JP3760599B2

JP3760599B2 - Laminated nonwoven fabric and absorbent article using the same

Info

Publication number: JP3760599B2
Application number: JP28788497A
Authority: JP
Inventors: 真吾堀内; 義実辻山; 寿克藤原
Original assignee: Chisso Corp
Current assignee: JNC Corp
Priority date: 1997-10-03
Filing date: 1997-10-03
Publication date: 2006-03-29
Anticipated expiration: 2017-10-03
Also published as: JPH11107155A

Description

【０００１】
【発明の属する技術分野】
本発明は積層不織布に関する。更に詳しくは混繊スパンボンド不織布とカ−ド不織布が積層された多層構造の不織布に関する。この不織布は紙おむつや生理用ナプキン等の吸収性物品の材料、ハツプ材のシ−ト、フイルタ−、衣料用、ワイパ−、建築材料等に使用される。
【０００２】
【従来の技術】
スパンボンド長繊維不織布は、安価に製造出来しかも毛羽立が無い等の理由で、カ−ペツトの基布や農業用カバ−シ−ト等として使用されてきた。しかしこの不織布は嵩高性が劣り、かつ風合いがペ−パ−ライクで柔軟性に劣るという問題があった。又スパンボンド不織布は、細繊度化により風合いを改良する試みも行われているが、細繊度化に伴い紡糸時に単糸切れが発生し太繊度糸が混合したり、糸切れ時の相互の繊維の熱融着による束状の繊維が混合し、風合いが更に悪化するという問題がある。
【０００３】
特開昭５４−１３４１７７号公報にはポリプロピレン極細繊維からなるメルトブロ−不織布が、特開昭６２−２９９５０１号公報にはメルトブロ−不織布を表面材として使用した紙おむつが開示されている。前記メルトブロ−不織布は繊維径が細いので風合いが柔らかであるという利点がある反面、通気性や、不織布強度が劣るという問題がある。
【０００４】
又特開平２−１１２４５８号公報にスパンボンド不織布とメルトブロ−不織布を積層した不織布が開示されている。このような不織布は従来の単層不織布に比べ風合いが柔らかであるが、嵩高性が劣り、通気度も小さいという問題がある。又スパンボンド不織布を構成する長繊維が単一繊維であるので積層面で剥離しやすい。又不織布強力も低いという問題がある。尚本発明で単一繊維とは複合繊維に対して使われた語であり、単一成分からなる繊維のことをいい、１種類の樹脂からなる場合、或いは２種類以上の樹脂が押出機の中に入るまでに混合されて１成分を構成する場合がある。
【０００５】
【発明が解決しようとする課題】
本発明は上記課題が解決され、通気性や嵩高に優れしかも風合いが柔らかな積層不織布を提供する事にある。更には不織布強力が大で、しかも積層面で剥離しにくい積層不織布を提供する事にある。更に上記積層不織布を用いた吸収性物品を提供する事にある。
【０００６】
【課題を解決する為の手段】
本発明は下記項目から構成される。
（１）混繊スパンボンド不織布とカ−ド不織布が積層されてなる多層構造の不織布であつて、該混繊スパンボンド不織布は融点差が１０℃以上ある樹脂からなる低融点長繊維１０〜９０重量％と高融点長繊維９０〜１０重量％が混繊され、且つ該低融点長繊維で繊維交点が熱融着されてなる不織布であり、該カ−ド不織布は捲縮を有する繊維長２５〜１２８ｍｍの短繊維からなり、該混繊スパンボンド不織布と該カ−ド不織布が、該混繊スパンボンド不織布の低融点長繊維及びカ−ド不織布の短繊維の内の少なくとも一方の熱融着により一体化され、且つ通気度８０〜２０００ｃｍ³／ｃｍ²／秒、比容積１５〜７０ｃｍ³ ／ｇ、である積層不織布。
（２）混繊スパンボンド不織布が平均繊度０．４〜１０ｄ／ｆの混繊長繊維からなり、カ−ド不織布が熱融着性短繊維のみからなり、且つ該熱融着性短繊維でその交点が熱融着されてなる不織布であり、積層不織布の横強力が１．２ｋｇ／５ｃｍ以上、通気度８５〜１３００ｃｍ³／ｃｍ²／秒、比容積１５〜６５ｃｍ³ ／ｇ、である（１）項に記載の積層不織布。
（３）混繊スパンボンド不織布が平均繊度０．４〜１０ｄ／ｆの混繊長繊維からなり、カ−ド不織布が少なくとも１０重量％の熱融着性短繊維と他の短繊維が混合された繊維からなり、且つ該熱融着性短繊維で繊維交点が熱融着された不織布であり、積層不織布の横強力が１．２ｋｇ／５ｃｍ以上、通気度８５〜１３００ｃｍ³／ｃｍ²／秒、比容積１５〜６５ｃｍ³ ／ｇ、である（１）項に記載の積層不織布。
（４）混繊スパンボンド不織布が繊度斑１５０％以下の混繊長繊維である（１）〜（３）項の何れかに記載の積層不織布。
（５）混繊スパンボンド不織布が、混繊紡糸口金が使用され、紡糸直後に低融点長繊維と高融点長繊維が均一に混繊紡糸された不織布である（１）〜（４）項の何れかに記載の積層不織布。
（６）カ−ド不織布が、２次元及び３次元捲縮の内の少なくとも一方を有する単一短繊維からなり、且つ繊維同士がその交点で熱融着された不織布である（１）〜（５）項の何れかに記載の積層不織布。
（７）カ−ド不織布が、２次元及び３次元捲縮の内の少なくとも一方を有し融点差が１０℃以上ある低融点樹脂１０〜９０重量％と高融点樹脂９０〜１０重量％からなり、該低融点樹脂が繊維表面の少なくとも一部を形成する複合繊維からなり、且つ該繊維の低融点樹脂で繊維交点が熱融着された不織布である（１）〜（５）項の何れかに記載の積層不織布。
（８）カ−ド不織布が、２次元及び３次元捲縮の内の少なくとも一方を有し且つ融点差が１０℃以上ある低融点繊維１０〜９０重量％と高融点繊維９０〜１０重量％が混合され、且つ該低融点繊維で繊維交点が熱融着された不織布である（１）〜（５）項の何れかに記載の積層不織布。
（９）混繊スパンボンド不織布の少なくとも一種の長繊維及びカ−ド不織布の少なくとも一種の繊維が、ポリエチレン、プロピレンと他のα−オレフインとの結晶性共重合体、ポリプロピレンの何れかから選ばれたポリオレフイン樹脂が使用された繊維である（１）〜（８）項の何れかに記載の積層不織布。
（１０）混繊スパンボンド不織布とカ−ド不織布が熱スル−エア−で繊維交点が熱融着された（１）〜（９）項の何れかに記載の積層不織布。
（１１）混繊スパンボンド不織布とカ−ド不織布が凸部面積５〜２５％のエンボスロ−ルで熱圧着された（１）〜（９）項の何れかに記載の積層不織布。
（１２）吸収性物品を構成する少なくとも一つの材料として、（１）〜（１１）項の何れかに記載された積層不織布が使用された吸収性物品。
【０００７】
【発明の実施の形態】
本発明の積層不織布は混繊スパンボンド不織布と短繊維カ−ド不織布が積層され、かつその両方が熱融着された多層構造の不織布である。不織布の使用される用途が紙おむつの表面材やワイパ−等の場合２〜４層、フイルタ−等の場合２〜８層の物が使用される。しかし大抵の場合、２〜４層の物が使用される。
【０００８】
本発明の積層不織布に使用する混繊スパンボンド不織布は、融点に１０℃以上差がある少なくとも二種の熱可塑性樹脂が混繊スパンボンド法で紡糸され且つ繊維同士の交点が低融点長繊維で熱融着された長繊維である。融点差の上限は本発明の実施上特に問題とはならない。
又混繊スパンボンド法とは、複数の押出機から複数の熱可塑性樹脂を溶融押出し、混繊紡糸用口金のそれぞれの紡糸孔から複数の熱可塑性長繊維を別々に吐出し吐出された繊維をエアサツカ−等の気流牽引型の牽引装置で引き取り、気流と共に長繊維をネツトコンベア−等の捕集装置に吹き付け、その後ウエブを加熱空気、加熱ロ−ル等の加熱装置を用い熱処理し繊維同士の交点を低融点長繊維の熱融着により不織布化する事による不織布の製造方法である。勿論熱融着は低融点長繊維のみならず高融点長繊維も熱融着していても良い。又紡糸からウエブの捕集工程までの間で、紡糸された混繊長繊維を機械延伸した後、エアサツカ−等の牽引装置で引き取り気流と共に混繊長繊維をネツトコンベア−等のウエブ捕集装置に吹き付け、その後ウエブを前記同様の方法で熱処理し、熱融着不織布を製造する方法であつても良い。
紡糸に使用する熱可塑性樹脂は実用上２〜４種使用する事が出来、その最高の融点と最低の融点差が１０℃以上ある樹脂の組み合わせであればよい。しかし大抵の用途では、二種で十分である。
【０００９】
混繊スパンボンド不織布の長繊維に使用される樹脂は溶融紡糸可能な熱可塑性樹脂であれば特別な制限はない。例えばポリエチレン、ポリプロピレン、線状低密度ポリエチレン、プロピレン・エチレン又はプロピレン・エチレン・ブテン−１からなる２若しくは３元共重合体等のようなプロピレンと他のα−オレフインとの結晶性ランダム共重合体、等のポリオレフイン、ナイロン−６、ナイロン−６６等のポリアミド、ポリエチレンテレフタレ−ト、ポリブチレンテレフタレ−ト、ポリ（エチレンテレフタレ−ト−ｃｏ−イソフタレ−ト）等の低融点ポリエステル、ポリエステル系エラストマ−等のポリエステル、フッソ系樹脂、ポリフエニレンサルフアイド、前記樹脂の混合物、その他紡糸可能な熱可塑性樹脂等が例示できる。
【００１０】
混繊スパンボンド紡糸の熱可塑性樹脂の組み合わせは、融点に１０℃以上差があるような樹脂の組み合わせである。例えば高密度ポリエチレン／ポリプロピレン、線状低密度ポリエチレン／ポリプロピレン、プロピレン・エチレン・ブテン−１結晶性共重合体／ポリプロピレン、プロピレン・エチレン結晶性共重合体／ポリプロピレン、高密度ポリエチレン／ポリエチレンテレフタレ−ト、低融点ポリエステル／ポリエチレンテレフタレ−ト、ポリプロピレン／ポリエチレンテレフタレ−ト、プロピレン・エチレン・ブテン−１結晶性共重合体／ポリエチレンテレフタレ−ト、ポリ弗化ビニリデン／ポリエチレンテレフタレ−ト、低密度ポリエチレンと高密度ポリエチレンとの混合物／ポリプロピレン等を例示できる。
【００１１】
混繊スパンボンド不織布の各長繊維の混繊状態は、低融点長繊維と高融点長繊維が実質的に均一に混繊された状態であれば良い。例えば１個の紡糸口金に、Ａ成分紡糸孔が孔数比で１０〜９０％、Ｂ成分紡糸孔が９０〜１０％となるように、それぞれの紡糸孔が分散して穿孔されたミクロ均一混繊型紡糸口金を備えた紡糸装置が使用出来る。又Ａ成分紡糸孔のみ備えた紡糸口金と、Ｂ成分紡糸孔のみ備えた紡糸口金とを備えた紡糸装置を組み合わせて使用することが出来る。
【００１２】
混繊スパンボンド不織布において、低融点長繊維と高融点長繊維の混繊比は低融点長繊維が１０〜９０重量％、高融点長繊維が９０〜１０重量％である。好ましくは低融点長繊維が３０〜７０重量％、高融点長繊維が７０〜３０重量％である。低融点長繊維が１０重量％未満の場合、混繊スパンボンド不織布自体の熱融着が不足するか、又はこの不織布とカ−ド不織布との積層面での熱融着が不足し積層面での剥離が起きたり、不織布強力不足等の問題がある。又、不織布の毛羽立ち等の問題もある。又低融点長繊維が９０重量％以上の場合、積層不織布の剥離強力はアツプするが、通気性や、嵩高等が何れも低くなるという問題がある。
【００１３】
混繊スパンボンド不織布の長繊維の繊度は特別な制限はない。積層不織布の用途が紙おむつや生理用ナプキン等に使用される場合、０．２〜１２ｄ／ｆ、ワイパ−の場合０．５〜２０ｄ／ｆ、フイルタ−の場合０．２〜３０００ｄ／ｆである。しかし繊度が０．３〜１０ｄ／ｆの範囲が最も好ましい。
混繊スパンボンド不織布を構成する長繊維は繊度斑が１５０％以下の物が好ましい。この繊度斑は更に好ましくは１２０％以下である。繊度斑が大であると不織布の用途が紙おむつ等に使用する場合、風合いが劣り、皮膚刺激等が発生するようになる。特に新生児用の紙おむつに使用する場合、皮膚刺激等を回避する必要がある。
又この不織布の目付けは特に限定されないが、不織布の均一性や後記熱処理時の均一加熱等の観点から、４〜１０００ｇ／ｍ²である。紙おむつ等の吸収性物品等に使用される場合４〜７０ｇ／ｍ²、ワイパ−等に用いられる場合、１０〜６００ｇ／ｍ²、フイルタ−に用いられる場合２０〜１０００ｇ／ｍ²である。
【００１４】
混繊スパンボンド不織布は、熱スル−エア−加熱機、交互熱風噴出型加熱機、超音波加熱機、熱カレンダ−ロ−ル、熱エンボスロ−ル等の熱処理機を用い、低融点長繊維の熱融着温度以上に加熱し繊維同士を熱融着し不織布強力の高い不織布とするのである。熱エンボスロ−ルを用いる場合、凸部面積５〜３５％である物が好ましい。該凸部面積は好ましくは１０〜３０％、更に好ましくは１２〜２７％である。凸部面積が１０％未満の場合不織布強力が小さく、３５％を超えると通気性や嵩高等が劣る。本発明の場合、不織布強力は横方向即ち幅方向の強力が１０００ｇ／５ｃｍ以上とする事が好ましい。高強力不織布は前記熱処理時の温度等の加工条件等をコントロ−ルする事により得られる。
【００１５】
混繊スパンボンドに積層するカ−ド不織布は捲縮があり且つ繊維長が２５〜１２８ｍｍの短繊維をカ−ド機を用いウエブを形成した後不織布化された物が用いられる。短繊維の繊維長は好ましくは２８〜１１５ｍｍ更に好ましくは３０〜８９ｍｍである。該短繊維は繊維長が２５ｍｍ未満の場合又は１２８ｍｍを超えた場合、カ−ド機での梳綿性が悪化するので均一な不織布が得られない。又カ−ド機の針布に短繊維が絡まり連続生産が困難である。又カ−ド機で半溶融化した塊状の繊維束等が発生し不織布に混合する等の問題が発生する。
【００１６】
該短繊維は二次元捲縮や三次元捲縮等の捲縮を有る繊維であれば、熱可塑性繊維、天然繊維、再生繊維等何れも使用出来る。又単一繊維、複合繊維等何れも使用出来る。捲縮数は１〜３５山／２５ｍｍであれば良い。捲縮数は好ましくは３〜２５山／２５ｍｍである。捲縮数が１山／２５ｍｍ未満の場合又は３５山／２５ｍｍを超える場合、カ−ド通過性や嵩高性等が劣る。又該短繊維は二種類以上混合して使用する事も可能であり、その場合カ−ドが可能であれば、主として混合する短繊維が捲縮がある繊維で、他の繊維は捲縮が無い繊維を使用しても良い。
【００１７】
カ−ド不織布に使用する短繊維は単糸繊度が特に限定されない。しかしカ−ド機を使用しウエブを作成する時のカ−ド性等の点で単糸繊度０．２〜３０００ｄ／ｆの繊維が好適に使用出来る。風合いが重視される紙おむつや生理用ナプキン等に使用される場合、０．２〜１２ｄ／ｆ、ワイパ−の場合０．５〜２０ｄ／ｆ、フイルタ−の場合０．２〜３０００ｄ／ｆである。しかし繊度が０．３〜１０ｄ／ｆの範囲が最も好ましい。
【００１８】
該短繊維は、綿、麻、レ−ヨン、アセテ−ト等のセルロ−ス系繊維、ポリプロピレン繊維、ポリアミド繊維、ポリエステル繊維、等及び前記混繊スパンボンドに例示したような種々の熱可塑性樹脂を繊維化した単一繊維等を使用出来る。又前記混繊スパンボンドに例示したような熱可塑性樹脂を用い、様々な樹脂の組み合わせの複合繊維を使用出来る。該複合繊維は、並列型、鞘芯型、海島型等何れも使用出来る。熱可塑性樹脂の組み合わせとして、融点差が１０℃以上あり、且つ低融点熱可塑性樹脂が繊維表面の一部を形成する熱融着性複合繊維の場合、不織布強力が大きい物が得られる。又後記積層後の熱処理で混繊スパンボンド不織布との熱融着が一層強くなり、剥離しにくく、しかも不織布強力の大きい積層不織布が得られる。
【００１９】
該熱融着性複合繊維の具体例として、例えば高密度ポリエチレン／ポリプロピレン、線状低密度ポリエチレン／ポリプロピレン、プロピレン・エチレン・ブテン−１結晶性共重合体／ポリプロピレン、プロピレン・エチレン結晶性共重合体／ポリプロピレン、高密度ポリエチレン／ポリエチレンテレフタレ−ト、低融点ポリエステル／ポリエチレンテレフタレ−ト、ポリプロピレン／ポリエチレンテレフタレ−ト、プロピレン・エチレン・ブテン−１結晶性共重合体／ポリエチレンテレフタレ−ト、ポリ弗化ビニリデン／ポリエチレンテレフタレ−ト、低密度ポリエチレンと高密度ポリエチレンとの混合物／ポリプロピレン等を例示できる。
【００２０】
前記短繊維１００重量％、又は低融点の短繊維１０〜９０重量％と高融点の他の短繊維９０〜１０重量％とを混合しカ−ド機で梳綿しウエブを形成する。該ウエブを前記混繊スパンボンドの熱処理同様に熱エアスル−処理機、熱エンボス処理機等を使用し、熱融着温度以上に加熱し、繊維同士を熱融着した不織布とする。熱エンボスロ−ルを用いる場合、前記混繊スパンボンド不織布同様凸部面積５〜３５％である物が好ましい。又熱処理は熱スル−エア−処理の方が熱エンボスロ−ル処理よりも、通気性や、嵩高な不織布が得られる。
【００２１】
本発明の積層不織布は前記混繊スパンボンド不織布とカ−ド不織布を積層し、その両方の不織布が熱融着するような温度以上に加熱等をし、本発明の積層不織布とする。勿論混繊スパンボンド不織布又はカ−ド不織布の何れか又はその両方がウエブ状の物を積層し、その両方の不織布が熱融着するような温度以上に加熱等をし積層不織布とする事ができる。
積層不織布の構造は、混繊スパンボンド不織布／カ−ド不織布のような２層構造の物、混繊スパンボンド不織布／カ−ド不織布／混繊スパンボンド不織布、カ−ド不織布／混繊スパンボンド不織布／カ−ド不織布のような３層構造の物、混繊スパンボンド不織布／カ−ド不織布／混繊スパンボンド不織布／カ−ド不織布等のような４層構造の物等、２〜１０層の物が例示出来る。しかし大抵の用途には２〜４層で使用される。
【００２２】
本発明の積層不織布は通気度が８０〜２０００ｃｍ³／ｃｍ²／秒、比容積が１５〜７０ｃｍ³ ／ｇである。通気度は好ましくは８０〜１５００ｃｍ³／ｃｍ²／秒、更に好ましくは８５〜１３００ｃｍ³／ｃｍ²／秒である。なお通気度は、積層不織布の目付けが２０〜１００ｇ／ｍ²の物が前記範囲に入ればよい。該目付けは積層不織布の実用性が最も高いからである。又比容積は好ましくは１５〜６８ｃｍ³ ／ｇ、更に好ましくは１５〜６５ｃｍ³ ／ｇである。積層不織布の用途が紙おむつ等に使用する場合、通気度、比容積が共に比較的高い物が使用される。又ワイパ−等に使用される場合通気度は比較的低くてもよいが、嵩高が比較的高い物が使用される。又フイルタ−等に使用される場合、比容積は比較的低い物でもよいが、通気度が比較的高い物が使用される。
【００２３】
本発明の積層不織布は不織布の強力が大である物程好ましいが、不織布４０ｇ／ｍ²換算時の横強力が１．２ｋｇ／５ｃｍ以上ある物が好ましい。該不織布強力は好ましくは１．２〜１５ｋｇ／５ｃｍ、更に好ましくは１．４〜８．０ｋｇ／５ｃｍである。
【００２４】
本発明の積層不織布はそのまま、或いは各種潤滑剤等を付着し、眼鏡、家具、床、機械等のワイパ−として使用出来る。又本発明の不織布はそのままでフイルタ−の材料として使用出来る。フイルタ−は各種の物を例示出来る。例えば該積層不織布を多孔性中芯に巻回し筒状成形体に加工した物、該積層不織布を襞折りした物、等を例示出来る。又多孔性中芯等を使用し、又は非多孔性金属中芯等を使用し、或いは中芯を使用せずに不織布をその巻回された層間が熱融着するような温度で加熱しながら巻回し筒状成形体とした物等を例示出来る。非多孔性金属中芯を使用した場合、この中芯は抜き取ってフイルタ−等に使用出来る。
【００２５】
又本発明の吸収性物品は、前記積層不織布が紙おむつ等の材料として使用された物である。例えば該積層不織布を紙おむつの表面材として用いたり、脚部の材料として用いたり、或いはバツクシ−ト等として用いた物等を例示出来る。又紙おむつのパルプと高分子吸水材を主とする液吸収材の包材等として用いた物等を例示出来る。本発明の積層不織布を用いた紙おむつは優れた風合い、通気性、液吸収性等を有する紙おむつが得られる。
【００２６】
【実施例】
以下本発明を実施例で詳細に説明する。なお以下に示す実施例等では不織布等の評価を下記の方法で行った。
スパンボンド不織布の繊度及び繊度斑：熱融着処理前のウエブ又は熱融着処理後の不織布からサンプルを切りとり、顕微鏡写真を撮り、任意に選んだ合計１００本の繊維の各々の直径を測定する。繊維の密度から１００本の繊維の単糸繊度を算出し、その平均値（Ｘ）を繊度（ｄ／ｆ）とした。
又繊度斑は以下の式によった。
繊度斑（％）＝｛（Ａ−Ｂ）／Ｘ｝×１００
Ａ：任意に選んだ１００個の繊維のうち繊度の大きい方から順に選んだ１０個の繊維の繊度の平均値。
Ｂ：上記選択した１００個の繊維のうち繊度の小さい方から順に選んだ１０個の繊維の繊度の平均値。
Ｘ：上記選択した１００本の単糸繊度の平均値。
【００２７】
通気度：ＪＩＳ−Ｌ−１０９６に定める方法で、フラジ−ル形試験機を用い測定した。単位ｃｍ³／ｃｍ²／秒。
【００２８】
比容積：不織布から２５ｃｍ×２５ｃｍの試験片を切りとり、その目付け及び厚みを測定し、比容積を算出した。単位ｃｍ³／ｇ。
【００２９】
実施例１
２台の押出機、混繊型紡糸口金、エアサツカ−、ネツトコンベア−、加熱機等を備えた混繊スパンボンド紡糸機を用い、繊維の交点が熱融着した不織布を製造した。使用した口金は一個の口金に孔径０．４ｍｍの第一成分紡糸孔と孔径０．４ｍｍの第二成分紡糸孔が均等に分散して穿孔された孔数比１／１の混繊型紡糸口金であった。第一成分として融点１２２℃、ＭＦＲ２４（１９０℃、ｇ／１０分）の線状低密度ポリエチレンを用い、第二成分として融点１６４℃、ＭＦＲ６５（２３０℃、ｇ／１０分）のポリプロピレンを用い、第一成分の紡糸温度２１０℃、第二成分の紡糸温度２６０℃、混繊比５０／５０（重量％）の条件で紡糸し、エアサツカ−で牽引し繊維をエア−と共にネツトコンベア−に吹き付けた。得られたウエブは紡糸直後に二種の長繊維が均一に混繊したウエブであつた。該ウエブは繊度１．７ｄ／ｆ、繊度斑６１％であつた。
該ウエブをスル−エア−型加熱機で温度１２５℃で加熱し、繊維の交点が線状ポリエチレン繊維で熱融着した不織布を得た。該不織布は目付け１９ｇ／ｍ²であつた。
融点１３３℃の高密度ポリエチレンと融点１６４℃のポリプロピレンからなる複合比５０／５０重量％の並列型複合繊維を用い、目付け１９ｇ／ｍ²のカ−ドウエブを作製した。この複合繊維は単糸繊度１．５ｄ／ｆ、繊維長５１ｍｍ、捲縮数１１山／２５ｍｍの立体捲縮を有する物であつた。
【００３０】
前記混繊スパンボンド不織布とカ−ドウエブを積層し、スル−エア−型加熱機を用い、温度１３５℃で加熱し、両層が熱融着した二層構造の積層不織布を得た。この熱処理でカ−ドウエブの単繊維同士も熱融着しているのが確認された。該積層不織布は両手で揉んでも剥離しない物であつた。
該積層不織布は熱処理により、目付けがわずかに上昇し、４０ｇ／ｍ²であつた。該積層不織布は横強力２．９９ｋｇ／５ｃｍ、通気度５２２ｃｍ³／ｃｍ²／秒、比容積６４ｃｍ³／ｇ、風合いが良であつた。
【００３１】
実施例２
前記実施例１と同様の製法で混繊スパンボンド不織布を製造した。用いた熱可塑性樹脂は、第一成分として融点１３４℃、ＭＦＲ３８（２３０℃、ｇ／１０分）のプロピレン・エチレン・ブテン−１三元共重合体を用い、第二成分として融点１６３℃、ＭＦＲ８３（２３０℃、ｇ／１０分）のポリプロピレンを用い、第一成分の紡糸温度２８０℃、第二成分の紡糸温度２８０℃、混繊比５０／５０（重量％）の条件で紡糸し、エアサツカ−で牽引し繊維をエア−と共にネツトコンベア−に吹き付けた。得られたウエブは紡糸直後に二種の長繊維が均一に混繊したウエブであつた。該ウエブは繊度１．３ｄ／ｆ、繊度斑４０％であつた。
該ウエブをスル−エア−型加熱機で温度１３８℃で加熱し、繊維の交点が線状ポリエチレン繊維で熱融着した不織布を得た。該不織布は目付け２０ｇ／ｍ²であつた。
融点１３４℃のプロピレン・エチレン・ブテン−１三元共重合体と融点１６４℃のポリプロピレンからなる複合比５０／５０重量％の鞘芯型複合繊維を用い、目付け１８ｇ／ｍ²のカ−ドウエブを作製した。この複合繊維は単糸繊度１．８ｄ／ｆ、繊維長３８ｍｍ、捲縮数１４山／２５ｍｍのジグザク捲縮を有する物であつた。
【００３２】
前記混繊スパンボンド不織布とカ−ドウエブを積層し、スル−エア−型加熱機を用い、温度１４２℃で加熱し、両層が熱融着した二層構造の積層不織布を得た。この熱処理でカ−ドウエブの単繊維同士も熱融着しているのが確認された。該積層不織布は両手で揉んでも剥離しない物であつた。
該積層不織布は熱処理により、目付けがわずかに上昇し、４１ｇ／ｍ²であつた。該積層不織布は横強力２．３３ｋｇ／５ｃｍ、通気度３７７ｃｍ³／ｃｍ²／秒、比容積６０ｃｍ³／ｇ、風合いが良であつた。
【００３３】
実施例３
前記実施例１同様の製法で混繊スパンボンド不織布を製造した。用いた熱可塑性樹脂は、第一成分として融点１６４℃、ＭＦＲ４５（２３０℃、ｇ／１０分）のポリプロピレンを用い、第二成分として融点２５７℃のポリエチレンテレフタレ−トを用い、第一成分の紡糸温度２８０℃、第二成分の紡糸温度３００℃、混繊比５０／５０（重量％）の条件で紡糸し、エアサツカ−で牽引し繊維をエア−と共にネツトコンベア−に吹き付けた。得られたウエブは紡糸直後に二種の長繊維が均一に混繊したウエブであつた。該ウエブは繊度３．３ｄ／ｆ、繊度斑９５％であつた。
該ウエブを凸部面積１４％のエンボスロ−ルとフラツトロ−ルからなる熱圧着装置を用い、エンボスロ−ル温度１４０℃、フラツトロ−ル温度１３６℃の条件で熱圧着処理し、熱融着した不織布を得た。該不織布は目付け１９ｇ／ｍ²であつた。繊度１．５ｄ／ｆ、繊維長５１ｍｍ、捲縮数１４山／２５ｍｍのジグザグ捲縮を有するレ−ヨン７０重量％と、繊度１．５ｄ／ｆ、繊維長５１ｍｍ、捲縮数１３山／２５ｍｍのジグザグ捲縮を有する融点１６３℃のポリプロピレン繊維３０重量％を混合し、目付け２０ｇ／ｍ²のカ−ドウエブを作製した。このウエブを前記同様の熱圧着装置を用い、エンボスロ−ル温度１４５℃、フラツトロ−ル温度１４０℃の条件で熱圧着処理し熱融着した不織布を得た。
【００３４】
前記混繊スパンボンド不織布とカ−ドウエブを積層し、前記に同じ熱圧着装置を用い、エンボスロ−ル温度１４０℃、フラツトロ−ル温度１４０℃で熱圧着処理し、両層が熱融着した二層構造の積層不織布を得た。この二回の熱処理でカ−ドウエブの単繊維同士も少し熱融着しているのが確認された。該積層不織布は両手で揉んでも剥離しない物であつた。
該積層不織布は熱処理により、目付けがわずかに上昇し、４０ｇ／ｍ²であつた。該積層不織布は横強力３．１２ｋｇ／５ｃｍ、通気度２８０ｃｍ³／ｃｍ²／秒、比容積３２ｃｍ³／ｇ、風合いが良であつた。
【００３５】
実施例４
前記実施例１と同様の製法で混繊スパンボンド不織布を製造した。但し用いた口金は一個の口金に孔径０．４ｍｍの第一成分紡糸孔と、孔径０．４ｍｍの第二成分紡糸孔が孔数比で３０／７０に均一に分散して穿孔された混繊型口金であった。用いた熱可塑性樹脂は、第一成分として融点１３３℃、ＭＦＲ３２（１９０℃、ｇ／１０分）の高密度ポリエチレン９５重量％と融点１６４℃、ＭＦＲ７１（２３０℃、ｇ／１０分）のポリプロピレン５重量％を混合した物を用い、第二成分として融点１６２℃、ＭＦＲ８１のポリプロピレンを用い、第一成分の紡糸温度２６０℃、第二成分の紡糸温度２９０℃、混繊比３０／７０（重量％）の条件で紡糸し、エアサツカ−で牽引し繊維をエア−と共にネツトコンベア−に吹き付けた。得られたウエブは紡糸直後に二種の長繊維が均一に混繊したウエブであつた。該ウエブは繊度２．０ｄ／ｆ、繊度斑７４％であつた。該ウエブは目付け２０ｇ／ｍ²であつた。
融点１３３℃の高密度ポリエチレンと融点１６５℃のポリプロピレンからなる複合比６０（鞘）／４０（芯）重量比の偏心鞘芯型複合繊維を用い、目付け２０ｇ／ｍ²のカ−ドウエブを作製した。この複合繊維は単糸繊度１．５ｄ／ｆ、繊維長３８ｍｍ、捲縮数１２山／２５ｍｍの立体捲縮を有する物であつた。
【００３６】
前記未熱処理の混繊スパンボンドウエブとカ−ドウエブを積層し、前記に同じ熱圧着装置を用い、エンボスロ−ル温度１２５℃、フラツトロ−ル温度１１８℃で熱圧着処理し、両層が熱圧着した二層構造の積層不織布を得た。この熱処理で混繊スパンボンド不織布及びカ−ド不織布は熱圧着部以外の部位も少し繊維同士の熱融着が認められた。該積層不織布は両手で揉んでも剥離しない物であつた。該積層不織布は熱処理により、目付けがわずかに上昇し、４２ｇ／ｍ²であつた。該積層不織布は横強力２．１０ｋｇ／５ｃｍ、通気度３０６ｃｍ³／ｃｍ²／秒、比容積４１ｃｍ³／ｇ、風合いが良であつた。
【００３７】
実施例５
前記実施例２で得た混繊スパンボンド不織布と、前記実施例２で得たカ−ドウエブを用い、カ−ドウエブ／スパンボンド不織布／カ−ドウエブの順に積層し、エンボスロ−ルによる三層の熱圧着不織布を製造した。
前記実施例３に記載のエンボスロ−ル熱圧着装置を用い、エンボスロ−ル温度１３５℃、フラツトロ−ル温度１３０℃の条件で熱圧着処理した。この熱処理で混繊スパンボンド不織布及びカ−ド不織布は熱圧着部以外の部位も少し繊維同士の熱融着が認められた。該積層不織布は両手で揉んでも剥離しない物であつた。
該積層不織布は熱処理により、目付けがわずかに上昇し、６１ｇ／ｍ²であつた。該積層不織布は横強力１．９８ｋｇ／５ｃｍ、通気度１２５ｃｍ³／ｃｍ²／秒、比容積３６ｃｍ³／ｇ、風合いが良であつた。
【００３８】
比較例１
単一繊維スパンボンド不織布とカ−ド不織布を積層し、エンボスロ−ル熱圧着した不織布を製造した。
前記実施例１類似の製造法で、押出機一台使用し、孔径０．４ｍｍの単一繊維用紡糸口金を用い、ポリプロピレンスパンボンド不織布を製造した。
融点１６４℃、ＭＦＲ７１（２３０℃、ｇ／１０分）のポリプロピレンを用い、紡糸温度３００℃で紡糸し、エアサツカ−で牽引し繊維をエア−と共にネツトコンベア−に吹き付けた。該ウエブは繊度２．１ｄ／ｆ、繊度斑４０％であつた。
このウエブを一対の金属フラツトロ−ルからなる熱圧着装置を用い、温度１３８℃／１３８℃の条件で熱圧着処理し、繊維同士が熱圧着した不織布を得た。該不織布は目付け１９ｇ／ｍ²であつた。
前記実施例３で用いた単糸繊度１．５ｄ／ｆ、繊維長５１ｍｍ、捲縮数１３山／２５ｍｍのジグザグ捲縮を有するポリプロピレン繊維のみ用い、目付け１９ｇ／ｍ²のカ−ドウエブを得た。前記実施例３記載のエンボスロ−ル熱圧着装置を用い、エンボスロ−ル温度１４５℃、フラツトロ−ル温度１４５℃の条件で熱圧着処理した。この熱処理で熱圧着部以外の部位も少し繊維同士の熱融着が認められた。
【００３９】
前記スパンボンド不織布とカ−ド不織布を積層し、前記実施例３に同じエンボスロ−ル熱圧着装置を用い、エンボスロ−ル温度１４５℃、フラツトロ−ル温度１４５℃の条件で熱圧着処理し、両層が熱圧着した二層構造の積層不織布を得た。該積層不織布は両手で揉んでも剥離しない物であつた。
該積層不織布は熱処理により、目付けがわずかに上昇し、４０ｇ／ｍ²であつた。該積層不織布は横強力３．３２ｋｇ／５ｃｍ、通気度５２ｃｍ³／ｃｍ²／秒、比容積１４ｃｍ³／ｇ、風合いが不良であつた。この不織布は通気度、嵩高性、風合いが何れも劣るので、紙おむつ等の表面材には使用不可能と判断された。
【００４０】
比較例２
単一繊維スパンボンド不織布とカ−ド不織布を積層し、エンボスロ−ル熱圧着した不織布を製造した。
スパンボンド不織布は前記比較例１類似の製造法で、押出機一台使用し、孔径０．４ｍｍの単一繊維用紡糸口金を用い、高密度ポリエチレンとポリプロピレンの混合樹脂スパンボンド不織布を製造した。
融点１３３℃、ＭＦＲ３２（１９０℃、ｇ／１０分）の高密度ポリエチレン９５重量％と融点１６４℃、ＭＦＲ７１（２３０℃、ｇ／１０分）のポリプロピレン５重量％を混合した物を用い、紡糸温度２８０℃で紡糸し、エアサツカ−で牽引し繊維をエア−と共にネツトコンベア−に吹き付けた。該ウエブは繊度３．２ｄ／ｆ、繊度斑８８％、目付け２２ｇ／ｍ²であつた。
このウエブを前記実施例３に同じエンボスロ−ル熱圧着装置を用い、エンボスロ−ル温度１２３℃、フラツトロ−ル温度１２３℃の条件で熱圧着処理し、繊維同士が熱圧着した不織布を得た。該不織布は目付け２２ｇ／ｍ²であつた。この熱圧着処理で熱圧着部以外の部位も多く繊維同士の熱融着が認められた。又随所に繊維が溶融し膜状化した物が認められた。
前記実施例４で用いた単糸繊度１．５ｄ／ｆ、繊維長３８ｍｍ、捲縮数１２山／２５ｍｍの立体捲縮を有する、高密度ポリエチレン／ポリプロピレン偏心鞘芯型複合繊維を用い、目付け２４ｇ／ｍ²のカ−ドウエブを作製した。
【００４１】
前記スパンボンド不織布と前記カ−ド不織布とを、カ−ド不織布／スパンボンド不織布／カ−ド不織布の順に積層し前記に同じエンボスロ−ル熱圧着装置を使用し、エンボスロ−ル温度１２７℃、フラツトロ−ル温度１２７℃の条件で熱圧着処理し、繊維が熱圧着した三層構造の不織布を得た。該不織布は熱処理により目付けがわずかに上昇し、７４ｇ／ｍ²であつた。該積層不織布は横強力４．１８ｋｇ／５ｃｍ、通気度３８ｃｍ³／ｃｍ²／秒、比容積１２ｃｍ³／ｇ、風合いが不良であつた。この不織布は通気度、嵩高性、風合いが何れも劣るので、紙おむつ等の表面材には使用不可能と判断された。
【００４２】
比較例３
単糸繊度の異なる二種のポリプロピレン単一繊維スパンボンド不織布を積層し、エンボスロ−ル熱圧着処理した積層不織布を製造した。
前記比較例１と同様の方法で細繊度ポリプロピレン単一繊維スパンボンド不織布を製造した。使用したポリプロピレンは前記比較例１に同じ物であつた。但し熱処理は前記実施例３に同じエンボスロ−ル熱圧着装置を使用し、エンボスロ−ル温度１３５℃、フラツトロ−ル温度１３５℃の条件で熱圧着処理した。該不織布は繊度２．１ｄ／ｆ、繊度斑４３％、目付け２０ｇ／ｍ²であつた。
前記同様の方法で太繊度ポリプロピレン単一繊維スパンボンド不織布を製造した。使用したポリプロピレンは前記比較例１に同じ物であつた。但し熱処理は前記同様エンボスロ−ル熱圧着装置を使用し、熱圧着条件も前記同条件１３５℃／１３５℃で熱圧着処理した。該不織布は平均繊度６．９ｄ／ｆ、繊度斑１５８％、目付け２２ｇ／ｍ²であつた。
【００４３】
前記二種のスパンボンド不織布を積層し、前記に同じエンボスロ−ル熱圧着装置を用い、エンボスロ−ル温度１３５℃、フラツトロ−ル１３５℃の条件で熱圧着処理した。該不織布は熱処理により目付けがわずかに上昇し、４３ｇ／ｍ²であつた。該積層不織布は横強力２．９８ｋｇ／５ｃｍ、通気度６９ｃｍ³／ｃｍ²／秒、比容積１１ｃｍ³／ｇ、風合いが不良であつた。この不織布は通気度、嵩高性、風合いが何れも劣るので、紙おむつ等の表面材には使用不可能と判断された。
【００４４】
比較例４
ポリエチレン単一繊維スパンボンド不織布とポリプロピレン単一繊維スパンボンド不織布を積層し、スル−エア−型加熱機で熱処理した積層不織布を製造した。
前記比較例２で得られた繊度３．２ｄ／ｆの高密度ポリエチレンとポリプロピレン混合樹脂スパンボンド不織布と前記比較例３で得られた繊度２．１ｄ／ｆのポリプロピレンスパンボンド不織布を積層し、前記実施例１に同じスル−エア−熱処理機を用い温度１４０℃で加熱し、両層が熱融着した二層構造の積層不織布を得た。又ポリエチレンスパンボンド不織布は随所に繊維が溶融し膜状化した物が認められた。該積層不織布は両手で揉んでも剥離しない物であつた。
該積層不織布は熱処理により、目付けが上昇し、５４ｇ／ｍ²であつた。又ポリエチレンスパンボンド不織布は随所に繊維が溶融し膜状化した物が認められた。又積層不織布全体が多数の皺が発生していた。該積層不織布は横強力２．６６ｋｇ／５ｃｍ、通気度９２ｃｍ³／ｃｍ²／秒、比容積２５ｃｍ³／ｇ、風合いが不良であつた。この不織布は通気度や嵩高性が比較的良いが、風合いが劣るので、紙おむつ等の表面材には使用不可能と判断された。
【００４５】
実施例６
市販されている紙おむつを用い、この紙おむつの表面材のみ前記実施例１記載の積層不織布を用いた新規紙おむつを製造した。この紙おむつは液漏れ防止用裏面材としてポリエチレンシ−トが使用され、該裏面材の上部にパルプ及び高分子吸水剤がテイシュで包まれた液吸収材があり、その上部にポリプロピレン短繊維カ−ド不織布が使用された物であつた。なおこの表面材はエンボスロ−ルで熱圧着された不織布であり、目付け２１ｇ／ｍ²、横強力が０．８７ｋｇ／５ｃｍ（４０ｇ／ｍ²換算）、比容積２７ｃｍ³／ｇ、であつた。この紙おむつから表面材をナイフで切りとりながら除去した。除去した表面材に代えて、前記実施例４で得た二層構造の不織布をそのカ−ド不織布が肌側（表面層）となるように積層し、更に紙おむつの周辺部を幅３ｍｍ熱圧着し、裏面材と表面材とを熱圧着し、本発明の紙おむつを得た。この紙おむつは嵩高で、横強力が大でしかも風合いが良い物であつた。又尿の吸収性が良い物であつた。
【００４６】
【発明の効果】
本発明の積層不織布は融点差のある少なくとも二種の長繊維が混繊し且つ熱融着した混繊スパンボンド不織布と、カ−ド不織布が積層し且つその両層で熱融着一体化された不織布である。しかもこの積層不織布は通気度や比容積が特定の範囲に設定された不織布である。そのため本発明の積層不織布は通気度や嵩高性が優れると共に積層面で剥離しにくく、横強力が大で風合いが柔らかいという効果を合わせ持つ。従って、本発明の積層不織布を用いた吸収性物品は上記不織布の特性をもつものである。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laminated nonwoven fabric. More specifically, the present invention relates to a multilayer nonwoven fabric in which a mixed fiber spunbond nonwoven fabric and a card nonwoven fabric are laminated. This non-woven fabric is used as a material for absorbent articles such as paper diapers and sanitary napkins, as a sheet for haps, as a filter, for clothing, wipers and building materials.
[0002]
[Prior art]
Spunbond long-fiber non-woven fabrics have been used as base fabrics for carpets, agricultural cover sheets, and the like because they can be manufactured at low cost and have no fuzz. However, this nonwoven fabric has a problem that the bulkiness is inferior and the texture is paper-like and inferior in flexibility. Attempts have also been made to improve the texture of spunbonded nonwoven fabrics by reducing the fineness. However, along with the increase in fineness, single yarn breakage occurs during spinning and thick yarns are mixed, or mutual fibers at the time of yarn breakage are mixed. There is a problem in that bundle-like fibers are mixed by heat fusion and the texture is further deteriorated.
[0003]
Japanese Patent Laid-Open No. 54-134177 discloses a melt blown nonwoven fabric made of polypropylene microfibers, and Japanese Patent Laid-Open No. 62-299501 discloses a paper diaper using a melt blown nonwoven fabric as a surface material. The melt blown non-woven fabric has the advantage that the fiber diameter is thin and the texture is soft, but there are problems of poor breathability and non-woven fabric strength.
[0004]
JP-A-2-111458 discloses a nonwoven fabric obtained by laminating a spunbond nonwoven fabric and a melt blown nonwoven fabric. Such a nonwoven fabric has a softer texture than a conventional single-layer nonwoven fabric, but has a problem that the bulkiness is inferior and the air permeability is small. Moreover, since the long fiber which comprises a spun bond nonwoven fabric is a single fiber, it peels easily on a lamination surface. There is also a problem that the nonwoven fabric has low strength. In the present invention, the term “single fiber” is a term used for a composite fiber, and refers to a fiber composed of a single component. When a single resin is used, or two or more resins are used in an extruder. There is a case where it is mixed before entering the inside and constitutes one component.
[0005]
[Problems to be solved by the invention]
An object of the present invention is to provide a laminated nonwoven fabric that solves the above-mentioned problems and is excellent in air permeability and bulkiness and has a soft texture. It is another object of the present invention to provide a laminated nonwoven fabric that has a large nonwoven fabric strength and is difficult to peel off on the laminated surface. Furthermore, it is providing the absorbent article using the said laminated nonwoven fabric.
[0006]
[Means for solving the problems]
The present invention includes the following items.
(1) A non-woven fabric having a multilayer structure in which a mixed fiber spunbonded nonwoven fabric and a carded nonwoven fabric are laminated, and the mixed fiber spunbonded nonwoven fabric has a low melting point long fiber 10 to 90 made of a resin having a melting point difference of 10 ° C. or more. The nonwoven fabric is a non-woven fabric in which 90% by weight and high-melting-length long fibers are mixed with each other and 90 to 10% by weight of the low-melting-length long fibers, and the fiber intersection is thermally fused. The mixed fiber spunbonded nonwoven fabric and the carded nonwoven fabric are heat-sealed at least one of the low melting point long fibers of the mixed fiber spunbonded nonwoven fabric and the short fibers of the carded nonwoven fabric. And air permeability 80-2000cm ^Three / Cm ² / Second, specific volume 15-70cm ^Three / G, laminated nonwoven fabric.
(2) The mixed fiber spunbond nonwoven fabric is composed of mixed filaments having an average fineness of 0.4 to 10 d / f, the card nonwoven fabric is composed only of heat-bondable staple fibers, and the heat-bondable staple fibers are The intersection is a non-woven fabric that is heat-sealed, and the lateral strength of the laminated non-woven fabric is 1.2 kg / 5 cm or more, and the air permeability is 85 to 1300 cm. ^Three / Cm ² / Second, specific volume 15-65cm ^Three / G, The laminated nonwoven fabric according to item (1).
(3) The mixed fiber spunbonded nonwoven fabric is composed of mixed continuous fibers having an average fineness of 0.4 to 10 d / f, and the carded nonwoven fabric is mixed with at least 10% by weight of heat-bondable short fibers and other short fibers. A non-woven fabric which is made of the above-mentioned fibers and has a heat-bondable short fiber whose fiber intersection is heat-sealed. The lateral strength of the laminated non-woven fabric is 1.2 kg / 5 cm or more, and the air permeability is 85 to 1300 cm. ^Three / Cm ² / Second, specific volume 15-65cm ^Three / G, The laminated nonwoven fabric according to item (1).
(4) The laminated nonwoven fabric according to any one of (1) to (3), wherein the mixed fiber spunbonded nonwoven fabric is a mixed fiber having a fineness of 150% or less.
(5) The mixed fiber spunbonded nonwoven fabric is a nonwoven fabric in which a mixed fiber spinneret is used, and a low melting point long fiber and a high melting point long fiber are uniformly mixed and spun immediately after spinning. The laminated nonwoven fabric according to any one of the above.
(6) The card nonwoven fabric is a nonwoven fabric composed of single short fibers having at least one of two-dimensional and three-dimensional crimps, and the fibers are heat-sealed at their intersections (1) to ( The laminated nonwoven fabric according to any one of 5).
(7) The card nonwoven fabric comprises 10 to 90% by weight of a low melting point resin and 90 to 10% by weight of a high melting point resin having at least one of two-dimensional and three-dimensional crimps and having a melting point difference of 10 ° C. or more. Any one of the items (1) to (5), wherein the low melting point resin is a non-woven fabric comprising a composite fiber that forms at least a part of the fiber surface, and the fiber intersection is thermally fused with the low melting point resin of the fiber. The laminated nonwoven fabric described in 1.
(8) The card nonwoven fabric has at least one of two-dimensional and three-dimensional crimps and has a melting point difference of 10 ° C. or more and 10 to 90% by weight of low melting point fibers and 90 to 10% by weight of high melting point fibers. The laminated nonwoven fabric according to any one of (1) to (5), wherein the laminated nonwoven fabric is a nonwoven fabric that is mixed and thermally fused at the fiber intersection.
(9) The at least one long fiber of the mixed fiber spunbonded nonwoven fabric and the at least one fiber of the carded nonwoven fabric are selected from polyethylene, a crystalline copolymer of propylene and another α-olefin, and polypropylene. The laminated nonwoven fabric according to any one of (1) to (8), which is a fiber using a polyolefin resin.
(10) The laminated nonwoven fabric according to any one of (1) to (9), wherein the fiber-intersection is heat-sealed between the mixed fiber spunbonded nonwoven fabric and the carded nonwoven fabric by heat through air.
(11) The laminated nonwoven fabric according to any one of (1) to (9), wherein a mixed fiber spunbond nonwoven fabric and a card nonwoven fabric are thermocompression bonded with an embossing roll having a convex area of 5 to 25%.
(12) An absorbent article in which the laminated nonwoven fabric described in any one of (1) to (11) is used as at least one material constituting the absorbent article.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The laminated nonwoven fabric of the present invention is a multilayered nonwoven fabric in which a mixed fiber spunbond nonwoven fabric and a short fiber carded nonwoven fabric are laminated and both are heat-sealed. When the nonwoven fabric is used as a surface material or wiper of a paper diaper, 2 to 4 layers are used. When a filter is used, 2 to 8 layers are used. In most cases, however, 2-4 layers are used.
[0008]
The mixed fiber spunbond nonwoven fabric used for the laminated nonwoven fabric of the present invention is a low-melting long fiber in which at least two types of thermoplastic resins having a melting point difference of 10 ° C. or more are spun by the mixed fiber spunbond method, It is a heat-bonded long fiber. The upper limit of the melting point difference is not particularly a problem in the practice of the present invention.
The mixed fiber spunbond method is a method in which a plurality of thermoplastic resins are melt-extruded from a plurality of extruders, and a plurality of thermoplastic long fibers are separately discharged from each spinning hole of a mixed fiber spinning base. Taken with an air traction type traction device such as an air sucker, sprays long fibers together with the air current onto a collection device such as a net conveyor, and then heats the web using a heating device such as heated air or a heating roll, This is a method for producing a nonwoven fabric by forming the intersection at a nonwoven fabric by thermal fusion of low melting point long fibers. Of course, in the heat fusion, not only the low-melting long fibers but also the high-melting long fibers may be heat-sealed. In addition, after spinning and spinning the mixed fiber long fiber from the spinning process to the web collecting step, the mixed fiber long fiber is taken together with the air flow by a pulling device such as an air sucker and the web collecting device such as a net conveyor. And then heat-treating the web in the same manner as described above to produce a heat-sealed nonwoven fabric.
As the thermoplastic resin used for spinning, 2 to 4 types of thermoplastic resins can be used practically, and any combination of resins having a difference between the highest melting point and the lowest melting point of 10 ° C. or more may be used. But for most applications, two are sufficient.
[0009]
The resin used for the long fibers of the mixed fiber spunbonded nonwoven fabric is not particularly limited as long as it is a thermoplastic resin that can be melt-spun. For example, crystalline random copolymers of propylene and other α-olefins such as polyethylene, polypropylene, linear low density polyethylene, two- or three-component copolymers composed of propylene / ethylene or propylene / ethylene / butene-1. Polyolefins such as nylon, polyamides such as nylon-6 and nylon-66, low melting point polyesters such as polyethylene terephthalate, polybutylene terephthalate, poly (ethylene terephthalate-co-isophthalate), polyester Examples thereof include polyesters such as elastomers, fluorine resins, polyphenylene sulfide, mixtures of the above resins, and other thermoplastic resins that can be spun.
[0010]
The combination of the thermoplastic resins in the mixed fiber spunbond spinning is a combination of resins having a difference in melting point of 10 ° C. or more. For example, high density polyethylene / polypropylene, linear low density polyethylene / polypropylene, propylene / ethylene / butene-1 crystalline copolymer / polypropylene, propylene / ethylene crystalline copolymer / polypropylene, high density polyethylene / polyethylene terephthalate Low melting point polyester / polyethylene terephthalate, polypropylene / polyethylene terephthalate, propylene / ethylene / butene-1 crystalline copolymer / polyethylene terephthalate, polyvinylidene fluoride / polyethylene terephthalate, low Examples thereof include a mixture of density polyethylene and high density polyethylene / polypropylene.
[0011]
The mixed fiber state of each long fiber of the mixed fiber spunbonded nonwoven fabric may be a state in which the low melting point long fiber and the high melting point long fiber are mixed substantially uniformly. For example, in a single spinneret, a micro uniform mixture in which each spinning hole is dispersed and perforated so that the A component spinning hole has a hole ratio of 10 to 90% and the B component spinning hole becomes 90 to 10%. A spinning device equipped with a fine spinneret can be used. Further, a spinning device having a spinneret having only the A component spinning hole and a spinneret having only the B component spinning hole can be used in combination.
[0012]
In the mixed fiber spunbonded nonwoven fabric, the mixing ratio of the low melting point long fiber and the high melting point long fiber is 10 to 90% by weight for the low melting point long fiber and 90 to 10% by weight for the high melting point long fiber. Preferably, the low melting point long fiber is 30 to 70% by weight and the high melting point long fiber is 70 to 30% by weight. When the low melting point long fiber is less than 10% by weight, thermal fusion of the mixed fiber spunbonded nonwoven fabric itself is insufficient, or thermal fusion at the laminated surface of the nonwoven fabric and the carded nonwoven fabric is insufficient. There are problems such as peeling of the fabric and insufficient strength of the nonwoven fabric. There is also a problem of non-woven fabric fluff. Further, when the low melting point long fiber is 90% by weight or more, the peel strength of the laminated nonwoven fabric is increased, but there is a problem that air permeability, bulkiness and the like are all lowered.
[0013]
There is no special restriction on the fineness of the long fibers of the mixed fiber spunbonded nonwoven fabric. When the use of the laminated nonwoven fabric is used for paper diapers, sanitary napkins, etc., it is 0.2 to 12 d / f, 0.5 to 20 d / f for wipers, and 0.2 to 3000 d / f for filters. . However, the fineness is most preferably in the range of 0.3 to 10 d / f.
The long fibers constituting the mixed fiber spunbonded nonwoven fabric preferably have a fineness unevenness of 150% or less. This fineness unevenness is more preferably 120% or less. When the fineness unevenness is large, when the nonwoven fabric is used for a disposable diaper or the like, the texture is inferior and skin irritation occurs. In particular, when used for disposable diapers for newborns, it is necessary to avoid skin irritation and the like.
The basis weight of the nonwoven fabric is not particularly limited, but it is 4 to 1000 g / m from the viewpoint of uniformity of the nonwoven fabric and uniform heating during heat treatment described later. ² It is. 4 to 70 g / m when used for absorbent articles such as disposable diapers ² When used for wipers, etc., 10 to 600 g / m ² 20-1000 g / m when used in filters ² It is.
[0014]
The mixed fiber spunbond nonwoven fabric uses a heat treatment machine such as a heat-through air heater, an alternating hot air jet type heater, an ultrasonic heater, a heat calender roll, a heat emboss roll, etc. Heating to a temperature equal to or higher than the heat-sealing temperature, the fibers are heat-sealed to form a non-woven fabric with high strength. When a hot embossing roll is used, a product having a convex area of 5 to 35% is preferable. The convex area is preferably 10 to 30%, more preferably 12 to 27%. If the convex area is less than 10%, the strength of the nonwoven fabric is small, and if it exceeds 35%, the air permeability and bulkiness are poor. In the case of the present invention, it is preferable that the nonwoven fabric strength is 1000 g / 5 cm or more in the transverse direction, that is, in the width direction. A high-strength nonwoven fabric can be obtained by controlling the processing conditions such as the temperature during the heat treatment.
[0015]
The card nonwoven fabric laminated on the mixed fiber spunbond is crimped and a nonwoven fabric is formed after forming a web of short fibers having a fiber length of 25 to 128 mm using a card machine. The fiber length of the short fibers is preferably 28 to 115 mm, more preferably 30 to 89 mm. When the short fiber has a fiber length of less than 25 mm or exceeds 128 mm, the carding machine deteriorates so that a uniform nonwoven fabric cannot be obtained. In addition, short fibers are entangled with the card cloth of the carding machine, making continuous production difficult. In addition, there is a problem that, for example, a lump-like fiber bundle semi-melted by a card machine is generated and mixed with the nonwoven fabric.
[0016]
As the short fiber, any fiber such as a thermoplastic fiber, a natural fiber, and a recycled fiber can be used as long as the fiber has a crimp such as a two-dimensional crimp or a three-dimensional crimp. Either single fiber or composite fiber can be used. The number of crimps may be 1 to 35/25 mm. The number of crimps is preferably 3-25 peaks / 25 mm. When the number of crimps is less than 1 crest / 25 mm or more than 35 crests / 25 mm, card passing property, bulkiness, etc. are inferior. It is also possible to use a mixture of two or more kinds of the short fibers. In this case, if the card is possible, the short fibers to be mixed are mainly fibers with crimps, and the other fibers are crimped. Non-fibres may be used.
[0017]
The short fiber used for the card nonwoven fabric is not particularly limited in the single yarn fineness. However, fibers having a single yarn fineness of 0.2 to 3000 d / f can be suitably used in terms of cardability when a web is produced using a card machine. When used for paper diapers, sanitary napkins, etc. where texture is important, 0.2 to 12 d / f for wipers, 0.5 to 20 d / f for wipers, and 0.2 to 3000 d / f for filters. . However, the fineness is most preferably in the range of 0.3 to 10 d / f.
[0018]
The short fibers are made of various thermoplastic resins such as cotton, hemp, rayon, acetate, etc., cellulose fibers, polypropylene fibers, polyamide fibers, polyester fibers, etc. and the above-mentioned mixed fiber spunbonds. A single fiber or the like obtained by fiberizing can be used. Moreover, the composite fiber of the combination of various resin can be used using the thermoplastic resin which was illustrated to the said mixed fiber spun bond. As the composite fiber, any of a parallel type, a sheath core type, a sea island type, and the like can be used. When the thermoplastic resin combination is a heat-fusible conjugate fiber having a melting point difference of 10 ° C. or more and the low melting point thermoplastic resin forming part of the fiber surface, a nonwoven fabric having high strength can be obtained. Further, the heat treatment after the lamination described later makes the thermal fusion with the mixed fiber spunbonded nonwoven fabric stronger, and it is possible to obtain a laminated nonwoven fabric which is difficult to peel off and has a strong nonwoven fabric strength.
[0019]
Specific examples of the heat-fusible composite fiber include high-density polyethylene / polypropylene, linear low-density polyethylene / polypropylene, propylene / ethylene / butene-1 crystalline copolymer / polypropylene, and propylene / ethylene crystalline copolymer. / Polypropylene, high density polyethylene / polyethylene terephthalate, low melting point polyester / polyethylene terephthalate, polypropylene / polyethylene terephthalate, propylene / ethylene / butene-1 crystalline copolymer / polyethylene terephthalate, Examples thereof include polyvinylidene fluoride / polyethylene terephthalate, a mixture of low density polyethylene and high density polyethylene / polypropylene, and the like.
[0020]
100% by weight of the short fibers or 10 to 90% by weight of short fibers having a low melting point and 90 to 10% by weight of other short fibers having a high melting point are mixed and carded with a card machine to form a web. The web is heated to a temperature equal to or higher than the heat fusion temperature by using a hot air through treatment machine, a heat embossing treatment machine or the like in the same manner as the heat treatment of the mixed fiber spunbond to obtain a nonwoven fabric in which the fibers are thermally fused. When using a heat embossing roll, the thing which is 5 to 35% of convex part area like the said mixed fiber spunbonded nonwoven fabric is preferable. Further, the heat treatment can be obtained by a heat-through air treatment, which is more breathable and bulky than a heat embossing roll treatment.
[0021]
The laminated nonwoven fabric of the present invention is obtained by laminating the mixed fiber spunbond nonwoven fabric and the carded nonwoven fabric, and heating them to a temperature at which both nonwoven fabrics are heat-sealed to form the laminated nonwoven fabric of the present invention. Of course, either a mixed fiber spunbonded nonwoven fabric or a carded nonwoven fabric or both of them may be laminated with a web-like material and heated to a temperature at which both nonwoven fabrics are heat-sealed to form a laminated nonwoven fabric. it can.
The laminated nonwoven fabric has a two-layer structure such as a mixed fiber spunbond nonwoven fabric / card nonwoven fabric, a mixed fiber spunbond nonwoven fabric / card nonwoven fabric / mixed fiber spunbond nonwoven fabric, a card nonwoven fabric / mixed fiber span. 3 layer structure such as bond nonwoven fabric / card nonwoven fabric, 4 layer structure such as mixed fiber spunbond nonwoven fabric / card nonwoven fabric / mixed fiber spunbond nonwoven fabric / card nonwoven fabric, etc. 10 layers can be exemplified. But for most applications it is used in 2-4 layers.
[0022]
The laminated nonwoven fabric of the present invention has an air permeability of 80 to 2000 cm. ^Three / Cm ² / Second, specific volume 15-70cm ^Three / G. The air permeability is preferably 80-1500cm ^Three / Cm ² / Second, more preferably 85 to 1300 cm ^Three / Cm ² / Sec. The air permeability of the laminated nonwoven fabric is 20 to 100 g / m. ² It suffices if the product falls within the above range. This is because the basis weight of the laminated nonwoven fabric is the highest. The specific volume is preferably 15 to 68 cm. ^Three / G, more preferably 15 to 65 cm ^Three / G. When the use of the laminated nonwoven fabric is used for a paper diaper or the like, a material having a relatively high air permeability and specific volume is used. When used for wipers, etc., the air permeability may be relatively low, but a material having a relatively high bulk is used. When used for a filter or the like, a product having a relatively low specific volume may be used, but a product having a relatively high air permeability is used.
[0023]
The laminated nonwoven fabric of the present invention is preferably a nonwoven fabric having a high strength, but the nonwoven fabric is 40 g / m. ² The thing with lateral strength at the time of conversion of 1.2 kg / 5 cm or more is preferable. The nonwoven fabric strength is preferably 1.2 to 15 kg / 5 cm, more preferably 1.4 to 8.0 kg / 5 cm.
[0024]
The laminated nonwoven fabric of the present invention can be used as it is or as a wiper for glasses, furniture, floors, machines, etc. with various lubricants attached. The nonwoven fabric of the present invention can be used as a filter material as it is. Various types of filters can be exemplified. For example, a product obtained by winding the laminated nonwoven fabric around a porous core and processing it into a cylindrical molded body, a product obtained by folding the laminated nonwoven fabric, and the like can be exemplified. While using a porous core or the like, or using a non-porous metal core or the like, while heating the nonwoven fabric at a temperature at which the wound layers are heat-sealed without using the core The thing etc. which were made into the wound cylindrical molded object can be illustrated. When a non-porous metal core is used, the core can be extracted and used for a filter or the like.
[0025]
The absorbent article of the present invention is a product in which the laminated nonwoven fabric is used as a material such as a disposable diaper. For example, the laminated nonwoven fabric can be used as a surface material for paper diapers, used as a material for legs, or used as a backsheet. Moreover, the thing etc. which were used as a packaging material etc. of the liquid absorbent material which mainly consists of pulp of a paper diaper and a polymeric water absorbing material can be illustrated. The paper diaper using the laminated nonwoven fabric of the present invention can be obtained as a paper diaper having excellent texture, air permeability, liquid absorbability and the like.
[0026]
【Example】
Hereinafter, the present invention will be described in detail with reference to examples. In the following examples and the like, the nonwoven fabric and the like were evaluated by the following method.
Fineness and fineness unevenness of spunbond nonwoven fabric: A sample is cut from the web before thermal fusion treatment or the nonwoven fabric after thermal fusion treatment, a micrograph is taken, and the diameter of each of a total of 100 fibers selected arbitrarily is measured. . The single yarn fineness of 100 fibers was calculated from the fiber density, and the average value (X) was defined as the fineness (d / f).
Further, fineness spots were according to the following formula.
Fineness spots (%) = {(A−B) / X} × 100
A: The average value of the fineness of 10 fibers selected in order from the one with the largest fineness among 100 arbitrarily selected fibers.
B: The average value of the fineness of 10 fibers selected in order from the one with the smallest fineness among the 100 selected fibers.
X: Average value of 100 selected single yarn finenesses.
[0027]
Air permeability: Measured by a method defined in JIS-L-1096 using a fragile type tester. Unit cm ^Three / Cm ² Per second.
[0028]
Specific volume: A test piece of 25 cm × 25 cm was cut out from the nonwoven fabric, its basis weight and thickness were measured, and the specific volume was calculated. Unit cm ^Three / G.
[0029]
Example 1
Using a mixed fiber spunbond spinning machine equipped with two extruders, a mixed fiber type spinneret, an air sather, a net conveyor, a heating machine, etc., a nonwoven fabric in which the intersections of the fibers were thermally fused was manufactured. The base used was a mixed fiber type spinneret having a hole ratio of 1/1, in which a first component spinning hole having a hole diameter of 0.4 mm and a second component spinning hole having a hole diameter of 0.4 mm were uniformly dispersed in a single nozzle. Met. Using a linear low density polyethylene having a melting point of 122 ° C. and MFR24 (190 ° C., g / 10 min) as the first component, and using a polypropylene having a melting point of 164 ° C. and MFR65 (230 ° C., g / 10 min) as the second component, Spinning was performed under the conditions of a spinning temperature of 210 ° C. for the first component, a spinning temperature of 260 ° C. for the second component, and a fiber mixing ratio of 50/50 (% by weight), and the fibers were pulled by an air sucker and sprayed onto a net conveyor together with air. . The obtained web was a web in which two types of long fibers were uniformly mixed immediately after spinning. The web had a fineness of 1.7 d / f and fineness spots of 61%.
The web was heated with a through-air heater at a temperature of 125 ° C. to obtain a nonwoven fabric in which the intersections of the fibers were heat-sealed with linear polyethylene fibers. The nonwoven fabric has a basis weight of 19 g / m ² It was hot.
Using a parallel type composite fiber having a composite ratio of 50/50% by weight made of high-density polyethylene having a melting point of 133 ° C. and polypropylene having a melting point of 164 ° C., the basis weight is 19 g / m. ² A card web was prepared. This composite fiber had a three-dimensional crimp of a single yarn fineness of 1.5 d / f, a fiber length of 51 mm, and a number of crimps of 11 peaks / 25 mm.
[0030]
The mixed fiber spunbonded nonwoven fabric and the card web were laminated and heated at a temperature of 135 ° C. using a through-air type heater to obtain a laminated nonwoven fabric having a two-layer structure in which both layers were heat-sealed. It was confirmed that the single fibers of the card web were also thermally fused by this heat treatment. The laminated nonwoven fabric was a material that did not peel even if it was held with both hands.
The laminated nonwoven fabric has a slightly increased basis weight due to heat treatment, and is 40 g / m. ² It was hot. The laminated nonwoven fabric has a transverse strength of 2.99 kg / 5 cm and an air permeability of 522 cm. ^Three / Cm ² / Sec, specific volume 64cm ^Three / G, the texture was good.
[0031]
Example 2
A mixed fiber spunbonded nonwoven fabric was produced by the same production method as in Example 1. The thermoplastic resin used was a propylene / ethylene / butene-1 terpolymer having a melting point of 134 ° C. and MFR38 (230 ° C., g / 10 min) as the first component, and a melting point of 163 ° C. and MFR83 as the second component. (230 ° C., g / 10 min) using polypropylene with a spinning temperature of 280 ° C. for the first component, a spinning temperature of 280 ° C. for the second component, and a fiber mixing ratio of 50/50 (% by weight). Then, the fiber was pulled on the net conveyor together with air. The obtained web was a web in which two types of long fibers were uniformly mixed immediately after spinning. The web had a fineness of 1.3 d / f and fineness spots of 40%.
The web was heated with a through-air heater at a temperature of 138 ° C. to obtain a nonwoven fabric in which the intersections of the fibers were heat-sealed with linear polyethylene fibers. The nonwoven fabric has a basis weight of 20 g / m. ² It was hot.
Using a sheath-core type composite fiber having a composite ratio of 50/50% by weight made of propylene / ethylene / butene-1 terpolymer having a melting point of 134 ° C. and polypropylene having a melting point of 164 ° C., the basis weight is 18 g / m. ² A card web was prepared. This composite fiber had a single yarn fineness of 1.8 d / f, a fiber length of 38 mm, and a zigzag crimp of 14 crests / 25 mm.
[0032]
The mixed fiber spunbonded nonwoven fabric and the card web were laminated and heated at a temperature of 142 ° C. using a through-air type heater to obtain a laminated nonwoven fabric having a two-layer structure in which both layers were heat-sealed. It was confirmed that the single fibers of the card web were also thermally fused by this heat treatment. The laminated nonwoven fabric was a material that did not peel even if it was held with both hands.
The laminated nonwoven fabric has a slightly increased basis weight due to heat treatment, and is 41 g / m. ² It was hot. The laminated nonwoven fabric has a transverse strength of 2.33 kg / 5 cm and an air permeability of 377 cm. ^Three / Cm ² / Second, specific volume 60cm ^Three / G, the texture was good.
[0033]
Example 3
A mixed fiber spunbonded nonwoven fabric was produced in the same manner as in Example 1. The thermoplastic resin used was polypropylene having a melting point of 164 ° C. and MFR45 (230 ° C., g / 10 min) as the first component, and polyethylene terephthalate having a melting point of 257 ° C. as the second component. Spinning was carried out under the conditions of a spinning temperature of 280 ° C., a spinning temperature of the second component of 300 ° C., and a blending ratio of 50/50 (% by weight). The fiber was pulled by an air sucker and sprayed onto a net conveyor together with air. The obtained web was a web in which two types of long fibers were uniformly mixed immediately after spinning. The web had a fineness of 3.3 d / f and fineness unevenness of 95%.
A nonwoven fabric obtained by heat-bonding the web using a thermocompression bonding apparatus composed of an embossing roll and a flat roll having a convex area of 14% under conditions of an embossing roll temperature of 140 ° C. and a flat roll temperature of 136 ° C. Got. The nonwoven fabric has a basis weight of 19 g / m ² It was hot. 70% by weight of a rayon having a zigzag crimp with a fineness of 1.5 d / f, a fiber length of 51 mm, and a crimp number of 14 peaks / 25 mm, a fineness of 1.5 d / f, a fiber length of 51 mm, and a crimp number of 13 peaks / 25 mm 30% by weight of polypropylene fibers having a zigzag crimp of 163 ° C. and a melting point of 163 ° C. were mixed, and the basis weight was 20 g / m. ² A card web was prepared. Using this thermocompression bonding apparatus, the web was subjected to thermocompression bonding under the conditions of an embossing roll temperature of 145 ° C. and a flat roll temperature of 140 ° C. to obtain a heat-bonded nonwoven fabric.
[0034]
The mixed fiber spunbonded nonwoven fabric and the card web were laminated, and the same thermocompression bonding apparatus was used for thermocompression bonding at an embossing roll temperature of 140 ° C. and a flat roll temperature of 140 ° C., and both layers were heat-sealed. A laminated nonwoven fabric having a layer structure was obtained. It was confirmed that the single fibers of the card web were slightly heat-sealed by the two heat treatments. The laminated nonwoven fabric was a material that did not peel even if it was held with both hands.
The laminated nonwoven fabric has a slightly increased basis weight due to heat treatment, and is 40 g / m. ² It was hot. The laminated nonwoven fabric has a lateral strength of 3.12 kg / 5 cm, and an air permeability of 280 cm. ^Three / Cm ² / Second, specific volume 32cm ^Three / G, the texture was good.
[0035]
Example 4
A mixed fiber spunbonded nonwoven fabric was produced by the same production method as in Example 1. However, the base used was a mixed fiber in which a first component spinning hole having a hole diameter of 0.4 mm and a second component spinning hole having a hole diameter of 0.4 mm were uniformly dispersed at a ratio of 30/70 in a single base. It was a mold base. The thermoplastic resin used was polypropylene 5 having a melting point of 133 ° C. as the first component, 95% by weight of high-density polyethylene having an MFR of 32 (190 ° C., g / 10 min), a melting point of 164 ° C., and an MFR of 71 (230 ° C., g / 10 min). Using a mixture of weight%, using polypropylene of MFR81, melting point 162 ° C. as the second component, spinning temperature of the first component 260 ° C., spinning temperature of the second component 290 ° C., blending ratio 30/70 (wt% The fiber was spun on an air conveyor and the fibers were sprayed onto a net conveyor together with air. The obtained web was a web in which two types of long fibers were uniformly mixed immediately after spinning. The web had a fineness of 2.0 d / f and fineness spots of 74%. The web has a basis weight of 20 g / m ² It was hot.
Using an eccentric sheath-core type composite fiber having a composite ratio of 60 (sheath) / 40 (core) weight ratio made of high-density polyethylene having a melting point of 133 ° C. and polypropylene having a melting point of 165 ° C., the basis weight is 20 g / m. ² A card web was prepared. The composite fiber had a solid crimp of 1.5 d / f, a fiber length of 38 mm, and a number of crimps of 12 peaks / 25 mm.
[0036]
The unheat-treated mixed fiber spunbond web and the card web are laminated, and using the same thermocompression bonding apparatus, thermocompression treatment is performed at an embossing roll temperature of 125 ° C. and a flat roll temperature of 118 ° C., and both layers are thermocompression bonded. A laminated nonwoven fabric having a two-layer structure was obtained. In this heat treatment, the mixed fiber spunbonded nonwoven fabric and the carded nonwoven fabric showed a slight thermal fusion between the fibers at portions other than the thermocompression bonding portion. The laminated nonwoven fabric was a material that did not peel even if it was held with both hands. The laminated nonwoven fabric has a slightly increased basis weight due to heat treatment, 42 g / m ² It was hot. The laminated nonwoven fabric has a lateral strength of 2.10 kg / 5 cm and a permeability of 306 cm. ^Three / Cm ² / Second, specific volume 41cm ^Three / G, the texture was good.
[0037]
Example 5
Using the mixed fiber spunbonded nonwoven fabric obtained in Example 2 and the card web obtained in Example 2, the card web / spunbond nonwoven fabric / card web were laminated in this order, and three layers were formed by embossing rolls. A thermocompression bonded nonwoven fabric was produced.
Using the embossing roll thermocompression bonding apparatus described in Example 3, thermocompression treatment was performed under conditions of an embossing roll temperature of 135 ° C. and a flat roll temperature of 130 ° C. In this heat treatment, the mixed fiber spunbonded nonwoven fabric and the carded nonwoven fabric showed a slight thermal fusion between the fibers at portions other than the thermocompression bonding portion. The laminated nonwoven fabric was a material that did not peel even if it was held with both hands.
The laminated nonwoven fabric has a slightly increased basis weight due to heat treatment, 61 g / m ² It was hot. The laminated nonwoven fabric has a transverse strength of 1.98 kg / 5 cm and an air permeability of 125 cm. ^Three / Cm ² / Sec, specific volume 36cm ^Three / G, the texture was good.
[0038]
Comparative Example 1
A single fiber spunbonded nonwoven fabric and a carded nonwoven fabric were laminated to produce a nonwoven fabric which was embossed roll thermocompression bonded.
A polypropylene spunbonded non-woven fabric was produced by using a single extruder and a single fiber spinneret with a hole diameter of 0.4 mm by the same production method as in Example 1.
Polypropylene having a melting point of 164 ° C. and MFR 71 (230 ° C., g / 10 min) was spun at a spinning temperature of 300 ° C., pulled by an air sucker, and the fibers were blown onto a net conveyor together with air. The web had a fineness of 2.1 d / f and fineness spots of 40%.
This web was subjected to thermocompression bonding under the conditions of a temperature of 138 ° C./138° C. using a thermocompression bonding apparatus comprising a pair of metal flat rolls to obtain a nonwoven fabric in which the fibers were thermocompression bonded. The nonwoven fabric has a basis weight of 19 g / m ² It was hot.
Using only a polypropylene fiber having a single yarn fineness of 1.5 d / f, a fiber length of 51 mm, and a number of crimps of 13 crests / 25 mm used in Example 3 and a basis weight of 19 g / m ² The card web was obtained. Using the embossing roll thermocompression bonding apparatus described in Example 3, thermocompression bonding was performed under the conditions of an embossing roll temperature of 145 ° C. and a flat roll temperature of 145 ° C. In this heat treatment, some parts other than the thermocompression bonding part were found to be thermally fused to each other.
[0039]
The spunbonded nonwoven fabric and the carded nonwoven fabric are laminated, and the same embossing roll thermocompression bonding apparatus as in Example 3 is used, and thermocompression bonding is performed under the conditions of an embossing roll temperature of 145 ° C and a flat roll temperature of 145 ° C. A laminated nonwoven fabric having a two-layer structure in which the layers were thermocompression bonded was obtained. The laminated nonwoven fabric was a material that did not peel even if it was held with both hands.
The laminated nonwoven fabric has a slightly increased basis weight due to heat treatment, and is 40 g / m. ² It was hot. The laminated nonwoven fabric has a transverse strength of 3.32 kg / 5 cm and an air permeability of 52 cm. ^Three / Cm ² / Sec, specific volume 14cm ^Three / G, the texture was poor. Since this nonwoven fabric was poor in air permeability, bulkiness and texture, it was judged that it could not be used for surface materials such as paper diapers.
[0040]
Comparative Example 2
A single fiber spunbonded nonwoven fabric and a carded nonwoven fabric were laminated to produce a nonwoven fabric which was embossed roll thermocompression bonded.
The spunbonded nonwoven fabric was manufactured in the same manner as in Comparative Example 1, using a single extruder and using a single fiber spinneret with a hole diameter of 0.4 mm to produce a mixed resin spunbonded nonwoven fabric of high-density polyethylene and polypropylene.
Spinning temperature using a mixture of 95% by weight of high-density polyethylene with a melting point of 133 ° C. and MFR32 (190 ° C., g / 10 minutes) and 5% by weight of polypropylene with a melting point of 164 ° C. and MFR71 (230 ° C., g / 10 minutes) The fiber was spun at 280 ° C., pulled by an air suction, and the fibers were blown onto a net conveyor together with air. The web has a fineness of 3.2 d / f, fineness of 88%, and a basis weight of 22 g / m. ² It was hot.
Using the same embossing roll thermocompression bonding apparatus as in Example 3, the web was subjected to thermocompression treatment under conditions of an embossing roll temperature of 123 ° C. and a flat roll temperature of 123 ° C. to obtain a nonwoven fabric in which fibers were thermocompression bonded. The nonwoven fabric has a basis weight of 22 g / m ² It was hot. In this thermocompression treatment, there were many parts other than the thermocompression bonding part, and thermal fusion between fibers was recognized. Moreover, the thing which the fiber melted and became a film form was recognized everywhere.
Using the high-density polyethylene / polypropylene eccentric sheath-core composite fiber having a solid crimp of 1.5 d / f, a fiber length of 38 mm, and a number of crimps of 12 peaks / 25 mm used in Example 4, the basis weight is 24 g. / M ² A card web was prepared.
[0041]
The spunbond non-woven fabric and the card non-woven fabric are laminated in the order of card non-woven fabric / spun bond non-woven fabric / card non-woven fabric, and the same emboss roll thermocompression bonding device is used. Thermocompression treatment was performed under the conditions of a flat roll temperature of 127 ° C. to obtain a nonwoven fabric having a three-layer structure in which fibers were thermocompression bonded. The nonwoven fabric has a slightly increased basis weight due to heat treatment and is 74 g / m. ² It was hot. The laminated nonwoven fabric has a lateral strength of 4.18 kg / 5 cm and a permeability of 38 cm. ^Three / Cm ² / Second, specific volume 12cm ^Three / G, the texture was poor. Since this nonwoven fabric was poor in air permeability, bulkiness and texture, it was judged that it could not be used for surface materials such as paper diapers.
[0042]
Comparative Example 3
Two types of polypropylene single fiber spunbond nonwoven fabrics having different single yarn finenesses were laminated to produce a laminated nonwoven fabric subjected to an embossing roll thermocompression treatment.
A fine-fineness polypropylene single fiber spunbonded nonwoven fabric was produced in the same manner as in Comparative Example 1. The polypropylene used was the same as in Comparative Example 1 above. However, the same embossing roll thermocompression bonding apparatus as in Example 3 was used for heat treatment, and thermocompression bonding was performed under the conditions of an embossing roll temperature of 135 ° C. and a flat roll temperature of 135 ° C. The nonwoven fabric has a fineness of 2.1 d / f, fineness unevenness of 43%, and a basis weight of 20 g / m. ² It was hot.
A high-fineness polypropylene single fiber spunbonded nonwoven fabric was produced in the same manner as described above. The polypropylene used was the same as in Comparative Example 1 above. However, the heat treatment was performed using an embossing roll thermocompression bonding device as described above, and the thermocompression bonding was performed under the same conditions of 135 ° C / 135 ° C. The nonwoven fabric has an average fineness of 6.9 d / f, fineness unevenness of 158%, and a basis weight of 22 g / m. ² It was hot.
[0043]
The two types of spunbonded nonwoven fabrics were laminated and subjected to thermocompression treatment using the same embossing roll thermocompression bonding device under the conditions of embossing roll temperature of 135 ° C. and flat roll 135 ° C. The nonwoven fabric has a slightly increased basis weight due to heat treatment and is 43 g / m ² It was hot. The laminated nonwoven fabric has a lateral strength of 2.98 kg / 5 cm and an air permeability of 69 cm. ^Three / Cm ² / Sec, specific volume 11cm ^Three / G, the texture was poor. Since this nonwoven fabric was poor in air permeability, bulkiness and texture, it was judged that it could not be used for surface materials such as paper diapers.
[0044]
Comparative Example 4
A polyethylene single fiber spunbond nonwoven fabric and a polypropylene single fiber spunbond nonwoven fabric were laminated, and a laminated nonwoven fabric was manufactured by heat treatment with a through-air type heating machine.
The high-density polyethylene and polypropylene mixed resin spunbond nonwoven fabric having a fineness of 3.2 d / f obtained in Comparative Example 2 and the polypropylene spunbond nonwoven fabric having a fineness of 2.1 d / f obtained in Comparative Example 3 were laminated, Using the same through-air heat treatment machine as in Example 1, heating was carried out at a temperature of 140 ° C. to obtain a laminated nonwoven fabric having a two-layer structure in which both layers were heat-sealed. Polyethylene spunbonded nonwoven fabrics were found to have been melted into a film everywhere. The laminated nonwoven fabric was a material that did not peel even if it was held with both hands.
The laminated nonwoven fabric has a weight per unit area of 54 g / m due to heat treatment. ² It was hot. Polyethylene spunbonded nonwoven fabrics were found to have been melted into a film everywhere. In addition, a large number of wrinkles occurred in the entire laminated nonwoven fabric. The laminated nonwoven fabric has a transverse strength of 2.66 kg / 5 cm and a permeability of 92 cm. ^Three / Cm ² / Second, specific volume 25cm ^Three / G, the texture was poor. Although this nonwoven fabric has relatively good air permeability and bulkiness, it has been judged that it cannot be used as a surface material such as a disposable diaper because the texture is poor.
[0045]
Example 6
Using a commercially available paper diaper, a new paper diaper was produced using the laminated nonwoven fabric described in Example 1 only for the surface material of the paper diaper. In this paper diaper, a polyethylene sheet is used as a back material for preventing liquid leakage, and there is a liquid absorbent material in which pulp and a polymer water absorbent are wrapped in a tissue on the top of the back material, and a polypropylene short fiber card is placed on the top. This is a product using a non-woven fabric. This surface material is a nonwoven fabric thermocompression bonded with an embossing roll and has a basis weight of 21 g / m. ² Lateral strength is 0.87kg / 5cm (40g / m ² Conversion), specific volume 27cm ^Three / G. The surface material was removed from the paper diaper while cutting with a knife. In place of the removed surface material, the two-layered nonwoven fabric obtained in Example 4 was laminated so that the carded nonwoven fabric was on the skin side (surface layer), and the peripheral portion of the paper diaper was thermocompression bonded to a width of 3 mm. And the back material and the surface material were thermocompression bonded, and the paper diaper of this invention was obtained. This paper diaper was bulky, had a high lateral strength and a good texture. The urine absorbability was good.
[0046]
【The invention's effect】
The laminated nonwoven fabric of the present invention is a laminated fiber spunbond nonwoven fabric in which at least two types of long fibers having different melting points are mixed and heat-sealed, and a carded nonwoven fabric, and both layers are heat-sealed and integrated. Non-woven fabric. Moreover, this laminated nonwoven fabric is a nonwoven fabric in which the air permeability and specific volume are set in a specific range. Therefore, the laminated nonwoven fabric of the present invention is excellent in air permeability and bulkiness and has an effect of being difficult to peel off on the laminated surface, having a large lateral strength and a soft texture. Therefore, the absorbent article using the laminated nonwoven fabric of the present invention has the properties of the nonwoven fabric.

Claims

A non-woven fabric having a multilayer structure in which a mixed fiber spunbond nonwoven fabric and a carded nonwoven fabric are laminated, and the mixed fiber spunbond nonwoven fabric has a low melting point long fiber of 10 to 90% by weight made of a resin having a melting point difference of 10 ° C. or more. A non-woven fabric in which 90 to 10% by weight of high-melting long fibers are mixed and the low-melting long fibers are heat-sealed at the fiber intersection, and the card non-woven fabric has a crimped fiber length of 25 to 128 mm. Composed of short fibers, the mixed fiber spunbonded nonwoven fabric and the carded nonwoven fabric are integrated by thermal fusion of at least one of the low melting point long fibers of the mixed fiber spunbonded nonwoven fabric and the short fibers of the carded nonwoven fabric. A laminated nonwoven fabric having an air permeability of 80 to 2000 cm ³ / cm ² / sec and a specific volume of 15 to 70 cm ³ / g.

The mixed fiber spunbond nonwoven fabric is composed of mixed filament long fibers having an average fineness of 0.4 to 10 d / f, the card nonwoven fabric is composed of only heat-fusible short fibers, and the intersection point of the heat-fusible short fibers is The nonwoven fabric formed by heat-sealing, wherein the laminated nonwoven fabric has a transverse strength of 1.2 kg / 5 cm or more, an air permeability of 85 to 1300 cm ³ / cm ² / sec, and a specific volume of 15 to 65 cm ³ / g. The laminated nonwoven fabric described.

The mixed fiber spunbonded nonwoven fabric is composed of mixed long fibers having an average fineness of 0.4 to 10 d / f, and the carded nonwoven fabric is composed of a fiber in which at least 10% by weight of heat-fusible short fibers and other short fibers are mixed. A non-woven fabric in which fiber intersections are heat-sealed with the heat-fusible short fibers, the lateral strength of the laminated nonwoven fabric is 1.2 kg / 5 cm or more, the air permeability is 85 to 1300 cm ³ / cm ² / sec, and the specific volume The laminated nonwoven fabric according to claim 1, which is 15 to 65 cm ³ / g.

The laminated nonwoven fabric according to any one of claims 1 to 3, wherein the mixed fiber spunbonded nonwoven fabric is a mixed fiber having a fineness of 150% or less.

The laminate according to any one of claims 1 to 4, wherein the mixed fiber spunbonded nonwoven fabric is a nonwoven fabric in which a mixed fiber spinneret is used, and a low melting point long fiber and a high melting point long fiber are uniformly mixed and spun immediately after spinning. Non-woven fabric.

The card nonwoven fabric is a nonwoven fabric comprising a single short fiber having at least one of two-dimensional and three-dimensional crimps, and the fibers are heat-sealed at the intersection. The laminated nonwoven fabric described in 1.

The card nonwoven fabric comprises 10 to 90% by weight of a low melting point resin and 90 to 10% by weight of a high melting point resin having at least one of two-dimensional and three-dimensional crimps and having a melting point difference of 10 ° C. or more. The laminated nonwoven fabric according to any one of claims 1 to 5, which is a nonwoven fabric in which the melting point resin is composed of composite fibers forming at least a part of the fiber surface, and the fiber intersection is thermally fused with the low melting point resin of the fibers.

10 to 90% by weight of low melting point fiber and 90 to 10% by weight of high melting point fiber having at least one of two-dimensional and three-dimensional crimps and having a melting point difference of 10 ° C. or more are mixed, The laminated nonwoven fabric according to any one of claims 1 to 5, which is a nonwoven fabric in which fiber intersections are heat-sealed with the low melting point fibers.

Polyolefin resin in which at least one long fiber of the mixed fiber spunbond nonwoven fabric and at least one fiber of the card nonwoven fabric are selected from polyethylene, propylene and other α-olefin crystalline copolymers, and polypropylene. The laminated nonwoven fabric according to any one of claims 1 to 8, wherein the laminated nonwoven fabric is used.

The laminated nonwoven fabric according to any one of claims 1 to 9, wherein the fiber intersection is heat-sealed between the mixed fiber spunbonded nonwoven fabric and the carded nonwoven fabric by heat through air.

The laminated nonwoven fabric according to any one of claims 1 to 9, wherein the mixed fiber spunbond nonwoven fabric and the card nonwoven fabric are thermocompression bonded with an embossing roll having a convex area of 5 to 25%.

The absorbent article in which the laminated nonwoven fabric according to any one of claims 1 to 11 is used as at least one material constituting the absorbent article.