JP4013346B2 - Nonwoven fabric and absorbent article using the same - Google Patents
Nonwoven fabric and absorbent article using the same Download PDFInfo
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- JP4013346B2 JP4013346B2 JP22380198A JP22380198A JP4013346B2 JP 4013346 B2 JP4013346 B2 JP 4013346B2 JP 22380198 A JP22380198 A JP 22380198A JP 22380198 A JP22380198 A JP 22380198A JP 4013346 B2 JP4013346 B2 JP 4013346B2
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Description
【０００１】
【発明の属する技術分野】
本発明は不織布及びそれを用いた吸収性物品等に関する。更に詳しくは、風合いが柔らかくかつ折れ角が発生せず、更に強度等に優れた熱圧着不織布およびこれを用いた液体の吸収性物品等に関する。
【０００２】
【従来の技術】
熱接着性繊維を原料として用いられた熱圧着不織布は、適度な柔軟性と機械的強度を有するので、使い捨ておむつや生理用ナプキンの表面材、使い捨ておしぼり、各種ワイパー等に広く利用されている。この不織布は最終用途が、人間の肌に直接触れる分野の用途に多用されるので、より良好な風合い等が要求されている。特に新生児用に用いられる紙おむつ等にあつては、柔軟で且つ不織布の折れ角が発生せず、該折れ角による肌荒れの起きない不織布が求められていた。
【０００３】
特開平8-49166号公報には、特定の油剤が付着された低配向性ポリプロピレン繊維を用いたエンボスロールによる熱圧着不織布が開示されている。また、特開昭62-263321号公報には、特定量の石油樹脂が添加されたポリオレフィン系熱融着性繊維を用いたエンボスロールによる熱圧着不織布が開示されている。
上記技術に開示されている不織布は、高い強度を持ち、風合いもある程度満足出来る不織布である。しかしエンボスロール等による熱圧着不織布等は、エンボス部以外の場所も熱融着され易く、しかもウエブ製造時の繊維同士の過度な絡合等が内在するので剛軟度が高い物になりやすい。
又特開昭60-162851号公報には、突起を有した金属ロールと弾性ロールとの一対のロール間に部分結合された不織布を通過させてその表面を該突起を有する金属ロールで摩擦し不織布を柔軟化させる方法が開示されている。しかし、この方法では柔軟性は改善されるものの、熱圧着点の破壊が生じるため機械的強度が低下したり、毛羽立つたりするという問題がある。又該不織布を紙おむつ等の表面材等に使用した場合、抜毛し、肌に付着するという問題がある。また、弾性ロールが金属ロールの突起で損傷され易く、しかも生産速度を大にする事が不可能であるという問題がある。特に薄物不織布の場合には破れ、毛羽等のない均一な不織布を製造する事が困難であつた。
又熱接着性複合繊維のエアスルー融着不織布は、比較的風合いが良いが不織布を折り曲げた際に、角が発生しやすいという問題点がある。
【０００４】
【発明が解決しようとする課題】
本発明は上記のような課題を解決するためになされた物であり、風合いが良く、折れ角等が発生せず、かつ優れた不織布強度とを併せ持つ熱圧着不織布及びそれを用いた液吸収性物品等を提供することにある。
【０００５】
【課題を解決するための手段】
本発明者らは上記課題を解決すべく鋭意検討を重ねた結果、以下の構成を取る事により、解決可能で有る事を知り、本発明を完成した。
【０００６】
１．カード法、エアレイド法、湿式抄紙法またはメルトブロー法で得られる主として熱接着性繊維からなる不織布であり、該繊維を熱圧着して不織布とした後、この不織布を機械方向に１．０５〜１．３０倍に延伸する処理を施し、熱圧着部間の繊維の緊張を解除して得られる不織布であって、熱圧着面積率が５〜３５％であり、機械方向における３％伸長時の応力Ｆ１（Ｆ１は幅５ｃｍ、目付１ｇ／ｍ2当たりに換算した時の応力を示す）が２５ｇｆ未満でかつ５％伸長時の応力Ｆ２（Ｆ２は幅５ｃｍ当たりの応力を示す）が５００ｇｆ以上である熱圧着不織布。
２．不織布が、カード法、エアレイド法または湿式抄紙法でウエブを形成し、続いて熱圧着処理して得られる、前記１項記載の熱圧着不織布。
３．熱圧着不織布が、機械方向の長さ１５ｃｍ、幅５ｃｍの不織布試験片とし、この試験片を湾曲しループを形成した際、折れ角が発生しないものであることを特徴とする前記１項または２項に記載の熱圧着不織布。
４．熱接着性繊維がモノコンポーネント繊維である前記１〜３項の何れかに記載の熱圧着不織布。
５．熱接着性繊維がポリオレフイン系モノコンポーネント繊維である前記１〜４項の何れかに記載の熱圧着不織布。
６．熱接着性繊維がポリプロピレンモノコンポーネント繊維である前記１〜５項の何れかに記載の熱圧着不織布。
７．熱接着性繊維が複合繊維である前記１、２または３項の何れかに記載の熱圧着不織布。
８．複合繊維が融点差が１５℃以上ある低融点熱可塑性樹脂と高融点熱可塑性樹脂からなり且つ該低融点熱可塑性樹脂が少なくとも繊維表面の一部を形成する熱接着性複合繊維である前記７項に記載の熱圧着不織布。
９．複合繊維が低融点ポリオレフン系樹脂と高融点ポリオレフイン系樹脂からなる鞘芯型若しくは並列型の熱接着性複合繊維である前記７項に記載の熱圧着不織布。
１０．複合繊維がポリオレフイン系樹脂とポリエステル系樹脂からなる鞘芯形若しくは並列形の熱接着性複合繊維である前記７項に記載の熱圧着不織布。
１１．複合繊維が低融点ポリエステル系樹脂と高融点ポリエステル系樹脂からなる鞘芯形若しくは並列形の熱接着性複合繊維である前記７項に記載の熱圧着不織布。
１２．前記１〜１１項の何れかに記載の熱圧着不織布が用いられた吸収性物品。
【０００７】
以下、本発明を詳細に説明する。
本発明は、主として熱融着性繊維からなる繊維集合体が熱圧着された不織布、及び該不織布を用いた吸収性物品等である。本発明で言う熱圧着不織布とは、主としてドット状に彫刻されたエンボスロールとフラットロール間で熱圧着された不織布である。
不織布の主繊維となる熱接着性繊維は、ポリオレフィン樹脂、ポリエステル樹脂、ポリアミド樹脂等の熱可塑性樹脂を原料に用いたモノコンポーネント繊維や複合繊維等である。不織布の加工性、コスト等の点からポリオレフィン系樹脂やポリエステル系樹脂等が繊維化された物が好適に用いられる。
熱可塑性樹脂として、ポリプロピレン、高密度ポリエチレン、低密度ポリエチレン、線状低密度ポリエチレン、エチレン−プロピレン共重合体、エチレン−ブテン-1共重合体、エチレン−プロピレン−ブテン-1共重合体、エチレン−酢酸ビニル共重合体等のポリオレフィン系樹脂、ナイロン６、ナイロン６６等のポリアミド系樹脂、ポリエチレンテレフタレート、ポリブチレンテレフタレート、ポリエチレンテレフタレートイソフタレート共重合体等のポリエステル系樹脂、ポリフェニレンスルフィド、ポリフッ化ビニリデン等が使用可能である。
【０００８】
熱融着性繊維がモノコンポーネント繊維の場合、上記熱可塑性樹脂樹脂単独又は二以上の均一に混合された樹脂を溶融紡糸等をし、繊維化した物が使用出来る。このような繊維はレギュラー繊維とも呼ばれている。又複合繊維の場合前記熱可塑性樹脂を複合紡糸した複合繊維等が使用出来る。
モノコンポーネント繊維の場合、ポリエチレン繊維、プロピレン・エチレン共重合体繊維、プロピレン・エチレン・ブテン−１共重合体繊維ポリプロピレン繊維、ポリエチレンテレフタレート繊維等が好ましく使用出来る。
又複合繊維の場合、並列型、鞘芯型、偏芯鞘芯型、海島型、多分散型等の複合繊維が何れも使用出来る。とりわけ融点差が１５℃以上あり且つ低融点熱可塑性樹脂が繊維表面の少なくとも一部を形成するような熱融着性複合繊維が好ましく使用出来る。例えば低密度ポリエチレン／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・エチレン共重合体／ポリプロピレン、プロピレン・エチレン・ブテン−１共重合体／ポリプロピレン、線状低密度ポリエチレン／ポリエチレンテレフタレート、プロピレン・エチレン共重合体／ポリエチレンテレフタレート、ポリ（エチレンテレフタレート−ｃｏ−イソフタレート）／ポリエチレンテレフタレート等の組み合わせの複合繊維等が例示出来る。
複合繊維の場合、低融点熱可塑性樹脂と高い融点熱可塑性樹脂の複合比は低融点樹脂が１０〜９０重量％、高融点樹脂が９０〜１０重量％、好ましくは低融点樹脂が２０〜８０重量％、更に好ましくは低融点樹脂が３０〜７０重量％、高融点樹脂が７０〜３０重量％である。該複合繊維の低融点樹脂が１０重量％未満の場合、又は高融点樹脂が９０重量％を超えると、低融点樹脂特有の物性に基ずく風合い改良、後記ポイントボンド熱圧着時の加工温度幅を広く設定出来る等の効果が減少する。
とりわけ低融点ポリオレフイン系樹脂／高融点ポリオレフイン系樹脂、ポリオレフイン系樹脂／ポリエチレンテレフタレート系樹脂等の組み合わせからなる熱融着性複合繊維等が好ましく使用出来る。
【０００９】
本発明の熱圧着不織布に使用される熱接着性繊維は、繊維長約３ｍｍ〜１３０ｍｍのステープル繊維、繊維長が実質的にエンドレスな長繊維等何れであつても良い。又該繊維は、捲縮があつても良いし、無くても良い。捲縮がある場合、略ジグザグ形、略Ｕ形、略オーム形、略スパイラル形等及びその混合された捲縮の物等何れも使用出来る。捲縮数は約０．３〜６５山／２５ｍｍで良い。
又該繊維の単糸繊度は少なくとも０．２ｄ／ｆあれば良く、その上限は特に限定されない。しかし不織布の用途が紙おむつ等の表面材等に使用する場合は、風合い等の観点から単糸繊度が約０．２〜１２ｄ／ｆ、とりわけ０．５〜８ｄ／ｆである。
【００１０】
本発明の熱圧着不織布は、前記熱接着性繊維を主とする不織布である。即ち主とするという意味は、熱接着性繊維を少なくとも５１重量％含む不織布である事を指す。
また、本発明の目的が達せられる範囲であれば、熱接着性繊維にレーヨン、コットン、アクリル繊維、絹、炭素繊維等、他の繊維を４９重量％未満混合しても何ら差し支えない。親水性等を目的として他の繊維を混合する場合、綿等の他の繊維は約５〜３０重量％で効果が発揮出来る。シルキー感等の肌触りを目的とする場合、絹や異形断面糸を約０．５〜１５重量％混合する事によりその効果が得られる。
【００１１】
本発明の熱圧着不織布は、前記熱接着性繊維１００重量％、又は前記熱接着性繊維と他の繊維を混合し、カード法、エアレイド法、湿式抄紙法等でウエブを形成し、続いて熱圧着処理し不織布とし、更に後記延伸処理をする事により得られる。又熱可塑性樹脂をメルトブロー法、通常のスパンボンド法または複合スパンボンド法で処理して熱融着性繊維のウエブを形成し、続いて熱圧着処理し不織布とし更に後記延伸処理をする事により得られる。勿論これらを組み合わせた不織布であつてもよい。中でも、カード法、スパンボンド法、あるいはこれらの組み合わせによる不織布が本発明の効果を奏するのに好ましい。
熱圧着は、金属エンボスロールと金属フラツトロールからなる熱圧着装置、超音波点接着装置、等が使用出来る。とりわけ金属エンボスロールと金属フラツトロールからなる熱圧着装置が好ましく使用出来る。前記熱圧着装置を用い、ウエブが熱圧着する温度以上の条件で加熱、圧着等をし、不織布とする。熱圧着温度や線圧等の熱圧着条件は、使用するウエブや加工速度により決定する。要するに次の延伸工程において熱圧着部分が破壊されないように十分に熱圧着しておけば良い。又エンボスロールの凸部面積、即ち熱圧着不織布の熱圧着面積は約５〜３５％が好ましい。熱圧着面積が５％未満であると、不織布強度が低下したり、毛羽等が発生する場合がある。又熱圧着面積が３５％を超えると不織布の柔軟性や、折れ角等の改善が困難になる場合がある。エンボスロールの凸部形状は円形、菱形、楕円形、正方形、長方形、棒状、十字状等、各種形状が可能である。又エンボス凸部間の距離は約０．５〜５．０ｍｍである物が適している。又本発明の不織布は、金属フラツトロール／金属フラルトロールで熱圧着された不織布であつても良い。又本発明の不織布はエアスルー熱融着とエンボスロール熱圧着が併用された物であつてもよい。
【００１２】
前記熱圧着不織布を延伸処理し、不織布の、低伸長領域での応力特性を前記本発明の数値に設定する。本発明の不織布は機械方向における３％伸長時の応力（Ｆ１）が２５ｇｆ未満、かつ５％伸長時の応力（Ｆ２）が５００ｇｆ以上である。ここでＦ１は幅５ｃｍ、目付１ｇ／ｍ2当たりに換算した時の応力で、Ｆ２は幅５ｃｍ当たりの目付け換算なしの応力である。Ｆ１が２５ｇｆ以上では不織布の柔軟性等の風合いが劣る。また、Ｆ２が５００ｇｆ未満ではこの不織布を他のシートや液吸収材等と積層等をし、中間製品や最終製品等に高速度で加工する際、不織布が過度に伸びたり不織布に皺が発生したりするため、加工性が劣り、最終製品の性能も劣る。
【００１３】
不織布の延伸は、前記熱圧着後の不織布を延伸機を用い、延伸倍率約１．０５倍以上且つ不織布が破断しない延伸倍率以下で延伸すれば良い。例えば破断伸度が約５５％の不織布の場合、延伸倍率は約１．０５〜１．４０倍で、不織布の低伸長領域での不織布応力を前記数値範囲内に設定することができる。熱圧着後の不織布伸度が比較的大である場合、延伸処理を比較的高倍率で行う事が出来る。延伸倍率は好ましくは約１．０８〜１．３０倍である。延伸倍率が１．０５倍未満では、不織布の柔軟性や、３％伸長時の応力（Ｆ１）を前記の数値に設定する事が困難である。又延伸倍率が１．４０倍以上の場合、不織布が破断する場合があり、破断しない場合であつても不織布強度が低下したり、毛羽等が発生したりする。又５％伸長時の応力（Ｆ２）を前記の数値に設定する事が困難である。不織布の延伸は、熱接着性繊維の融点または軟化点より低い温度で行う。延伸温度が高すぎると不織布が硬くなるため好ましくない。
又不織布の延伸は機械方向のみならず、横方向にも延伸する事が出来る。
又、熱圧着した不織布を延伸した後、緩和処理する事も出来る。緩和処理は、不織布の延伸から巻取りの工程の間に、張力吸収バー、張力吸収ロール、エアーブロー機、等で処理しても良い。又熱圧着、延伸等は不織布製造工程で、連続法で行う事が出来る。又一旦熱圧着不織布を製造した後不織布を巻き取り、その後不織布を巻戻し不織布を他の製品と併用し中間製品や最終製品等に加工する際、に巻戻して延伸処理する事が出来る。
【００１４】
本発明の熱圧着不織布の目付は特に限定されない。しかし風合いや、不織布の折れ角等の改良等の点で、１０〜１００ｇ／ｍ2が好ましく、さらに好ましくは１２〜５０ｇ／ｍ2である。特に液吸収性物品等の用途には、目付け１２〜３０ｇ／ｍ2である。目付けが１０ｇ／ｍ2未満の場合、不織布応力Ｆ２が低くなりすぎるので好ましくない。又１００ｇ／ｍ2を超えると、熱圧着が困難となり、その風合いが悪い物となる。
【００１５】
本発明の吸収性物品は、前記の不織布を液吸収性物品を構成する材料として用いられた物である。例えば紙おむつの場合、該不織布と他の不織布やテイシュ、パルプ、高吸水材、フイルム等と積層し、紙おむつを形成した物である。例えば、ポリエチレンシートを液防漏用裏面シートとし、テイシュに包まれたパルプ及び高吸水剤を含有する液吸収材、及び前記本発明の不織布を表面材とし、裏面シートと表面材が熱圧着等で一体化された紙おむつ等の液吸収性物品等が例示出来る。このような液吸収性物品は表面材が柔らかく、しかも折れ角が出来ないのでおむつかぶれ等が発生しにくい。
又本発明の不織布にポリエチレンシートを不織布層が外側を形成する様に積層し且つ、その両方が少なくとも部分的に融着一体化されたラミネート構造のシートを裏面シートとし、前記液吸収材、本発明の不織布又は他の不織布や他の開孔フイルム等を表面材とし、裏面材と表面材が熱圧着等で一体化された紙おむつ等の液吸収性物品等は、裏面材が良い風合いの物となる。
又本発明の不織布と他の不織布やウエブ等を積層し、表面材とした前記、表面材／液吸収材／裏面材のような構造をとる紙おむつ等が例示できる。この紙おむつは、風合いが良く、おむつかぶれれ阻止効果があり、更に液吸収性が向上するという効果を併せ持つ物である。
又、レーヨン、熱融着性繊維からなる熱融着不織布を液吸収材として用い、レーヨン等の親水性繊維が５〜４０重量％、熱融着性繊維９５〜６０重量％混合し且つ該繊維で熱融着した本発明の不織布をカバー材として用い、該液吸収材全体を包み込むような構造を有する物品は、汗取り材や化粧落し材等として使用出来る。
【００１６】
本発明の不織布は、部分的に熱圧着した不織布を特定の比率で延伸し、低伸長領域での二種の応力特性等が何れも特定の数値を有するように設定された物である。
その延伸処理による効果は次のように考えられる。即ち、熱圧着不織布において、高い機械的強度を持たせるためにはエンボスロール等で強固に熱圧着させる必要があるが、この時、熱圧着部以外の繊維にも少なからず熱がかかり、繊維同士の弱い熱融着が生成される。又、熱圧着処理時の僅かな熱収縮等により、それぞれの熱圧着部間で、繊維が過剰に緊張するといった現象が起こる。即ち熱圧着部間の単繊維間の応力に対する自由度が少ない物となり易い。このことが起因し、風合いが硬く、触感の悪い不織布となってしまう。
そこで、このような不織布に対し適度の延伸、及び必要により緩和処理等を施し、不織布の低伸長領域の二種の応力特性を、本願発明のように設定することによって、熱圧着部間の繊維の緊張を解除すことができるのである。この結果、柔軟性等の風合いが良く、かつ高い不織布強度を備え、機械加工適性も維持することができるのである。更に、前記特徴に加え、折れ角の発生しない、不織布を提供出来るのである。
【００１７】
【実施例】
以下、実施例により本発明を具体的に説明する。但し本発明はこれらの実施例に限定されるものではない。以下の実施例及び比較例等における各物性値は次の測定方法による。
【００１８】
［Ｆ１およびＦ２］
不織布から機械方向の長さが１５ｃｍで幅が５ｃｍの試験片を切り取る。引っ張り強度試験機を用い、つかみ間隔１００ｍｍ、引張速度１００ｍｍ／ｍｉｎの条件で引張試験を行い、機械方向における３％伸張時の応力（Ｆ１）、及び：５％伸長時の応力（Ｆ２）を測定した。
ここでＦ１は幅５ｃｍ、目付１ｇ／ｍ2当たりに換算した時の応力（単位ｇｆ）で、Ｆ２は幅５ｃｍ当たりの目付け換算なしの応力（単位ｇｆ）である。
【００１９】
［破断強力および破断伸度］
不織布から機械方向の長さが１５ｃｍで幅が５ｃｍの試験片を切り取る。引っ張り強度試験機を用い、つかみ間隔１００ｍｍ、引張速度１００ｍｍ／ｍｉｎの条件で引張試験を行い、破断時の強力（単位ｇｆ）および伸度（単位％）を測定した。
【００２０】
［剛軟度］
不織布から機械方向の長さが１５ｃｍで幅が５ｃｍの試験片を切り取る。ＪＩＳ−１０９６ Ａ法（４５度カンチレバー法）に準じて機械方向における剛軟度を測定する。単位（ｍｍ）
【００２１】
［折れ角の発生］
不織布から機械方向の長さが１５ｃｍで幅が５ｃｍの試験片を切り取る。試験片を机上に置き、手でその両端を湾曲密着させる。湾曲させた状態で不織布の頂部近傍を観察し、折れ角の発生の有無を確認する。折れ角が発生した場合「有り」、発生しなかつた場合「無し」と判定する。
【００２２】
［風合い］
２５ｃｍ×２５ｃｍの不織布を５人のパネラーが手で触り、柔軟性、毛羽立ち等の観点から風合いを「良」又は「不良」で評価した。３人以上が「良」と判定した場合、風合い「良」と判定し、それ以外の場合、風合い「不良」と判定した。
【００２３】
実施例１及び比較例１〜３
メルトフローレート（ＡＳＴＭ １２３８Ｌ）１５のエチレン−プロピレン−ブテン-１共重合体（エチレン３．０％、プロピレン９２．５％、ブテン-１、 ４．５％）を鞘成分とし、メルトフローレート１５の結晶性ポリプロピレンを芯成分とする複合比５０重量％対５０重量％の鞘芯型複合繊維を溶融紡糸した。この未延伸糸を延伸機を用い、温度９０℃の熱ロール間で２．５倍で延伸し、次いで繊維仕上剤を付着させた後、スタフィングボックス形クリンパーで機械捲縮を付与し、サクションドライヤーで乾燥し、切断して繊度２ｄ／ｆ、繊維長３８ｍｍのステープル繊維を得た。
次に、上記繊維をカード機を用いウェッブとし、凸部形状菱形、凸部面積率２３％、の金属エンボスロールと金属フラットロールからなる熱圧着装置を用い、金属エンボスロール温度１３０℃、金属フラツトロール温度１３０℃、線圧２０ｋｇｆの条件で熱圧着処理し、目付２０ｇ／ｍ2の不織布（ａ）を得た。
【００２４】
この不織布（ａ）を、延伸機を用い、不織布の機械方向にそれぞれの延伸比で延伸し、本発明の不織布（実施例１）及び本発明以外の不織布（比較例１〜３）を得た。得られた不織布の各物性値等を表１に示す。
【００２５】
延伸処理されかつＦ１、Ｆ２が本発明で定める特定の数値範囲内にある実施例１の不織布は風合いが良く、折れ角が発生せず、しかも破断強度が大である不織布であつた。一方延伸処理されていないか、又は延伸処理されていてもＦ１又はＦ２が本発明で定める特定の数値範囲外である比較例１、２、３の不織布は、風合い、破断強度等の何れかが劣る物であつた。又比較例３は不織布に毛羽があり、風合い不良であり、Ｆ２及び破断強度が何れも低い物であつた。
【００２６】
実施例２、比較例４
メルトインデツクス（ＡＳＴＭ １２３８Ｅ）２０の高密度ポリエチレンを鞘成分とし、固有粘度０．６７のポリエチレンテレフタレートを芯成分とする複合比６０重量％（鞘）対４０重量％（芯）の鞘芯型複合繊維を溶融紡糸した。この未延伸糸を延伸機を用い温度９０℃の熱ロール間で３．０の延伸し、次いで繊維仕上剤を付着させた後、スタフィングボックス形クリンパーで機械捲縮を付与し、サクションドライヤーで乾燥し、切断して繊度２ｄ／ｆ、繊維長５１ｍｍのステープル繊維を得た。
次に、上記繊維をカード機を用いウェッブとし、前記実施例１に同じ熱圧着装置を用い、金属エンボスロール温度１２８℃、金属フラツトロール温度１２８℃、線圧２０ｋｇ／ｃｍ、の条件で熱圧着し目付２０ｇ／ｍ2の不織布（ｂ）を得た。
【００２７】
この不織布（ｂ）を、延伸機を用い、不織布の機械方向に延伸し、本発明の不織布（実施例２）を得た。得られた不織布の各物性値等を表１に示す。
【００２８】
延伸処理されかつＦ１、Ｆ２が本発明で定める特定の数値範囲内にある実施例２の不織布は風合いが良く、折れ角が発生せず、しかも破断強度が大である不織布であつた。一方延伸処理等がされていない比較例４の不織布は、風合い等が劣る物であつた。
【００２９】
実施例３及び比較例５
モノコンポーネント繊維からなるスパンボンド法長繊維不織布を製造した。
スパンボンド法でメルトフローレート（ＡＳＴＭ １２３８Ｌ）４０のポリプロピレンを溶融紡糸し、繊度２ｄ／ｆの連続長繊維をコンベア上に捕集した。凸部形状菱形、凸部面積率１５％の金属エンボスロールと、金属フラットロールからなる熱圧着装置を用い、金属エンボスロール温度１３５℃、金属フラツトロール温度１３５℃、線圧８０ｋｇｆの条件で熱圧着処理し、目付２５ｇ／ｍ2の不織布（ｃ）を得た。
【００３０】
この不織布（ｃ）を、延伸機を用い、不織布の機械方向に延伸し、本発明の不織布（実施例３）を得た。得られた不織布の各物性値等を表１に示す。
【００３１】
延伸処理されかつＦ１、Ｆ２が本発明で定める特定の数値範囲内にある実施例２の不織布は風合いが良く、折れ角が発生せず、しかも破断強度が大である不織布であつた。一方延伸処理されていない比較例５の不織布は、風合い等が劣る物であつた。
【００３２】
実施例４及び比較例６
複合繊維からなるスパンボンド法長繊維熱圧着不織布を製造した。
複合スパンボンド法でメルトフローレート（ＡＳＴＭ１２３８Ｌ）１８の、プロピレン・エチレン・共重合体（プロピレン９６．２重量％、エチレン３．８重量％）を鞘成分とし、メルトフローレート（ＡＳＴＭ１２３８Ｌ）２９のポリプロピレンを芯成分とする複合比５０重量％（鞘）対５０重量％（芯）の鞘芯型複合長繊維を紡糸し、繊度２．２ｄ／ｆの連続長繊維をコンベア上に捕集した。凸部形状菱形、凸部面積率１５％の金属エンボスロールと、金属フラットロールからなる熱圧着装置を用い、金属エンボスロール温度１３０℃、金属フラツトロール温度１３０℃、線圧６０ｋｇｆの条件で熱圧着処理し、目付２５ｇ／ｍ2の不織布（ｄ）を得た。
【００３３】
この不織布（ｄ）を、延伸機を用い、不織布の機械方向に延伸し、本発明の不織布（実施例４）を得た。なおこの不織布は延伸後、テンション吸収ロールを用い、テンション緩和処理した。得られた不織布の各物性値等を表１に示す。
【００３４】
延伸処理されかつＦ１、Ｆ２が本発明で定める特定の数値範囲内にある実施例４の不織布は風合いが良く、折れ角が発生せず、しかも破断強度が大である不織布であつた。一方延伸処理されていない比較例６の不織布は、風合い等が劣る物であつた。
【００３５】
比較例７
前記実施例２で得た高密度ポリエチレン／ポリエチレンテレフタレート複合繊維を、カード機を用いウエブとし、スルーエアー型熱処理機を用い温度１４０℃で熱処理し、繊維同士の交点が熱接着した目付け１９．８ｇ／ｍ2の不織布（ｅ）を得た。この不織布の各物性値等を表１に示す。
この不織布は風合いが良であつたが、５％伸長時の応力（Ｆ２）が低く、しかも折れ角が発生する物であつた。
【００３６】
実施例５
市販の紙おむつを用い、この紙おむつの表面材のみ前記実施例１で得た不織布を用いた新規紙おむつを製造した。この市販の紙おむつは、液漏れ防止用裏面材としてポリエチレンシートが使用され、該裏面材の上部にテイシュに包まれたパルプ及び高分子吸水剤からなる液吸水材、及びその上部に表面材としてスパンボンド法ポリプロピレン長繊維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熱圧着不織布であつた。この紙おむつから表面材のみ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１で得た熱圧着不織布を積層し、更に紙おむつの周辺部を幅３ｍｍ熱圧着し、表面材と裏面材を熱圧着し、本発明の紙おむつを得た。この紙おむつは風合いが良い物であつた。又着用時、及び着用後、表面材の破れ等も起きず、実用上の強度も十分であると判断された。
【００３７】
【表１】
【発明の効果】
本発明の不織布は低伸長時の引っ張り応力特性が、特定の数値を有する延伸された不織布である。この不織布は風合いが良く、しかも折り曲げた時に折れ角等が発生しないという効果がある。しかも不織布強度が大である等の効果がある。この不織布は紙おむつ、生理用ナプキン、ワイパー、使い捨ておしぼり、包帯、使い捨てカイロ、等に使用可能である。又この不織布を紙おむつ等の材料として用いた液吸収性物品は、風合いや液吸収性等に優れた物であつた。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a nonwoven fabric and an absorbent article using the same. More specifically, the present invention relates to a thermocompression bonded nonwoven fabric having a soft texture and having no bending angle and having excellent strength and the like, and a liquid absorbent article using the same.
[0002]
[Prior art]
Thermocompression-bonded nonwoven fabrics using heat-adhesive fibers as raw materials have appropriate flexibility and mechanical strength, and are therefore widely used for disposable diapers, sanitary napkin surface materials, disposable towels, various wipers, and the like. Since this non-woven fabric is frequently used for applications in the field of direct contact with human skin, a better texture and the like are required. Particularly for paper diapers and the like used for newborns, there has been a demand for a nonwoven fabric that is flexible and does not cause a bending angle of the nonwoven fabric and does not cause rough skin due to the bending angle.
[0003]
Japanese Patent Application Laid-Open No. 8-49166 discloses a thermocompression bonded nonwoven fabric using an embossing roll using a low-orientation polypropylene fiber to which a specific oil agent is attached. Japanese Laid-Open Patent Publication No. 62-263321 discloses a thermocompression bonded nonwoven fabric using an embossing roll using a polyolefin heat-fusible fiber to which a specific amount of petroleum resin is added.
The nonwoven fabric disclosed in the above technology is a nonwoven fabric having high strength and satisfactory texture to some extent. However, a thermocompression-bonded nonwoven fabric or the like using an embossing roll or the like is likely to be heat-sealed in places other than the embossed portion, and moreover, the fiber is excessively entangled and the like at the time of manufacturing the web, so that it tends to be a high bending resistance.
Japanese Laid-Open Patent Publication No. 60-162851 discloses a nonwoven fabric in which a nonwoven fabric partially bonded between a pair of rolls of a metal roll having projections and an elastic roll is passed and the surface is rubbed with the metal roll having projections. A method of softening is disclosed. However, although this method improves the flexibility, there is a problem in that mechanical strength is lowered or fluffing occurs due to breakage of the thermocompression bonding point. Further, when the nonwoven fabric is used as a surface material such as a paper diaper, there is a problem that hair is removed and adheres to the skin. In addition, there is a problem that the elastic roll is easily damaged by the protrusions of the metal roll and it is impossible to increase the production speed. In particular, in the case of a thin nonwoven fabric, it was difficult to produce a uniform nonwoven fabric without tearing and fluff.
The air-through fused nonwoven fabric of heat-adhesive conjugate fiber has a relatively good texture, but has a problem that corners are easily generated when the nonwoven fabric is folded.
[0004]
[Problems to be solved by the invention]
The present invention has been made in order to solve the above problems, and has a good texture, no bending angle, etc., and a thermocompression bonded nonwoven fabric having excellent nonwoven fabric strength, and a liquid absorbency using the same. It is to provide articles and the like.
[0005]
[Means for Solving the Problems]
As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that they can be solved by adopting the following configuration, and thus completed the present invention.
[0006]
1. A nonwoven fabric mainly composed of heat-adhesive fibers obtained by a card method, an airlaid method, a wet papermaking method, or a melt blow method. A nonwoven fabric obtained by applying a treatment of stretching 30 times and releasing the tension of the fibers between the thermocompression bonding portions, the thermocompression bonding area ratio is 5 to 35%, and the stress F1 at the time of 3% elongation in the machine direction (F1 has a width of 5 cm and a basis weight of 1 g / m 2 A thermocompression-bonded nonwoven fabric having a stress when converted to a hit of less than 25 gf and a stress F2 at 5% elongation (F2 indicates a stress per width of 5 cm) of 500 gf or more.
2. 2. The thermocompression-bonding nonwoven fabric according to 1 above, wherein the nonwoven fabric is obtained by forming a web by a card method, an airlaid method or a wet papermaking method, followed by thermocompression treatment.
3. Item 1 or 2 above, wherein the thermocompression-bonded nonwoven fabric is a nonwoven fabric test piece having a length of 15 cm in the machine direction and a width of 5 cm, and when the test piece is bent to form a loop, a bending angle does not occur. The thermocompression-bonded nonwoven fabric according to item.
4). 4. The thermocompression-bonding nonwoven fabric according to any one of items 1 to 3, wherein the heat-adhesive fiber is a monocomponent fiber.
5 . 1 to 3 above, wherein the heat-adhesive fiber is a polyolefin-based monocomponent fiber. 4 The thermocompression-bonded nonwoven fabric according to any one of the items.
6 . The above 1 to 5, wherein the heat-adhesive fiber is a polypropylene monocomponent fiber 5 The thermocompression-bonded nonwoven fabric according to any one of the items.
7 . The above 1, 2 wherein the heat-adhesive fiber is a composite fiber Or 3 The thermocompression-bonded nonwoven fabric according to any one of the items.
8 . The composite fiber is a heat-adhesive composite fiber comprising a low-melting point thermoplastic resin having a melting point difference of 15 ° C. or higher and a high-melting point thermoplastic resin, and the low-melting point thermoplastic resin forms at least a part of the fiber surface. 7 The thermocompression-bonded nonwoven fabric according to item.
9 . The above-mentioned composite fiber is a sheath-core type or parallel type thermal adhesive composite fiber made of a low melting point polyolefin resin and a high melting point polyolefin resin 7 The thermocompression-bonded nonwoven fabric according to item.
10 . The conjugate fiber is a sheath-core-shaped or parallel-type thermally adhesive conjugate fiber composed of a polyolefin resin and a polyester resin. 7 The thermocompression-bonded nonwoven fabric according to item.
11 . The aforementioned conjugate fiber is a sheath-core-shaped or parallel-type thermally adhesive conjugate fiber comprising a low-melting polyester resin and a high-melting polyester resin 7 The thermocompression-bonded nonwoven fabric according to item.
12 . 1 to 11 An absorbent article using the thermocompression-bonded nonwoven fabric according to any one of the items.
[0007]
Hereinafter, the present invention will be described in detail.
The present invention is a nonwoven fabric obtained by thermocompression bonding of a fiber assembly mainly composed of heat-fusible fibers, and an absorbent article using the nonwoven fabric. The thermocompression-bonded non-woven fabric referred to in the present invention is a non-woven fabric thermocompression-bonded between an embossed roll engraved in a dot shape and a flat roll.
The heat-adhesive fiber that is the main fiber of the nonwoven fabric is a monocomponent fiber or a composite fiber using a thermoplastic resin such as a polyolefin resin, a polyester resin, or a polyamide resin as a raw material. From the viewpoint of processability, cost, etc. of the nonwoven fabric, a material obtained by fiberizing a polyolefin resin or a polyester resin is preferably used.
As thermoplastic resins, polypropylene, high density polyethylene, low density polyethylene, linear low density polyethylene, ethylene-propylene copolymer, ethylene-butene-1 copolymer, ethylene-propylene-butene-1 copolymer, ethylene- Polyolefin resins such as vinyl acetate copolymer, polyamide resins such as nylon 6 and nylon 66, polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene terephthalate isophthalate copolymer, polyphenylene sulfide, polyvinylidene fluoride, etc. It can be used.
[0008]
In the case where the heat-fusible fiber is a monocomponent fiber, the above-mentioned thermoplastic resin resin alone or two or more uniformly mixed resins can be melt-spun or the like to be fiberized. Such fibers are also called regular fibers. In the case of a composite fiber, a composite fiber obtained by composite spinning of the thermoplastic resin can be used.
In the case of monocomponent fibers, polyethylene fibers, propylene / ethylene copolymer fibers, propylene / ethylene / butene-1 copolymer fibers, polypropylene fibers, polyethylene terephthalate fibers, and the like can be preferably used.
In the case of a composite fiber, any of composite fibers such as a parallel type, a sheath core type, an eccentric sheath core type, a sea island type, and a polydisperse type can be used. In particular, a heat-fusible conjugate fiber having a melting point difference of 15 ° C. or more and a low melting point thermoplastic resin forming at least a part of the fiber surface can be preferably used. For example, low density polyethylene / polypropylene, linear low density polyethylene / polypropylene, propylene / ethylene copolymer / polypropylene, propylene / ethylene / butene-1 copolymer / polypropylene, linear low density polyethylene / polyethylene terephthalate, propylene / ethylene copolymer Examples thereof include a composite fiber of a combination of polymer / polyethylene terephthalate, poly (ethylene terephthalate-co-isophthalate) / polyethylene terephthalate, and the like.
In the case of a composite fiber, the composite ratio of the low melting point thermoplastic resin and the high melting point thermoplastic resin is 10 to 90% by weight for the low melting point resin, 90 to 10% by weight for the high melting point resin, and preferably 20 to 80% for the low melting point resin. %, More preferably 30 to 70% by weight of the low melting point resin and 70 to 30% by weight of the high melting point resin. When the low melting point resin of the composite fiber is less than 10% by weight, or when the high melting point resin exceeds 90% by weight, the texture improvement based on the physical properties peculiar to the low melting point resin, and the processing temperature width at the time of point bond thermocompression bonding are described later. The effect of being able to set widely will decrease.
In particular, a heat-fusible composite fiber made of a combination of a low-melting-point polyolefin resin / a high-melting-point polyolefin resin, a polyolefin-based resin / polyethylene terephthalate resin, or the like can be preferably used.
[0009]
The thermoadhesive fibers used in the thermocompression bonded nonwoven fabric of the present invention may be any of staple fibers having a fiber length of about 3 mm to 130 mm, long fibers having a substantially endless fiber length, and the like. The fiber may or may not be crimped. When there is a crimp, any of a substantially zigzag shape, a substantially U shape, a substantially ohmic shape, a substantially spiral shape, etc., and a mixed crimped product thereof can be used. The number of crimps may be about 0.3 to 65 peaks / 25 mm.
The single yarn fineness of the fiber may be at least 0.2 d / f, and the upper limit is not particularly limited. However, when the nonwoven fabric is used for a surface material such as a paper diaper, the single yarn fineness is about 0.2 to 12 d / f, particularly 0.5 to 8 d / f from the viewpoint of texture and the like.
[0010]
The thermocompression-bonding nonwoven fabric of the present invention is a nonwoven fabric mainly composed of the thermoadhesive fibers. That is, the main meaning means a non-woven fabric containing at least 51% by weight of heat-adhesive fibers.
Moreover, as long as the object of the present invention can be achieved, it is possible to mix less than 49% by weight of other fibers such as rayon, cotton, acrylic fiber, silk, and carbon fiber with the heat-adhesive fiber. When other fibers are mixed for the purpose of hydrophilicity or the like, the effect of other fibers such as cotton is about 5 to 30% by weight. For the purpose of touch such as silky feeling, the effect can be obtained by mixing about 0.5 to 15% by weight of silk or modified cross-section yarn.
[0011]
The thermocompression-bonding nonwoven fabric of the present invention is formed by mixing the heat-adhesive fiber 100% by weight or the heat-adhesive fiber with other fibers, and forming a web by a card method, an airlaid method, a wet papermaking method, etc. It can be obtained by crimping to a non-woven fabric and then subjecting it to a drawing process described below. Also, the thermoplastic resin is processed by a melt blow method, a normal spunbond method or a composite spunbond method to form a heat-fusible fiber web, followed by thermocompression treatment to obtain a nonwoven fabric, which is further stretched as described below. It is done. Of course, it may be a non-woven fabric combining these. Of these, the card method, the spunbond method, or a non-woven fabric based on a combination thereof is preferable for achieving the effects of the present invention.
For thermocompression bonding, a thermocompression bonding apparatus composed of a metal embossing roll and a metal flat roll, an ultrasonic point bonding apparatus, or the like can be used. In particular, a thermocompression bonding apparatus composed of a metal embossing roll and a metal flat roll can be preferably used. Using the thermocompression bonding apparatus, heating, pressure bonding, or the like is performed under conditions equal to or higher than the temperature at which the web is thermocompression bonded to obtain a nonwoven fabric. Thermocompression bonding conditions such as thermocompression bonding temperature and linear pressure are determined by the web used and the processing speed. In short, it may be sufficiently thermocompression-bonded so that the thermocompression-bonded portion is not destroyed in the next stretching step. The convex area of the embossing roll, that is, the thermocompression bonding area of the thermocompression bonding nonwoven fabric is preferably about 5 to 35%. If the thermocompression bonding area is less than 5%, the strength of the nonwoven fabric may be reduced or fluff may be generated. On the other hand, if the area of thermocompression bonding exceeds 35%, it may be difficult to improve the flexibility and bending angle of the nonwoven fabric. The convex shape of the embossing roll can be various shapes such as a circle, a rhombus, an ellipse, a square, a rectangle, a rod, and a cross. Moreover, the thing whose distance between embossing convex parts is about 0.5-5.0 mm is suitable. The non-woven fabric of the present invention may be a non-woven fabric thermocompression bonded with a metal flat roll / metal flat roll. The nonwoven fabric of the present invention may be a combination of air-through heat fusion and emboss roll thermocompression bonding.
[0012]
The thermocompression bonded nonwoven fabric is stretched, and the stress characteristic of the nonwoven fabric in the low elongation region is set to the numerical value of the present invention. The nonwoven fabric of the present invention has a stress (F1) at 3% elongation in the machine direction of less than 25 gf and a stress (F2) at 5% elongation of 500 gf or more. Here, F1 is 5 cm wide and has a basis weight of 1 g / m. 2 F2 is a stress when converted to a hit, and F2 is a stress without basis weight conversion per width of 5 cm. When F1 is 25 gf or more, the texture of the nonwoven fabric is inferior. In addition, when F2 is less than 500 gf, this nonwoven fabric is laminated with other sheets, liquid absorbents, etc., and when processed into an intermediate product or final product at a high speed, the nonwoven fabric stretches excessively or wrinkles occur in the nonwoven fabric. Therefore, workability is inferior and the performance of the final product is also inferior.
[0013]
The non-woven fabric may be stretched by stretching the non-woven fabric after thermocompression bonding at a draw ratio of about 1.05 times or more and below the draw ratio at which the non-woven fabric does not break. For example, in the case of a nonwoven fabric having a breaking elongation of about 55%, the draw ratio is about 1.05 to 1.40 times, and the nonwoven fabric stress in the low elongation region of the nonwoven fabric can be set within the above numerical range. When the nonwoven fabric elongation after thermocompression bonding is relatively large, the stretching treatment can be performed at a relatively high magnification. The draw ratio is preferably about 1.08 to 1.30. When the draw ratio is less than 1.05, it is difficult to set the flexibility of the nonwoven fabric and the stress (F1) at 3% elongation to the above-mentioned numerical values. Further, when the draw ratio is 1.40 times or more, the nonwoven fabric may break, and even if it does not break, the strength of the nonwoven fabric is reduced, and fluff and the like are generated. Moreover, it is difficult to set the stress (F2) at 5% elongation to the above value. The nonwoven fabric is stretched at a temperature lower than the melting point or softening point of the thermoadhesive fiber. If the stretching temperature is too high, the nonwoven fabric becomes hard, which is not preferable.
The nonwoven fabric can be stretched not only in the machine direction but also in the transverse direction.
Moreover, after extending | stretching the nonwoven fabric which carried out thermocompression bonding, it can also carry out a relaxation process. The relaxation treatment may be performed with a tension absorbing bar, a tension absorbing roll, an air blower, or the like between the stretching and winding processes of the nonwoven fabric. Moreover, thermocompression bonding, stretching, etc. can be performed by a continuous method in the nonwoven fabric manufacturing process. Further, once the thermocompression bonded nonwoven fabric is produced, the nonwoven fabric is wound up, and then the nonwoven fabric can be unwound and stretched when processed into an intermediate product or final product using the nonwoven fabric in combination with other products.
[0014]
The basis weight of the thermocompression bonded nonwoven fabric of the present invention is not particularly limited. However, 10-100 g / m in terms of improvement in texture and bending angle of the nonwoven fabric, etc. 2 Is more preferable, and 12 to 50 g / m is more preferable. 2 It is. Especially for applications such as liquid absorbent articles, the basis weight is 12 to 30 g / m. 2 It is. The basis weight is 10g / m 2 If it is less than 1, the nonwoven fabric stress F2 becomes too low, which is not preferable. 100g / m 2 If it exceeds 1, thermocompression bonding becomes difficult, and the texture becomes poor.
[0015]
The absorbent article of the present invention is a product in which the above-mentioned nonwoven fabric is used as a material constituting the liquid absorbent article. For example, in the case of a disposable diaper, the nonwoven fabric is laminated with another nonwoven fabric, a tissue, pulp, a super absorbent material, a film, etc. to form a disposable diaper. For example, a polyethylene sheet is used as a liquid leakage preventing back sheet, a liquid absorbent containing pulp and a superabsorbent that is wrapped in a tissue, and the nonwoven fabric of the present invention is used as a surface material. Examples thereof include liquid absorbent articles such as paper diapers integrated together. Such a liquid-absorbent article has a soft surface material and cannot be bent, so that diaper rash and the like are unlikely to occur.
Further, a laminate sheet in which a polyethylene sheet is laminated on the nonwoven fabric of the present invention so that the nonwoven fabric layer forms the outside and both of them are at least partially fused and integrated is used as the back sheet, and the liquid absorbent material, Liquid absorbent articles such as paper diapers in which the nonwoven fabric of the invention or other nonwoven fabric or other perforated film is used as the surface material, and the back material and the surface material are integrated by thermocompression bonding, etc. It becomes.
Moreover, the paper diaper etc. which take the structure like the said surface material / liquid absorption material / back surface material which laminated | stacked the nonwoven fabric of this invention, another nonwoven fabric, a web, etc. and made it a surface material can be illustrated. This paper diaper has a good texture, has an effect of preventing diaper rash, and further has an effect of improving liquid absorbency.
Also, a heat-bonding nonwoven fabric made of rayon or heat-fusible fiber is used as a liquid absorbent, and 5-40% by weight of hydrophilic fiber such as rayon and 95-60% by weight of heat-fusible fiber are mixed and the fiber. Articles having a structure in which the non-woven fabric of the present invention heat-sealed in (1) is used as a cover material and wraps around the entire liquid absorbent material can be used as a sweat-absorbing material or a makeup remover.
[0016]
The nonwoven fabric of the present invention is a product in which a partially thermocompression-bonded nonwoven fabric is stretched at a specific ratio, and the two kinds of stress characteristics and the like in a low elongation region both have specific numerical values.
The effect of the stretching process is considered as follows. That is, in order to give a high mechanical strength in the thermocompression bonding nonwoven fabric, it is necessary to strongly heat-compress with an embossing roll or the like. A weak heat seal is produced. In addition, due to slight thermal shrinkage during the thermocompression treatment, a phenomenon occurs in which the fibers are excessively tensioned between the thermocompression bonding portions. That is, it tends to be a thing with few degrees of freedom with respect to the stress between the single fibers between thermocompression bonding parts. This results in a nonwoven fabric with a hard texture and a poor tactile feel.
Therefore, by appropriately stretching such nonwoven fabric and performing relaxation treatment if necessary, by setting the two kinds of stress characteristics in the low elongation region of the nonwoven fabric as in the present invention, the fibers between the thermocompression bonding portions The tension can be released. As a result, the texture such as flexibility is good, the nonwoven fabric has high strength, and the machinability can be maintained. Furthermore, in addition to the above features, it is possible to provide a non-woven fabric that does not generate a bending angle.
[0017]
【Example】
Hereinafter, the present invention will be described specifically by way of examples. However, the present invention is not limited to these examples. The physical property values in the following examples and comparative examples are based on the following measuring methods.
[0018]
[F1 and F2]
A test piece having a length of 15 cm in the machine direction and a width of 5 cm is cut from the nonwoven fabric. Using a tensile strength tester, perform a tensile test under the conditions of a grip interval of 100 mm and a tensile speed of 100 mm / min, and measure the stress at the time of 3% elongation (F1) and the stress at the time of 5% elongation (F2) in the machine direction. did.
Here, F1 is 5 cm wide and has a basis weight of 1 g / m. 2 F2 is a stress (unit gf) without weight per unit area per width of 5 cm.
[0019]
[Breaking strength and breaking elongation]
A test piece having a length of 15 cm in the machine direction and a width of 5 cm is cut from the nonwoven fabric. Using a tensile strength tester, a tensile test was performed under the conditions of a grip interval of 100 mm and a tensile speed of 100 mm / min, and the strength at break (unit: gf) and elongation (unit:%) were measured.
[0020]
[Bending softness]
A test piece having a length of 15 cm in the machine direction and a width of 5 cm is cut from the nonwoven fabric. The bending resistance in the machine direction is measured according to JIS-1096 A method (45 degree cantilever method). Unit (mm)
[0021]
[Generation of corners]
A test piece having a length of 15 cm in the machine direction and a width of 5 cm is cut from the nonwoven fabric. Place the test piece on a desk, and make curved contact with both ends by hand. In the bent state, the vicinity of the top of the nonwoven fabric is observed to check for the occurrence of folds. If there is a bend, “Yes” is determined, and if it does not occur, “No” is determined.
[0022]
[Texture]
Five panelists touched a 25 cm × 25 cm non-woven fabric, and the texture was evaluated as “good” or “bad” from the viewpoints of flexibility, fluffing and the like. When three or more people judged “good”, the texture was judged “good”, and in other cases, the texture was judged “bad”.
[0023]
Example 1 and Comparative Examples 1-3
Melt flow rate (ASTM 1238L) 15 ethylene-propylene-butene-1 copolymer (ethylene 3.0%, propylene 92.5%, butene-1, 4.5%) as sheath component, melt flow rate 15 A sheath-core type composite fiber having a composite ratio of 50% by weight to 50% by weight with a crystalline polypropylene as a core component was melt-spun. This undrawn yarn is drawn 2.5 times between hot rolls at a temperature of 90 ° C. using a drawing machine, and then a fiber finish is attached, then mechanical crimping is applied with a stuffing box type crimper, and suction is applied. It was dried with a drier and cut to obtain staple fibers having a fineness of 2 d / f and a fiber length of 38 mm.
Next, the above fiber is made into a web using a card machine, and a metal embossing roll temperature of 130 ° C., a metal flat is used, using a thermocompression bonding device composed of a metal embossing roll and a metal flat roll with a convex diamond shape and a convex area ratio of 23% Thermocompression bonding is performed under the conditions of a trawl temperature of 130 ° C. and a linear pressure of 20 kgf, and the basis weight is 20 g / m. 2 Nonwoven fabric (a) was obtained.
[0024]
This nonwoven fabric (a) was stretched at a respective stretching ratio in the machine direction of the nonwoven fabric using a stretching machine to obtain the nonwoven fabric of the present invention (Example 1) and the nonwoven fabrics other than the present invention (Comparative Examples 1 to 3). . Table 1 shows each physical property value of the obtained nonwoven fabric.
[0025]
The nonwoven fabric of Example 1 that was stretched and F1 and F2 were within the specific numerical range defined by the present invention was a nonwoven fabric that had good texture, did not generate a fold angle, and had a high breaking strength. On the other hand, the nonwoven fabrics of Comparative Examples 1, 2, and 3 in which F1 or F2 is outside the specific numerical range defined in the present invention even if stretch treatment is performed, is any of texture, breaking strength, etc. It was inferior. In Comparative Example 3, the nonwoven fabric had fluff, poor texture, and both F2 and fracture strength were low.
[0026]
Example 2 and Comparative Example 4
A sheath-core composite with a composite ratio of 60% by weight (sheath) vs. 40% by weight (core) comprising melt index (ASTM 1238E) 20 high-density polyethylene as the sheath component and polyethylene terephthalate having an intrinsic viscosity of 0.67 as the core component. The fiber was melt spun. This unstretched yarn is stretched by 3.0 between hot rolls at a temperature of 90 ° C. using a stretching machine, and then a fiber finish is attached. Then, mechanical crimping is applied with a stuffing box type crimper, and a suction dryer is used. It was dried and cut to obtain staple fibers having a fineness of 2 d / f and a fiber length of 51 mm.
Next, the fiber is made into a web using a card machine, and the same thermocompression bonding apparatus as in Example 1 is used, and thermocompression bonding is performed under the conditions of a metal embossing roll temperature of 128 ° C., a metal flat roll temperature of 128 ° C., and a linear pressure of 20 kg / cm. Weighing 20 g / m 2 Nonwoven fabric (b) was obtained.
[0027]
The nonwoven fabric (b) was stretched in the machine direction of the nonwoven fabric using a stretching machine to obtain the nonwoven fabric (Example 2) of the present invention. Table 1 shows each physical property value of the obtained nonwoven fabric.
[0028]
The nonwoven fabric of Example 2, which was stretched and F1 and F2 were within the specific numerical range defined by the present invention, had a good texture, no bending angle, and a high breaking strength. On the other hand, the nonwoven fabric of Comparative Example 4 which was not subjected to stretching treatment or the like was inferior in texture or the like.
[0029]
Example 3 and Comparative Example 5
A spunbonded long-fiber nonwoven fabric made of monocomponent fibers was produced.
A melt flow rate (ASTM 1238L) 40 polypropylene was melt spun by the spunbond method, and continuous long fibers having a fineness of 2 d / f were collected on a conveyor. Using a thermocompression bonding device consisting of a convex embossed rhombus, a metal embossing roll with a convex area ratio of 15%, and a metal flat roll, thermocompression bonding is performed under the conditions of a metal embossing roll temperature of 135 ° C, a metal flat roll temperature of 135 ° C, and a linear pressure of 80 kgf. Processed, basis weight 25g / m 2 Nonwoven fabric (c) was obtained.
[0030]
The nonwoven fabric (c) was stretched in the machine direction of the nonwoven fabric using a stretching machine to obtain the nonwoven fabric (Example 3) of the present invention. Table 1 shows each physical property value of the obtained nonwoven fabric.
[0031]
The nonwoven fabric of Example 2, which was stretched and F1 and F2 were within the specific numerical range defined by the present invention, had a good texture, no bending angle, and a high breaking strength. On the other hand, the nonwoven fabric of Comparative Example 5 that was not stretched was inferior in texture and the like.
[0032]
Example 4 and Comparative Example 6
A spunbonded long-fiber thermocompression bonded nonwoven fabric made of composite fibers was produced.
Polypropylene with a melt flow rate (ASTM 1238L) 29 of a melt flow rate (ASTM 1238L) 29 using a composite spunbond method with a propylene / ethylene copolymer (propylene 96.2% by weight, ethylene 3.8% by weight) of 18 A sheath-core composite long fiber having a composite ratio of 50% by weight (sheath) to 50% by weight (core) was spun, and continuous long fibers having a fineness of 2.2 d / f were collected on a conveyor. Using a thermocompression bonding device consisting of a convex embossed rhombus, a metal embossing roll with a convex area ratio of 15%, and a metal flat roll, thermocompression bonding is performed under the conditions of a metal embossing roll temperature of 130 ° C, a metal flat roll temperature of 130 ° C, and a linear pressure of 60 kgf. Processed, basis weight 25g / m 2 Nonwoven fabric (d) was obtained.
[0033]
This nonwoven fabric (d) was stretched in the machine direction of the nonwoven fabric using a stretching machine to obtain a nonwoven fabric (Example 4) of the present invention. The nonwoven fabric was subjected to tension relaxation treatment using a tension absorbing roll after stretching. Table 1 shows each physical property value of the obtained nonwoven fabric.
[0034]
The nonwoven fabric of Example 4 which was stretched and F1 and F2 were in the specific numerical range defined by the present invention was a nonwoven fabric having a good texture, no bending angle, and high breaking strength. On the other hand, the nonwoven fabric of Comparative Example 6 that was not stretched was inferior in texture and the like.
[0035]
Comparative Example 7
The high density polyethylene / polyethylene terephthalate composite fiber obtained in Example 2 was made into a web using a card machine, heat treated at a temperature of 140 ° C. using a through-air heat treatment machine, and the weight per unit area of 19.8 g where the intersections of the fibers were thermally bonded. / M 2 Nonwoven fabric (e) was obtained. Table 1 shows each physical property value of the nonwoven fabric.
This non-woven fabric had a good texture but had a low stress (F2) at 5% elongation and a bending angle.
[0036]
Example 5
Using a commercially available paper diaper, a new paper diaper was manufactured using only the surface material of this paper diaper and the nonwoven fabric obtained in Example 1 above. In this commercially available paper diaper, a polyethylene sheet is used as a back material for preventing liquid leakage, a liquid water-absorbing material comprising pulp and a polymer water-absorbing agent wrapped in a tissue on the back material, and a span material as a surface material on the top. The bond method polypropylene long fiber nonwoven fabric was used. This surface material was an embossed thermocompression nonwoven fabric. Only the surface material was removed from the paper diaper while cutting with a knife. Instead of the removed surface material, the thermocompression bonded nonwoven fabric obtained in Example 1 is laminated, and the peripheral part of the paper diaper is thermocompression bonded 3 mm in width, and the surface material and the back surface material are thermocompression bonded to obtain the paper diaper of the present invention. It was. This paper diaper had a good texture. Further, it was judged that the surface material was not torn during and after wearing, and that the practical strength was sufficient.
[0037]
[Table 1]
【The invention's effect】
The non-woven fabric of the present invention is a stretched non-woven fabric having a specific numerical value for tensile stress characteristics at low elongation. This nonwoven fabric has a good texture and has an effect that no bending angle or the like is generated when it is bent. In addition, there is an effect that the strength of the nonwoven fabric is large. This nonwoven fabric can be used for paper diapers, sanitary napkins, wipers, disposable towels, bandages, disposable warmers, and the like. A liquid absorbent article using this nonwoven fabric as a material such as a paper diaper was excellent in texture and liquid absorbency.
Claims (12)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22380198A JP4013346B2 (en) | 1998-08-07 | 1998-08-07 | Nonwoven fabric and absorbent article using the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22380198A JP4013346B2 (en) | 1998-08-07 | 1998-08-07 | Nonwoven fabric and absorbent article using the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2000054251A JP2000054251A (en) | 2000-02-22 |
| JP4013346B2 true JP4013346B2 (en) | 2007-11-28 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP22380198A Expired - Lifetime JP4013346B2 (en) | 1998-08-07 | 1998-08-07 | Nonwoven fabric and absorbent article using the same |
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| JP (1) | JP4013346B2 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4581185B2 (en) * | 2000-06-08 | 2010-11-17 | チッソ株式会社 | Non-woven fabric and fiber product using the same |
| US8123734B2 (en) | 2001-08-22 | 2012-02-28 | Sca Hygiene Products Ab | Absorbent article |
| JP5731948B2 (en) * | 2011-04-06 | 2015-06-10 | 旭化成せんい株式会社 | Thermoplastic nonwoven fabric |
| JP2019085661A (en) * | 2017-11-02 | 2019-06-06 | 旭化成株式会社 | Conjugate filament nonwoven fabric |
| JP2020162934A (en) * | 2019-03-29 | 2020-10-08 | Jnc株式会社 | Top sheet for absorbent article and absorbent article |
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1998
- 1998-08-07 JP JP22380198A patent/JP4013346B2/en not_active Expired - Lifetime
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