properties. However, these nonwoven fabrics have significantly reduced strength and dimensional stability in a wet environment. There was a limit to the development of some applications. Furthermore, since these nonwoven fabrics are non-thermoplastic, they do not have thermoformability and are inferior in workability.
[0003]
As a biodegradable nonwoven fabric that solves these problems, a nonwoven fabric using a biodegradable thermoplastic polymer is disclosed in JP-A-5-93318 or JP-A-5-195407. However, in these, since the spun yarn is inferior in cooling property and spinnability, it is difficult to produce by the spunbond method, and since it is a fully fused type, the obtained nonwoven fabric is inferior in mechanical properties and flexibility. It was a thing. This is because the melting point and crystallization temperature of a polymer having biodegradability are generally low and the crystallization rate is slow. That is, in the cooling, draw-thinning, collection, and deposition steps after melt spinning, adhesion between yarns occurs and sufficient opening cannot be performed, which impairs the texture of the resulting nonwoven fabric. In addition, problems such as difficulty in controlling the biodegradation rate occur.
[0004]
In addition, conventional long fibers having a fiber cross section such as a single type or a single hollow type composed of only one component have a relatively high melting point and crystallization temperature in the production of nonwoven fabrics by the spunbond method. If importance is attached to the cooling property and the fiber opening property of the spun yarn using a polymer having degradability, the biodegradability of the resulting nonwoven fabric is inferior. On the other hand, if a polymer having biodegradability with a relatively low melting point and crystallization temperature is used with emphasis on biodegradability, the cooling and opening properties of the spun yarn will be inferior. Moreover, in the conventional method, the biodegradation performance can be controlled somewhat by changing the type and fineness of the polymer to be applied, the composite ratio and the degree of orientation of the fiber, but subtle control is not possible. It was possible.
[0005]
Furthermore, the nonwoven fabric formed by using the long fiber alone using the biodegradable thermoplastic polymer as described above is excellent in mechanical properties but inferior in hygroscopicity and water absorption, and its use is limited. It was. As a method for improving this, it is conceivable to laminate natural fibers or the like having excellent water absorption, but a long fiber nonwoven web made of a biodegradable thermoplastic polymer and a nonwoven web made of natural fiber are laminated. In the case of applying partial heat fusion, according to a conventional hot-pressing apparatus using an embossing roll, the adhesive strength between the two webs is weak, and the resulting laminated nonwoven fabric cannot withstand use.
[0006]
[Problems to be solved by the invention]
The present invention solves such a problem. The biodegradation performance is controllable, and the nonwoven fabric has excellent texture and mechanical properties, excellent spinning yarn cooling and spinnability, and has a thermal bonding function. It is intended to provide a biodegradable nonwoven fabric that can be further provided and can exhibit water absorption as required, and a method for producing the same.
[0007]
[Means for Solving the Problems]
In order to solve this problem, the present invention has the following structure.
(1) A first aliphatic polyester in which a long-fiber non-woven web composed of composite long fibers is partially heat-welded to maintain a predetermined form, and the composite long fibers are biodegradable A cyclic uniform array type composite continuous fiber formed from a high melting point component comprising: a low melting point component comprising a second aliphatic polyester having a biodegradability lower than that of the high melting point component. High melting point component and low melting point component In the circumferential direction of the fiber cross section Occupies a certain range alternately, and has a hollow portion in the fiber cross section, and both components are in the fiber cross section 3 to 20 segments with equal area each The high melting point component and the low melting point component are continuous in the fiber axis direction and exposed to the fiber surface and the hollow part. And the single filament fineness of the composite long fiber is 1.5 to 10 denier A biodegradable nonwoven fabric characterized by that.
(2) A laminated nonwoven fabric obtained by laminating a long-fiber nonwoven web made of composite long fibers and a natural fiber nonwoven web made of natural fibers and integrated by partial pressure welding, wherein the composite long fibers are biodegradable Cyclic homogeneous array composite formed from a high melting point component comprising a first aliphatic polyester having properties and a low melting point component comprising a second aliphatic polyester having a lower melting point than the high melting point component It is a long fiber, and a high melting point component and a low melting point component are present in the fiber cross section of the annular uniform array type composite long fiber. In the circumferential direction of the fiber cross section Occupies a certain range alternately, and has a hollow portion in the fiber cross section, and both components are in the fiber cross section 3 to 20 segments with equal area each The high melting point component and the low melting point component are continuous in the fiber axis direction and exposed to the fiber surface and the hollow part. And the single filament fineness of the composite long fiber is 1.5 to 10 denier A biodegradable nonwoven fabric characterized by that.
(3) A method for producing a nonwoven fabric in which a long-fiber nonwoven web composed of composite long fibers is partially heat-welded to maintain a predetermined form, wherein the composite long fibers are biodegradable first Formed using a high melting point component composed of an aliphatic polyester and a low melting point component composed of a second aliphatic polyester having a lower biodegradability than the high melting point component. Melting point component In the circumferential direction of the fiber cross section Occupying a certain range alternately, and having a hollow portion in the fiber cross section, both the components in the fiber cross section 3 to 20 segments with equal area each This annular uniform array type composite length is obtained by melt spinning an annular uniform array type composite long fiber that is divided and has a high melting point component and a low melting point component continuous in the fiber axis direction and exposed to the fiber surface and hollow part. After pulling the fiber at a pulling speed of 2000 m / min or more, The single filament fineness of the composite long fiber is 1.5 to 10 denier A method for producing a biodegradable nonwoven fabric, characterized in that it is a long-fiber nonwoven web, and the long-fiber nonwoven web is partially heat-welded by a heat-welding device.
(4) A method for producing a laminated nonwoven fabric obtained by laminating a long-fiber non-woven web composed of composite long fibers and a natural-fiber non-woven web composed of natural fibers and then partially pressing them together, Using a high melting point component made of a first aliphatic polyester having biodegradability and a low melting point component made of a second aliphatic polyester having a lower melting point than the high melting point component of the composite long fiber Forming a high melting point component and a low melting point component in the fiber cross section In the circumferential direction of the fiber cross section Occupying a certain range alternately, and having a hollow portion in the fiber cross section, both the components in the fiber cross section 3 to 20 segments with equal area each This annular uniform array type composite length is obtained by melt spinning an annular uniform array type composite long fiber that is divided and has a high melting point component and a low melting point component continuous in the fiber axis direction and exposed to the fiber surface and hollow part. After pulling the fiber at a pulling speed of 2000 m / min or more, The single filament fineness of the composite long fiber is 1.5 to 10 denier A long-fiber nonwoven web is formed, and a non-woven web of natural fibers separately prepared by a conventional method is laminated on the long-fiber nonwoven web, followed by ultrasonic fusing to partially melt both nonwoven webs. A method for producing a biodegradable nonwoven fabric, characterized in that it is put on and integrated.
[0008]
According to the present invention, the high melting point component and the low melting point component are arranged in a plurality of states in the fiber cross section of the long fiber, and the high melting point component and the low melting point component are continuous in the fiber axis direction. In addition, since it is exposed on the fiber surface and hollow part, it subdivides the high melting point component which is inferior in biodegradability but excellent in cooling and opening, and inferior in cooling and opening. It is possible to subdivide a low melting point component having excellent decomposition performance. Thereby, the nonwoven fabric which is excellent in all of cooling property, spreadability, and biodegradability can be obtained. Moreover, the high melting point component and the low melting point component are both arranged in an evenly divided state, so that the high melting point component excellent in the cooling and opening properties of the spun yarn and the low melting point excellent in biodegradability are achieved. The components are arranged in a well-balanced manner on the surface of the fiber, and can impart uniform cooling properties, fiber opening properties and biodegradability of the spun yarn.
[0009]
Moreover, among the biodegradable nonwoven fabrics of the present invention, a laminated nonwoven fabric obtained by laminating a long fiber nonwoven web and a natural fiber nonwoven web exhibits water absorption by natural fibers and is inferior in mechanical strength when wet. The properties of natural fibers are reinforced by a long-fiber nonwoven web. Moreover, since the long fiber nonwoven web is composed of an aliphatic polyester polymer and the natural fiber nonwoven web is composed of a degradable material such as cotton, the constituent materials of the laminated nonwoven fabric of the present invention are all in a natural environment. It can be decomposed.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
First, among the biodegradable nonwoven fabrics of the present invention, a long fiber nonwoven fabric in which a long fiber nonwoven web is partially heat-welded to maintain a predetermined form will be described.
[0011]
The long fibers applied to the present invention are formed from two components of aliphatic polyester having biodegradability. That is, the long fibers applied to the present invention are composite long fibers composed of an aliphatic polyester having a high melting point component and an aliphatic polyester having a low melting point component. In general, the high melting point component is excellent in the cooling and opening properties of the spun yarn, but its biodegradability is inferior due to the high degree of crystallinity. Conversely, the low melting point component is a cooling agent for the spun yarn. However, the biodegradability is excellent because the degree of crystallinity is low. For example, when the fiber cross section is a single phase having a high melting point component, the target biodegradation performance cannot be obtained, although it is excellent in spinning and nonwoven fabric formation. On the other hand, when the fiber cross section is a low-melting-point component single phase, the cooling property of the spun yarn is inferior, and even a non-woven fabric cannot be obtained. According to the present invention, in the fiber cross section, the high melting point component which is inferior in biodegradability but excellent in cooling property and opening property is subdivided, and is inferior in cooling property and opening property but excellent in biodegradation property. By subdividing the low melting point component and alternately arranging the subdivided components in the circumferential direction, it is possible to obtain a nonwoven fabric excellent in all of cooling performance, fiber opening property and biodegradability.
[0012]
Therefore, in the long fiber in the present invention, the difference in melting point between the high melting point component and the low melting point component is preferably 5 ° C. or more, and more preferably 10 ° C. or more. When the difference in melting point between the high melting point component and the low melting point component is less than 5 ° C., the fiber cross section approaches the full melting type as in the case of a single phase, so that only the low melting point component in the partial heat welding of the nonwoven fabric in the next process In other words, even a high-melting-point component causes thermal damage, and the resulting nonwoven fabric cannot have mechanical properties and flexibility.
[0013]
First, the aliphatic polyester forming the cyclic uniform array type composite continuous fiber in the present invention will be described. The high melting point component is preferably polybutylene succinate. The low melting point component is preferably one having butylene succinate as the main repeating unit and copolymerized with repeating unit elements constituting other aliphatic polyester. Examples of other aliphatic polyesters copolymerized with the butylene succinate include poly (α-hydroxy acids) such as polyglycolic acid and polylactic acid, or copolymers of repeating unit elements constituting them. It is done. Further, poly (ω-hydroxyalkanoate) such as poly (ε-caprolactone) and poly (β-propiolactone) is further added to poly-3-hydroxypropionate, poly-3-hydroxybutyrate, poly Poly (β-hydroxyalkanoates) such as -3-hydroxycaproate, poly-3-hydroxyheptanoate, poly-3-hydroxyoctanoate, and repeating unit elements constituting them and poly-3-hydroxy Examples thereof include a copolymer with a repeating unit element constituting valerate or poly-4-hydroxybutyrate. Examples of polycondensates of diol and dicarboxylic acid include polyethylene oxalate, polyethylene succinate, polyethylene adipate, polyethylene azate, polybutylene oxalate, polybutylene adipate, polybutylene sebacate, and polyhexamethylene sebacate. , Polyneopentyl oxalate or a copolymer of repeating unit elements constituting these. Among the above aliphatic polyesters, polyethylene succinate and polybutylene adipate are particularly preferably used for reasons such as excellent spinning properties and biodegradability.
[0014]
In the copolymer constituting the low melting point component, the copolymerization ratio of butylene succinate is preferably 70 to 90 mol%. If the copolymerization ratio of butylene succinate is less than 70 mol%, the biodegradability is excellent, but the cooling and opening properties of the spun yarn are inferior, and the intended long fiber and thus the nonwoven fabric cannot be obtained. It will be. On the contrary, when it exceeds 90 mol%, although it is excellent in cooling property and spreadability, it is inferior in biodegradability and is not the object of the present invention.
[0015]
The polymer used in the present invention preferably has a melt flow rate value (hereinafter referred to as MFR value) of 20 to 70 g / 10 min for the high melting point component and 15 to 50 g / 10 min for the low melting point component. . However, the MFR value in the present invention is measured according to the method described in ASTM-D-1238 (E). When the MFR value of the high melting point component is less than 20 g / 10 minutes and / or the MFR value of the low melting point component is less than 15 g / 10 minutes, the spun yarn is smoothly thinned because the viscosity is too high. As a result, the operability is impaired, and the resulting fiber is thick and inferior in uniformity. Conversely, if the MFR value of the high melting point component exceeds 70 g / 10 minutes and / or the MFR value of the low melting point component exceeds 50 g / 10 minutes, the composite cross section becomes unstable because the viscosity is too low, In the spinning process, yarn breakage occurs and the operability is impaired, and the resulting nonwoven fabric has poor mechanical properties. For these reasons, the MFR value of the high melting point component is more preferably 25 to 65 g / 10 minutes, and the MFR value of the low melting point component is more preferably 18 to 45 g / 10 minutes.
[0016]
The viscosity of the high melting point component is preferably lower than the viscosity of the low melting point component. In general, in composite spinning of a thermoplastic resin, a low viscosity component tends to cover a high viscosity component. That is, in the present invention, the high melting point component that is inferior in biodegradation performance but excellent in the cooling property of the spun yarn is made low in viscosity, thereby reducing the exposure ratio of the low melting point component on the fiber surface and spinning yarn. It is possible to prevent the close contact of the strips and improve the spreadability, and to stabilize the wedge-shaped form of both components.
[0017]
In the present invention, the aliphatic polyester applied to the high melting point component and the low melting point component has a number average molecular weight of about 20,000 or more, preferably 40,000 or more, more preferably 60,000 or more. And good in terms of the properties of the yarn obtained. Further, in order to increase the degree of polymerization, the chain may be extended with a small amount of diisocyanate or tetracarboxylic dianhydride.
[0018]
In the long fiber applied in the present invention, it is preferable that a crystal nucleating agent is added to at least a low melting point component among the constituent components. By adding a crystal nucleating agent, it is possible to prevent adhesion between the spun yarns even if the polymer has low crystallinity and is difficult to solidify after melt spinning. Further, the crystal nucleating agent is added in the polymerization step or the melting step. At this time, it is preferable that the crystal nucleating agent is dispersed as uniformly as possible in order to improve the mechanical performance and the uniformity of the obtained yarn.
[0019]
The crystal nucleating agent is not particularly limited as long as it is a powdered inorganic substance and does not dissolve in the melt, but talc, calcium carbonate, titanium oxide, boron nitride, silica gel, magnesium oxide, etc. are usually used. Among these, talc, titanium oxide or a mixture thereof is preferably used.
[0020]
The average particle size of the inorganic powder as the crystal nucleating agent is preferably 5 μm or less. When the average particle diameter exceeds 5 μm, it tends to be difficult to obtain finer fibers, or the filter in the spinneret having a plurality of discharge holes is likely to be clogged, and the spinning operation. There is a tendency for the sex to decline. For these reasons, the average particle size of the inorganic powder as the crystal nucleating agent is 5 μm or less, preferably 4 μm or less, more preferably 3 μm or less.
[0021]
The bulk specific volume of the inorganic powder as the crystal nucleating agent is preferably 2 to 10 cc / g, and more preferably 3 to 8 cc / g. The bulk specific volume is the volume of inorganic powder per unit weight. As the bulk specific volume increases, the surface area of the inorganic powder increases and the effect as a crystal nucleating agent increases. If the bulk specific volume of the inorganic powder is less than 2 cc / g, the effect as a crystal nucleating agent is reduced, and for this purpose, the amount of the crystal nucleating agent added (content in the polymer) must be increased, The mechanical strength of the resulting long fibers and thus the nonwoven fabric is reduced. Moreover, it is difficult to produce an inorganic powder having a bulk specific volume exceeding 10 cc / g. If an attempt is made to obtain such an inorganic powder, the cost of the inorganic powder increases, and the cost of the resulting long fiber also increases. It becomes.
[0022]
The crystal nucleating agent has a QA (wt%) addition amount of the crystal nucleating agent in the high melting point component and a QB (wt%) addition amount of the crystal nucleating agent in the low melting point component. It is preferable that it is added so as to satisfy the expressions (1) and (2).
[(ΔTA + ΔTB) / 100] −2 / 3 ≦ QA + QB ≦ [(ΔTA + ΔTB) / 100] +4 (1)
QA ≤ QB (2)
Where ΔTA = melting point of high melting point component−crystallization temperature of high melting point component ≧ 35
ΔTB = melting point of low melting point component−crystallization temperature of low melting point component ≧ 35
When the total addition amount QA + QB (% by weight) of the crystal nucleating agent exceeds the upper limit defined by the formula (1), although the cooling effect of the spun yarn is high, the long fiber obtained as a result of the decrease in the spinning property and the The mechanical performance of the nonwoven fabric is inferior, which is not preferable. On the contrary, when the total amount of crystal nucleating agent QA + QB (% by weight) is lower than the lower limit defined by the formula (1), the cooling property of the spun yarn is lowered and adhesion between the spun yarns occurs. And it becomes difficult to obtain the target nonwoven fabric. When the amount QA (wt%) of the crystal nucleating agent added to the high melting point component is larger than the amount QB (wt%) of the crystal nucleating agent added to the low melting point component, the cooling property of the high melting point component is Although further improved, the cooling property of the low-melting point component is lowered, which is not preferable because adhesion between the spun yarns is likely to occur.
[0023]
By the way, in the formula (1), ΔT is the difference between the melting point and the crystallization temperature of each component. In the spinning process, the smaller the ΔT, the better the cooling performance of the spun yarn. In the polymer of the present invention, ΔT is usually as large as 35 or more, but the cooling of the spun yarn can be effectively promoted by adding a crystal nucleating agent.
[0024]
In addition, various additives such as a matting agent, a pigment, a light stabilizer, a weathering agent, and an antioxidant are added to the thermoplastic polymer applied in the present invention as necessary, so long as the effects of the present invention are not impaired. Can be added within.
[0025]
Next, the fiber cross-sectional shape of the composite long fiber applied to the present invention will be described.
In the annular uniform array type composite cross section of the present invention, the high melting point component and the low melting point component alternately occupy a certain range in the circumferential direction and have a hollow portion in the fiber cross section, and the high melting point component and the low melting point component. The components are continuous in the fiber axis direction and are exposed on the fiber surface and in the hollow portion, and both components must be divided into segments each having an equal area in the fiber cross section. By arranging the high melting point component and the low melting point component alternately, for example, even if the low melting point component is a polymer inferior in cooling property and opening property, the adjacent high melting point component causes the spinning yarn to be Coolability and spreadability can be improved. In addition, even if the high melting point component is inferior in biodegradation performance, the adjacent low melting point component has excellent biodegradation performance, so that when the low melting point component decomposes over time, the high melting point component has a very fine wedge-shaped flake. As a result, the biodegradability of the nonwoven fabric is excellent. Moreover, by having a hollow part in a fiber cross section, the cooling property of the spun yarn can be improved, and further, the biodegradation rate can be promoted. That is, when the decomposition of the low melting point component proceeds, the hollow portion is present, so that the high melting point component is left as an arcuate flake, and the biodegradation rate is accelerated. Furthermore, it is necessary for both the high melting point component and the low melting point component to be continuous in the fiber axis direction in order to improve the stability of the fiber cross section, the yarn forming property, and the mechanical properties of the fiber. Further, it is necessary for both of the above-mentioned components to be exposed on the fiber surface and in the hollow portion in order to promote and control the cooling property, fiber opening property and biodegradability of the spun yarn. For example, when the low melting point component does not penetrate to the hollow portion of the fiber cross section, it takes time for the high melting point component to become arcuate, resulting in poor biodegradation performance. Furthermore, the high melting point component and the low melting point component are arranged in segments each having an equal area, so that the high melting point component excellent in cooling and opening properties of the spun yarn and the low melting point excellent in biodegradability are obtained. Since the components are arranged in a well-balanced manner on the fiber surface, it is possible to uniformly impart the cooling property, fiber opening property and biodegradability of the spun yarn without any bias.
[0026]
In the fiber cross section of the composite long fiber applied to the present invention, the composite ratio of the high melting point component / low melting point component is preferably 1/3 to 3/1 (weight ratio). If the composite ratio is out of this range, it is not possible to satisfy all of the cooling property, fiber opening property and biodegradability of the spun yarn, and furthermore, instability of the fiber cross-sectional shape is induced, which is preferable. Absent. For example, when the composite ratio of the high melting point component / low melting point component exceeds 1/3, the biodegradation performance is excellent, but the cooling property and the fiber opening property of the spun yarn are poor. On the other hand, when the composite ratio of the high melting point component / low melting point component exceeds 3/1, the spinning yarn is excellent in cooling property and fiber opening property but is inferior in biodegradability. If the low melting point component is a polymer having poor biodegradability, the biodegradation rate can be accelerated by increasing the composite ratio of the high melting point component. For this reason, the composite ratio of the high melting point component / low melting point component is more preferably 1/2 to 2/1 (weight ratio).
[0027]
Moreover, it is preferable that a hollow rate is 5 to 30% in the fiber cross section of the composite long fiber applied to this invention. Here, as shown in FIG. 1, the hollow ratio is a value represented by the following equation when the diameter of the yarn in the fiber cross section is (A) and the diameter of the hollow portion is (a).
[0028]
Hollow ratio (%) = (a ² / A ² ) × 100
If the hollow ratio is less than 5%, it is insufficient for promoting cooling and biodegradation speed. Conversely, if the hollow ratio exceeds 30%, the hollow part is punctured or high-speed spinning in the spinning stage. It becomes inferior and is not preferable. For this reason, the hollowness is more preferably 10 to 25%.
[0029]
In the fiber cross section of the composite long fiber applied to the present invention, the number of segments of the high melting point component and the low melting point component is 3 to 20 is necessary . Here, the number of segments refers to the number of minimum constitutional units in which the high melting point component and the low melting point component are arranged and occupied in the fiber cross section. When the number of each segment is less than 3, the cooling and opening properties of the spun yarn are inferior and the biodegradability is also inferior. On the other hand, when the number of segments exceeds 20, the number of openings in the spinneret decreases and the productivity is inferior, and a stable composite cross section cannot be obtained. Therefore, the low melting point component is a polymer inferior in the cooling property and the opening property of the spun yarn, and if the number of segments is less than 3, it is difficult to improve the cooling property and the opening property because the segment is too large. It becomes. Moreover, if the high melting point component is a polymer inferior in biodegradability, the biodegradation rate can be promoted by increasing the number of segments and subdividing the high melting point component. For this reason, the number of segments is more preferably 6-16.
[0030]
The single yarn fineness of the composite continuous fiber applied to the present invention is 1.5 to 10 denier is necessary. If it is less than 1.5 denier, the spinneret becomes complicated, the yarn breakage increases in the spinning process, the production volume decreases, and the fiber cross-sectional shape is unstable. Occurs. On the contrary, if it exceeds 10 deniers, the cooling performance of the spun yarn is inferior and the biodegradability is also inferior. For this reason, 2 to 8 denier is more preferable.
[0031]
Since the biodegradable nonwoven fabric of the present invention is formed from a cyclic uniform array type composite long fiber composed of a high melting point component and a low melting point component having different biodegradability, the composite ratio of both components, each of both components By appropriately combining the number of segments, the hollowness, and the single yarn fineness, the required cooling, fiber opening and biodegradability of the spun yarn can be demonstrated, and the biodegradability can be finely controlled. it can.
[0032]
Next, among the biodegradable nonwoven fabrics of the present invention, a laminated nonwoven fabric obtained by laminating a natural fiber nonwoven web on the long fiber nonwoven web and integrating them by ultrasonic fusion will be described.
[0033]
The natural fiber applied to the present invention is not particularly limited as long as it has biodegradability, but cotton, ramie, silk fiber cut into short fibers, etc. are particularly preferably used. Here, examples of cotton include combed yarn that has not been subjected to bleaching processing, bleached cotton that has been subjected to bleaching processing, or garments / knitted fabrics.
[0034]
The natural fiber non-woven web in the present invention is a web prepared by combining the natural fibers singly or in combination, a parallel web arranged in the traveling direction of the card machine, a cross-laid web of parallel webs, and a randomly arranged web. Either a random web or a semi-random web arranged moderately may be used, and it can be appropriately selected depending on the intended use. In particular, when used for clothing, it is preferable to use a card web having a longitudinal / lateral strength ratio of approximately 1/1 in terms of strength as a nonwoven fabric.
[0035]
When the natural fiber nonwoven web is laminated, the lamination ratio of the natural fiber nonwoven web and the long fiber nonwoven web is preferably 10/90 to 90/10 (% by weight). If the natural fiber is less than 10% by weight, the laminated nonwoven fabric has excellent mechanical properties, but the hygroscopicity and water absorption cannot be sufficiently improved, and the purpose of laminating natural fibers cannot be achieved. It is not preferable. On the other hand, if the natural fiber exceeds 90% by weight, the hygroscopic property and the water absorbing property are excellent, but the mechanical properties are impaired. For these reasons, the lamination ratio of the natural fiber nonwoven web and the long fiber nonwoven web is more preferably 20/80 to 80/20 (% by weight).
[0036]
Integration of the laminated long fiber nonwoven web and the natural fiber nonwoven web is performed by ultrasonic fusion treatment. This ultrasonic fusing process is to form a partial fusing area using an ultrasonic fusing device, which will be described later. The composite long fiber in the fusing area is thermally melted and embedded in the natural fiber. By this, the long fiber nonwoven web and the natural fiber nonwoven web are fused. Thereby, the long-fiber non-woven web and the natural fiber having no thermal adhesiveness can be integrated with an adhesive force that can withstand practical use.
[0037]
Next, the manufacturing method of the biodegradable nonwoven fabric of this invention is demonstrated.
First, among the biodegradable nonwoven fabrics of the present invention, a method for producing a long fiber nonwoven fabric in which a long fiber nonwoven web is partially heat-welded to maintain a predetermined form will be described.
[0038]
The biodegradable nonwoven fabric of the present invention can be produced using a normal composite spinning apparatus. The above-described aliphatic polyester having biodegradability, that is, polybutylene succinate as a high melting point component, butylene succinate having a copolymerization ratio of butylene succinate as a low melting point component of 70 to 90 mol% as a main repeating unit. The copolymerized polyester was used as a suitable material, which was melted separately and weighed separately so that the composite ratio of the high melting point component / low melting point component was 1/3 to 3/1 (weight ratio). The spun yarn discharged from the annular uniform array type composite spinneret capable of forming a fiber cross-sectional structure satisfying the number of segments, the hollowness, and the single yarn fineness of both components is cooled by a known cooling device. Next, the air is used to draw and pull it to a target fineness. The drawn and chopped composite long fibers are opened using a known opening device, and then spread and deposited on a movable collection surface such as a screen conveyor to form a long fiber nonwoven web. Thereafter, this non-woven nonwoven web is partially heat-pressed using a heat-welding device to obtain a biodegradable nonwoven fabric.
[0039]
In the method for producing the biodegradable nonwoven fabric of the present invention, the above-described crystal nucleating agent is added to the polymer to be used, particularly the polymer constituting the low melting point component, thereby preventing adhesion of the spun yarn and cooling ability. , The spreadability can be improved.
[0040]
In melt spinning, the spinning temperature varies depending on the aliphatic polyester to be used, but can be set as appropriate in consideration of at least the MFR value of the polymer and the fiber forming property, that is, the spinning property. Usually, the spinning temperature is at least 40 ° C. higher than the melting point of the polymer, preferably 120 to 300 ° C. If the spinning temperature is less than 120 ° C., unmelted matter is generated, or the melt viscosity of the polymer is too high, making it difficult to extrude the polymer using a melt extruder. If the temperature exceeds ℃, the polymer starts to thermally decompose, which is not preferable.
[0041]
For traction thinning, the traction speed needs to be 2000 m / min or more, and particularly 2500 m / min or more is preferable because the dimensional stability of the nonwoven fabric is improved. When the pulling speed is less than 2000 m / min, the yarn is inadequately oriented so that the yarn is in close contact with each other and the opening property is also deteriorated, so that a target nonwoven fabric cannot be obtained.
[0042]
When a long-fiber nonwoven web is subjected to partial hot-pressing treatment to maintain a predetermined form, a hot-embossing roll and a metal roll with a smooth surface are used to form a dotted fusion zone between the long fibers. Or a method of applying a high frequency by an ultrasonic wave on a pattern roll using an ultrasonic fusing apparatus to form a dotted fusing area between the long fibers of the pattern portion.
[0043]
The partial heat welding means that the low melting point components are heat-welded to each other between the constituent fibers to maintain the web form, and at least the high melting point components are not fused to each other and the constituent fibers are completely fused. This is referred to as heat pressure welding that can be prevented. By using such partial heat pressure welding, it is possible to exhibit biodegradation performance and flexibility while maintaining a predetermined nonwoven fabric form.
[0044]
The pressure welding region formed by partial heat welding has a specific region with respect to the total surface area of the long-fiber nonwoven web. Specifically, each of the heat welding regions is round, elliptical, diamond It may be any shape such as a mold, triangle, T-shape, or well, but 0.07-1.5mm ² The density, that is, the pressure contact density is 10 to 120 points / cm. ² , Preferably 20-60 points / cm ² It is good to be. Pressure contact density is 10 points / cm ² The mechanical properties and dimensional stability of the resulting nonwoven fabric are not improved, and conversely, the pressure contact density is 120 points / cm. ² If it exceeds 1, the flexibility and bulkiness will not be improved, and neither is preferred. Further, the ratio of the area of the total heat pressure area to the total surface area of the web, that is, the pressure area ratio, is 3 to 40%, preferably 4 to 30%. If the pressure contact area ratio is less than 3%, the resulting nonwoven fabric is inferior in dimensional stability, which is not preferable. On the contrary, when the pressure contact area ratio exceeds 40%, the flexibility and bulkiness of the obtained nonwoven fabric are impaired, and the biodegradability is also inferior.
[0045]
When a heated embossing roll is used, the surface temperature of the roll, that is, the processing temperature, must be a temperature not higher than the melting point of the low melting point component. When the melting point of the low melting point component is exceeded, the polymer is fixed to the hot-pressing apparatus and the operability is remarkably impaired, and the texture of the nonwoven fabric becomes hard and a flexible nonwoven fabric cannot be obtained. More preferably, the processing temperature is in the range of (Tm-25) ° C. to (Tm) ° C., where the melting point of the low melting point component is (Tm) ° C. If the processing temperature is lower than (Tm-25) ° C., the resulting nonwoven fabric is inferior in mechanical function and fuzz prevention, which is not preferable.
[0046]
When using an ultrasonic fusion apparatus, an apparatus composed of an ultrasonic oscillator generally called a horn having a frequency of about 20 kHz and a pattern roll having convex protrusions in the form of dots or bands on the circumference is adopted. The The pattern roll is disposed below the ultrasonic oscillator, and the long fiber nonwoven web can be partially heat-sealed by passing between the ultrasonic oscillator and the pattern roll. One row or a plurality of rows of convex protrusions arranged on the pattern roll may be provided, and when the arrangement is a plurality of rows, either a parallel or staggered arrangement may be used.
[0047]
In addition, you may perform a partial heat-pressure-bonding process in any of a continuous process or another process. In addition, for the heat-bonding treatment, either the heated embossing roll or the ultrasonic fusing apparatus described above may be selected. As a general life-related material such as a wipe, a nonwoven fabric having excellent performance can be obtained by using an ultrasonic fusion device.
[0048]
Next, a method for obtaining a laminated nonwoven fabric obtained by laminating a long fiber nonwoven web and a natural fiber nonwoven web among the biodegradable nonwoven fabrics of the present invention will be described.
In the same manner as described above, natural fibers separately prepared by a conventional method are laminated on a long-fiber nonwoven web spread and deposited on a movable collection surface, and this is subjected to ultrasonic fusion treatment to be integrated. A laminated nonwoven fabric is obtained.
[0049]
When performing the ultrasonic fusing process, the same ultrasonic fusing apparatus as in the case of the above-mentioned partial heat welding process is preferably used, air pressure is used for pressurizing the roll, and the line where the horn contacts the roll. The pressure is preferably in the range of 1.0 to 50 kg / cm. When the linear pressure is less than 1.0 kg / cm, the pressing pressure is insufficient with respect to the thickness of the laminated nonwoven fabric, and the peel strength of the laminate is reduced, which is not preferable. On the other hand, if the linear pressure exceeds 50 kg / cm, too much pressure is applied to the fused portion, and thus the adhesive strength is similarly lowered due to film formation at the fused portion.
[0050]
In the present invention, before laminating the long-fiber non-woven web and the natural fiber non-woven web that have been spread and deposited on the movable collecting surface, a pre-heating pressure welding process or a hot-air bonding process is performed on the long-fiber non-woven web in advance. Or it is preferable to perform a three-dimensional entanglement process by a well-known method. Thereby, when laminating the long fiber non-woven web and the natural fiber non-woven web, the form of the long fiber woven web can be preliminarily maintained.
[0051]
The basis weight of the biodegradable nonwoven fabric of the present invention is not particularly limited because it is selected depending on the purpose of use, but generally 10 to 150 g / m. ² Is preferable, and more preferably 15 to 70 g / m. ² Range. The basis weight is 10g / m ² Below, it is excellent in flexibility and biodegradation speed, but is inferior in mechanical strength and is not practical. Conversely, the basis weight is 150 g / m ² If it exceeds 1, the non-woven fabric has a hard texture and is inferior in flexibility.
[0052]
【Example】
EXAMPLES Next, although this invention is demonstrated concretely based on an Example, this invention is not limited at all by these Examples.
[0053]
In the examples, each physical property value was measured by the following method.
Melt flow rate value (g / 10 min): measured at a temperature of 190 ° C. according to the method described in ASTM-D-1238 (E). (Hereafter referred to as MFR value)
[0054]
Melting point (° C.): Temperature that gives the extreme value of the melting endothermic curve obtained by using a differential scanning calorimeter DSC-2 manufactured by Perkin Elma and measuring the sample weight at 5 mg and a heating rate of 20 ° C./min. Was the melting point (° C.).
[0055]
, Crystallization temperature (° C.): Using a differential scanning calorimeter DSC-2 manufactured by Perkin Elma Co., Ltd., gives the extreme value of the solidification exothermic curve obtained by measuring the sample weight at 5 mg and the temperature drop rate at 20 ° C./min. The temperature was defined as the crystallization temperature (° C.).
[0056]
Hollow ratio (%): Taking a cross-sectional photograph of yarn using an optical microscope manufactured by Nippon Optical Co., Ltd., as shown in FIG. 1, the diameter (A) of the yarn and the diameter (a) of the hollow portion 3 are obtained. The hollow ratio was determined.
[0057]
Hollow ratio (%) = (a ² / A ² ) × 100
[0058]
Coolability: The spun yarn was visually observed and evaluated according to the following four levels.
A: Adherent yarn is not recognized.
○: Adherent yarn is slightly recognized.
Δ: Adhesive yarn is present, and some fibers are converged.
X: Most of them are in close contact with each other and cannot be opened.
[0059]
-Opening property: The long-fiber nonwoven web formed with the spun yarn discharged from the opening device was visually evaluated in the following four stages.
A: Constituent fibers are separated, and no contact yarn or convergent yarn is observed.
A: Adherent yarn and convergent yarn are slightly observed.
Δ: Adherent yarn and convergent yarn are present, and the openability is slightly poor.
X: Most of the constituent fibers are in close contact with each other, and the openability is poor.
[0060]
・ Weight (g / m ² ); Ten sample pieces having a sample length of 10 cm and a sample width of 10 cm were prepared from the sample in the standard state and made into equilibrium moisture. Then, the weight (g) of each sample piece was weighed, and the average value of the obtained values was calculated. Converted per unit area, basis weight (g / m ² ).
[0061]
-Strength of non-woven fabric (kg / 5 cm width): Measured according to the method described in JIS-L-1096A. That is, 10 sample pieces having a sample length of 20 cm and a sample width of 5 cm were prepared, and a constant-speed extension type tensile tester (Tensilon UTM-4-1-1 manufactured by Toyo Baldwin Co., Ltd.) was used for each sample piece in the longitudinal direction of the nonwoven fabric. 100) was used and stretched at a pulling speed of 10 cm / min, and the average value of the obtained load values at the time of cutting was determined to be strong (kg / 5 cm width).
[0062]
・ Compressive bending resistance of nonwoven fabric (g): Create 5 sample pieces with a sample length of 10 cm and a sample width of 5 cm, bend each sample piece in the horizontal direction to form a cylindrical object, and join the ends of each sample piece This was used as a sample for measuring compression bending resistance. Next, for each measurement sample, the axial direction was obtained by compressing at a compression speed of 5 cm / min using a constant speed extension type tensile tester (Tensilon UTM-4-1-100 manufactured by Toyo Baldwin). The average value of the maximum load value (g) was defined as the compression stiffness (g). The compression bending resistance means that the smaller the value, the better the flexibility.
[0063]
・ Biodegradation performance: When the nonwoven fabric is buried in the soil and taken out after 6 months and the nonwoven fabric does not retain its form, or even if it retains its form, the strength is relative to the initial strength value before embedding When it is reduced to 50% or less, the biodegradation performance is good (; ○), and when the strength is reduced to 75% or less with respect to the initial strength before embedding, the biodegradation performance is good ( It was evaluated that the biodegradability was poor (; x) when the strength exceeded 75% with respect to the initial strength value before embedding.
[0064]
Delamination strength (g / 5 cm width): A total of 3 sample pieces with a sample length of 15 cm and a sample width of 5 cm were prepared, and a constant-speed stretch type tensile tester (Toyo Ball) for each sample in the longitudinal direction of the nonwoven fabric. Using the Tensilon UTM-4--1-100) manufactured by Wynn Corporation, the end of the long-fiber non-woven web and the end of the natural-fiber non-woven web in the laminated nonwoven fabric are gripped by the upper and lower chucks, and the peeling speed is 5 cm. The average value of the load values obtained by forcibly peeling 5 cm length at / was defined as delamination (g / 5 cm width).
[0065]
Water absorption (mm): Measured according to the birec method described in JIS-L-1096. That is, five sample pieces having a sample length of 20 cm and a sample width of 2.5 cm were prepared, and each sample piece was pinned on a horizontal bar supported at a certain height on a water tank containing 20 ± 2 ° C. water. Fasten and hang. The lower end of the sample piece is aligned and the horizontal bar is lowered so that 1 cm of the lower end of the sample piece is just immersed in water. The height (mm) at which the water rose after being allowed to stand for 10 minutes was measured, and the average value was defined as the water absorption (mm).
[0066]
Example 1
As a high melting point component, polybutylene succinate having an MFR value of 40 g / 10 min and a melting point of 114 ° C. and a crystallization temperature of 75 ° C., and as a low melting point component, an MFR value of 30 g / 10 min and a melting point of 102 ° C. and a crystallization temperature of 52 ° C. A non-woven fabric made of cyclic uniform array type composite continuous fibers was produced using a copolymer polyester of butylene succinate / ethylene succinate = 85/15 (mol%) at 0 ° C.
[0067]
That is, the two components are individually weighed so that the composite ratio of high melting point component / low melting point component is 1/1 (weight ratio), and then melted at a temperature of 180 ° C. using a separate extruder type melt extruder. Then, using a spinneret having a fiber cross section as shown in FIG. 1 (the number of segments of both components = 6), an annular uniform array type composite continuous fiber was melt-spun at a single-hole discharge rate of 1.8 g / min. The spun yarn was cooled by a known cooling device, and then pulled using an air soccer installed below the base at a traction speed of 4050 m / min. Then, it is opened with a known opening device, and on the moving screen conveyor, the single yarn fineness is 4.0 denier (high melting point component segment fineness = 0.33 denier, low melting point component segment fineness = 0.33 denier), The fiber was spread and deposited as a long-fiber nonwoven web composed of a composite long fiber having a hollow ratio of 20.3%. This nonwoven fabric nonwoven web is heat-welded with a heat-welding device comprising a hot embossing roll, and the basis weight is 30 g / m. ² A biodegradable nonwoven fabric was obtained. As the heat welding condition, the area is 0.6 mm. ² Pressure contact density of 20 points / cm ² The processing temperature was set to 95 ° C. using a hot embossing roll disposed at a pressure contact area ratio of 15% and a metal roll having a smooth surface. Table 1 shows operability, non-woven fabric properties, and biodegradability.
[0068]
Example 2
As the low melting point component, a copolymer polyester of butylene succinate / butylene adipate = 80/20 (mol%) having an MFR value of 25 g / 10 min, a melting point of 94 ° C., and a crystallization temperature of 48 ° C. is used. The cyclic uniform array type composite continuous fiber was melt-spun under the same conditions as in Example 1 except that the composite ratio was 3/1 (weight ratio). The spun yarn was cooled by a known cooling device, and then pulled using an air soccer at a pulling speed of 4000 m / min. Then, it is opened with a known opening device, and the single yarn fineness is 4.1 denier on the moving screen conveyor (high melting point component segment fineness = 0.51 denier, low melting point component segment fineness = 0.17 denier), The fiber was spread and deposited as a long-fiber nonwoven web composed of composite long fibers having a hollowness of 21.2%. This nonwoven fabric nonwoven web is heat-welded with a heat-welding device comprising a hot embossing roll, and the basis weight is 30 g / m. ² A biodegradable nonwoven fabric was obtained. The hot pressing conditions were the same as those in Example 1 except that the processing temperature was 87 ° C. Table 1 shows operability, non-woven fabric properties, and biodegradability.
[0069]
Example 3
As the low melting point component, a copolymer polyester of butylene succinate / ethylene succinate = 70/30 (mol%) having an MFR value of 20 g / 10 min and a melting point of 82 ° C. and a crystallization temperature of 25 ° C. is used. Under the same conditions as in Example 1 except that the composite ratio of the components was 3/1 (weight ratio), a cyclic uniform array type composite continuous fiber was melt-spun. The spun yarn was cooled by a known cooling device, and then pulled using an air soccer ball at a pulling speed of 3200 m / min. Then, it is opened with a known opening device, and on the moving screen conveyor, the single yarn fineness 5.1 denier (high melting point component segment fineness = 0.64 denier, low melting point component segment fineness = 0.21 denier), The fiber was spread and deposited as a long-fiber nonwoven web composed of composite long fibers having a hollow ratio of 22.6%. The nonwoven fabric non-woven web is heat-welded with a heat-welding apparatus comprising a hot embossing roll, and the basis weight is 30 g / m. ² A biodegradable nonwoven fabric was obtained. The hot pressing conditions were the same as those in Example 1 except that the processing temperature was 75 ° C. Table 1 shows operability, non-woven fabric properties, and biodegradability.
[0070]
Example 4
As a low melting point component, a copolymer polyester of butylene succinate / ethylene succinate = 90/10 (mol%) having an MFR value of 30 g / 10 min and a melting point of 106 ° C. and a crystallization temperature of 58 ° C. is used. Under the same conditions as in Example 1 except that the composite ratio of the components was 1/2 (weight ratio), the cyclic uniform array type composite continuous fiber was melt-spun. The spun yarn was cooled with a known cooling device, and then pulled using an air soccer at a pulling speed of 4200 m / min. Then, it is opened with a known opening device, and on a moving screen conveyor, the single yarn fineness is 3.9 denier (high melting point component segment fineness = 0.21 denier, low melting point component segment fineness = 0.43 denier), The fiber was spread and deposited as a long-fiber nonwoven web composed of composite long fibers having a hollowness ratio of 20.5%. The nonwoven fabric non-woven web is heat-welded with a heat-welding apparatus comprising a hot embossing roll, and the basis weight is 30 g / m. ² A biodegradable nonwoven fabric was obtained. The hot pressing conditions were the same as those in Example 1 except that the processing temperature was 99 ° C. Table 1 shows operability, non-woven fabric properties, and biodegradability.
[0071]
Example 5
Under the same conditions as in Example 1, except that the same two components as in Example 1 are used as raw materials and a spinneret having a fiber cross-section with 3 segments each having a high melting point component and a low melting point component is used. The cyclic uniform array type composite continuous fiber was melt-spun. The spun yarn was cooled with a known cooling device, and then pulled using an air soccer at a pulling speed of 4000 m / min. Then, it is opened with a known opening device, and the single yarn fineness is 4.1 denier on the moving screen conveyor (high melting point component segment fineness = 0.68 denier, low melting point component segment fineness = 0.68 denier), The fiber was spread and deposited as a long-fiber nonwoven web composed of composite long fibers with a hollowness of 20.0%. The nonwoven fabric non-woven web is heat-welded with a heat-welding apparatus comprising a hot embossing roll, and the basis weight is 30 g / m. ² A biodegradable nonwoven fabric was obtained. The heat welding conditions were the same as in Example 1. Table 1 shows operability, non-woven fabric properties, and biodegradability.
[0072]
Example 6
Under the same conditions as in Example 1, except that the same two components as in Example 1 are used as raw materials, and a spinneret having a fiber cross section in which the number of segments of the high melting point component and the low melting point component is 18 is used. The cyclic uniform array type composite continuous fiber was melt-spun. The spun yarn was cooled with a known cooling device, and then pulled using an air soccer at a pulling speed of 3750 m / min. Subsequently, the yarn is opened with a known opening device, and the single yarn fineness is 4.3 denier on the moving screen conveyor (high melting point component segment fineness = 0.12 denier, low melting point component segment fineness = 0.12 denier), The fiber was spread and deposited as a long-fiber nonwoven web composed of composite long fibers with a hollowness of 16.8%. The nonwoven fabric non-woven web is heat-welded with a heat-welding apparatus comprising a hot embossing roll, and the basis weight is 30 g / m. ² A biodegradable nonwoven fabric was obtained. The heat welding conditions were the same as in Example 1. Table 1 shows operability, non-woven fabric properties, and biodegradability.
[0073]
Example 7
The same two components as in Example 1 were used as raw materials, and individually weighed so that the composite ratio of high melting point component / low melting point component was 1/3 (weight ratio), and then the single-hole discharge rate was 0.72 g / min. The cyclic uniform array type composite continuous fiber was melt-spun under the same conditions as in Example 1 except that. The spun yarn was cooled with a known cooling device, and then pulled using an air soccer at a traction speed of 3600 m / min. Then, it is opened with a known opening device, and on the moving screen conveyor, the single yarn fineness 1.8 denier (high melting point component segment fineness = 0.08 denier, low melting point component segment fineness = 0.23 denier), The fiber was spread and deposited as a long-fiber nonwoven web composed of composite long fibers having a hollowness of 18.2%. The nonwoven fabric non-woven web is heat-welded with a heat-welding apparatus comprising a hot embossing roll, and the basis weight is 30 g / m. ² A biodegradable nonwoven fabric was obtained. The heat welding conditions were the same as in Example 1. Table 2 shows operability, physical properties of the nonwoven fabric, and biodegradability.
[0074]
Example 8
The same two components as in Example 1 were used as raw materials, and individually weighed so that the composite ratio of high melting point component / low melting point component was 3/1 (weight ratio), and then the single-hole discharge rate was 3.5 g / min. The cyclic uniform array type composite continuous fiber was melt-spun under the same conditions as in Example 1 except that. The spun yarn was cooled with a known cooling device, and then pulled using an air soccer at a pulling speed of 4500 m / min. Next, it is opened with a known opening device, and on the moving screen conveyor, the single yarn fineness is 7.0 denier (high melting point component segment fineness = 0.88 denier, low melting point component segment fineness = 0.29 denier), hollow The fiber was spread and deposited as a long fiber nonwoven web composed of composite long fibers having a rate of 23.5%. The nonwoven fabric non-woven web is heat-welded with a heat-welding apparatus comprising a hot embossing roll, and the basis weight is 30 g / m. ² A biodegradable nonwoven fabric was obtained. The heat welding conditions were the same as in Example 1. Table 2 shows operability, physical properties of the nonwoven fabric, and biodegradability.
[0075]
Example 9
A cyclic uniform array type composite under the same conditions as in Example 1 except that the same two components as in Example 1 are used as raw materials and the composite ratio of the high melting point component / low melting point component is 1/4 (weight ratio). Long fibers were melt spun. The spun yarn was cooled with a known cooling device, and then pulled using an air soccer at a traction speed of 3800 m / min. Then, it is opened with a known opening device, and on a moving screen conveyor, the single yarn fineness is 4.3 denier (high melting point component segment fineness = 0.14 denier, low melting point component segment fineness = 0.57 denier), The fiber was spread and deposited as a long-fiber nonwoven web composed of composite long fibers with a hollowness of 21.9%. Table 2 shows the operability.
[0076]
Example 10
A cyclic uniform array type composite under the same conditions as in Example 1 except that the same two components as in Example 1 are used as raw materials and the composite ratio of the high melting point component / low melting point component is 4/1 (weight ratio). Long fibers were melt spun. The spun yarn was cooled with a known cooling device, and then pulled using an air soccer at a traction speed of 4350 m / min. Subsequently, the fiber is opened with a known opening device, and on the moving screen conveyor, the single yarn fineness is 3.7 denier (high melting point component segment fineness = 0.49 denier, low melting point component segment fineness = 0.12 denier), The fiber was spread and deposited as a long-fiber nonwoven web composed of composite long fibers with a hollowness of 19.6%. The nonwoven fabric non-woven web is heat-welded with a heat-welding apparatus comprising a hot embossing roll, and the basis weight is 30 g / m. ² A biodegradable nonwoven fabric was obtained. The heat welding conditions were the same as in Example 1. Table 2 shows operability, physical properties of the nonwoven fabric, and biodegradability.
[0077]
Example 11
Under the same conditions as in Example 1 except that the same two components as in Example 1 were used as raw materials, the spinning temperature was 250 ° C., and the single hole discharge rate was 0.72 g / min. The fiber was melt spun. The spun yarn was cooled with a known cooling device, and then pulled using an air soccer at a traction speed of 3800 m / min. Next, it is opened with a known opening device, and on the moving screen conveyor, the single yarn fineness is 1.7 denier (high melting point component segment fineness = 0.14 denier, low melting point component segment fineness = 0.14 denier), hollow The fiber was spread and deposited as a long fiber nonwoven web composed of a composite long fiber having a rate of 5.0%. The nonwoven fabric non-woven web is heat-welded with a heat-welding apparatus comprising a hot embossing roll, and the basis weight is 30 g / m. ² A biodegradable nonwoven fabric was obtained. The heat welding conditions were the same as in Example 1. Table 3 shows operability, physical properties of the nonwoven fabric, and biodegradability.
[0078]
Example 12
Under the same conditions as in Example 1 except that the same two components as in Example 1 are used as raw materials, the spinning temperature is 160 ° C., and the single hole discharge rate is 3.5 g / min. The fiber was melt spun. The spun yarn was cooled by a known cooling device, and then pulled using an air soccer ball at a pulling speed of 3200 m / min. Next, it is opened with a known opening device, and the single yarn fineness is 9.8 denier (high melting point component segment fineness = 0.82 denier, low melting point component segment fineness = 0.82 denier), hollow on the moving screen conveyor The fiber was spread and deposited as a long-fiber nonwoven web composed of composite long fibers having a rate of 30.0%. The nonwoven fabric non-woven web is heat-welded with a heat-welding apparatus comprising a hot embossing roll, and the basis weight is 30 g / m. ² A biodegradable nonwoven fabric was obtained. The heat welding conditions were the same as in Example 1. Table 3 shows operability, physical properties of the nonwoven fabric, and biodegradability.
[0079]
Example 13
Polybutylene succinate with an MFR value of 18 g / 10 min at a melting point of 114 ° C. and a crystallization temperature of 75 ° C. as a high melting point component, and an MFR value of 10 g / 10 min as a low melting point component with a melting point of 102 ° C. and a crystallization temperature of 52 ° C. The same conditions as in Example 1 except that a copolymer polyester of butylene succinate / ethylene succinate = 85/15 (mol%) was used, the spinning temperature was 160 ° C., and the single-hole discharge rate was 3.0 g / min. Below, an annular uniform array type composite continuous fiber was melt-spun. The spun yarn was cooled with a known cooling device, and then pulled using an air soccer at a pulling speed of 2900 m / min. Then, it is opened with a known opening device, and the single yarn fineness is 9.3 denier on the moving screen conveyor (high melting point component segment fineness = 0.78 denier, low melting point component segment fineness = 0.78 denier), The fiber was spread and deposited as a long-fiber nonwoven web composed of composite long fibers with a hollowness of 35.0%. Table 3 shows the operability.
[0080]
Example 14
Under the same conditions as in Example 1, an annular uniform array type composite continuous fiber was melt-spun. The spun yarn was cooled with a known cooling device, and then pulled using an air soccer at a pulling speed of 2000 m / min. Subsequently, the yarn is opened with a known opening device, and the single yarn fineness is 8.1 denier on the moving screen conveyor (high melting point component segment fineness = 0.68 denier, low melting point component segment fineness = 0.68 denier), The fiber was spread and deposited as a long-fiber nonwoven web composed of composite long fibers with a hollowness of 19.6%. The nonwoven fabric non-woven web is heat-welded with a heat-welding apparatus comprising a hot embossing roll, and the basis weight is 30 g / m. ² A biodegradable nonwoven fabric was obtained. The heat welding conditions were the same as in Example 1. Table 3 shows operability, physical properties of the nonwoven fabric, and biodegradability.
[0081]
Example 15
Under the same conditions as in Example 1, a circular uniform array type composite continuous fiber was melt-spun, and then drawn, thinned and opened, and a single yarn fineness of 4.0 denier (high melting point component segment fineness = 0.33 denier). The low-melting-point component segment fineness = 0.33 denier) and spread and deposited as a long-fiber nonwoven web composed of composite long fibers having a hollowness of 20.3%. This long-fiber nonwoven web is heat-welded with an ultrasonic fusion device, and the basis weight is 30 g / m. ² A biodegradable nonwoven fabric was obtained. Ultrasonic welding conditions are area 0.6mm ² Pressure contact density of 20 points / cm ² A roll having a pressure contact area ratio of 15% was used, and the frequency was 19.15 kHz. Table 3 shows operability, physical properties of the nonwoven fabric, and biodegradability.
[0082]
Example 16
Under the same conditions as in Example 1, a circular uniform array type composite continuous fiber was melt-spun, and then drawn, thinned and opened, and a single yarn fineness of 4.0 denier (high melting point component segment fineness = 0.33 denier). The low-melting-point component segment fineness = 0.33 denier) and spread and deposited as a long-fiber nonwoven web composed of composite long fibers having a hollowness of 20.3%. The nonwoven fabric non-woven web is heat-welded with a heat-welding apparatus comprising a hot embossing roll, and the basis weight is 30 g / m. ² A biodegradable nonwoven fabric was obtained. The hot pressing conditions were the same as in Example 1 except that the processing temperature was 67 ° C. Table 4 shows the operability, physical properties of the nonwoven fabric, and biodegradability.
[0083]
Example 17
Under the same conditions as in Example 1, a circular uniform array type composite continuous fiber was melt-spun, and then drawn, thinned and opened, and a single yarn fineness of 4.0 denier (high melting point component segment fineness = 0.33 denier, The low-melting-point component segment fineness = 0.33 denier), and the fiber was spread and deposited as a long-fiber nonwoven web composed of composite long fibers having a hollow ratio of 20.3%. The nonwoven fabric non-woven web is heat-welded with a heat-welding apparatus comprising a hot embossing roll, and the basis weight is 30 g / m. ² A biodegradable nonwoven fabric was obtained. The hot pressing conditions were the same as in Example 1 except that the processing temperature was 77 ° C. Table 4 shows the operability, physical properties of the nonwoven fabric, and biodegradability.
[0084]
Example 18
Under the same conditions as in Example 1, a circular uniform array type composite continuous fiber was melt-spun, and then drawn, thinned and opened, and a single yarn fineness of 4.0 denier (high melting point component segment fineness = 0.33 denier). The low-melting-point component segment fineness = 0.33 denier) and spread and deposited as a long-fiber nonwoven web composed of composite long fibers having a hollowness of 20.3%. The nonwoven fabric non-woven web is heat-welded with a heat-welding apparatus comprising a hot embossing roll, and the basis weight is 30 g / m. ² A biodegradable nonwoven fabric was obtained. The hot pressing conditions were the same as in Example 1 except that the processing temperature was 102 ° C. Table 4 shows the operability, physical properties of the nonwoven fabric, and biodegradability.
[0085]
Example 19
A long fiber nonwoven fabric was obtained under the same conditions as in Example 1 except that the same polymer as in Example 1 was used and a crystal nucleating agent was added thereto. That is, as a crystal nucleating agent, a master batch containing 20% by weight of talc / titanium oxide = 1/1 (weight ratio) having an average particle diameter of 1.0 μm is based on a high melting point component polymer and a low melting point component polymer. Prepared in advance and blended each masterbatch and the corresponding polymer, 0.2% by weight of the crystal nucleating agent added to the high melting point component, and 1.0% by weight of the crystal nucleating agent added to the low melting point component %, A biodegradable nonwoven fabric was obtained in the same manner as in Example 1 except that the raw material was used. Table 4 shows the operability, physical properties of the nonwoven fabric, and biodegradability.
[0086]
Example 20
The same conditions as in Example 19 were used, except that a copolymer polyester of butylene succinate / ethylene succinate = 60/40 (mol%) having an MFR value of 25 g / 10 min, a melting point of 63 ° C. and a crystallization temperature of 22 ° C. was used as the low melting point component. A cyclic uniform array type composite continuous fiber was melt-spun in the same manner as in Example 1 except that the crystal nucleating agent was added below. The spun yarn was cooled with a known cooling device, and then pulled using an air soccer at a pulling speed of 3850 m / min. Then, it is opened with a known opening device, and the single yarn fineness is 4.2 denier on the moving screen conveyor (high melting point component segment fineness = 0.35 denier, low melting point component segment fineness = 0.35 denier), The fiber was spread and deposited as a long-fiber nonwoven web composed of a composite long fiber having a hollow ratio of 20.8%. Table 4 shows the operability.
[0087]
Example 21
Except that the same two components as in Example 1 were used as raw materials, the spinning temperature was 280 ° C., the single hole discharge rate was 0.55 g / min, and the crystal nucleating agent was added under the same conditions as in Example 19. In the same manner as in Example 1, an annular uniform array type composite continuous fiber was melt-spun. The spun yarn was cooled with a known cooling device, and then pulled using an air soccer at a pulling speed of 2900 m / min. Next, it is opened with a known opening device, and on the moving screen conveyor, the single yarn fineness is 1.7 denier (high melting point component segment fineness = 0.14 denier, low melting point component segment fineness = 0.14 denier), hollow The fiber was spread and deposited as a long-fiber nonwoven web composed of composite long fibers with a rate of 2.0%. Table 4 shows the operability.
[0088]
Example 22
Under the same conditions as in Example 1, a long-fiber nonwoven web composed of cyclic uniform array type composite continuous fibers was obtained, and a laminated nonwoven fabric obtained by laminating a nonwoven web composed of natural fibers was obtained. That is, temporary hot-pressure welding was performed on a long-fiber nonwoven web spread and deposited on a movable collecting surface in advance by a hot-pressure welding device composed of an embossing roll. As the heat welding condition, the area is 0.6 mm. ² Pressure contact density of 20 points / cm ² The embossing roll disposed at a pressure contact area ratio of 15% and a metal roll having a smooth surface were used, and the processing temperature was 55 ° C.
[0089]
On the other hand, as a non-woven web made of natural fibers, cotton bleached cotton is used, and the basis weight is 25 g / m using a random card machine. ² A card web was created.
Next, a natural fiber nonwoven web made of cotton is laminated on the above-mentioned long fiber nonwoven web that has been subjected to the pre-heat pressure welding treatment, and is subjected to a fusion treatment with an ultrasonic fusion apparatus, with a basis weight of 50 g / m. ² A laminated nonwoven fabric was obtained. As the fusion treatment conditions, the frequency is 19.7 kHz and the area is 0.4 cm. ² The roll with the engraving pattern was provided with a convex portion, and the pressure contact area ratio of the convex portion was 15% and the linear pressure was 2.0 kg / cm. Table 5 shows the operability, physical properties of the nonwoven fabric, and biodegradability.
[0090]
Example 23
Using the same long fiber nonwoven web and natural fiber nonwoven web as in Example 22, the basis weight of the long fiber nonwoven web was 10 g / m. ² And the basis weight of the natural fiber nonwoven web is 40 g / m ² Except for the above, the basis weight was 50 g / m under the same conditions as in Example 22. ² A laminated nonwoven fabric was obtained. Table 5 shows the operability, physical properties of the nonwoven fabric, and biodegradability.
[0091]
Example 24
The same long fiber nonwoven web and natural fiber nonwoven web as in Example 22 were used, and the basis weight of the long fiber nonwoven web was 40 g / m. ² And the basis weight of the natural fiber nonwoven web is 10 g / m ² Except for the above, the basis weight was 50 g / m under the same conditions as in Example 22. ² A laminated nonwoven fabric was obtained. Table 5 shows the operability, physical properties of the nonwoven fabric, and biodegradability.
[0092]
Comparative Example 1
Single-phase long fibers were melt spun under the same conditions as in Example 1 except that the same high-melting-point component as in Example 1 was used alone and a spinneret having a single-phase fiber cross section was used. . The spun yarn was cooled with a known cooling device, and then pulled using an air soccer at a pulling speed of 4500 m / min. Subsequently, the fiber was opened with a known fiber opening device, and spread and deposited as a long-fiber nonwoven web composed of long fibers having a single yarn fineness of 3.6 denier on a moving screen conveyor. The nonwoven fabric non-woven web is heat-welded with a heat-welding apparatus comprising a hot embossing roll, and the basis weight is 30 g / m. ² A biodegradable nonwoven fabric was obtained. The hot pressing conditions were the same as in Example 1 except that the processing temperature was 107 ° C. Table 5 shows the operability, physical properties of the nonwoven fabric, and biodegradability.
[0093]
Comparative Example 2
Using the same two components as in Example 1, using a spinneret in which the fiber cross-section is a core-sheath type, the core portion becomes a high melting point component, the sheath portion becomes a low melting point component, and the composite ratio of the two components is 1. The core-sheath type composite continuous fiber was melt-spun under the same conditions as in Example 1 except that the ratio was / 1 (polymerization ratio). The spun yarn was cooled with a known cooling device, and then pulled using an air soccer at a traction speed of 4400 m / min. Subsequently, the fiber was opened with a known fiber opening device, and spread and deposited as a long-fiber nonwoven web composed of long fibers having a single yarn fineness of 3.7 denier on a moving screen conveyor. Table 5 shows the operability.
[0094]
Comparative Example 3
Under the same conditions as in Example 1, an annular uniform array type composite continuous fiber was melt-spun. The spun yarn was cooled with a known cooling device, and then pulled using an air soccer at a pulling speed of 1800 m / min. Then, it is opened with a known opening instrument, and the single yarn fineness is 9.0 denier on the moving screen conveyor (high melting point component segment fineness = 0.75 denier, low melting point component segment fineness = 0.75 denier), The fiber was spread and deposited as a long-fiber nonwoven web composed of a composite long fiber having a hollow ratio of 20.3%. Table 5 shows the operability.
[0095]
Comparative Example 4
Same basis weight as Example 16 is 25 g / m ² Long fiber non-woven web and basis weight 25g / m ² Laminated natural fiber non-woven web made of cotton and heat-bonded with a hot embossing roller, with a basis weight of 50 g / m ² A laminated nonwoven fabric was obtained. As heat fusion processing conditions, the roll has an engraved area of 0.4 cm. ² Convex portions having a sculpture pattern were arranged, and the pressure contact area ratio of the convex portions was 15%, the linear pressure was 50 kg / cm, and the processing temperature was 90 ° C. The results are shown in Table 5.
[0096]
[Table 1]

[0097]
[Table 2]

[0098]
[Table 3]

[0099]
[Table 4]

[0100]
[Table 5]

[0101]
As is apparent from Table 1, Example 1 uses the cyclic uniform array type composite continuous fiber of the present invention in which butylene succinate / ethylene succinate copolymer polyester is used as the low melting point component. The cooling property, spinnability, and fiber opening property of the strip were also good, and the mechanical performance was also excellent. The nonwoven fabric was also found to have good biodegradability.
[0102]
In Example 2, since the cyclic uniform array type composite continuous fiber of the present invention using butylene succinate / butylene adipate copolymer polyester as a low melting point component is applied, the cooling property of the spun yarn, the spinnability, In addition, the opening property was good, and the mechanical performance was also excellent. The nonwoven fabric was also found to have good biodegradability.
[0103]
Example 3 is a cyclic uniform array type composite long fiber of the present invention, although the butylene succinate / polyethylene succinate copolymer polyester used as the low melting point component has a lower butylene succinate copolymerization ratio than that of Example 1. And increased the composite ratio of high melting point components and increased butylene succinate, so that the spinning yarn has good cooling performance, spinnability, and openability, and excellent mechanical performance. there were. The nonwoven fabric was also found to have good biodegradability.
[0104]
Example 4 is a cyclic uniform array type composite long fiber of the present invention although the butylene succinate copolymerized polyester used as the low melting point component has a higher butylene succinate copolymerization ratio than Example 1. And increased the composite ratio of low melting point components and increased the amount of butylene succinate / ethylene succinate, so that the spinning yarn has good cooling performance, spinnability, and fiber opening performance, and has improved mechanical performance. Was also excellent. The nonwoven fabric was also found to have good biodegradability.
[0105]
In Example 5, although the number of segments of both components is smaller than that in Example 1, the cyclic uniform array type composite continuous fiber of the present invention is applied. Property and spreadability were also good, and the mechanical performance was also excellent. The nonwoven fabric was also found to have good biodegradability.
[0106]
In Example 6, although the number of segments of both components is larger than that in Example 1, the cyclic uniform array type composite continuous fiber of the present invention is applied. Property and spreadability were also good, and the mechanical performance was also excellent. The nonwoven fabric was also found to have very good biodegradability.
[0107]
As is apparent from Table 2, Example 7 increased the composite ratio of the low melting point component, but the fineness was reduced and the cyclic uniform array type composite continuous fiber of the present invention was applied. The cooling property, spinnability, and fiber opening property were also good, and the mechanical performance was also excellent. Further, the biodegradation performance was better than that of the nonwoven fabric obtained in Example 1.
[0108]
In Example 8, although the composite ratio of the high melting point component was increased, the fineness was increased, and the cyclic uniform array type composite continuous fiber of the present invention was applied. Therefore, the cooling property of the spun yarn, the spinnability, In addition, the opening property was good, and the mechanical performance was also excellent. In addition, the biodegradation performance was good because the high melting point component was subdivided with the low melting point component.
[0109]
In Example 9, since the amount of the low-melting point component was further increased as compared with Example 7, the exposed portion of the low-melting point component on the fiber surface was increased, and the cooling property of the spun yarn was inferior, which was not preferable in terms of operability.
[0110]
In Example 10, since the low melting point component was further reduced as compared with Example 8, the exposed portion of the low melting point component on the fiber surface was reduced, and thus the biodegradability of the obtained nonwoven fabric was slightly inferior, but the spun yarn The cooling property, spinnability and openness of the film were also good, and the mechanical performance was also excellent.
[0111]
As is apparent from Table 3, Example 11 is an annular uniform array type composite according to the present invention, although the spinning temperature is increased and the single-hole discharge rate is decreased to lower the hollowness than that of Example 1. Since long fibers were applied, the spinning yarns had good cooling properties, spinnability, and openability, and had excellent mechanical performance. The nonwoven fabric was also found to have good biodegradability.
[0112]
In Example 12, although the spinning temperature was lowered and the single-hole discharge rate was increased so that the hollow ratio was higher than that in Example 1, the annular uniform array type composite long fiber of the present invention was applied. The spinning yarns had good cooling properties, spinnability, and fiber opening properties, and had excellent mechanical properties although the fineness was thick and slightly lacking flexibility. The nonwoven fabric was also found to have good biodegradability.
[0113]
In Example 13, since the high melting point component and the low melting point component were made to have high viscosity, the spinning temperature was lowered, and the single-hole discharge rate was increased, the hollow ratio was high, and the hollow portion of the spun yarn was easily punctured during the spinning process. It became a tendency and was not so preferable in terms of operability.
[0114]
In Example 14, although the pulling speed was slower than that in Example 1, the cyclic uniform array type composite continuous fiber of the present invention was applied, so the cooling and spinning performance of the spun yarn was good. Met. Although it was slightly inferior to the spreadability and flexibility, it was excellent in mechanical properties. The nonwoven fabric was also found to have good biodegradability.
[0115]
In Example 15, since the long-fiber nonwoven web obtained in Example 1 is heat-welded using an ultrasonic fusion apparatus, a nonwoven fabric excellent in flexibility is obtained although the mechanical properties are slightly inferior in the nonwoven fabric properties. It was.
[0116]
As is apparent from Table 4, since the processing temperature in the hot pressing process was low in Example 16, the flexibility was excellent, but the mechanical properties were inferior and fluff was likely to occur. The nonwoven fabric was also found to have good biodegradability.
[0117]
In Example 17, the cyclic uniform array type composite continuous fiber according to the present invention was applied despite the fact that the processing temperature in the hot pressing process was lowered. It was excellent. The nonwoven fabric was also found to have good biodegradability.
[0118]
In Example 18, the cyclic uniform array type composite continuous fiber according to the present invention was applied despite the fact that the processing temperature in the hot pressing process was increased, so that it was inferior in flexibility but excellent in mechanical properties. Met. The nonwoven fabric was also found to have good biodegradability.
[0119]
In Example 19, since the crystal nucleating agent was added, the cooling property of each single fiber of the spun yarn became uniform, and the cooling property of the yarn was improved, so that the spinning property was further improved. The nonwoven fabric was also excellent in mechanical properties and biodegradability.
[0120]
In Example 20, a polymer having a lower melting point than that in Example 1 was used as the low-melting point component. Therefore, although the effect of the crystal nucleating agent greatly contributed, it was slightly inferior in the cooling property and fiber opening property of the spun yarn. It was a result.
[0121]
In Example 21, the hollowness decreased because the spinning temperature was increased and the single-hole discharge rate was decreased to reduce the fineness. However, since the crystal nucleating agent was added, the cooling property and opening of the spun yarn were reduced. It was found that there was no major problem with the fineness.
[0122]
As is clear from Table 5, Example 22 is a biodegradable nonwoven fabric of the present invention in which a nonwoven web made of natural fibers is laminated. Since it has excellent mechanical properties and the composite long fiber has a biodegradation rate comparable to that of natural fiber, it was recognized that the laminated nonwoven fabric is a nonwoven fabric excellent in biodegradability.
[0123]
In Example 23, since the lamination ratio of the natural fiber nonwoven web is larger than that in Example 22, the obtained nonwoven fabric is further excellent in water absorption, and the composite long fiber has a biodegradation rate comparable to that of natural fiber. Therefore, it was excellent in biodegradation performance. Moreover, since the nonwoven fabric nonwoven web was small, the strength of the nonwoven fabric was somewhat low, but it had practical mechanical properties.
[0124]
In Example 24, the lamination ratio of the natural fiber nonwoven web is smaller than that in Example 22, so that the water absorption is slightly inferior, but the laminated nonwoven fabric has practical mechanical properties, and the composite long fiber is a natural fiber. Since the biodegradation rate was comparable, the biodegradation performance was excellent.
[0125]
On the other hand, as is apparent from Table 5, Comparative Example 1 uses the same high melting point component as Example 1, but is a single-phase type in which the fiber cross section is outside the scope of the present invention. Although it is excellent in mechanical performance, the nonwoven fabric was embedded in the soil for 6 months and then excavated and observed to maintain the nonwoven fabric form. The strength of the nonwoven fabric was 91% of the initial strength value before embedding. The biodegradation performance was extremely inferior.
[0126]
Although the comparative example 2 uses the same raw material as Example 1, since it is a core-sheath type whose fiber cross section is outside the scope of the present invention, the spun yarn is in close contact with each other, and the openability is also poor. There was no target nonwoven fabric.
[0127]
In Comparative Example 3, the pulling speed was low and out of the scope of the present invention, so the spun yarn had a low pulling tension, poor cooling and opening properties, and a target nonwoven fabric could not be obtained. .
[0128]
Comparative Example 4 is a laminated non-woven fabric of a natural fiber non-woven web and a long fiber non-woven web. However, since the two webs were integrated by a heat welding apparatus comprising a hot embossing roll, the natural fiber non-woven web was It was taken by a roller and could not be fixed by heat and pressure, and a laminated nonwoven fabric in which a natural fiber nonwoven web and a long fiber nonwoven web were integrated could not be obtained.
[0129]
【The invention's effect】
According to the present invention, the biodegradation performance is controllable, and the nonwoven fabric is provided with excellent texture and mechanical properties, excellent spinning yarn cooling and spinning properties, and has a thermal bonding function. It is possible to provide a biodegradable nonwoven fabric that can also exhibit water absorption and a method for producing these.
[0130]
Non-woven fabrics of the present invention include medical and sanitary material materials such as diapers and sanitary products, wipes such as disposable towels and wiping cloths, disposable packaging materials, bags for collecting garbage for household and business use, and other waste treatment materials. It is suitable as a raw material for daily life or as an industrial material represented by agriculture / horticulture / civil engineering. Moreover, since this non-woven fabric is biodegradable, it completely decomposes and disappears after its use, so that it is also beneficial from the viewpoint of protecting the natural environment, or can be reused, for example, by composting it into a fertilizer. Therefore, it is also beneficial from the viewpoint of resource reuse.
[Brief description of the drawings]
FIG. 1 is a model diagram of a fiber cross section of an annular uniform array type composite continuous fiber of the present invention.
[Explanation of symbols]
1 High melting point components
2 Low melting point components
3 Hollow part
4 Circular uniform array type composite long fiber

Claims

A nonwoven fabric in which a long-fiber nonwoven web composed of composite long fibers is partially heat-welded to maintain a predetermined shape, and the composite long fibers are made of a first aliphatic polyester having biodegradability. A cyclic uniform array type composite long fiber formed from a melting point component and a low melting point component comprising a second aliphatic polyester having a biodegradability lower than that of the high melting point component. In the fiber cross section of the fiber, the high melting point component and the low melting point component alternately occupy a certain range in the circumferential direction of the fiber cross section, and the fiber cross section has a hollow portion, and both the components are equal in the fiber cross section such areas are each divided into 3 to 20 segments having, moreover are exposed to the fiber surface and a hollow portion with a high melting point component and the low melting point component is continuous in the fiber axis direction, the Biodegradable nonwoven fabric fineness merging long fibers, characterized in that 1.5 to 10 denier.

A laminated non-woven fabric obtained by laminating a long-fiber non-woven web made of composite long fibers and a natural-fiber non-woven web made of natural fibers and integrated by partial pressure welding, wherein the composite long fibers have biodegradability A cyclic uniform array type composite long fiber formed of a high melting point component composed of a first aliphatic polyester and a low melting point component composed of a second aliphatic polyester having a biodegradability lower than the high melting point component. There, the cyclic equivalent array type composite long high melting point component and the low melting component in the fiber cross section of the fiber is occupied alternately by a predetermined range in the circumferential direction of the fiber cross-section, and has a hollow portion in the fiber cross-section, and fibers with the both components are each divided into 3 to 20 segments having a uniform area in the textile cross-section, and with high melting point component and the low melting point component is continuous in the fiber axis direction Surface and is exposed to the hollow portion, biodegradable nonwoven fabric fineness of the composite long fibers, characterized in that 1.5 to 10 denier.

It is characterized in that at least the high melting point components are not heat-welded to each other so that a non-heat-welding region is maintained between the composite long fibers, and the low-melting point components are heat-welded to each other to maintain a predetermined form. The biodegradable nonwoven fabric according to claim 1.

The biodegradable nonwoven fabric according to claim 2, wherein the natural fiber is any one of cotton, ramie, and silk fiber cut into short fibers.

The biodegradable nonwoven fabric according to claim 2 or 4, wherein the lamination ratio of the natural fiber nonwoven web and the long fiber nonwoven web is 10/90 to 90/10 (wt%).

The high melting point component is polybutylene succinate, the low melting point component is butylene succinate as a main repeating unit, and the copolymerization amount ratio of butylene succinate is 70 to 90 mol%. The biodegradable nonwoven fabric according to any one of claims 1 to 5.

The biodegradable nonwoven fabric according to any one of claims 1 to 6, wherein the low melting point component is a copolyester obtained by copolymerizing butylene succinate with ethylene succinate or butylene adipate.

The biodegradable nonwoven fabric according to any one of claims 1 to 7, wherein a crystal nucleating agent is added to at least the low melting point component of the low melting point component and the high melting point component.

The biodegradable nonwoven fabric according to any one of claims 1 to 8, wherein a composite ratio of the high melting point component / low melting point component is 1/3 to 3/1 (weight ratio).

In the fiber cross section of the composite long fiber constituting the long fiber nonwoven web, when the diameter of the yarn is (A) and the diameter of the hollow portion is (a),
(A ² / A ² ) × 100 (%)
The biodegradable nonwoven fabric according to any one of claims 1 to 9 , wherein the hollow ratio indicated by is 5 to 30%.

A method for producing a nonwoven fabric in which a long-fiber nonwoven web composed of composite long fibers is partially heat-welded to maintain a predetermined form, and the composite aliphatic fibers are biodegradable first aliphatic polyester And a low melting point component comprising a second aliphatic polyester having a biodegradability lower than that of the high melting point component. The high melting point component and the low melting point component are formed in the fiber cross section. The fiber cross section alternately occupies a certain range in the circumferential direction , and the fiber cross section has a hollow portion, and both components are divided into 3 to 20 segments having an equal area in the fiber cross section. In addition, an annular uniform array type composite continuous fiber in which the high melting point component and the low melting point component are continuous in the fiber axis direction and exposed to the fiber surface and the hollow portion is melt-spun, After towing thinned long fibers pulling speed 2000 m / min or more, the composite long fibers having a single fiber fineness of the long fibrous nonwoven web and without which is 1.5 to 10 denier, thermocompression bonding the long fibers nonwoven web A method for producing a biodegradable nonwoven fabric, characterized in that it is partially hot-pressed by an apparatus.

When the melting point of the low melting point component is (Tm) ° C., the nonwoven fabric non-woven web is partially heat-welded with an embossing roll at a temperature satisfying the range of (Tm−25) ° C. to (Tm) ° C. the method according to claim 11 biodegradable nonwoven fabric, wherein a.

The method for producing a biodegradable nonwoven fabric according to claim 11, wherein the non-woven fabric web is partially heat-welded by an ultrasonic fusing apparatus using an ultrasonic oscillator.

A method for producing a laminated nonwoven fabric obtained by laminating a long-fiber nonwoven web composed of composite long fibers and a natural fiber nonwoven web composed of natural fibers and then partially pressing them together, the composite long fibers Using a high melting point component made of a first aliphatic polyester having biodegradability and a low melting point component made of a second aliphatic polyester having a lower melting point than the high melting point component, In the fiber cross section, the high melting point component and the low melting point component alternately occupy a certain range in the circumferential direction of the fiber cross section, and the fiber cross section has a hollow portion, and both the components have an equal area in the fiber cross section. 3-20 are each divided into segments, moreover cyclic equivalent sequences as exposed on the fiber surface and a hollow portion with a high melting point component and the low melting point component is continuous in the fiber axial direction with The conjugated filaments were melt-spun, after pulling thinned this annular evenly array type composite long fiber tow speed 2000 m / min or more, long fiber fineness of the composite long fibers is 1.5 to 10 denier not A non-woven web, and a non-woven web of natural fibers separately prepared by a conventional method is laminated to this long-fiber non-woven web, followed by ultrasonic fusing to partially fuse both non-woven webs. A method for producing a biodegradable nonwoven fabric characterized by comprising:

Before laminating the long-fiber non-woven web and the natural-fiber non-woven web, the form of the long-fiber non-woven web is obtained by subjecting the long-fiber non-woven web to a pre-heating pressure welding process, a hot air bonding process or a three-dimensional entanglement process. The method for producing a biodegradable nonwoven fabric according to claim 14 , wherein the biodegradable nonwoven fabric is retained.

The method for producing a biodegradable nonwoven fabric according to any one of claims 11 to 15 , wherein a crystal nucleating agent is added to at least the low melting point component of the low melting point component and the high melting point component.