技術分野
本発明はハイパイル、ボア、毛布、マット、カーペットなどのパイル状布帛全般に使用され、布帛にボリューム感を付与できるレギュラーアクリル系合成繊維に関するものである。
背景技術
アクリル系合成繊維でハイパイル生地を製造する時には差し毛となる大繊度繊維（通常１７〜３３ｄｔｅｘの難燃繊維）と小繊度繊維（通常２．２〜４．４ｄｔｅｘ程度）を混合し、使用する。場合によってはこれらの中間繊度の繊維（７．８〜１１ｄｔｅｘ程度）も混合することもある。このうち、小繊度繊維に高収縮（乾熱収縮率２５％以上、好ましくは３０％以上）繊維を使用するとハイパイル生地のボリューム感を増すことができる。これはハイパイル生地の後処理工程（毛抜け防止用糊の乾燥工程）において小繊度繊維が収縮し、大、中繊度繊維を支える形となり、大、中繊度繊維が倒れにくくなるためである。小繊度繊維に非収縮もしくは収縮率が小さい繊維を用いた場合には大、中繊度繊維を支えることができないか、その効果が小さいため、容易に倒れ、ボリューム感が不足する。なお、特に記載のない限り「繊維」とはアクリル系合成繊維を差す。また、ジャガード編み機を使用すると非収縮繊維生地に収縮繊維で模様を描くことができ、後処理工程（毛抜け防止用糊の乾燥工程）において収縮繊維部分のみが収縮し、立体的な模様とすることができる。
小繊度の高収縮繊維は多くの場合は難燃繊維であるが、これは収縮率、特に乾熱収縮率が得られやすいためである。しかし、一般に難燃アクリル系合成繊維は難燃成分として塩化ビニリデン、塩化ビニルなどの高比重成分を多く含むため、繊維比重が大きく、同じ繊度のレギュラー（非難燃）繊維と比較して、繊維の実直径が小さくなる。そのため、生地のボリューム感が低減しがちである。実直径が大きい繊維を使用した場合は生地が重くなってしまう。
なお、以下本明細書ではハロゲン化ビニル成分のような難燃成分を含まないアクリル系合成繊維を「レギュラー繊維」と称する。
一方、塩化ビニリデン、塩化ビニルなどの高比重成分を含まないレギュラー繊維にも高収縮繊維はある。ただし、これはボア、毛布、マット、カーペットなどに混紡使用する繊維で湿熱収縮率は２５％程度であるが、乾熱１２０〜１３０℃、１〜２分間で処理する通常のハイパイル製造工程（毛抜け防止用糊の乾燥工程）では充分な乾熱収縮率（２５％以上）を得ることができない（特開昭６０−１１０９１０号公報、特開昭５３−１７６９１号公報）。
特開平８−７４１１９号公報にはハイパイル用途向けの乾熱高収縮レギュラー繊維の例がある。これによれば、紡糸延伸・乾燥緻密化後、１１０〜１５０℃好ましくは１１５〜１３５℃の加圧水蒸気下で３０％以上収縮後、乾熱１００〜１４０℃で１．６〜２．２倍延伸するとあるが、熱可塑性分が少ない通常のポリマーでかつ通常行われている連続方式ではこの温度で３０％以上収縮するのは困難である。また、可塑成分が少ないため、収縮後にこれだけ延伸するのは困難である。また、乾熱収縮率の測定方法も１３０℃×１０分加熱と実際のハイパイル製造工程とかけ離れている。
一方、大繊度繊維も難燃繊維であることが多い。これは通常、難燃繊維はレギュラー繊維と比較して、ポリマー自身が柔軟であり、クリンプが除去しやすいからである。しかし、収縮繊維の場合と同様に繊維比重が大きく、同じ繊度のレギュラー（非難燃）繊維と比較して、繊維の実直径（断面積）が小さくなる。そのため、生地のボリューム感が不足しがちである。また、その断面は扁平であることが多い。これは繊維同士が絡みにくく、サラサラとした良い風合いの生地が得られやすいためである。しかし、扁平繊維は逆に繊維が倒れやすく、ボリューム感が得られにくいという欠点がある。クリンプ解除性に優れた難燃繊維であるが、染色した場合には繊維が収縮し、固定化されるため、クリンプ解除性が悪化する。染色時のクリンプ解除性を向上させるために、特開２００１−１８１９２６号公報、特開２００１−１８１９３７号公報、特開２００１−１８１９２７号公報にある方法はクリンプ付与前に充分な弛緩工程を実施することによりアクリル繊維の残留収縮（染色などの熱加工時に発生する収縮）を限りなく小さくすることを目的としており、確かにこの方法で得られた繊維はクリンプ解除性に優れているが、繊維を構成するポリマー自体が硬い従来のレギュラー繊維では有効性が低い。
また、ボア、毛布、マットなどでは繊維を混綿・紡績した後、染色、編み立てして、製品に加工する。この時、湿熱収縮繊維を混合すると染色時に収縮繊維が収縮し、非収縮繊維を巻き込みバネ状になり、ボリューム感が増す。従来、このような紡績糸に用いられる収縮性繊維の湿熱収縮率は２０〜２５％程度であり、ボリューム感は得られるものの、強くはない。発明者らはこの湿熱収縮率を３０％以上に高めれば、パイルにより強いボリューム感を付与でき、４０％を超えると逆に布帛が固くなりすぎることを見出した。
また、ベロアカーペットは５．５〜１７ｄｔｅｘの非収縮繊維を綿染めした後、未染色の収縮繊維を混綿し、紡績した後、編み立てする。編みたて後の後加工はハイパイルとほぼ同様で、毛抜け防止用糊の乾燥工程にて混綿した収縮繊維を収縮させる。このため、収縮繊維の収縮率が２５％以上、好ましくは３０％以上であれば、非収縮繊維を効果的に支えることができ、ボリューム感を付与できる。
先に記載した主にハイパイルに使用される乾熱収縮率で２５％以上の繊維をボア、毛布、マットなどに使用した場合には紡績糸の染色工程で過剰（５０％以上）に収縮し、製品風合いが固くなりすぎる。延伸倍率を調整するなどして、ある程度は収縮率を抑えることはできるが、それでも適切範囲（湿熱収縮率３０〜４０％）にすることは困難である。そのため、従来は主にハイパイルに用いられ乾熱で収縮させる繊維と主にボア、毛布、マットに用いられ湿熱（染色）で収縮させる繊維とを別々のポリマーで作り分けていた。
前述のボア、毛布、マット、ベロアカーペットでも収縮性小繊度繊維と同時に大もしくは／および中繊度繊維を使用するが、これはレギュラー繊維であることが多い。これはこれらの製品はその上を歩いたり、寝たりするなど大きな圧力がかかるため、特にボリューム感が要求されるためである。何度か述べているように難燃繊維ではクリンプが除去しやすく、風合いが良くなるが、ボリューム感が不足しがちである。
発明の開示
本発明の目的は▲１▼パイル状布帛全般にボリューム感を付与できる乾熱に対して優れた速収縮性、高収縮性（２５％以上、好ましくは３０％以上）を有する繊維、同じく▲２▼ボリューム感に優れ、かつ、固すぎないボア、毛布、マット、カーペットなどを得るための適度な湿熱収縮率（３０〜４０％、好ましくは３５〜４０％）を有する繊維、加えて▲３▼これらと組み合わせる優れたボリューム感・クリンプ除去性を兼ね備えた繊維およびこれらを同じポリマーより製造する方法を提供することにある。なお、本明細書で言う速収縮性（率）とはハイパイル製造工程のうち、毛抜け防止用糊の乾燥工程（テンター）の通過時間１〜２分内での収縮性（率）のことを指す。そのため、実施例、比較例中に記載されている乾熱収縮率とは速収縮性（率）を指している。
上記目的はアクリロニトリルを主成分とする熱可塑成分が１３〜２２重量％、スルホン酸基含有ビニルモノマー０．３〜２．０重量％であり、かつ粘度平均分子量Ｍηが４３０００〜６００００であるポリマーを湿式紡糸、水洗した後、乾燥緻密化工程にて０．８５〜０．９５倍に収縮した後に乾熱にて１．３〜２．７倍に延伸することにより達成される。ボア、毛布、マット、カーペットなど紡績糸にして使用する繊維を作る場合には同じポリマーを湿式紡糸、水洗、乾燥緻密化工程もしくはその後に乾熱にて０．９〜１．３倍に収縮・延伸する。さらにクリンプ除去性に優れた繊維は乾燥緻密化後、湿熱にて１．１〜２．０倍延伸し、その後、湿熱にて０．６〜０．９倍に収縮させる。
なお、本明細書では収縮倍率もしくは延伸倍率とはその工程への入り速度に対する出速度の比率を表している。例えば、延伸倍率１．４は工程からの出速度が入り速度に対して、１．４倍であることを示しており、収縮倍率０．８は工程からの出速度が入り速度に対して、０．８倍であることを示している。さらに詳しく説明すると１０ｍ／分で延伸工程に入る繊維束を１．４倍延伸した直後に０．８倍収縮させる場合は延伸工程の出速度は１４ｍ／分となり、直後の収縮工程の出速度はこの速度に対して０．８倍となり、最終速度は１１．２ｍ／分となる。
発明を実施するための最良の形態
以下に本発明についてさらに詳細に述べる。本発明の合成樹脂はアクリロニトリルを主成分とし、熱可塑成分が１３〜２２重量％、スルホン酸基含有ビニルモノマー０．３〜２．０重量％であり、かつ粘度平均分子量Ｍηが４３０００〜６００００である。
熱可塑成分が１３重量％未満であると繊維を構成するポリマーの柔軟性が低下し、紡糸時の延伸性および製品の収縮性、加えてクリンプ除去性が悪化し、風合いが低下する。２２重量％を超えるとポリマーの柔軟性は増し、クリンプ除去性、風合いは向上するものの、繊維同士の膠着が激しくなり、繊維化が困難である。また、好ましくは１５〜１８重量％、さらに好ましくは１５〜１７重量％である。熱可塑成分共重合量が制限されるに従い、紡糸時の延伸性および製品の収縮性と繊維膠着のバランスが取れ、好ましいものになる。
熱可塑成分としてはアクリル酸、メタクリル酸あるいはこれらのアルキルエステル類、酢酸ビニルなどが使用でき、これらに限定されるものではないが、アクリル酸あるいはそのアルキルエステル類、酢酸ビニルが望ましく、コスト・扱い易さなどからアクリル酸メチルがさらに好ましい。
染色性付与のためにスルホン酸基含有ビニルモノマーを０．３〜２．０重量％共重合させる。０．３重量％未満であると染色性が不足し、２．０重量％を超えると染色性（染料の吸着）が強くなり、染色が著しく速くなり、染色斑が発生する。スルホン酸基含有ビニルモノマーにはアリルスルホン酸ナトリウム、メタリルスルホン酸ナトリウム、スチレンスルホン酸ナトリウム、２−アクリルアミド−２−メチルプロパンスルホン酸ナトリウムなどが挙げられるがこれらに限られるものではない。ポリマー分子量、繊維白度、コスト、重合操業性などからメタリルスルホン酸ナトリウムと２−アクリルアミド−２−メチルプロパンスルホン酸ナトリウムを併用し、かつ、その重量比率は１：３〜５が好ましい。
アクリロニトリル、スルホン酸基含有ビニルモノマー、熱可塑成分以外のビニルモノマーを繊維化能、操業性、収縮率を損なわない範囲で共重合しても良い。
さらに粘度平均分子量Ｍηは４３０００〜６００００である必要がある。好ましくは４７０００〜５００００である。４３０００未満であると紡糸時の延伸性、製品の収縮性およびクリンプ除去性は良いものの、膠着が強くなり、６００００を超えると膠着は低減するものの、紡糸時の延伸性、製品の収縮性およびクリンプ除去性が低下し、目的の繊維が得られない。また、重合時のポリマー溶液の粘度が高くなり過ぎ、扱いにくくなる。粘度低下のため、濃度を低下した場合には重合効率が低下する。一般的に熱可塑成分が多い場合には分子量を高めに、少ない場合には低めにする。分子量は重合開始剤量、モノマー濃度、重合温度・時間およびスルホン酸基含有ビニルモノマーの種類・共重合量などにより調節する。
上記ポリマーを公知の湿式紡糸法で繊維化する。すなわち、上記ポリマーをジメチルホルムアミド（ＤＭＦ）、ロダン塩水溶液、ジメチルスルホキシドなどの溶媒に２３〜３２重量％の濃度に溶解し、紡糸原液とする。ただし、溶媒はこれらに限られるものではない。この時、この紡糸原液に紡糸操業性、繊維形成能、延伸性を損なわない範囲で抗菌剤、顔料、耐光剤などの添加剤を加えても良い。この紡糸原液を口金より溶媒を含む水中（凝固浴）へ紡出する。紡出されゲル状態にあるトウを順次、溶媒濃度が低下する数段の延伸浴にて３〜７倍、好ましくは４〜６倍に延伸し、水洗・オイル付与を行い、乾燥緻密化する。
ハイパイルなどに用いる乾熱収縮率２５％以上の繊維を生産する場合にはまず乾燥緻密化工程にて０．８５〜０．９５倍に収縮させる。０．８５倍未満では繊維がたるみがちになり、操業が難しい。０．９５倍を超える場合には最終製品の乾熱収縮率が低下する。
その後、乾熱にて１．３〜２．７倍延伸する。１．３倍未満では収縮率が低下し、２．７倍を超える倍率では収縮率はほとんど向上しないばかりか、繊維切断などが発生し、操業が難しい。この範囲内であれば、製品収縮率と操業性を両立させやすい。なお、延伸温度はトウ温度が１２０℃前後になるようにする。極度に温度が低い場合、同じ延伸倍率でも収縮率は向上するが、操業性（延伸性）が悪化する。高い場合、操業性は良好だが、同じ延伸倍率でも収縮率が低下する。
一方、ボア、毛布、マット、カーペットなど紡績糸にして使用するため、湿熱収縮率３０〜４０％が必要な場合には水洗・オイル付与後の乾燥緻密化工程もしくはその後の乾熱延伸（収縮）工程において０．９〜１．３倍に収縮もしくは延伸する。なお、延伸温度はトウ温度が１２０℃前後になるようにすることが好ましい。
加えて、クリンプ除去性に優れた繊維を得るには水洗、乾燥緻密化した後、１．１〜２．０倍延伸し、その後、０．６〜０．９倍に収縮させる。０．６倍未満ではクリンプ除去性が良くなるが、トウがたるみがちになり、操業性が悪化する。０．９倍を超えるとクリンプ除去性が不充分となる。これは弛緩処理が不充分であると染色時に収縮（残留収縮）するため、クリンプが固定されるからである。
その後、必要に応じて油剤を付与するが、乾燥工程での収縮を防ぐため、油剤付与は行わないか、行う場合でもできるだけ水分量が上がらないようにすることが望ましい。油剤付与後、クリンプ付与・カット・梱包し、製品とする。また、同様の理由でクリンプ付与はできるだけ低温で行うことが望ましい。
実施例
以下に本発明を実施例により具体的に説明する。なお、乾熱収縮率は単繊維を無荷重で１３０℃の乾熱雰囲気で１分間処理し、湿熱収縮率は単繊維を無荷重の状態で沸水（１００℃）処理を３０分間行い、処理前後の繊維の長さを測定し、式２により計算した。粘度平均分子量Ｍηは以下の（式１）により求めた。
（式１）Ｍη＝（Ｓ／Ｂ−１）×５３／６×１００００
（ただし、Ｂはオストワルド粘度管で測定した（３０℃）Ｎ，Ｎ−ジメチルホルムアミド（ＤＭＦ）の粘度（秒）およびＳは同様に測定したポリマー０．２ｇをＤＭＦに溶解し、５０ｍｌとした溶液の粘度（秒）とする。）
（式２）乾熱、湿熱収縮率（％）＝（収縮前の長さ−収縮後の長さ）／収縮前の長さ×１００
（ただし、収縮前後の長さは１ｔｅｘあたり２．９４ｍＮの荷重をかけて測定する。）
（表１、実施例１〜４、比較例１、２）
ＤＭＦを溶媒とした溶液重合法により表１に示す共重合比でアクリロニトリル（ＡＮ）／アクリル酸メチル（ＭＡ）／メタリルスルホン酸ナトリウム（ＳＭＡＳ）／２−アクリルアミド−２−メチルプロパンスルホン酸ナトリウム（ＳＡＭ）からなるポリマーを得た。粘度平均分子量Ｍηはいずれも４８０００〜５３０００の範囲であった。
重合終了後のポリマー溶液より未反応のモノマーを除き、ポリマー濃度が２５重量％となるように調整した。この紡糸原液を孔径０．０４ｍｍ×孔数４０００個の口金よりＤＭＦ５３％水溶液に紡出した。この凝固し、ゲル状態にあるトウを順次ＤＭＦ濃度が低下する３段の浴にて４．５倍に延伸した。その後、水洗・油剤付与・乾燥緻密化を行った。乾燥緻密化工程にて０．９５倍に収縮させた。次いでヒーターローラー、乾燥熱風にてトウ温度が１２０℃になるように加熱し、１．６倍に延伸した。延伸後、クリンプ付与、カットを行い２．２ｄｔｅｘ×３２ｍｍの繊維を得た。
このようにして得られた乾熱高収縮繊維４０重量％とその断面の扁平率が１：６である１７ｄｔｅｘ×５１ｍｍの難燃扁平アクリル系合成繊維６０重量％を混綿・編み立てし、公知の方法で後加工し、パイル長２０ｍｍ、目付け６００ｇ／ｍ２のハイパイル生地を得た。なお、毛抜け防止用糊の乾燥は１３０℃×１．５分で行った。
繊維膠着は乾燥緻密化後のトウを目視にてＥ：膠着が著しく激しい、Ｄ：膠着が激しい、Ｃ：膠着気味、Ｂ：良好、Ａ：非常に良好の５段階で評価、ＢおよびＡがその後の操業および製品の使用が問題ない（合格）レベルである。
操業性は繊維切断およびたるみの有無によりＥ：悪い、Ｃ：良好、Ａ：非常に良好の３段階で判断した。
乾熱収縮率は２５％以上を合格とする。ハイパイルのボリューム感は有識者５人により、Ｅ：同規格（繊度、繊維長）の非収縮繊維を用いた場合と同程度、Ｃ：同規格の非収縮繊維を用いた場合よりボリューム感が若干強い、Ａ：Ｃよりボリューム感がさらに強いの３段階で判断した。
表１から判るように熱可塑成分であるアクリル酸メチル共重合量が１３〜２２重量％の範囲である実施例１〜４は膠着もなく、操業性も良好で、乾熱収縮率も３０％以上である。実施例３、４の繊維膠着は実施例１、２と比較して若干劣るが、これもその後の延伸・捲縮付与で実施例１、２と同じレベルとなる。一方、熱可塑成分が少ない比較例１は繊維膠着、操業性共に問題ないが、乾熱収縮率が低い。逆に熱可塑成分が多い比較例２は乾燥緻密化工程での膠着が激しくリボン状になり、その後の操業が困難になり、繊維化できなかった。また、乾熱収縮率が３０％以上である実施例１〜４の繊維を用いたハイパイル生地はボリューム感が強く感じられたが、乾熱収縮率２０％である比較例１の繊維を用いた生地では非収縮繊維を用いた場合とほとんど同じ程度のボリューム感しか感じられなかった。
（表２、実施例５〜８、比較例３）
実施例１〜４および比較例１と同じ紡糸原液を０．５０４ｍｍ×０．０６３ｍｍ、孔数６５０個の口金よりＤＭＦ５３％水溶液に紡出した。この凝固し、ゲル状態にあるトウを順次ＤＭＦ濃度が低下する３段の浴にて６倍に延伸した。その後、水洗・油剤付与・乾燥緻密化を行った（延伸・収縮ともなし）。次いで１１０℃の蒸気で加熱し、１．４倍に延伸した。延伸後、１４０℃の蒸気で加熱し、０．７倍に収縮させた。その後、捲縮付与、カットを行い１７ｄｔｅｘ×５１ｍｍ、断面形状が１：７の長方形の繊維を得た。得られた繊維を９８℃×３０分の条件で茶色に染色し、この染色綿６０重量％と実施例２の乾熱高収縮綿４０重量％を混綿・編み立てし、公知の方法で後加工し、パイル長２０ｍｍ、目付け６００ｇ／ｍ２のハイパイル生地を得た。
ハイパイルの風合いは有識者５人により、Ｅ：不良、Ｃ：同規格の難燃繊維を用いた場合と同じ程度、Ａ：同規格の難燃繊維を用いた場合に勝るの３段階で判断した。ＣおよびＡを合格とする。
表２でのボリューム感は有識者５人の判定によりＥ：ボリューム感不良、Ｃ：同規格の難燃繊維を用いた場合と同等、Ａ：同規格のレギュラー繊維を用いた場合と同等とし、Ａを合格とする。残留収縮率は染色工程での収縮率を差し、測定は湿熱収縮率と同様の方法で行い、７％以下を合格とする。
表２にある実施例５〜８、比較例３は繊維膠着および操業性は実施例１〜４および比較例１と同様であった。残留収縮率は熱可塑性分ＭＡ量が多いものほど、大きかった。風合いもＭＡ量が多いほど良好であったが、実施例５〜８はいずれも良好であった。ボリューム感は実施例５〜８、比較例３のいずれも良好だった。比較例３は残留収縮率は小さかったが、クリンプが解除しにくく、ハイパイル生地の風合いが不良だった。加えて、比較例３のポリマーは比較例１と同じだが、表１にあるように乾熱高収縮綿（収縮率２５％以上）を作ることができない。
（表３、実施例９〜１２、比較例４）
実施例１〜４および比較例１と同じ紡糸原液をφ０．０４ｍｍ×孔数４０００個の口金よりＤＭＦ５３％水溶液に紡出した。この凝固し、ゲル状態にあるトウを順次ＤＭＦ濃度が低下する３段の浴にて５倍に延伸した。その後、水洗・油剤付与を行った。乾燥緻密化工程にて表３にある倍率にて収縮もしくは延伸した。その後、捲縮付与、カットを行い２．２ｄｔｅｘ×１０２ｍｍＶＣ（８０〜１２０ｍｍ）の繊維を得た。得られた繊維４０重量％と非収縮繊維（２．２ｄｔｅｘ×１０２ｍｍＶＣ）６０重量％を混綿・紡績（２８番双糸）し、茶色に染色した。染色した紡績糸を編み立てし、公知の方法で後加工し、パイル長１２ｍｍ、目付け４５０ｇ／ｍ２のボア生地を得た。
ボアのボリューム感は有識者５人により、Ｅ：同規格の従来収縮繊維（湿熱収縮率２０〜２５％程度）を用いた場合と同程度、Ｃ：同規格の従来収縮繊維を用いた場合よりボリューム感が若干強い、Ａ：Ｃよりさらにボリューム感が強いの３段階で判断した。表３において延伸・収縮倍率が１．０未満の場合は収縮を、１．０を超える場合は延伸を示す（１．０は延伸・収縮ともなし）。
表３の実施例９〜１２は湿熱収縮率は３０〜４０％になり、ボリューム感も強くなった。一方、比較例４は収縮率が低いため、従来品と同程度のボリューム感しかなかった。比較例４のポリマーは熱可塑性分ＭＡ共重合量が低いため、延伸倍率を高くしても、収縮率は向上しない。
（表４、実施例２、比較例５、６）
実施例２のポリマーおよび表４中の比較例５、６の組成のポリマーを実施例１〜４と同じ条件で繊維化し、２．２ｄｔｅｘ×３２ｍｍの繊維を得た。
表４にあるように実施例２のポリマーはスルホン酸基含有ビニルモノマーであるＳＡＭ／ＳＭＡＳの共重合量および比率が適切であるため、分子量が４３０００〜６００００の範囲となり、紡糸時の繊維膠着もなく、操業性も良好、加えてそれからなる繊維をハイパイルやボアに用いた場合もボリューム感および風合いを同規格の従来繊維より向上させることができた。一方、ＳＡＭ／ＳＭＡＳ比が小さい（ＳＡＭが少ない）比較例５は分子量が６００００を超え、繊維膠着はないものの、延伸性が悪化し、繊維化が困難となった。ＳＡＭ／ＳＭＡＳ比が大きい（ＳＡＭが多い）比較例６は分子量が４３０００未満となり、繊維膠着が発生し、その後の工程（延伸など）が困難になった。
（表５、実施例２、１３〜１６、比較例７〜１０）
実施例２のポリマーおよび条件で紡糸し、水洗・油剤付与する。その後、表５の条件で乾燥緻密化工程にて収縮、乾熱延伸工程にて延伸し、クリンプ付与・カットし、２．２ｄｔｅｘ×３２ｍｍの繊維を得た。
収縮倍率が０．８５〜０．９５、その後の延伸倍率が１．３〜２．７倍である実施例２および１３〜１６は操業性、乾熱収縮率ともに良好だが、延伸倍率が低い比較例７は乾熱収縮率が低く、延伸倍率が過大な比較例８は繊維切断で操業できなかった。乾燥緻密化工程での収縮倍率が低い（過大に収縮させた）比較例９はたるみが発生し、操業が困難となり、収縮させなかった比較例１０は乾熱収縮率が低くなった。
（表６、実施例１７、比較例１１、１２）
実施例２のポリマーおよび条件で紡糸し、水洗・油剤付与・乾燥緻密化する。その後、表６の条件で乾熱にて延伸もしくは収縮させる。収縮後、クリンプ付与・カットし、２．２ｄｔｅｘ×１０２ｍｍＶＣの繊維を得た。表６において延伸・収縮倍率が１．０未満の場合は収縮を、１．０を超える場合は延伸を示す（１．０は延伸・収縮ともなし）。
延伸・収縮倍率が０．９〜１．３倍の範囲である実施例１７は湿熱収縮率が適切な範囲となり、ボア生地のボリューム感も向上し、硬すぎることもなかった。収縮させすぎた比較例１１は収縮率が低く、ボリューム感向上も大きくなかった。延伸倍率が大きすぎる比較例１２は収縮率が大きすぎ、生地が固くなり過ぎた。
（表７、実施例７、比較例１３、１４）
実施例７（実施例２と同じ）と同じ条件にて紡糸・水洗・油剤付与・乾燥緻密化を行った。次いで１１０℃の蒸気で１．４倍に延伸、その後１４０℃の蒸気で加熱し、表７の倍率にて収縮させた。その後、捲縮付与、カットを行い１７ｄｔｅｘ×５１ｍｍ、断面形状が１：７の長方形の繊維を得た。得られた繊維６０重量％と実施例２の乾熱高収縮綿４０重量％を混綿・編み立てし、公知の方法で後加工し、パイル長２０ｍｍ、目付け６００ｇ／ｍ２のハイパイル生地を得た。
収縮倍率が０．６〜０．９倍の範囲である実施例１８は風合い・ボリューム感ともに良好だが、収縮倍率が小さい（過大に収縮させた）比較例１３は繊維がたるみ、操業が困難だった。一方、倍率が大きい（ほとんど収縮させていない）比較例１４は残留収縮大きく染色時に繊維が硬くなり、風合いが悪化した。
（表８、実施例６、比較例１５、１６）
表８にある組成となるように比較例１５および１６を重合した。未反応のモノマーを除き、実施例６と同じ方法・条件で紡糸、水洗、オイル付与、乾燥緻密化、延伸、収縮、クリンプ付与およびカットして、繊維を得た。
染色性は染色液に繊維重量に対して３％となるように黒染料を加え、９８℃×３０分で染色した後、染色液の着色を肉眼で判定。着色が見られる（残染料がある）ものはＥ（不合格）、肉眼では着色が見られないものをＡ（合格）とする。染色斑は染色液に繊維重量に対して０．５％となるように茶染料を加え、９８℃×３０分で染色した後、染色綿の斑を肉眼で判定。染色斑がないものをＡ（合格）、染色斑があるものをＥ（不合格）とした。
実施例６は染色性も良く、斑もないのに対して、スルホン酸基含有ビニルモノマーが少ない比較例１５は染色性が悪く、染料が吸着されずに残った。一方、多い実施例１６は染色性は良いものの、染色斑が多かった。
産業上の利用可能性
本発明のポリマーおよび製造方法を用いることによりパイル状布帛全般にボリューム感を付与できる乾熱に対して優れた速収縮性、高収縮性（２５％以上、好ましくは３０％以上）を有する繊維、同じくボリューム感に優れ、かつ、固すぎないボア、毛布、マット、カーペットなどを得るための適度な湿熱収縮率（３０〜４０％、好ましくは３５〜４０％）を有するレギュラーアクリル繊維、加えてこれらと組み合わせる優れたボリューム感・クリンプ除去性を兼ね備えた繊維およびこれらを同じポリマーより製造する方法を提供できる。Technical field
The present invention relates to a regular acrylic synthetic fiber that can be used for pile fabrics such as high piles, bores, blankets, mats, and carpets and that can impart a sense of volume to the fabrics.
Background art
When producing high-pile fabrics with acrylic synthetic fibers, large fine fibers (usually flame retardant fibers of 17 to 33 dtex) and small fine fibers (usually about 2.2 to 4.4 dtex) which are used as hairs are mixed and used. In some cases, these intermediate fine fibers (about 7.8 to 11 dtex) may be mixed. Among these, the use of high shrinkage (dry heat shrinkage rate of 25% or more, preferably 30% or more) fiber for the small fineness fiber can increase the volume feeling of the high pile fabric. This is because in the post-processing step of the high-pile fabric (drying step for preventing hair loss), the small fine fibers shrink to form a shape that supports the large and medium fine fibers, and the large and medium fine fibers are less likely to fall. When a non-shrinkable or small shrinkage fiber is used as the small fineness fiber, the medium fineness fiber cannot be supported or its effect is small, so that it easily falls down and lacks volume. Unless otherwise specified, “fiber” refers to an acrylic synthetic fiber. In addition, if a jacquard knitting machine is used, a pattern can be drawn with a shrink fiber on a non-shrink fiber fabric, and only the shrink fiber portion shrinks in a post-processing step (drying process for preventing hair loss) to form a three-dimensional pattern. be able to.
High shrinkage fibers with small fineness are in many cases flame retardant fibers, because this is because a shrinkage rate, particularly a dry heat shrinkage rate, is easily obtained. However, in general, flame retardant acrylic synthetic fibers contain many high specific gravity components such as vinylidene chloride and vinyl chloride as flame retardant components, so the fiber specific gravity is large and compared to regular (non-flame retardant) fibers with the same fineness. The actual diameter is reduced. For this reason, the volume feeling of the fabric tends to be reduced. If fibers with a large actual diameter are used, the fabric becomes heavy.
In the present specification, an acrylic synthetic fiber that does not contain a flame retardant component such as a vinyl halide component is hereinafter referred to as “regular fiber”.
On the other hand, there are high shrinkage fibers in regular fibers that do not contain high specific gravity components such as vinylidene chloride and vinyl chloride. However, this is a fiber used for blending in bores, blankets, mats, carpets, etc., and its wet heat shrinkage is about 25%. A sufficient dry heat shrinkage rate (25% or more) cannot be obtained in the drying prevention paste drying step (Japanese Patent Laid-Open Nos. 60-110910 and 53-17691).
JP-A-8-74119 discloses an example of dry heat and high shrinkage regular fibers for high pile applications. According to this, after spinning drawing / drying densification, 110-150 ° C., preferably after shrinkage of 30% or more under pressurized steam at 115-135 ° C., and stretching 1.6-2.2 times at 100-140 ° C. dry heat. However, it is difficult to shrink by 30% or more at this temperature with a normal polymer having a small thermoplastic content and a conventional continuous method. Moreover, since there are few plastic components, it is difficult to extend | stretch so much after shrinkage | contraction. The dry heat shrinkage measurement method is also far from 130 ° C. × 10 minutes heating and the actual high pile manufacturing process.
On the other hand, large fine fibers are often flame retardant fibers. This is because the flame retardant fiber is usually softer than the regular fiber, and the crimp is easy to remove. However, the fiber specific gravity is large as in the case of the shrink fiber, and the actual diameter (cross-sectional area) of the fiber is smaller than that of a regular (non-flame retardant) fiber having the same fineness. Therefore, the sense of volume of the fabric tends to be insufficient. Moreover, the cross section is often flat. This is because the fibers are not easily entangled and a fabric with a smooth texture is easily obtained. However, flat fibers, on the other hand, have the disadvantages that the fibers tend to fall and it is difficult to obtain a volume feeling. Although it is a flame retardant fiber excellent in crimp release property, when dyed, the fiber shrinks and is fixed, so that the crimp release property is deteriorated. In order to improve the crimp release property at the time of dyeing, the methods described in JP-A-2001-181926, JP-A-2001-181937, and JP-A-2001-181927 carry out a sufficient relaxation step before crimping. The purpose of this is to reduce the residual shrinkage of acrylic fibers (shrinkage that occurs during thermal processing such as dyeing) as much as possible. Certainly, the fibers obtained by this method have excellent crimp release properties. The effectiveness of conventional regular fibers in which the polymer itself is hard is low.
For bores, blankets, mats, etc., fibers are blended and spun, then dyed and knitted, and processed into products. At this time, when wet heat shrink fibers are mixed, the shrink fibers contract during dyeing, and the non-shrink fibers are wound into a spring shape, increasing the volume feeling. Conventionally, the wet heat shrinkage rate of the shrinkable fibers used in such spun yarn is about 20 to 25%, and a volume feeling is obtained but not strong. The inventors have found that if this wet heat shrinkage is increased to 30% or more, a strong volume feeling can be imparted to the pile, and if it exceeds 40%, the fabric becomes too hard.
The velor carpet is dyed with 5.5 to 17 dtex of non-shrink fibers, then blended with undyed shrink fibers, spun, and then knitted. The post-processing after knitting is almost the same as the high pile, and the shrinking fibers mixed in the drying process of the hair loss prevention paste are shrunk. For this reason, if the shrinkage ratio of the shrinkable fibers is 25% or more, preferably 30% or more, the non-shrinkable fibers can be effectively supported and a volume feeling can be imparted.
When fibers of 25% or more with a dry heat shrinkage ratio mainly used for high pile as described above are used for bores, blankets, mats, etc., they shrink excessively (50% or more) in the dyeing process of the spun yarn, The product texture is too hard. Although the shrinkage rate can be suppressed to some extent by adjusting the draw ratio, it is still difficult to make it within an appropriate range (wet heat shrinkage rate of 30 to 40%). Therefore, conventionally, fibers that are mainly used for high piles and shrink by dry heat and fibers that are mainly used for bores, blankets and mats and are shrunk by wet heat (dyeing) are made of different polymers.
The aforementioned bores, blankets, mats, and velor carpets also use large or / and medium fine fibers simultaneously with shrinkable small fine fibers, which are often regular fibers. This is because these products require a great sense of volume because they are subjected to great pressure, such as walking on them or sleeping. As mentioned several times, flame retardant fibers are easy to remove crimp and feel better, but tend to lack volume.
Disclosure of the invention
The object of the present invention is (1) a fiber having excellent rapid shrinkage and high shrinkage (25% or more, preferably 30% or more) with respect to dry heat, which can give a volume feeling to the whole pile fabric, and (2) ▼ Fibers with excellent moist heat shrinkage (30 to 40%, preferably 35 to 40%) to obtain bores, blankets, mats, carpets, etc. that are excellent in volume and not too hard, in addition to (3) It is an object of the present invention to provide a fiber having excellent volume feeling and crimp removal property combined with these and a method for producing them from the same polymer. In addition, the rapid shrinkability (rate) in this specification means the shrinkage (rate) within a passage time of 1 to 2 minutes in the drying process (tenter) of the hair removal prevention paste in the high pile manufacturing process. Point to. Therefore, the dry heat shrinkage rate described in Examples and Comparative Examples refers to fast shrinkage (rate).
The purpose is to provide a polymer having a acrylonitrile-based thermoplastic component of 13 to 22% by weight, a sulfonic acid group-containing vinyl monomer of 0.3 to 2.0% by weight, and a viscosity average molecular weight Mη of 43,000 to 60,000. This is achieved by wet spinning, washing with water, shrinking 0.85 to 0.95 times in the drying densification step, and then stretching 1.3 to 2.7 times with dry heat. When making fibers to be used as spinning yarns such as bores, blankets, mats, and carpets, the same polymer is contracted 0.9 to 1.3 times by wet spinning, water washing, drying densification process, or subsequent dry heat. Stretch. Further, the fiber having excellent crimp removability is dried and densified, stretched 1.1 to 2.0 times with wet heat, and then contracted 0.6 to 0.9 times with wet heat.
In the present specification, the shrinkage ratio or the draw ratio represents the ratio of the exit speed to the entry speed into the process. For example, a draw ratio of 1.4 indicates that the exit speed from the process is 1.4 times the entry speed, and a shrinkage ratio of 0.8 indicates that the exit speed from the process is relative to the entry speed. It shows that it is 0.8 times. More specifically, when the fiber bundle entering the stretching process at 10 m / min is contracted 0.8 times immediately after being stretched 1.4 times, the exit speed of the stretching process is 14 m / min, and the exit speed of the immediately following contraction process is This speed is 0.8 times, and the final speed is 11.2 m / min.
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention is described in further detail below. The synthetic resin of the present invention is mainly composed of acrylonitrile, has a thermoplastic component of 13 to 22% by weight, a sulfonic acid group-containing vinyl monomer of 0.3 to 2.0% by weight, and a viscosity average molecular weight Mη of 43,000 to 60000. is there.
When the thermoplastic component is less than 13% by weight, the flexibility of the polymer constituting the fiber is lowered, the drawability during spinning, the shrinkage of the product, and the crimp removability are deteriorated, and the texture is lowered. If the content exceeds 22% by weight, the flexibility of the polymer increases and the crimp removal property and texture are improved, but the fibers are hardened together, making fiberization difficult. Moreover, Preferably it is 15-18 weight%, More preferably, it is 15-17 weight%. As the amount of thermoplastic component copolymerization is limited, the stretchability during spinning, the shrinkage of the product, and the fiber agglomeration are balanced, which is preferable.
As the thermoplastic component, acrylic acid, methacrylic acid or their alkyl esters, vinyl acetate, etc. can be used, but it is not limited to these, but acrylic acid or its alkyl esters, vinyl acetate is desirable. Methyl acrylate is more preferable because of its ease.
In order to impart dyeability, 0.3 to 2.0% by weight of a sulfonic acid group-containing vinyl monomer is copolymerized. If it is less than 0.3% by weight, the dyeability is insufficient, and if it exceeds 2.0% by weight, the dyeability (dye adsorption) becomes strong, the dyeing is remarkably accelerated, and dyeing spots are generated. Examples of the sulfonic acid group-containing vinyl monomer include, but are not limited to, sodium allyl sulfonate, sodium methallyl sulfonate, sodium styrene sulfonate, sodium 2-acrylamido-2-methylpropane sulfonate, and the like. From the viewpoint of polymer molecular weight, fiber whiteness, cost, polymerization operability, and the like, sodium methallylsulfonate and sodium 2-acrylamido-2-methylpropanesulfonate are used in combination, and the weight ratio is preferably 1: 3 to 5.
Acrylonitrile, sulfonic acid group-containing vinyl monomers, and vinyl monomers other than thermoplastic components may be copolymerized within a range that does not impair fiberizing ability, operability, and shrinkage.
Furthermore, the viscosity average molecular weight Mη needs to be 43,000 to 60,000. Preferably it is 47000-50000. If it is less than 43,000, the stretchability during spinning, the shrinkage of the product, and the crimp removal property are good, but the agglutination becomes strong. The removability is lowered and the target fiber cannot be obtained. Moreover, the viscosity of the polymer solution at the time of superposition | polymerization becomes high too much, and becomes difficult to handle. Due to the decrease in viscosity, the polymerization efficiency decreases when the concentration is decreased. Generally, when the thermoplastic component is large, the molecular weight is increased, and when it is small, the molecular weight is decreased. The molecular weight is adjusted by the amount of polymerization initiator, monomer concentration, polymerization temperature / time, type of sulfonic acid group-containing vinyl monomer, amount of copolymerization, and the like.
The polymer is fiberized by a known wet spinning method. That is, the polymer is dissolved in a solvent such as dimethylformamide (DMF), a rhodan salt aqueous solution, dimethyl sulfoxide at a concentration of 23 to 32% by weight to obtain a spinning dope. However, the solvent is not limited to these. At this time, additives such as antibacterial agents, pigments, and light resistance agents may be added to the spinning dope so long as the spinning operability, fiber forming ability and stretchability are not impaired. The spinning solution is spun from a die into water containing a solvent (coagulation bath). The tow that has been spun and is in a gel state is stretched 3 to 7 times, preferably 4 to 6 times, in several stages of stretching baths in which the solvent concentration is lowered, washed with water and oiled, and dried and densified.
When producing a fiber having a dry heat shrinkage of 25% or more used for high pile or the like, the fiber is first shrunk 0.85 to 0.95 times in a dry densification step. If it is less than 0.85 times, the fibers tend to sag and operation is difficult. When it exceeds 0.95 times, the dry heat shrinkage rate of the final product is lowered.
Thereafter, the film is stretched 1.3 to 2.7 times by dry heat. If the ratio is less than 1.3 times, the shrinkage rate decreases, and if the magnification exceeds 2.7 times, the shrinkage rate is hardly improved, and fiber cutting or the like occurs, making operation difficult. Within this range, it is easy to achieve both product shrinkage and operability. The stretching temperature is such that the tow temperature is around 120 ° C. When the temperature is extremely low, the shrinkage ratio is improved even at the same stretch ratio, but the operability (stretchability) is deteriorated. When it is high, the operability is good, but the shrinkage rate is lowered even at the same draw ratio.
On the other hand, when it is used as a spun yarn such as bore, blanket, mat, carpet, etc., when wet heat shrinkage of 30-40% is required, it is a dry densification step after water washing and oil application or subsequent dry heat stretching (shrinking). In the process, it contracts or stretches by 0.9 to 1.3 times. The stretching temperature is preferably such that the tow temperature is around 120 ° C.
In addition, in order to obtain a fiber excellent in crimp removability, it is washed with water, dried and densified, stretched 1.1 to 2.0 times, and then contracted to 0.6 to 0.9 times. If it is less than 0.6 times, the crimp removal property is improved, but the tow tends to sag and the operability is deteriorated. If it exceeds 0.9 times, the crimp removability becomes insufficient. This is because if the relaxation treatment is insufficient, the crimp is fixed at the time of dyeing (residual shrinkage), so that the crimp is fixed.
Thereafter, an oil agent is applied as necessary, but in order to prevent shrinkage in the drying process, it is desirable not to apply the oil agent or to prevent the water content from increasing as much as possible. After applying the oil, apply crimp, cut, and pack to make the product. For the same reason, it is desirable to apply the crimp at the lowest possible temperature.
Example
Hereinafter, the present invention will be described specifically by way of examples. The dry heat shrinkage rate is obtained by treating a single fiber in a dry heat atmosphere at 130 ° C. for 1 minute with no load, and the wet heat shrinkage rate is obtained by performing boiling water (100 ° C.) treatment for 30 minutes in a no load state before and after the treatment. The fiber length was measured and calculated according to Equation 2. The viscosity average molecular weight Mη was determined by the following (Formula 1).
(Formula 1) Mη = (S / B-1) × 53/6 × 10000
(However, B is the viscosity (second) of N, N-dimethylformamide (DMF) measured with an Ostwald viscosity tube (30 ° C.) and S is a solution obtained by dissolving 0.2 g of the same measured polymer in DMF to make 50 ml. Viscosity (seconds)
(Formula 2) Dry heat, wet heat shrinkage rate (%) = (length before shrinkage−length after shrinkage) / length before shrinkage × 100
(However, the length before and after shrinkage is measured by applying a load of 2.94 mN per tex.)
(Table 1, Examples 1-4, Comparative Examples 1 and 2)
Acrylonitrile (AN) / methyl acrylate (MA) / sodium methallyl sulfonate (SMAS) / 2-acrylamido-2-methylpropane sulfonic acid sodium salt with a copolymerization ratio shown in Table 1 by a solution polymerization method using DMF as a solvent ( SAM) was obtained. The viscosity average molecular weight Mη was in the range of 48000-53000.
Unreacted monomers were removed from the polymer solution after completion of the polymerization, and the polymer concentration was adjusted to 25% by weight. This spinning dope was spun into a DMF 53% aqueous solution from a die having a hole diameter of 0.04 mm and a hole number of 4000. This solidified and gelled tow was stretched 4.5 times in a three-stage bath in which the DMF concentration was successively lowered. Thereafter, washing with water, application of an oil agent, and drying and densification were performed. In the drying densification step, the film was shrunk 0.95 times. Subsequently, it heated so that a tow | toe temperature might be set to 120 degreeC with a heater roller and dry hot air, and extended | stretched 1.6 time. After stretching, crimping and cutting were performed to obtain 2.2 dtex × 32 mm fibers.
40% by weight of dry heat highly shrinkable fiber thus obtained and 60% by weight of a 17 dtex × 51 mm flame-retardant flat acrylic synthetic fiber having a cross-sectional flatness of 1: 6 are blended and knitted. After processing by the method, pile length 20mm, basis weight 600g / m 2 High pile fabric was obtained. The hair loss prevention paste was dried at 130 ° C. for 1.5 minutes.
Fiber agglomeration is evaluated by five stages: E: agglomeration is extremely severe, D: agglomeration is severe, C: agglutination, B: good, A: very good. Subsequent operation and use of the product are at a level where there is no problem (pass).
The operability was judged in three stages of E: bad, C: good, and A: very good depending on the presence or absence of fiber cutting and sagging.
The dry heat shrinkage rate is 25% or more. The volume of the high pile is 5 by the experts, E: the same level as when using non-shrinkable fibers of the same standard (fineness, fiber length), C: slightly more volume than when using non-shrinkable fibers of the same standard , A: Judgment was made in three stages, the volume feeling is stronger than C.
As can be seen from Table 1, Examples 1 to 4 in which the amount of copolymerized methyl acrylate, which is a thermoplastic component, is in the range of 13 to 22% by weight are free of sticking, have good operability, and have a dry heat shrinkage of 30%. That's it. The fiber sticking of Examples 3 and 4 is slightly inferior to that of Examples 1 and 2, but this also becomes the same level as in Examples 1 and 2 by the subsequent stretching and crimping. On the other hand, Comparative Example 1 with few thermoplastic components has no problem in both fiber sticking and operability, but has a low dry heat shrinkage rate. On the other hand, Comparative Example 2 having a large amount of thermoplastic component was severely stuck in the drying and densification step and became ribbon-like, making subsequent operation difficult and making it impossible to fiberize. In addition, the high pile fabric using the fibers of Examples 1 to 4 having a dry heat shrinkage rate of 30% or more felt strong in volume, but the fibers of Comparative Example 1 having a dry heat shrinkage rate of 20% were used. In the fabric, only the same volume feeling as when non-shrinkable fibers were used was felt.
(Table 2, Examples 5-8, Comparative Example 3)
The same spinning dope as in Examples 1 to 4 and Comparative Example 1 was spun into a 53% DMF aqueous solution from a die having a diameter of 0.504 mm × 0.063 mm and 650 holes. This solidified tow in the gel state was stretched 6 times in a three-stage bath in which the DMF concentration was successively lowered. Thereafter, washing with water, applying an oil agent, and drying and densification were performed (there was neither stretching nor shrinkage). Subsequently, it heated with the steam of 110 degreeC, and extended | stretched 1.4 times. After stretching, it was heated with steam at 140 ° C. and contracted by 0.7 times. Thereafter, crimping and cutting were performed to obtain a rectangular fiber having 17 dtex × 51 mm and a cross-sectional shape of 1: 7. The obtained fiber is dyed brown under conditions of 98 ° C. × 30 minutes, 60% by weight of this dyed cotton and 40% by weight of dry heat high-shrinkage cotton of Example 2 are mixed and knitted, and then post-processed by a known method Pile length 20mm, basis weight 600g / m 2 High pile fabric was obtained.
The texture of the high pile was judged by three experts in three stages: E: bad, C: the same level as when using the flame retardant fiber of the same standard, and A: better than when using the flame retardant fiber of the same standard. C and A are accepted.
The volume feeling in Table 2 is determined by five experts, E: poor volume feeling, C: equivalent to the case using flame retardant fiber of the same standard, A: equivalent to the case using regular fiber of the same standard, A: To pass. The residual shrinkage rate is the shrinkage rate in the dyeing process, and the measurement is performed in the same manner as the wet heat shrinkage rate, and 7% or less is accepted.
In Examples 2 to 8 and Comparative Example 3 in Table 2, fiber sticking and operability were the same as those in Examples 1 to 4 and Comparative Example 1. The residual shrinkage ratio was larger as the amount of thermoplastic MA was larger. The texture was also better as the amount of MA was larger, but Examples 5 to 8 were all good. The volume feeling was good in all of Examples 5 to 8 and Comparative Example 3. In Comparative Example 3, the residual shrinkage was small, but the crimp was difficult to release and the texture of the high pile fabric was poor. In addition, the polymer of Comparative Example 3 is the same as that of Comparative Example 1, but as shown in Table 1, dry heat highly shrinkable cotton (shrinkage rate of 25% or more) cannot be made.
(Table 3, Examples 9-12, Comparative Example 4)
The same spinning dope as in Examples 1 to 4 and Comparative Example 1 was spun into a DMF 53% aqueous solution from a die having a diameter of 0.04 mm and a hole number of 4000. The coagulated and gelled tow was stretched five times in a three-stage bath in which the DMF concentration was successively lowered. Thereafter, washing with water and oiling were performed. In the drying densification step, the film was shrunk or stretched at a magnification shown in Table 3. Thereafter, crimping and cutting were performed to obtain 2.2 dtex × 102 mm VC (80 to 120 mm) fibers. 40% by weight of the obtained fiber and 60% by weight of non-shrinkable fibers (2.2 dtex × 102 mm VC) were mixed and spun (No. 28 twin yarn), and dyed brown. The dyed spun yarn is knitted and post-processed by a known method. The pile length is 12 mm and the basis weight is 450 g / m. 2 Boa dough.
The sense of volume of the bore by five experts, E: about the same as when using conventional shrink fibers of the same standard (wet heat shrinkage of about 20-25%), C: volume than when using conventional shrink fibers of the same standard Judgment was made in three stages, with a slightly strong feeling and a stronger volume feeling than A: C. In Table 3, when the stretching / shrinking ratio is less than 1.0, shrinkage is indicated, and when it exceeds 1.0, stretching is indicated (1.0 indicates neither stretching nor shrinking).
In Examples 9 to 12 in Table 3, the wet heat shrinkage was 30 to 40%, and the volume feeling was also strong. On the other hand, since Comparative Example 4 had a low shrinkage rate, it had only the same volume feeling as the conventional product. Since the polymer of Comparative Example 4 has a low thermoplastic content MA copolymerization amount, the shrinkage ratio is not improved even if the stretch ratio is increased.
(Table 4, Example 2, Comparative Examples 5 and 6)
The polymer of Example 2 and the polymers of the compositions of Comparative Examples 5 and 6 in Table 4 were fiberized under the same conditions as in Examples 1 to 4 to obtain 2.2 dtex × 32 mm fibers.
As shown in Table 4, since the copolymer of SAM / SMAS, which is a sulfonic acid group-containing vinyl monomer, is suitable for the polymer of Example 2, the molecular weight is in the range of 43,000 to 60000, and fiber sticking during spinning is also possible. In addition, the operability was good, and in addition, when the resulting fibers were used in high piles and bores, the volume and texture could be improved over conventional fibers of the same standard. On the other hand, Comparative Example 5 having a small SAM / SMAS ratio (low SAM) had a molecular weight of over 60000 and no fiber sticking, but the drawability deteriorated and fiberization became difficult. Comparative Example 6 having a large SAM / SMAS ratio (many SAMs) had a molecular weight of less than 43,000, fiber sticking occurred, and subsequent steps (such as stretching) became difficult.
(Table 5, Examples 2, 13-16, Comparative Examples 7-10)
Spin with the polymer and conditions of Example 2 and wash with water and apply oil. Thereafter, shrinkage was performed in the dry densification process under the conditions shown in Table 5, and the film was stretched in the dry heat stretching process, and crimped and cut to obtain 2.2 dtex × 32 mm fibers.
Examples 2 and 13 to 16 in which the shrinkage ratio is 0.85 to 0.95 and the subsequent draw ratio is 1.3 to 2.7 times are good in both operability and dry heat shrinkage, but the draw ratio is low. Example 7 had a low dry heat shrinkage, and Comparative Example 8 having an excessive stretch ratio could not be operated by fiber cutting. In Comparative Example 9 in which the shrinkage ratio in the drying densification step was low (excessively contracted), sagging occurred, operation became difficult, and in Comparative Example 10 in which the shrinkage did not shrink, the dry heat shrinkage rate was low.
(Table 6, Example 17, Comparative Examples 11 and 12)
Spin with the polymer and conditions of Example 2, wash with water, apply oil, and densify. Thereafter, the film is stretched or shrunk with dry heat under the conditions shown in Table 6. After shrinkage, crimping was applied and cut to obtain 2.2 dtex × 102 mm VC fibers. In Table 6, when the stretching / shrinking ratio is less than 1.0, shrinkage is indicated, and when it exceeds 1.0, stretching is indicated (1.0 indicates neither stretching nor shrinking).
In Example 17 in which the stretch / shrinkage ratio was in the range of 0.9 to 1.3 times, the wet heat shrinkage ratio was in an appropriate range, the volume feeling of the bore fabric was improved, and it was not too hard. In Comparative Example 11, which was excessively contracted, the contraction rate was low and the volume feeling was not greatly improved. In Comparative Example 12 in which the draw ratio was too large, the shrinkage ratio was too large, and the fabric became too hard.
(Table 7, Example 7, Comparative Examples 13 and 14)
Spinning, washing, oiling, and drying densification were performed under the same conditions as in Example 7 (same as Example 2). Subsequently, the film was stretched 1.4 times with steam at 110 ° C., then heated with steam at 140 ° C., and contracted at a magnification shown in Table 7. Thereafter, crimping and cutting were performed to obtain a rectangular fiber having 17 dtex × 51 mm and a cross-sectional shape of 1: 7. 60% by weight of the obtained fiber and 40% by weight of dry heat highly shrinkable cotton of Example 2 were knitted and knitted and post-processed by a known method to obtain a pile length of 20 mm and a basis weight of 600 g / m. 2 High pile fabric was obtained.
In Example 18 in which the shrinkage ratio is in the range of 0.6 to 0.9 times, both the texture and volume feel are good, but in Comparative Example 13 in which the shrinkage ratio is small (excessively contracted), the fibers are slack and operation is difficult. It was. On the other hand, in Comparative Example 14 having a large magnification (almost no shrinkage), the residual shrinkage was large and the fibers became harder during dyeing, and the texture deteriorated.
(Table 8, Example 6, Comparative Examples 15 and 16)
Comparative Examples 15 and 16 were polymerized to give the composition shown in Table 8. Except for the unreacted monomer, spinning, washing with water, oil application, drying densification, stretching, shrinkage, crimp application and cutting were performed in the same manner and conditions as in Example 6 to obtain fibers.
For dyeability, add black dye to the dyeing solution to 3% of the fiber weight, dye it at 98 ° C for 30 minutes, and then visually determine the coloring of the dyeing solution. E (failed) is colored (with residual dye), and A (accepted) is colored with the naked eye. For the stained spots, add a brown dye to the dyeing solution so that it becomes 0.5% of the fiber weight, and after staining at 98 ° C. for 30 minutes, visually check the stained cotton spots. A sample having no stained spots was designated as A (passed), and a sample having stained spots was designated as E (failed).
Example 6 had good dyeability and no spots, whereas Comparative Example 15 with a small amount of sulfonic acid group-containing vinyl monomer had poor dyeability and the dye remained without being adsorbed. On the other hand, although many Examples 16 had good dyeability, there were many dyeing spots.
Industrial applicability
Fibers having excellent rapid shrinkage and high shrinkage (25% or more, preferably 30% or more) with respect to dry heat, which can give a feeling of volume to the entire pile fabric by using the polymer and the production method of the present invention, Regular acrylic fibers that have a good wet heat shrinkage (30-40%, preferably 35-40%) to obtain bores, blankets, mats, carpets, etc. that are also excellent in volume and are not too hard, in addition to these It is possible to provide a fiber having an excellent volume feeling and crimp removal property combined with the above and a method for producing them from the same polymer.
