JPS635495B2 - - Google Patents
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- Publication number
- JPS635495B2 JPS635495B2 JP55183092A JP18309280A JPS635495B2 JP S635495 B2 JPS635495 B2 JP S635495B2 JP 55183092 A JP55183092 A JP 55183092A JP 18309280 A JP18309280 A JP 18309280A JP S635495 B2 JPS635495 B2 JP S635495B2
- Authority
- JP
- Japan
- Prior art keywords
- melting point
- fibers
- point component
- fiber
- composite
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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- 239000000835 fiber Substances 0.000 claims description 72
- 238000002844 melting Methods 0.000 claims description 57
- 230000008018 melting Effects 0.000 claims description 53
- 239000004745 nonwoven fabric Substances 0.000 claims description 40
- 239000002131 composite material Substances 0.000 claims description 33
- 239000000853 adhesive Substances 0.000 claims description 23
- 238000000034 method Methods 0.000 claims description 21
- 229920002994 synthetic fiber Polymers 0.000 claims description 11
- 239000012209 synthetic fiber Substances 0.000 claims description 11
- 230000001070 adhesive effect Effects 0.000 claims description 10
- 238000004519 manufacturing process Methods 0.000 claims description 6
- 229920000642 polymer Polymers 0.000 claims description 2
- 229920005989 resin Polymers 0.000 description 15
- 239000011347 resin Substances 0.000 description 15
- -1 polypropylene Polymers 0.000 description 12
- 229920001577 copolymer Polymers 0.000 description 9
- 239000004743 Polypropylene Substances 0.000 description 5
- 239000011230 binding agent Substances 0.000 description 5
- 238000005520 cutting process Methods 0.000 description 5
- 238000010438 heat treatment Methods 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 238000002156 mixing Methods 0.000 description 5
- 229920001200 poly(ethylene-vinyl acetate) Polymers 0.000 description 5
- 229920001155 polypropylene Polymers 0.000 description 5
- 238000009987 spinning Methods 0.000 description 5
- 239000004677 Nylon Substances 0.000 description 4
- 239000000470 constituent Substances 0.000 description 4
- 239000005038 ethylene vinyl acetate Substances 0.000 description 4
- 239000004744 fabric Substances 0.000 description 4
- 230000004927 fusion Effects 0.000 description 4
- 229920001684 low density polyethylene Polymers 0.000 description 4
- 239000004702 low-density polyethylene Substances 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 229920001778 nylon Polymers 0.000 description 4
- 239000000047 product Substances 0.000 description 4
- 229920000297 Rayon Polymers 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- 229920000728 polyester Polymers 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- 239000002964 rayon Substances 0.000 description 3
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 description 2
- 239000004698 Polyethylene Substances 0.000 description 2
- KKEYFWRCBNTPAC-UHFFFAOYSA-N Terephthalic acid Chemical compound OC(=O)C1=CC=C(C(O)=O)C=C1 KKEYFWRCBNTPAC-UHFFFAOYSA-N 0.000 description 2
- 238000009960 carding Methods 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 229920000573 polyethylene Polymers 0.000 description 2
- 229920000139 polyethylene terephthalate Polymers 0.000 description 2
- 239000005020 polyethylene terephthalate Substances 0.000 description 2
- 229920000098 polyolefin Polymers 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 239000004952 Polyamide Substances 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- 238000010009 beating Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- FYIBGDKNYYMMAG-UHFFFAOYSA-N ethane-1,2-diol;terephthalic acid Chemical compound OCCO.OC(=O)C1=CC=C(C(O)=O)C=C1 FYIBGDKNYYMMAG-UHFFFAOYSA-N 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 230000002209 hydrophobic effect Effects 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 238000004898 kneading Methods 0.000 description 1
- 238000007562 laser obscuration time method Methods 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 229920002647 polyamide Polymers 0.000 description 1
- 229920000874 polytetramethylene terephthalate Polymers 0.000 description 1
- 229920002215 polytrimethylene terephthalate Polymers 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 1
- 229920005653 propylene-ethylene copolymer Polymers 0.000 description 1
- 230000001953 sensory effect Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 239000004753 textile Substances 0.000 description 1
- 229920001169 thermoplastic Polymers 0.000 description 1
- 229920005992 thermoplastic resin Polymers 0.000 description 1
- 239000004416 thermosoftening plastic Substances 0.000 description 1
- 239000000052 vinegar Substances 0.000 description 1
- 235000021419 vinegar Nutrition 0.000 description 1
Landscapes
- Nonwoven Fabrics (AREA)
Description
本発明は薄物の湿式不織布の製造方法に関する
ものである。更に詳しくは、化合繊を構成素材と
し、フイブリル化した複合繊維の熱接着によつて
不織布化された湿式不織布の製造方法に関するも
のである。
近年不織布の需要の延びは大きく、特に使い捨
て不織布として薄物即ち低目付の分野の延びは顕
著である。一般に低目付の範疇に属する不織布
は、目付10〜50ｇ／cm2、中でも15〜25ｇ／cm2のも
のが多く、この分野の不織布は風合いが重要視さ
れることが多く、ソフトな感触が好まれる。その
上最近、使い捨ておしめやウエツトテイツシユの
表面材といつた用途に薄物不織布が使用されるに
及び、風合と共に乾強度は勿論湿潤強度に対する
要求も厳しくなつて来ている。
従来多く使用されてきたバインダー接着による
不織布では、強度向上の要請に応えてバインダー
の使用量を増すと、風合が損なわれることにな
る。更に、使い捨ておしめの表面材の様な用途で
は、法律による残存ホルマリン量の規制により、
使用可能なバインダーに著しい制約を受ける上、
不織布原料として、ポリプロピレンやポリエステ
ルといつた疎水性合繊が主流となる傾向にあり、
バインダー方式では強度及び風合を併せて維持す
るとが技術的にも経剤的にも益々困難となつてき
ている。ポリプロピレン或はポリエチレンの様な
比較的融点の低い熱可塑性繊維の熱融着により不
織布の繊維を固定する所謂ノーバインダー方式に
よる不織布の製造方法が脚光を浴びつつある。こ
れらは低融点繊維が単体繊維として用いられる場
合には、該繊維は熱融着時に収縮や凝集を伴つて
溶融し、繊維形状を失うため、熱融着点の分布が
粗らく且つ不均一になり、使用量に比らべて強度
向上への寄与効果が少く、風合はゴツゴツした感
じとなり好ましくない。一方、融点を異にする成
分から成る複合型熱接着繊維が優れた不織布を与
えることが知られている（特公昭52−12830）。し
かしながら薄物不織布の製造に一般的に使用され
る乾式カード法ではウエツブ構成繊維の方向性を
回避することがむずかしく、横方向の強度が低く
なり、充分な強度を得るためには複合型熱接着繊
維であつてもその混入率を高める必要があり、製
品は硬い感じで風合の劣つたものとなる。
風合の改良のために原料として細デニールの繊
維を用いる方法が知られているが、薄物不織布で
はすでに３デニール程度の細デニール繊維が使用
されており、これより更に細い繊維を用いる場合
には、カード機の針布中に繊維が沈み込み、均質
な不織布が得られないといつた問題が起る。又、
ランダムウエブ法はこのような細い繊細では生産
性が上らず実際的でない。
一方湿式法では、レーヨン、ポリプロピレン、
ポリエステル等の化合繊を構成素材として抄紙す
る場合、これらの化合繊はフイブリル構造を有し
ないため繊維間の絡み合いに欠け、抄紙時の湿潤
シートの強度が低く、該シートを抄紙スクリーン
から剥す際に切断し易く満足に不織布化できな
い。化合繊にパルプを混抄することにより前記湿
潤シートの強度を高めることができるが、このよ
うにし得られた不織布は紙に似た感触となり、乾
式不織布の示す柔らかな風合の製品は得られな
い。化合繊をフイブリル化させる試みも種々なさ
れており、特公昭48−7881、特開昭48−1403、特
開昭50−154530等に示されている。これらはいず
れも互いに相溶性の乏しい熱加塑性樹脂の混合物
を加熱混練、押出成型、延伸配向、切断、叩解と
いう一連の操作を施し、微細に混合された構成成
分の界面で剥離を起させることによりフイブリル
化した繊維を得るものであり、このようにして得
られた繊維を用いて造つた不織布は、特に加熱処
理により強度を高めた場合には、前述の単体熱接
着繊維混抄の例と同様に風合の劣つたものとな
る。
本発明者は化合繊を素材とする湿式不織布の前
記の諸欠点を改良し、バインダーを使用せずに充
分な乾並びに湿潤強度を維持し、且つ柔軟な風合
を有する不織布の製造方法につき鋭意効討な結果
本発明に到達したものである。
本発明は平均繊度が1.5デニール以下の化合繊
繊維で構成され、且つフイブリル化した複合型熱
接着繊維を25重量％以上含み、該熱接着繊維の熱
接着によつて繊維間の結合を行わしめることを特
徴とする縦横いずれの方向の乾並びに湿潤強度の
優れた湿式不織布の製造方法である。
本発明において構成繊維の平均繊度を1.5デニ
ール以下と限定する理由は以下の通りである。最
近の薄物不織布の多岐にわたる用途の要求に応え
るには、縦横いずれの乾並びに湿潤強度とも500
ｇ以上を必要とするが、従来の平均繊度３デニー
ル程度の構成繊維で複合型熱接着繊維の熱接着に
よつてこの要求を満たそうとすると、該熱接着繊
維の混入率は50％以上となり優れた風合の製品は
得られない。
乾式カード法によつて平均繊度の風合に及ぼす
効果について検討した結果、平均繊度1.5デニー
ル以下であれば複合型熱接着繊維を50％以上混合
しても柔軟な風合を得ることはできるが、カード
シリンダーの針布中に繊維が沈み込み、ネツプの
発生が多く、且つ均質な不織布が得られず、工業
的生産には問題があることが判明した。又、平均
繊度が2.0デニールであれば、不織布は一応安定
して得られるが、その風合はなを不充分なもので
あつた。
次に、湿式手抄き法により同様の検討を行つた
ところ、平均繊度1.5デニール以下であれば、乾
式不織布の場合と同様の良好な風合の不織布が得
られることを見出した。更に、平均繊度が1.5デ
ニール以下であつても、3.0デニール以上の繊維
を含有しない方が好ましいことも見出した。
しかし、このような構成の化合繊繊維を湿式抄
紙機により不織布化しようとすると、繊維間の絡
らみ合いの不足により抄紙工程に於て前述のトラ
ブルを生ずる。
本発明の目的の一つは、この抄紙工程のトラブ
ルの解決にあり、熱接着繊維としてフイブリル化
した複合型熱接着繊維を用いることにより抄紙時
の湿潤シートの紙力を高め、切断することなく抄
紙することを可能とし、且つ該シートを加熱乾燥
して複合型熱接着繊維による熱接着により柔軟な
風合の湿式不織布を得んとするものである。
本発明において用いるフイブリル化した複合型
熱接着繊維は、高融点成分の最大延伸比（以下
HM（MS）と記す）が低融点成分の最大延伸比
（以下LM（MS）と記す）の２倍以上（HM（MS）
＞2LM（MS））である様に選らべれた繊維形成性
重合体を、低融点成分が繊維外面の70％以上を占
める様に並列型あるいは鞘芯型に組み合わせ、得
られた複合未延伸糸をLM（MS）の1.2乃至2.0倍
で且つ延伸倍率が4.5倍以下の範囲で延伸するこ
とによつて得ることができる。
HM（MS）＞2LM（MS）の関係を満足する樹脂
から成る複合未延伸糸を（LM（MS）の1.2倍以
上且つ2.0倍以下の条件で延伸する理由は、
1.2LM（MS）〜2.0LM（MS）の範囲内では高融
点成分は延伸によつて切断されないが、低融点成
分は高融点成分上にあつて切断を生じ、この切断
によつて図面に示される様な複雑なフイブリル構
造をもたらすことにある。延伸比がLM（MS）の
1.2倍以下では低融点成分の切断が不充分な場合
も生じ、切断部のフイブリル構造も不完全なもの
となり、繊維間の絡み合いが弱く抄紙時に湿潤シ
ートが切断し易い。又LM（MS）の２倍以上延伸
すると、低融点成分は切断個所が多くなり小片化
すると共に、高融点成分が延伸により細くなる際
に両成分間に剥離を起し易くなる。更に、低融点
成分が繊維外面の70％以上を占め且つ延伸倍率を
4.5倍以下とする理由も、これらの条件を満足し
ていないと、切断した低融点成分が容易に高融点
成分より剥離し単体繊維化乃至粉末化するためで
ある。
高融点成分の融点は低融点成分の融点より20℃
以上高く設定される。好ましくは25℃以上高くす
る。高融点成分と低融点成分との融点の差が20℃
より小さい場合は、両融点間の温度で熱処理して
不織布化することが困難になるからである。高融
点成分の融点は、通常155乃至300℃、好ましくは
160乃至260℃である。
低融点成分としてはポリオレフイン（ポリエチ
レン、エチレン共重合体例えばエチレン―ブテン
共重合体、エチレン―酢ビ共重合体、エチレン―
酢ビ共重合体の任意のケン化物、エチレン―プロ
ピレン共重合体、エチレン―ブテン共重合体、エ
チレン―ブテン―プロピレン共重合体、およびプ
ロピレン共重合体など）等通常複合繊維に用いら
れる樹脂があげられる。
また高融点成分としてはポリオレフイン（結晶
性ポリプロピレン、プロピレン共重合体例えばプ
ロピレン―エチレン共重合体、プロピレン―ブテ
ン共重合体、プロピレン―エチレン―ブテン共重
合体など）、ポリアミド（66―ナイロン、６―ナ
イロン、６，10―ナイロン、11―ナイロンなど）、
ポリエステル（テレフタル酸系樹脂例えばポリエ
チレンテレフタレート、ポリトリメチレンテレフ
タレート、ポリテトラメチレンテレフタレートな
ど）、等通常複合繊維に用いられる樹脂があげら
れる。
低融点成分と高融点成分とを組み合わせて複合
繊維（本発明に用いる複合繊維としては並列型、
鞘芯型のいずれも用いることができる）を構成す
るに際し上記の融点差の関係及び最大延伸比の関
係（HM（MS）＞2LM（MS））を満足する限りに
おいて、その組み合わせは特に限定されるもので
ない。樹脂の最大延伸比は延伸温度によつて変化
するので、両成分は適当に選択された同一の延伸
温度で前記最大延伸比の関係と満足させねばなら
ない。
複合繊維において、低融点成分と高融点成分と
の重量比は、40：60乃至60：40が通常好ましく用
いられる範囲である。低融点成分が繊維の外面の
70％以上を占める複合繊維は、該低融点成分を鞘
成分とする鞘芯型とするか、或は並列型であれば
特公昭55−26209号公報に示された方法によつて
製造できる。
本発明に使用される複合型熱接着繊維は公知の
溶融複合紡糸方法によつて製造することができ
る。紡糸装置並びに延伸装置も公知のものでよ
い。
このようにして得られたフイブリル化した複合
型熱接着繊維を不織布中に25重量％以上混抄する
理由は、25重量％以下では抄紙時の湿潤シートの
強度が不充分で切断し易く、且つ得られた不織布
の強度が目標とする500ｇ以上を維持することが
むずかしいことにある。
抄紙方法は公知の抄紙方法を用いることがで
き、抄紙機も、傾斜長網やロートホーマーに限ら
ず、短網や丸網など通常の抄紙機が使用できる。
抄紙時に、ポリビニルアルコール繊維或は本発明
に係る複合型熱接着性繊維の低融点成分より融点
の低い化合繊維を接着繊維として併用混抄するこ
とも可能であるが、これら接着繊維は一般に単体
繊維であり融着時に繊維形状を消失して接着に寄
与するものであるため、前述の如く不織布の風合
を損う惧れがあり、混抄率は10重量％以下、更に
は５重量％以下が好ましい。
繊維間の結合を発現させるための熱処理は、抄
紙工程中の乾燥工程を複合型熱接着性繊維の両成
分の融点間の温度で行うことによつて実現され、
一般には低融点成分の融点より約10℃高い温度で
充分に熱融着が可能である。複合型熱接着繊維の
低融点成分の融点が高く。ヤンキードライヤー等
の抄紙機に付属した乾燥工程では熱融着が不充分
な場合、或は最終製品にエンボス加工を行う様な
場合には、仕上加工の為に、乾燥工程とは別の加
熱処理を施すことも可能である。
かくして、フイブリル化した複合型熱接着繊維
を用いることにより繊維間の絡み合いの効果を与
え、化合繊繊維のみの構成であつても充分に連続
抄紙が可能となり、製品不織布の繊維間の結合が
複合型熱接着繊維の熱接着であるから湿潤時にお
いても強度の低下が殆んどなく、目付が10Kg／m3
程度の薄物であつても乾並びに湿潤強度500ｇ以
上で且つ良好な風合の不織布を容易に製造するこ
とができる。
本発明を実施例によつて更に説明する。
本発明における各種特性の測定法又は定義をま
とめて示しておく。
不織布乾並びに湿潤強度
・ JIS L1096（一般織物試験方法）に準じ、
５cm巾の試料片を、つかみ間隔10cm、伸長速
度１分間当り100％で測定した。
・ 湿潤強度は、あらかじめ１時間水中に浸漬
した試料片を用いて上記試験方法で測定し
た。
HM（MS）並びにLM（MS）
複合繊維の紡糸時と同一の条件で高融点成分
樹脂及び低融点成分樹脂をそれぞれ単独で紡糸
し、未延伸糸を得る。電気加熱方式の熱ロール
を有する延伸機を用い所定の温度で上記未延伸
糸を延伸し、単糸切れの生じない範囲の最大の
延伸倍率をもつてHM（MS）或はLM（MS）と
する。
湿潤シート強度の評価
所定の配合比の素材30Kgを水に0.25％に希釈
したものを、長網ラストマシンを用いて抄紙
し、金網→フエルト，フエルト→ドライヤーへ
の移行時に、湿潤シートの切断を生じた場合：
×、切断は生じないが割れ目が観察された：
△、切断も割れ目も観察されなかつた場合：
〇、と評価した。
風合の評価
強度的には不充分であるが、風合が優れてい
る下記の２種の接着法による不織布を基準試料
とし、５人のパネラーによる官能試験を行い、
全員がこれら基準試料の風合と同等もしくはそ
れ以上と判定した場合：〇、３名以上が同等も
しくはそれ以上と判定したが１乃至２名が劣る
と判定した場合：△、３名以上が劣ると判定し
た場合：×、と評価した。
Ａ；レーヨン3d×51mm100％、乾式カード法、
酢ビバイダー15％使用、目付20ｇ／m2
Ｂ；ポリプロピレン／ポリエチレン複合型熱接
着繊維（ES繊維）3d×64mm30％、レーヨ
ン3d×51mm70％、乾式カード法、目付15
ｇ／m2
実施例１〜６、比較例１〜６
実施例並びに比較例に使用した複合型熱接着繊
維８種（〜）の原料樹脂及び紡糸条件を第１
表に示した。
・ 〜に使用した高融点成分樹脂；結晶性ポ
リプロピレン（pp）、
・ ，に使用した高融点成分樹脂；エチレン
グリコールテレフタレート重合体（PET）
・ 〜に使用した低融点成分樹脂；低密度ポ
リエチレン（LDPE）
・ ，に使用した低融点成分樹脂；低密度ポ
リエチレン75％とエチレン酢ビコポリマー25％
の混合物（PE―EVA）、
・ ，で使用した低融点成分樹脂；酢酸ビニ
ル含量５％のエチレン酢ビコポリマー（EVA
―５）、
これらの樹脂を両成分とし、所定の複合比に配
した鞘芯型又は並列型の複合繊維を製造した。紡
糸温度は、いずれも、高融点成分側が300℃、低
融点成分側が230℃である。延伸温度は〜が
50℃、〜が60℃であり、これはいずれも成分
樹脂の最大延伸比を測定した温度と等しい。
第１表に記された複合型熱接着繊維と化合繊維
を種々の比率で混合し、長網ラストマシンで抄紙
し、得られた不織布の特性をその原料組成と共に
第２表に示した。ドライヤー温度は、複合型熱接
着繊維の低融点成分が、
LDPEの場合 120℃
PE―EVAの場合 115％
EVA―５の場合 120℃
で運転した。
The present invention relates to a method for producing a thin wet-laid nonwoven fabric. More specifically, the present invention relates to a method for manufacturing a wet-laid nonwoven fabric made of synthetic fibers and made into a nonwoven fabric by thermal bonding of fibrillated composite fibers. In recent years, the demand for nonwoven fabrics has increased significantly, particularly in the field of thin, low basis weight disposable nonwoven fabrics. In general, nonwoven fabrics that belong to the category of low basis weight have a basis weight of 10 to 50 g/cm 2 , and most of them are 15 to 25 g/cm 2 . For nonwoven fabrics in this field, texture is often important, and a soft feel is preferred. It can be done. Moreover, recently, as thin nonwoven fabrics have been used for applications such as surface materials for disposable diapers and wet tissues, requirements for not only dry strength but also wet strength as well as texture have become stricter. In conventionally widely used nonwoven fabrics bonded with binders, if the amount of binder used is increased in response to demands for improved strength, the texture will be impaired. Furthermore, in applications such as surface materials for disposable diapers, due to legal restrictions on the amount of formalin remaining,
In addition to being severely limited by the binders that can be used,
Hydrophobic synthetic fibers such as polypropylene and polyester are becoming mainstream as raw materials for nonwoven fabrics.
With the binder method, it is becoming increasingly difficult to maintain both strength and texture both technically and pharmaceutically. BACKGROUND OF THE INVENTION A so-called binder-free method for producing nonwoven fabrics, in which the fibers of nonwoven fabrics are fixed by thermal fusion of thermoplastic fibers with a relatively low melting point, such as polypropylene or polyethylene, is attracting attention. When low-melting point fibers are used as single fibers, the fibers shrink or aggregate during heat-fusion and melt, losing their fiber shape, resulting in a rough and uneven distribution of heat-fusion points. Therefore, the contribution to strength improvement is small compared to the amount used, and the texture becomes rough, which is not preferable. On the other hand, it is known that composite heat-adhesive fibers composed of components having different melting points provide excellent nonwoven fabrics (Japanese Patent Publication No. 52-12830). However, in the dry carding method commonly used to produce thin nonwoven fabrics, it is difficult to avoid the orientation of the fibers that make up the web, resulting in low strength in the transverse direction. Even if it is, it is necessary to increase the mixing rate, and the product will feel hard and have an inferior texture. A method of using fine denier fibers as a raw material to improve texture is known, but fine denier fibers of about 3 denier are already used in thin nonwoven fabrics, and when using fibers even finer than this, However, the problem arises that the fibers sink into the clothing of the carding machine, making it impossible to obtain a homogeneous nonwoven fabric. or,
The random web method is not practical for such thin and delicate materials because it does not increase productivity. On the other hand, in the wet method, rayon, polypropylene,
When paper is made using synthetic fibers such as polyester as constituent materials, these synthetic fibers do not have a fibrillar structure, so they lack entanglement between fibers, and the strength of the wet sheet during papermaking is low, making it difficult to remove the sheet from the papermaking screen. It is easy to cut and cannot be made into a non-woven fabric satisfactorily. The strength of the wet sheet can be increased by mixing pulp with synthetic fibers, but the nonwoven fabric obtained in this way has a feel similar to paper, and it is not possible to obtain a product with the soft texture of a dry nonwoven fabric. . Various attempts have been made to fibrillate synthetic fibers, as disclosed in Japanese Patent Publication No. 7881-1981, Japanese Patent Publication No. 48-1403, and Japanese Patent Publication No. 154530-1974. In both of these methods, a mixture of thermoplastic resins with poor compatibility with each other is subjected to a series of operations such as heating and kneading, extrusion molding, stretching orientation, cutting, and beating to cause peeling at the interface of the finely mixed constituent components. Fibrillated fibers are obtained by this method, and nonwoven fabrics made using the fibers obtained in this way, especially when the strength is increased by heat treatment, are similar to the above-mentioned example of single heat-bonded fiber mixture. The texture becomes inferior. The present inventor has made efforts to improve the above-mentioned drawbacks of wet-laid nonwoven fabrics made from synthetic fibers, and to develop a method for producing nonwoven fabrics that maintain sufficient dry and wet strength without using a binder and have a flexible texture. As a result of effective investigations, we have arrived at the present invention. The present invention is composed of synthetic fibers with an average fineness of 1.5 denier or less, and contains 25% by weight or more of fibrillated composite heat-adhesive fibers, and the fibers are bonded by thermal bonding of the heat-adhesive fibers. This is a method for producing a wet-laid nonwoven fabric having excellent dry and wet strength in both the vertical and horizontal directions. The reason why the average fineness of the constituent fibers is limited to 1.5 denier or less in the present invention is as follows. In order to meet the demands of modern thin non-woven fabrics for a wide variety of applications, both vertical and horizontal dry and wet strengths must be 500%
g or more, but if we try to meet this requirement by thermally adhering composite thermally adhesive fibers using conventional constituent fibers with an average fineness of about 3 deniers, the mixing rate of the thermally adhesive fibers will be more than 50%. A product with excellent texture cannot be obtained. As a result of examining the effect of average fineness on texture using the dry card method, it was found that if the average fineness was 1.5 denier or less, a flexible texture could be obtained even if 50% or more of composite thermal adhesive fiber was mixed. It has been found that there are problems in industrial production, as the fibers sink into the clothing of the card cylinder, many neps occur, and a homogeneous nonwoven fabric cannot be obtained. Further, if the average fineness is 2.0 denier, a nonwoven fabric can be obtained stably to some extent, but its texture is unsatisfactory. Next, we conducted a similar study using the wet hand-sheeting method, and found that if the average fineness was 1.5 denier or less, a nonwoven fabric with a good feel similar to that of dry-processed nonwoven fabrics could be obtained. Furthermore, it has been found that even if the average fineness is 1.5 denier or less, it is preferable not to contain fibers of 3.0 denier or more. However, when synthetic fibers having such a structure are attempted to be made into a nonwoven fabric using a wet paper machine, the above-mentioned troubles occur in the paper making process due to insufficient entanglement between the fibers. One of the purposes of the present invention is to solve this problem in the papermaking process, and by using fibrillated composite heat-adhesive fibers as heat-adhesive fibers, the paper strength of the wet sheet during papermaking can be increased, without the need for cutting. The purpose is to make it possible to make paper, heat dry the sheet, and obtain a wet nonwoven fabric with a soft texture by heat bonding with composite heat bonding fibers. The fibrillated composite heat-adhesive fiber used in the present invention has a maximum draw ratio (hereinafter referred to as
HM (MS)) is more than twice the maximum drawing ratio of the low melting point component (hereinafter referred to as LM (MS))
>2LM (MS)) are combined in a parallel type or sheath-core type so that the low melting point component occupies 70% or more of the outer surface of the fibers, and the resulting composite unstretched It can be obtained by stretching the yarn at a stretching ratio of 1.2 to 2.0 times LM (MS) and a stretching ratio of 4.5 times or less. The reason why a composite undrawn yarn made of a resin that satisfies the relationship of HM (MS) > 2 LM (MS) is stretched under the conditions of 1.2 times or more and 2.0 times or less of LM (MS) is as follows.
Within the range of 1.2LM (MS) to 2.0LM (MS), the high melting point component is not cut by stretching, but the low melting point component is on top of the high melting point component and is cut, and this cutting causes the The aim is to create a complex fibrillar structure that can be Stretching ratio is LM (MS)
If it is less than 1.2 times, the cutting of the low-melting point component may be insufficient, and the fibril structure at the cut portion will be incomplete, and the entanglement between the fibers will be weak, making it easy to cut the wet sheet during paper making. Furthermore, when stretched more than twice the LM (MS), the low melting point component has many cut points and becomes small pieces, and when the high melting point component becomes thinner due to stretching, separation between the two components tends to occur. Furthermore, the low melting point component occupies more than 70% of the outer surface of the fiber and the draw ratio
The reason why it is set to 4.5 times or less is that if these conditions are not satisfied, the cut low melting point component will easily separate from the high melting point component and become a single fiber or powder. The melting point of the high melting point component is 20℃ higher than the melting point of the low melting point component.
It is set higher than that. Preferably, the temperature is raised by 25°C or more. The difference in melting point between high melting point component and low melting point component is 20℃
This is because if the size is smaller, it becomes difficult to heat-treat at a temperature between both melting points to form a nonwoven fabric. The melting point of the high melting point component is usually 155 to 300°C, preferably
The temperature is 160 to 260°C. Low melting point components include polyolefins (polyethylene, ethylene copolymers such as ethylene-butene copolymers, ethylene-vinyl acetate copolymers, ethylene-
Resins commonly used for composite fibers such as any saponified vinyl acetate copolymer, ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-butene-propylene copolymer, propylene copolymer, etc.) can give. In addition, high melting point components include polyolefins (crystalline polypropylene, propylene copolymers such as propylene-ethylene copolymers, propylene-butene copolymers, propylene-ethylene-butene copolymers, etc.), polyamides (66-nylon, 6- nylon, 6,10-nylon, 11-nylon, etc.)
Examples of the resin include polyester (terephthalic acid resins such as polyethylene terephthalate, polytrimethylene terephthalate, polytetramethylene terephthalate, etc.), which are commonly used in composite fibers. A composite fiber made by combining a low melting point component and a high melting point component (the composite fiber used in the present invention is a parallel type,
As long as the relationship between the melting point difference and the maximum draw ratio (HM (MS) > 2LM (MS)) is satisfied, the combination is not particularly limited. It's not something you can do. Since the maximum stretching ratio of the resin varies depending on the stretching temperature, both components must satisfy the above-mentioned maximum stretching ratio relationship at the same appropriately selected stretching temperature. In the composite fiber, the weight ratio of the low melting point component to the high melting point component is usually preferably in the range of 40:60 to 60:40. The low melting point component is on the outer surface of the fiber.
Composite fibers accounting for 70% or more can be produced by the method disclosed in Japanese Patent Publication No. 55-26209 if they are of a sheath-core type in which the low melting point component is a sheath component, or if they are of a parallel type. The composite heat-adhesive fiber used in the present invention can be produced by a known melt composite spinning method. The spinning device and the stretching device may also be of known type. The reason why 25% by weight or more of the fibrillated composite heat-adhesive fiber thus obtained is mixed into the nonwoven fabric is that if it is less than 25% by weight, the strength of the wet sheet during paper making is insufficient and it is easy to cut. The problem is that it is difficult to maintain the strength of the nonwoven fabric at the target of 500 g or more. A known paper making method can be used for the paper making method, and the paper making machine is not limited to an inclined Fourdrinier or a rotary former, but a normal paper making machine such as a short screen or a round screen can be used.
During paper making, it is also possible to use polyvinyl alcohol fibers or compound fibers with a lower melting point than the low melting point components of the composite heat-adhesive fiber according to the present invention as adhesive fibers, but these adhesive fibers are generally single fibers. Since the fiber shape disappears during fusion and contributes to adhesion, as mentioned above, there is a risk of damaging the texture of the nonwoven fabric, so the mixing ratio is preferably 10% by weight or less, and more preferably 5% by weight or less. . The heat treatment to develop the bond between the fibers is achieved by performing the drying process during the papermaking process at a temperature between the melting points of both components of the composite thermoadhesive fiber,
Generally, sufficient heat fusion is possible at a temperature approximately 10°C higher than the melting point of the low melting point component. The low melting point component of the composite thermal adhesive fiber has a high melting point. If the drying process attached to a paper machine such as a Yankee dryer does not provide sufficient heat fusion, or if the final product is to be embossed, a heat treatment separate from the drying process may be used for finishing. It is also possible to apply In this way, the use of fibrillated composite heat-adhesive fibers provides the effect of intertwining between fibers, making continuous papermaking possible even with only synthetic fibers, and the bonding between fibers of the product nonwoven fabric becomes composite. Since it is thermally bonded with type thermally bonded fibers, there is almost no decrease in strength even when wet, and the fabric weight is 10Kg/ m3.
Even if the fabric is fairly thin, it is possible to easily produce a nonwoven fabric with a dry and wet strength of 500 g or more and a good feel. The present invention will be further explained by examples. The measurement methods or definitions of various characteristics in the present invention will be summarized below. Nonwoven fabric dry and wet strength ・According to JIS L1096 (general textile testing method),
A 5 cm wide sample piece was measured at a gripping interval of 10 cm and an elongation rate of 100% per minute. - Wet strength was measured using the above test method using a sample piece that had been immersed in water for 1 hour. HM (MS) and LM (MS) A high melting point component resin and a low melting point component resin are individually spun under the same conditions as when spinning composite fibers to obtain undrawn yarns. HM (MS) or LM (MS) is drawn by stretching the undrawn yarn at a predetermined temperature using a stretching machine equipped with electrically heated heating rolls at the maximum stretching ratio within the range that does not cause single yarn breakage. do. Evaluation of wet sheet strength 30 kg of material with a specified blending ratio was diluted to 0.25% in water and made into paper using a fourdrinier last machine, and the wet sheet was cut at the time of transition from wire mesh to felt and felt to dryer. If this occurs:
×, no cutting occurred but cracks were observed:
△, when no cuts or cracks were observed:
Rated as ○. Evaluation of texture Using nonwoven fabrics produced by the following two adhesive methods as standard samples, which have insufficient strength but excellent texture, a sensory test was conducted by five panelists.
If everyone judged the texture to be the same as or better than those of these reference samples: ○, If 3 or more people judged it to be the same or better, but 1 or 2 people judged it to be inferior: △, 3 or more people judged it to be inferior When it was determined that: × was evaluated. A; Rayon 3D x 51mm 100%, dry card method,
Using 15% vinegar vibrator, fabric weight 20g/m 2 B; polypropylene/polyethylene composite thermal adhesive fiber (ES fiber) 3D x 64mm 30%, rayon 3D x 51mm 70%, dry card method, fabric weight 15
g/m 2 Examples 1 to 6, Comparative Examples 1 to 6 The raw resin and spinning conditions of the 8 types (~) of composite thermal adhesive fibers used in the Examples and Comparative Examples were
Shown in the table.・ High melting point component resin used in ~; crystalline polypropylene (pp); ・ High melting point component resin used in ~: ethylene glycol terephthalate polymer (PET) ・ Low melting point component resin used in ~; low density polyethylene (LDPE) ) Low melting point resin used for , 75% low density polyethylene and 25% ethylene acetate copolymer
mixture (PE-EVA), low melting point component resin used in ,; ethylene vinyl acetate copolymer (EVA
-5) A sheath-core type or parallel type composite fiber was manufactured using these resins as both components and arranging them at a predetermined composite ratio. The spinning temperature is 300°C for the high melting point component and 230°C for the low melting point component. The stretching temperature is ~
50°C and 60°C, both of which are equal to the temperatures at which the maximum stretch ratios of the component resins were measured. The composite heat-adhesive fibers and compound fibers listed in Table 1 were mixed in various ratios and paper was made using a Fourdrinier last machine. The properties of the resulting nonwoven fabrics are shown in Table 2 along with their raw material compositions. The dryer temperature was 120°C for LDPE, 115% for PE-EVA, and 120°C for EVA-5.
【表】【table】
【表】【table】
図面は低融点成分及び高融点成分を複合成分と
するフイブリル化した複合型熱接着繊維の鞘芯型
及び並列型単繊維を拡大模式図であり、図中の符
号は次の如くである。
１：鞘芯型 １：低融点成分、２：並列型
２：高融点成分。
The drawing is an enlarged schematic diagram of a sheath-core type and a parallel type single fiber of a fibrillated composite heat-adhesive fiber containing a low-melting point component and a high-melting point component as composite components, and the symbols in the figure are as follows. 1: Sheath-core type 1: Low melting point component, 2: Parallel type
2: High melting point component.
Claims (1)
構成され、且つ高融点成分の最大延伸比が低融点
成分の最大延伸比の２倍以上である様に選ばれた
繊維形成性重合体を、低融点成分が繊維外面の70
％以上を占める様に並列型あるいは鞘芯型に組み
合わせ、得られた未延伸糸を低融点成分の最大延
伸比の1.2倍乃至2.0倍で且つ延伸倍率が4.5倍以下
の範囲で延伸することによつて得られたフイブリ
ル化した複合型熱接着繊維を25重量％以下含み、
該熱接着繊維の熱接着によつて繊維間の結合を行
わしめることを特徴とする、縦横いずれの方向の
乾並びに湿潤強度の優れた湿式不織布の製造方
法。1 A fiber-forming polymer composed of synthetic fibers with an average fineness of 1.5 denier or less and selected such that the maximum drawing ratio of the high melting point component is at least twice the maximum drawing ratio of the low melting point component is The melting point component is 70 on the outer surface of the fiber.
% or more, and the resulting undrawn yarn is drawn in a range of 1.2 to 2.0 times the maximum drawing ratio of the low melting point component and 4.5 times or less. Contains 25% by weight or less of the fibrillated composite heat-adhesive fiber obtained by
A method for producing a wet-laid nonwoven fabric having excellent dry and wet strength in both the vertical and horizontal directions, the method comprising bonding the fibers by thermally bonding the thermally adhesive fibers.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP55183092A JPS57106755A (en) | 1980-12-24 | 1980-12-24 | Production of wet nonwoven fabric |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP55183092A JPS57106755A (en) | 1980-12-24 | 1980-12-24 | Production of wet nonwoven fabric |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS57106755A JPS57106755A (en) | 1982-07-02 |
| JPS635495B2 true JPS635495B2 (en) | 1988-02-03 |
Family
ID=16129613
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP55183092A Granted JPS57106755A (en) | 1980-12-24 | 1980-12-24 | Production of wet nonwoven fabric |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS57106755A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2017075440A (en) * | 2016-11-30 | 2017-04-20 | ユニ・チャーム株式会社 | Nonwoven fabric, absorbent article containing nonwoven fabric and nonwoven fabric forming method |
-
1980
- 1980-12-24 JP JP55183092A patent/JPS57106755A/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2017075440A (en) * | 2016-11-30 | 2017-04-20 | ユニ・チャーム株式会社 | Nonwoven fabric, absorbent article containing nonwoven fabric and nonwoven fabric forming method |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS57106755A (en) | 1982-07-02 |
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