JP3935703B2 - Method for producing polyester fiber - Google Patents

Description

【００１９】
【化５】

【化９】

【化１０】

【化１１】

【００２０】
【発明の実施の形態】
以下、本発明についてさらに詳細に説明する。
【００２１】
本発明のポリエステルは、ポリマー中に可溶なチタン化合物を全ジカルボン酸成分に対し、チタン金属元素として２〜１２ミリモル％含有し、下記一般式（１）及び（２）を満足する必要がある。
【００２２】
【数３】

本発明において、用いられるリン化合物としては、下記一般式（ＩＩ）で表されるホスホネート化合物であることが必要である。
【００２３】
【化６】

上述のホスホネート化合物としては、ホスホン酸のジメチル−、ジエチル−、ジプロピル−及びジブチルエステルが挙げられ、具体的にはカルボメトキシメタンホスホン酸、カルボエトキシメタンホスホン酸、カルボプロポキシメタンホスホン酸、カルボプトキシメタンホスホン酸、カルボメトキシ−ホスホノ−フェニル酢酸、カルボエトキシ−ホスホノ−フェニル酢酸、カルボプロトキシ−ホスホノ−フェニル酢酸、カルボブトキシ−ホスホノ−フェニル酢酸等が挙げられる。
【００２４】
上記のホスホネート化合物の好ましい理由は、通常安定剤として使用されリン化合物に比較し、チタン化合物との反応が比較的緩やかに進行する為、チタン化合物の触媒活性が、重縮合反応中における持続時間も長く、結果としてポリエステルへの添加量が少なくでき、また、本特許のように触媒に対し多量安定剤を添加する場合でも、ポリエステルの熱安定性を損ないにくい特性を有している為である。
【００２５】
これら、リン化合物の添加時期は、エステル交換反応またはエステル化反応が実質的に終了した後であればいつでもよく、例えば、重縮合反応を開始する以前の大気圧下でも、重縮合反応を開始した後の減圧下でも、重縮合反応の末期でもまた、重縮合反応の終了後、すなわちポリマーを得た後に添加してもよい。
【００２６】
本発明において、用いられるチタン化合物は、触媒起因の異物低減の点で、ポリマー中に可溶なチタン化合物を使用することが必要である。本発明において用いられるチタン化合物としては、下記一般式（ＩＩＩ）で表される化合物と下記一般式（ＩＶ）で表される芳香族多価カルボン酸又はその無水物とを反応させた生成物である。
【００２７】
【化７】

【００２８】
【化８】

一般式（ＩＩＩ）で表されるチタン化合物としては、Ｒ３、Ｒ３’、Ｒ３’’、Ｒ３’’’がそれぞれ同一若しくは異なって、アルキル基及び／又はフェニル基であれば特に限定されないが、テトライソプロポキシチタン、テトラプロポキシチタン、テトラ−ｎ−ブトキシチタン、テトラエトキシチタン、テトラフェノキシチタン、オクタアルキルトリチタネート、ヘキサアルキルジチタネートなどが好ましく用いられる。
【００２９】
また、該化合物として反応させる一般式（ＩＶ）で表される芳香族多価カルボン酸又はその無水物としては、フタル酸、トリメリット酸、ヘミメリット酸、ピロメリット酸及びこれらの無水物が好ましく用いられる。
【００３０】
上記チタン化合物と芳香族多価カルボン酸又はその無水物とを反応させる場合には、溶媒に芳香族多価カルボン酸又はその無水物の一部を溶解し、これにチタン化合物を滴下して、０〜２００℃の温度で少なくとも３０分間反応させれば良い。
【００３１】
本発明のポリエステルにはポリマー中に可溶なチタン化合物を全ジカルボン酸成分に対し、チタン金属元素として２〜１２ミリモル％含有する必要がある。該チタン金属元素が２ミリモル％未満ではポリエステルの生産性が低下し、目標とする分子量のポリエステルが得られない。
【００３２】
また、該チタン金属元素が１２ミリモル％を越える場合は熱安定性が逆に低下し、繊維製造時の分子量低下が大きくなり品質の優れたポリエステル繊維が得られない。チタン金属元素量は２．５〜１２ミリモル％の範囲が好ましく、３〜１０ミリモル％の範囲がさらに好ましい。なお、ここで言う”ポリマー中に可溶なチタン化合物”とは、二酸化チタン粒子に含まれるチタンは含まないことを示し、”チタン金属元素量”とは、エステル交換反応による第１段階反応を行う場合は、エステル交換反応触媒として使用されたチタン化合物と重縮合反応触媒として使用されたチタン化合物との合計量を示す。
【００３３】
本発明におけるポリエステルは、チタン化合物を触媒とし、かつリン化合物を安定剤として製造され、そして下記式（１）、（２）のいずれも満足する必要がある。
【００３４】
【数４】

（Ｐ／Ｔｉ）が２未満の場合、色相が著しく黄味を帯び好ましくない。また、（Ｐ／Ｔｉ）が１５を越えるとポリエステルの重合反応性が大幅に低下し、目的のポリエステルを得ることができない。本発明で用いるポリエステルにおいて、（Ｐ／Ｔｉ）の適正範囲は通常の金属触媒よりも狭いことが特徴的であるが、適正範囲にある場合、本発明のように従来にない効果を得ることができる。一方、（Ｔｉ＋Ｐ）が１０に満たない場合は、製糸プロセスにおける生産性が大きく低下し、満足な性能が得られなくなる。また、（Ｔｉ＋Ｐ）が１００を越える場合は、触媒に起因する異物が少量ではあるが発生し好ましくない。
【００３５】
式（１）、（２）の範囲は好ましくは（１）式中の（Ｐ／Ｔｉ）は３〜１２の範囲、（２）式中の（Ｔｉ＋Ｐ）は１５〜８５の範囲であり、さらに好ましくは、（１）式中の（Ｐ／Ｔｉ）は４〜１０の範囲、（２）式中の（Ｔｉ＋Ｐ）は２０〜７０の範囲である。
【００３６】
一般的にエチレンテレフタレートを主たる繰り返し単位とするポリエステルの原料としてテレフタル酸に代表される芳香族ジカルボン酸を用いる製造方法とジメチルテレフタレートに代表される芳香族ジカルボン酸のエステル形成性誘導体を原料として用いる二つの方法が知られている。
【００３７】
本発明におけるポリエステルは、その製造方法により特に制限はないが、好ましくはエチレンテレフタレート単位の出発原料のうち８０ｍｏｌ％以上をジメチルテレフタレートが占める、エステル交換反応を経由する製造方法である。ジメチルテレフタレートを原料物質に使用する製造方法は、テレフタル酸を原料とする製造方法に比較し、重縮合反応中に安定剤として添加したリン化合物の飛散が少ないという利点がある。
【００３８】
また、ジメチルテレフタレートを原料物質とする製造方法では、チタン化合物の添加量を低減できる、チタン化合物の一部及び／又は全量をエステル交換反応開始前に添加し、エステル交換反応触媒と重縮合反応触媒の二つ触媒を兼用させる製造方法が好ましく、さらにエステル交換反応が、０．０５〜０．２０ＭＰａの加圧下にて実施する方法がより好ましい。
【００３９】
エステル交換反応時の圧力が、０．０５ＭＰａ以下では、チタン化合物の触媒作用による反応の促進が充分部は無く、一方０．２０ＭＰａ以上では、副生成物として発生するジエチレングリコールのポリマー中の含有量が著しく増加し、ポリマーの熱安定性等の特性が劣ってしまう。
【００４０】
さらに、得られるポリエステルのカラーを微調整するために、反応系にポリエステルの製造段階において、アゾ系、トリフェニルメタン系、キノリン系、アントラキノン系、フタロシアニン系等の有機青色顔料及び無機青色顔料の一種以上からなる整色剤を添加することができる。なお、本発明の製造方法においては、当然のことながらポリエステルの溶融熱安定性を低下させるコバルト等を含む無機青色顔料を整色剤としては用いる必要はなく、したがって得られるポリエステルには実質的にコバルトを含まないことが好ましい。
【００４１】
本発明で使用するスルホン酸金属塩を示す下記一般式（Ｉ）中、Ａｒは芳香族基であり、なかでもベンゼン環又はナフタレン環が好ましい。Ｒ₄はエステル形成性官能基であり、−ＣＯＯＲ’（但し、Ｒ’は水素原子、炭素原子１〜４のアルキル基、フェニル基又は−ＣＯ−｛Ｏ−（ＣＨ ₂ ） _l ｝ _p −ＯＨ（但し、lは２以上の整数、Ｐは１以上の整数。）等が好ましい。Ｍ及びＭ’は金属であり、Ｍとしてはアルカリ金属又はアルカリ土類金属が好ましく、なかでもＬｉ，Ｎａ，Ｋ，Ｃａ_1/2，Ｍｇ_1/2が特に好ましい。Ｍ′としてはアルカリ金属、アルカリ土類金属、Ｍｎ_1/2，Ｚｎ_1/2が好ましく、なかでもＬｉ，Ｎａ，Ｋ，Ｃａ_1/2，Ｍｇ_1/2，Ｂａ_1/2，が特に好ましい。Ｍ及びＭ′は同一でも異なっていてもよい。ｍは０〜４の整数、ｎは１〜５の整数であって、且つｍ＋ｎが１〜５になる整数である。
【００４２】
このスルホン酸金属塩の好ましい具体例としては、３−カルボメトキシ・ベンゼンスルホン酸Ｎａ−５−カルボン酸Ｎａ、３−カルボメトキシ・ベンゼンスルホン酸Ｎａ−５一カルボン酸Ｋ、３−カルボメトキシ・ベンゼンスルホン酸Ｋ−５−カルボン酸Ｋ、３−ヒドロキシエトキシカルボニル・ベンゼンスルホン酸Ｎａ−５−カルボン酸Ｎａ、３−カルボキシ・ベンゼンスルホン酸Ｎａ−５−カルボン酸Ｎａ、３−ヒドロキシエトキシカルボニル・ベンゼンスルホン酸Ｎａ−５−カルボン酸Ｍｇ_1/2、ベンゼンスルホン酸Ｎａ−３，５−ジ（カルボン酸Ｎａ）、ベンゼンスルホン酸Ｎａ−３，５−ジ（カルボン酸Ｍｇ_1/2）、ベンゼンスルホン酸Ｎａ−３−カルボン酸Ｎａ、３−カルボメトキシ・ナフタレン−１−スルホン酸Ｎａ−７−カルボン酸Ｎａ、ナフタレン−１−スルホン酸Ｎａ−３，７−ジ（カルボン酸Ｍｇ_1/2）等をあげることができる。
【００４３】
上記スルホン酸金属塩は１種のみ単独で使用しても、また２種以上併用してもよい。その添加時期は、ポリエステルを溶融紡糸する紡糸工程が終了する以前の任意の段階でよく、例えばポリエステルの原料中に添加混合しても、ポリエステルの合成中に添加しても、また合成終了から溶融紡糸するまでの問に添加してもよい。いずれにしても、添加後溶融状態で混合されるようにするのが好ましい。
【００４４】
上記スルホン酸金属塩の配合量は、余りに少ないと最終的に得られるポリエステル繊維のドライ感が不充分になり、逆に余りに多いとその添加時期がポリエステルの合成が終了する以前では、充分な重合度のポリエステルが得られ難く、またその添加時期が合成終了後から溶融紡糸終了以前のときは紡糸時にトラブルを発生し易い。このため、添加量は添加すべきポリエステルを構成する酸成分に対し０．１〜２５モル％の範囲にすべきであり、０．３〜１５モル％の範囲が好ましく、なかでも０．５〜５モル％の範囲が特に好ましい。
【００４５】
上記スルホン酸金属塩を配合した変性ポリエステルを溶融紡糸して中実繊維とするには、格別な方法を採用する必要はなく、ポリエステルの中実繊維の溶融紡糸方法が任意に採用される。ここで紡出する繊維の横断面における形状は円形であっても異形であってもよく、また、単繊維繊度についても特に制限する必要はないが、約１ｄｔｅｘ以下になるとドライ感のみならず、吸水性にも優れるようになったり、肌を刺さないようになったりするため、用途によっては約１ｄｔｅｘ以下が好ましい。
【００４６】
さらに、紡糸するに際して、上記のスルホン酸金属塩を配合した変性ポリエステルとスルホン酸金属塩を配合しない未変性ポリエステルとを使用し、変性ポリエステルを鞘成分とし、未変性ポリエステルを芯成分とする芯鞘型複合繊維にしても、変性ポリエステルと未変性ポリエステルとを用いて２層又はそれ以上の多層のサイド・バイ・サイド型複合繊維にしてもよい。
【００４７】
このようにして得られたポリエステル繊維から、上記スルホン酸金属塩の少なくとも一部を除去するには、必要に応じて廷伸熱処理又は仮撚加工等を施した後、又はさらに布帛にした後アルカリ化合物の水溶液に浸漬処理することにより容易に行うことができる。
【００４８】
ここで使用するアルカリ化合物としては、水酸化ナトリウム、水酸化カリウム、テトラメチルアンモニウムハイドロオキサイド、炭酸ナトリウム、炭酸カリウム等をあげることができる。なかでも水酸化ナトリウム、水酸化カリウムが特に好ましい。
【００４９】
このようなアルカリ化合物の水溶液の濃度は、アルカリ化合物の種類、処理条件等によって異なるが、通常、０．０１〜４０重量％の範囲が好ましく、特に０．１〜３０重量％の範囲が好ましい。処理温度は常温〜１００℃の範囲が好ましく、処理時間は１分間〜４時間の範囲で通常行われる。このようにアルカリ化合物の水溶液で処理することによって、上記スルホン酸金属塩と共にポリエステルが選択的に溶出し、繊維表面のみならず繊維内面にまで外部に連通した多数の微細孔を形成させることができ、優れたドライ感を呈するようになる。
【００５０】
本発明方法によって得られるポリエステルは、通常、ハンター型色差計より得られるＬ値が８０．０以上、ｂ値が−２．０〜５．０の範囲にあるものである。ポリエステルのＬ値が８０．０未満であると、白色度が低くなるため実用に供し得る高白色度成形物を得ることができないことがある。
【００５１】
また、ｂ値が−２．０未満であると、このポリエステルの黄味は少ないが、青味が増し、一方、ｂ値が５．０を越えると、得られるポリエステルの黄味が強くなるため、実用上有用な成形物の製造に供することができないことがある。本発明方法により得られるポリエステルのＬ値は好ましくは８２以上、特に好ましくは８３以上であり、ｂ値の好ましい範囲は−１．０〜４．５であり、特に好ましくは０．０〜４．０である。
【００５２】
なお、本発明方法により得られるポリエステルのＬ値及びｂ値は、下記の方法により測定される。すなわち、ポリエステルの試料を２９０℃、真空下で１０分間溶融し、これをアルミニウム板上において、厚さ３．０±１．０ｍｍのプレートに成形し、このプレートをただちに氷水中で急冷し、このプレートを１６０℃、１時間乾燥し、次に結晶化処理を施し、その後、プレートを色差計調整用の白色標準プレート上に置き、供試プレート表面の色調を、ミノルタ社製ハンター型色差計ＣＲ−２００を用いて測定した。
【００５３】
本発明のポリエステルは、実質的に、整色用コバルト化合物に由来するコバルト原子を含まないものである。コバルト原子を含むポリエステルには、溶融熱安定性が低く、分解が起こりやすくなるという欠点がある。なお、ここで“実質的に含まない”とは、整色剤若しくは重縮合触媒としてコバルト化合物を使用せず、したがって、得られるポリエステルが、上記コバルト化合物に由来するコバルト原子を含まないことを意味する。したがって、本発明のポリエステルは、整色剤及び触媒以外の目的をもって添加されたコバルト化合物に由来するコバルト原子を含むことがあってもよい。
【００５４】
本発明におけるポリエステルの固有粘度は適宜選択すればよいが、０．５５〜１．０の範囲にあることが好ましい。該固有粘度がこの範囲内にあると、溶融成形が容易でかつ成形物の強度も高いものとなる。該固有粘度のさらに好ましい範囲は、０．６０〜０．９０であり、特に好ましくは０．６２〜０．８０である。
【００５５】
【実施例】
本発明をさらに下記実施例により具体的に説明するが、本発明の範囲はこれら実施例により限定されるものではない。ただし上述の通り、固有粘度、色相、チタン含有量、異物数、溶融熱安定性及び紡糸口金に発生する付着物の層については、下記記載の方法により測定された。
【００５６】
（１）固有粘度：
ポリエステルポリマーの固有粘度は、オルソクロロフェノール溶液について、３５℃において測定した粘度の値から求めた。
【００５７】
（２）色調（Ｌ値及びｂ値）：
ポリマー試料を２９０℃、真空下で１０分間溶融し、これをアルミニウム板上で厚さ３．０±１．０ｍｍのプレートに成形後ただちに氷水中で急冷し、該プレートを１６０℃、１時間乾燥結晶化処理後、色差計調整用の白色標準プレート上に置き、プレート表面のハンターＬ値及びｂ値を、ミノルタ社製ハンター型色差計ＣＲ−２００を用いて測定した。Ｌ値は明度を示し、その数値が大きいほど明度が高いことを示し、ｂ値はその値が大きいほど黄着色の度合いが大きいことを示す。
【００５８】
（３）触媒のチタン含有量：
触媒化合物中のチタン濃度は、リガク社製蛍光Ｘ線測定装置３２７０を用いて測定した。
【００５９】
（４）動摩擦係数比の測定方法：
温度２０℃、相対湿度８０％に調温調湿したボックス内に設置したテーブル上に水平に張った牛皮上に、幅１０ｃｍ、長さ１０ｃｍの試験布（重量Ｗグラム）を板状台座（重量６０グラム）の底面に固定した状態で置き、さらに板状台座上に５０グラムの荷重をかける。台座の先端に連結した紐を水平方向からベアリングを介して垂直上方へ紐の他端に取り付けたストレインゲージまで導き、ストレインゲージを一定速度で上昇させることによって、試験布を１０ｍｍ／分の速度で牛皮上を滑走せしめて引張応力を自動記録し、付着（ｓｔｉｃｋ）−滑り（ｓｌｉｐ）の平均の引張応力Ｆ（グラム）を読み取り、下式によって動摩擦係数μを求める。
【００６０】
【数５】

試験布に一定量の水分を保水させて上記方法により測定した湿潤状態における動摩擦係数と、試験布を絶乾状態にして同様に測定した乾燥状態における動摩擦係数との比として動摩擦係数比を定める。
【００６１】
図１は本方法によって測定した動摩擦係数比と保水率の関係の例を示す図であって、曲線Ａは本発明の方法によって製造したポリエステル繊維を使用した編物（実施例１）、曲線Ｂは本発明における共重合を行っていないポリトリメチレンテレフタレート繊維を使用した編物（比較例１）、曲線Ｃは４０番手綿糸を使用した布帛、曲線Ｄは通常のポリエチレンテレフタレート繊維を使用した布帛（比較例３）についての測定結果を示したものである。
【００６２】
図１から明らかなように、本発明の方法になるポリエステル繊維は通常のポリエステル繊維や木綿に比較して、動摩擦係数比値の１．０からの隔たりが小さく、且つ約１００％の保水率においてさえなお、ほぼ絶乾時の動摩擦係数の水準を維持しており、木綿を凌駕する優れたドライ感を有していることがわかる。
【００６３】
なお、ここで言う保水率とは下式から得たものである。
【００６４】
【数６】

【００６５】
（５）紡糸口金に発生する付着物の層：
ポリエステルをチップとなし、これを２９０℃で溶融し、孔径０．１５ｍｍφ、孔数１２個の紡糸口金から吐出し、６００ｍ／分で２日間紡糸し、口金の吐出口外縁に発生する付着物の層の高さを測定した。この付着物層の高さが大きいほど吐出されたポリエステルメルトのフィラメント状流にベンディングが発生しやすく、このポリエステルの成形性は低くなる。すなわち、紡糸口金に発生する付着物層の高さは、当該ポリエステルの成形性の指標である。
【００６６】
［参考例１］
テレフタル酸ジメチル１９４重量部、エチレングリコール１２４重量部及びテトラ−ｎ−ブチルチタネート０．０１７重量部を加圧反応が可能なステンレス製容器に投入し、０．０７ＭＰａの加圧下、２２０℃においてエステル交換反応を行った後、この反応混合物にトリエチルホスホノアセテート０．０８部を加えて第１段階の反応を終了した。
【００６７】
次いで前記反応混合物を精留塔付き重縮合用フラスコへ入れ、この反応混合物に、整色剤としてテラゾールブルー０．０００２重量部、３−ヒドロキシカルボニル・ベンゼンスルホン酸Ｎａ−５−カルボン酸Ｎａの２５％エチレングリコール溶液７．７部及び二酸化チタンの２０％エチレングリコールスラリー２．９部を添加した。
【００６８】
次いで１時間かけて１０１ｋＰａから０．１ｋＰａまで減圧し、同時に１時間３０分かけて２３０℃から２８０℃まで昇温した。０．１ｋＰａ以下の減圧下、重合温度２８０℃でさらに３時間、合計４時間３０分重合して固有粘度０．６４０のポリマーを得、常法に従いチップ化した。
【００６９】
このチップを常法により乾燥し、孔径０．３ｍｍの円型紡糸孔を３６個設けた紡糸口金を使用し、常法に従って溶融紡糸して３４０ｄｔｅｘ／３６フィラメントの未延伸糸を得た。次いでこの未延伸糸を常法に従って４．２倍に延伸して８１ｄｔｅｘ／３６フィラメントを得た。
【００７０】
得られたマルチフィラメントを密度５２本／インチ×３４本／インチの２８Ｇトリコットハーフ編物に製編し、常法に従って精練、プリセットを施した後、減量率が２０％になるように１％の水酸化ナトリウム水溶液で沸騰温度にて処理した。この布帛の保水率と動摩擦係数比の関係は図１の曲線Ｂで示した通りであり、優れたドライ感を有していた。その他の結果は表１に示した。
【００７１】
［実施例２］
参考例１において、チタン化合物を下記参考例の方法にて合成したトリメリット酸チタン０．０３１部に変更する以外は同様にして重縮合反応を行いポリエステル及び繊維を得た。結果を表１に示す。
【００７２】
［参考例］
トリメリット酸チタンの合成方法：
無水トリメリット酸のエチレングリコール溶液（０．２％）にテトラブトキシチタンを無水トリメリット酸に対して１／２モル添加し、空気中常圧下で８０℃に保持して６０分間反応せしめ、その後、常温に冷却し、１０倍量のアセトンによって生成触媒を再結晶化させ、析出物をろ紙によって濾過し、１００℃で２時間乾燥せしめ、目的の化合物を得た。
【００７３】
［実施例３〜５、参考例６、７、比較例１〜６］
チタン化合物及びリン化合物を表１示す化合物及び値に変更する以外は、参考例１と同様にして重縮合反応を行いポリエステル及び繊維を得た。結果を表１に示す。
【００７４】
［比較例７］
テレフタル酸ジメチル１９４重量部とエチレングリコール１２４重量部の混合物に、テトラ−ｎ−ブチルチタネート０．０１７重量部を加圧反応が可能なステンレス製容器に仕込み、０．０７ＭＰａの加圧を行い１４０℃から２４０℃に昇温しながらエステル交換反応させた後、トリエチルホスホノアセテート０．０８部を添加し、エステル交換反応を終了させた。
【００７５】
その後反応生成物に三酸化二アンチモン０．１０１重量部を添加し、混合物を重合容器に移し、２９０℃まで昇温し、０．２ｍｍＨｇ以下の高真空にて重縮合反応を行って、固有粘度０．６４０、ジエチレングリコール量が１．４重量％であるポリエステルを得た。
【００７６】
得られたポリエステルは参考例１と同様に繊維化した。結果を表１に示す。
【００７７】
【表１】

【００７８】
【発明の効果】
本発明のポリエステル繊維及びその製造方法によれば、色調に優れ、かつ特殊な微細孔を有し、吸湿性、吸水性、ドライ感に優れているうえ、さらに紡糸口金を通して長時間連続的に紡糸しても口金付着物の発生量が非常に少なく、成形性に優れているポリエステル繊維及びその製造方法を提供することができる。
【図面の簡単な説明】
【図１】 本方法によって測定した動摩擦係数比と保水率との関係を示す図である。
【符号の説明】
Ａ：本発明の方法によって製造したポリエステル繊維を使用した編物（参考例１）について測定した動摩擦係数比と保水率との関係を表す曲線。
Ｂ：本発明の方法によって製造したポリエステル繊維を使用した編物（実施例２）について測定した動摩擦係数比と保水率との関係を表す曲線。
Ｃ：４０番手綿糸を使用した布帛について測定した動摩擦係数比と保水率との関係を表す曲線。
Ｄ：比較例１に従って製造したポリエステル繊維を使用した編物について測定した動摩擦係数比と保水率との関係を表す曲線。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a process for producing a polyester textiles, more particularly, using a polyester production catalyst comprising a specific titanium compound and a phosphorus compound having a polyester good color tone (color value b), and special micropores the a, a method of manufacturing a superior polyester textiles dry feeling.
[0002]
[Prior art]
Polyesters, especially polyethylene terephthalate, polyethylene naphthalate, polytrimethylene terephthalate and polytetramethylene terephthalate are widely used in fibers, films and other molded products because of their excellent mechanical, physical and chemical performance. Yes.
[0003]
For example, polyethylene terephthalate is usually obtained by direct esterification of terephthalic acid and ethylene glycol, transesterification of lower alkyl ester of terephthalic acid such as dimethyl terephthalate and ethylene glycol, or terephthalic acid and ethylene oxide. Reacted to produce ethylene glycol ester of terephthalic acid and / or its low polymer, and then this reaction product is heated under reduced pressure in the presence of a polymerization catalyst and subjected to a polycondensation reaction until a predetermined polymerization degree is reached Has been. Polyethylene naphthalate, polytrimethylene terephthalate, and polytetramethylene terephthalate are also produced by the same method as described above.
[0004]
It is well known that the reaction rate and the quality of the resulting polyester are greatly affected by the type of catalyst used in these polycondensation reaction steps. As a polycondensation catalyst of polyethylene terephthalate, an antimony compound is most widely used because it has excellent polycondensation catalyst performance and a polyester having a good color tone can be obtained.
[0005]
However, when an antimony compound is used as a polycondensation catalyst, if the polyester is melt-spun continuously for a long time, foreign matter (hereinafter, sometimes referred to simply as a base foreign matter) adheres and accumulates around the mouthpiece hole, resulting in a molten polymer. There is a problem of formability in which a flow bending phenomenon (bending) occurs, which causes fluff and / or yarn breakage in the spinning and drawing processes.
[0006]
Although it has been proposed to use a titanium compound such as titanium tetrabutoxide as a polycondensation catalyst other than the antimony compound, when such a titanium compound is used, the above-described molding caused by the deposition of foreign matter in the die However, there is a new problem that the obtained polyester itself is colored yellow and the heat stability of the melt is poor.
[0007]
In order to solve the above-mentioned coloring problem, it is generally performed to add a cobalt compound to polyester to suppress yellowing. Certainly, the color tone (color b value) of the polyester can be improved by adding a cobalt compound. However, the addition of a cobalt compound decreases the melt heat stability of the polyester, and the polymer tends to decompose. There's a problem.
[0008]
As other titanium compounds, Japanese Patent Publication No. 48-2229 discloses the use of titanium hydroxide, and Japanese Patent Publication No. 47-26597 uses α-titanic acid as a catalyst for producing polyester. ing. However, in the former method, powdering of titanium hydroxide is not easy. On the other hand, in the latter method, α-titanic acid is easily changed in quality, so its storage and handling are not easy. In addition, it is difficult to obtain a polymer having a good color tone (b value).
[0009]
JP-B-59-46258 discloses a product obtained by reacting a titanium compound with trimellitic acid, and JP-A-58-38822 discloses a reaction between a titanium compound and a phosphite. It is disclosed that each of the products obtained in this manner is used as a catalyst for producing a polyester. Certainly, according to this method, although the melt heat stability of the polyester is improved to some extent, the color tone of the obtained polymer is not sufficient, and therefore further improvement of the polymer color tone is desired.
[0010]
Furthermore, in JP-A-7-138354, it is proposed to use a complex of a titanium compound and a phosphorus compound as a catalyst for producing a polyester. According to this method, although the heat of fusion stability is improved to some extent, The color tone of the polymer obtained is not sufficient.
[0011]
These titanium-phosphorus catalysts often remain as foreign substances in the polyester polymer, and it has been desired to solve this problem.
[0012]
Further, since polyester fibers are generally hydrophobic, their use in fields requiring water absorption and hygroscopicity is limited. In particular, in order to give an unpleasant feeling of feeling due to stickiness during sweating, 100% use of polyester fiber is rarely used in the inner clothing field such as shirts and blouses, and the inner clothing field such as underwear, and it is used by mixing with cotton and linen. It has only been done.
[0013]
According to Japanese Examined Patent Publication No. 63-00545, there is provided a polyester fiber which exhibits excellent dry feeling with less stickiness even in a wet state due to sweating while maintaining the excellent easy care property inherent in the polyester fiber. For this purpose, polyester fibers blended with a specific metal salt of sulfonic acid are subjected to an alkali weight reduction treatment, so that not only the surface of the polyester fibers but also the inside of the fibers are provided with a large number of micropores, thereby making the cotton It has been reported that fibers having a dry feeling exceeding the above can be obtained. However, the fibers using such polyethylene terephthalate are soft due to the chemical modification thereof, and thus are affected by the above-mentioned foreign matter of the base. Cheap.
[0014]
This problem can be solved by using a method that does not use antimony as a polymerization catalyst as described above, but with this method, since the color of the yarn is lowered, it is difficult to actually use it. Therefore, antimony is not used as a polymerization catalyst, it is excellent in hue, hygroscopicity, water absorption, and dry feeling. Furthermore, even when spinning continuously through a spinneret for a long time, the amount of deposits on the die is very small. There has been a demand for a polyester fiber excellent in moldability and a method for producing the same.
[0015]
[Problems to be solved by the invention]
The object of the present invention is to solve the above-mentioned problems of the prior art, have a good color tone (b value) using a catalyst for producing a polyester containing a specific titanium compound and a phosphorus compound, and have a special It has fine pores and is excellent in hygroscopicity, water absorption, and dryness. In addition, even if it is spun continuously for a long time through the spinneret, the amount of deposits on the die is very small and the moldability is excellent. It is in providing a polyester fiber and its manufacturing method.
[0016]
[Means for Solving the Problems]
As a result of intensive studies in view of the above prior art, the present inventors have found that the above object can be achieved by using a specific polyester production catalyst, and have completed the present invention.
[0017]
That is, the object of the present invention is to
In producing a fiber comprising a polyester having ethylene terephthalate as a main repeating unit, the polyester contains a titanium compound soluble in the polyester and a phosphorus compound soluble in the polyester, and is soluble in the polyester. A phosphorus compound containing a phosphonate compound represented by the following general formula (II) as a phosphorus compound, and a titanium compound soluble in the polyester is represented by a compound represented by the following general formula (III) and the following general formula (IV) It is a product obtained by reacting an aromatic polyvalent carboxylic acid or its anhydride, and the titanium compound soluble in the polyester is 2 to 12 mmol as a titanium metal element based on the total dicarboxylic acid component constituting the polyester. % And a polyester polymer satisfying the following general formulas (1) and (2): Obtained by melt spinning after blending the sulfonic acid metal salt represented by the following general formula (I) in an amount of 0.1 to 25 mol% at an arbitrary stage until the melt spinning of the polyester is completed. This can be achieved by a method for producing a polyester fiber, wherein the fiber is treated with an aqueous solution of an alkali compound to remove at least a part of the metal sulfonate.
[0018]
[Expression 2]

[0019]
[Chemical formula 5]

[Chemical 9]

[Chemical Formula 10]

Embedded image

[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail.
[0021]
The polyester of the present invention contains a titanium compound soluble in a polymer in an amount of 2 to 12 mmol% as a titanium metal element with respect to all dicarboxylic acid components, and must satisfy the following general formulas (1) and (2). is there.
[0022]
[Equation 3]

In the present invention, the phosphorus compound used is required to be a phosphonate compound represented by the following general formula (II).
[0023]
[Chemical 6]

The above-mentioned phosphonate compounds include dimethyl-, diethyl-, dipropyl- and dibutyl esters of phosphonic acid, specifically carbomethoxymethanephosphonic acid, carboethoxymethanephosphonic acid, carbopropoxymethanephosphonic acid, carboptoxy. Examples include methanephosphonic acid, carbomethoxy-phosphono-phenylacetic acid, carboethoxy-phosphono-phenylacetic acid, carboprotooxy-phosphono-phenylacetic acid, carbobutoxy-phosphono-phenylacetic acid, and the like.
[0024]
The reason why the above-mentioned phosphonate compound is preferable is that the reaction with the titanium compound is generally used as a stabilizer and the reaction with the titanium compound proceeds relatively slowly, so that the catalytic activity of the titanium compound is also maintained during the polycondensation reaction. As a result, the amount added to the polyester can be reduced as a result, and even when a large amount of stabilizer is added to the catalyst as in this patent, the thermal stability of the polyester is hardly impaired.
[0025]
These phosphorus compounds may be added at any time after the transesterification or esterification reaction is substantially completed. For example, the polycondensation reaction was started even under atmospheric pressure before the polycondensation reaction was started. It may be added at a later reduced pressure, at the end of the polycondensation reaction, or after completion of the polycondensation reaction, that is, after the polymer is obtained.
[0026]
In the present invention, the titanium compound used needs to use a titanium compound that is soluble in the polymer from the viewpoint of reducing foreign matters caused by the catalyst. The titanium compound used in the present invention is a product obtained by reacting a compound represented by the following general formula (III) with an aromatic polycarboxylic acid represented by the following general formula (IV) or an anhydride thereof. is there.
[0027]
[Chemical 7]

[0028]
[Chemical 8]

The titanium compound represented by the general formula (III) is not particularly limited as long as R3, R3 ′, R3 ″, and R3 ′ ″ are the same or different and are an alkyl group and / or a phenyl group. Isopropoxy titanium, tetrapropoxy titanium, tetra-n-butoxy titanium, tetraethoxy titanium, tetraphenoxy titanium, octaalkyl trititanate, hexaalkyl dititanate and the like are preferably used.
[0029]
The aromatic polyvalent carboxylic acid represented by the general formula (IV) to be reacted as the compound or an anhydride thereof is preferably phthalic acid, trimellitic acid, hemimellitic acid, pyromellitic acid or an anhydride thereof. Used.
[0030]
When the titanium compound and the aromatic polyvalent carboxylic acid or anhydride thereof are reacted, a part of the aromatic polyvalent carboxylic acid or anhydride thereof is dissolved in a solvent, and the titanium compound is dropped into this, What is necessary is just to make it react at the temperature of 0-200 degreeC for at least 30 minutes.
[0031]
The polyester of the present invention must contain a titanium compound soluble in the polymer in an amount of 2 to 12 mmol% as a titanium metal element with respect to the total dicarboxylic acid component. If the titanium metal element is less than 2 mmol%, the productivity of the polyester is lowered, and a polyester having a target molecular weight cannot be obtained.
[0032]
On the other hand, when the titanium metal element exceeds 12 mmol%, the thermal stability is lowered, and the molecular weight during fiber production is greatly reduced, so that a polyester fiber having excellent quality cannot be obtained. The amount of titanium metal element is preferably in the range of 2.5 to 12 mmol%, more preferably in the range of 3 to 10 mmol%. The “titanium compound soluble in the polymer” mentioned here means that titanium contained in the titanium dioxide particles is not included, and the “amount of titanium metal element” means the first stage reaction by transesterification. When performed, the total amount of the titanium compound used as the transesterification reaction catalyst and the titanium compound used as the polycondensation reaction catalyst is shown.
[0033]
The polyester in the present invention is produced using a titanium compound as a catalyst and a phosphorus compound as a stabilizer, and must satisfy both of the following formulas (1) and (2).
[0034]
[Expression 4]

When (P / Ti) is less than 2, the hue is extremely yellowish, which is not preferable. On the other hand, if (P / Ti) exceeds 15, the polymerization reactivity of the polyester is significantly lowered, and the desired polyester cannot be obtained. The polyester used in the present invention is characterized in that the appropriate range of (P / Ti) is narrower than that of a normal metal catalyst. However, when it is within the appropriate range, an unprecedented effect as in the present invention can be obtained. it can. On the other hand, when (Ti + P) is less than 10, the productivity in the spinning process is greatly reduced, and satisfactory performance cannot be obtained. Further, when (Ti + P) exceeds 100, a small amount of foreign matter due to the catalyst is generated, which is not preferable.
[0035]
The ranges of formulas (1) and (2) are preferably (P / Ti) in the range of (1) in the range of 3 to 12, (Ti) in the formula (2) in the range of 15 to 85, and Preferably, (P / Ti) in the formula (1) is in the range of 4 to 10, and (Ti + P) in the formula (2) is in the range of 20 to 70.
[0036]
In general, a production method using an aromatic dicarboxylic acid typified by terephthalic acid as a raw material for a polyester having ethylene terephthalate as a main repeating unit, and an ester-forming derivative of an aromatic dicarboxylic acid typified by dimethyl terephthalate are used as a raw material. Two methods are known.
[0037]
The polyester in the present invention is not particularly limited depending on its production method, but is preferably a production method via a transesterification in which dimethyl terephthalate occupies 80 mol% or more of the starting material of ethylene terephthalate units. The production method using dimethyl terephthalate as a raw material has an advantage that the phosphorus compound added as a stabilizer during the polycondensation reaction is less scattered than the production method using terephthalic acid as a raw material.
[0038]
In addition, in the production method using dimethyl terephthalate as a raw material, a part and / or whole amount of a titanium compound can be added before the transesterification reaction, and the transesterification catalyst and polycondensation reaction catalyst can be reduced. And a method in which the transesterification is carried out under a pressure of 0.05 to 0.20 MPa is more preferable.
[0039]
The pressure during the transesterification reaction, 0.05 M P a below, is sufficiently unit acceleration of the reaction catalyzed by a titanium compound is not, on the one hand above 0.20 MPa, containing diethylene glycol in the polymer produced as a by-product The amount is remarkably increased and the properties such as the thermal stability of the polymer are deteriorated.
[0040]
Furthermore, in order to fine-tune the color of the polyester obtained, a kind of organic blue pigment and inorganic blue pigment such as azo, triphenylmethane, quinoline, anthraquinone, phthalocyanine, etc. The color adjusting agent which consists of the above can be added. In the production method of the present invention, as a matter of course, it is not necessary to use an inorganic blue pigment containing cobalt or the like that lowers the thermal stability of the polyester as a color adjusting agent. It is preferable not to contain cobalt.
[0041]
In the following general formula (I) showing the sulfonic acid metal salt used in the present invention, Ar is an aromatic group, and among them, a benzene ring or a naphthalene ring is preferable. R ₄ is an ester-forming functional group, -COOR '(where, R' is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, phenyl or _{-CO- {O- (CH 2) l} } p - O H (where, l is an integer of 2 or more, P is an integer of 1 or more.) and the like are preferable .M and M 'is a metal, preferably an alkali metal or alkaline earth metal as M, among others Li, Na, K, Ca _1/2 , and Mg _1/2 are particularly preferable, and M ′ is preferably an alkali metal, an alkaline earth metal, Mn _1/2 , or Zn _1/2 , and particularly Li, Na, K, Ca. _1/2 , Mg1 _{/ 2} , Ba1 _{/ 2} are particularly preferred, M and M 'may be the same or different, m is an integer of 0-4, n is an integer of 1-5, And m + n is an integer from 1 to 5.
[0042]
Preferred examples of the sulfonic acid metal salt include 3-carbomethoxy benzene sulfonic acid Na-5-carboxylic acid Na, 3-carbomethoxy benzene sulfonic acid Na-5 monocarboxylic acid K, and 3-carbomethoxy benzene. Sulfonic acid K-5-carboxylic acid K, 3-hydroxyethoxycarbonyl-benzenesulfonic acid Na-5-carboxylic acid Na, 3-carboxy-benzenesulfonic acid Na-5-carboxylic acid Na, 3-hydroxyethoxycarbonyl-benzenesulfone Acid Na-5-carboxylic acid Mg _1/2 , benzenesulfonic acid Na-3,5-di (carboxylic acid Na), benzenesulfonic acid Na-3,5-di (carboxylic acid Mg _1/2 ), benzenesulfonic acid Na-3-carboxylic acid Na, 3-carbomethoxy naphthalene-1-sulfonic acid Na-7-cal Examples thereof include sodium boronic acid, naphthalene-1-sulfonic acid Na-3,7-di (carboxylic acid Mg _1/2 ), and the like.
[0043]
The above sulfonic acid metal salts may be used alone or in combination of two or more. The addition time may be an arbitrary stage before the end of the spinning process for melt-spinning the polyester. For example, it may be added and mixed in the raw material of the polyester, added during the synthesis of the polyester, It may be added to the questions before spinning. In any case, it is preferable to mix in a molten state after addition.
[0044]
If the amount of the sulfonic acid metal salt is too small, the final feeling of the polyester fiber obtained will be insufficient, and if it is too large, sufficient polymerization will occur before the synthesis of the polyester is completed. Is difficult to obtain, and when the addition time is after the end of synthesis and before the end of melt spinning, troubles are likely to occur during spinning. For this reason, the addition amount should be in the range of 0.1 to 25 mol% with respect to the acid component constituting the polyester to be added, preferably in the range of 0.3 to 15 mol%, and more preferably 0.5 to A range of 5 mol% is particularly preferred.
[0045]
In order to melt-spun the modified polyester blended with the sulfonic acid metal salt into a solid fiber, it is not necessary to employ a special method, and a melt-spinning method of the solid fiber of the polyester is arbitrarily employed. The shape in the cross section of the fiber spun here may be circular or irregular, and it is not necessary to particularly limit the single fiber fineness, but when it is about 1 dtex or less, not only dry feeling, Depending on the application, about 1 dtex or less is preferable because it is excellent in water absorption and does not pierce the skin.
[0046]
Further, when spinning, a modified sheath containing the above sulfonic acid metal salt and an unmodified polyester containing no sulfonic acid metal salt are used, the modified polyester is a sheath component, and the unmodified polyester is a core component. Even a type composite fiber may be made into a two-layer or more multilayer side-by-side type composite fiber using a modified polyester and an unmodified polyester.
[0047]
In order to remove at least a part of the sulfonic acid metal salt from the polyester fiber thus obtained, an alkali is applied after applying a court heat treatment or false twisting as necessary, or after further forming a fabric. It can be easily carried out by immersing in an aqueous solution of the compound.
[0048]
Examples of the alkali compound used here include sodium hydroxide, potassium hydroxide, tetramethylammonium hydroxide, sodium carbonate, potassium carbonate and the like. Of these, sodium hydroxide and potassium hydroxide are particularly preferred.
[0049]
The concentration of such an aqueous solution of an alkali compound varies depending on the type of alkali compound, processing conditions, and the like, but is usually preferably in the range of 0.01 to 40% by weight, particularly preferably in the range of 0.1 to 30% by weight. The treatment temperature is preferably in the range of room temperature to 100 ° C., and the treatment time is usually in the range of 1 minute to 4 hours. By treating with an aqueous solution of an alkali compound in this manner, the polyester is selectively eluted together with the sulfonic acid metal salt, and a large number of fine pores communicating with the outside can be formed not only on the fiber surface but also on the fiber inner surface. , Will exhibit an excellent dry feeling.
[0050]
The polyester obtained by the method of the present invention usually has an L value obtained from a hunter-type color difference meter of 80.0 or more and a b value in the range of -2.0 to 5.0. If the L value of the polyester is less than 80.0, the whiteness will be low, and a high whiteness molded product that can be used in practice may not be obtained.
[0051]
If the b value is less than −2.0, the yellowness of the polyester is small, but the bluish color increases. On the other hand, if the b value exceeds 5.0, the yellowness of the resulting polyester becomes strong. In some cases, it cannot be used for the production of a practically useful molded product. The L value of the polyester obtained by the method of the present invention is preferably 82 or more, particularly preferably 83 or more, and the preferable range of the b value is -1.0 to 4.5, particularly preferably 0.0 to 4. 0.
[0052]
The L value and b value of the polyester obtained by the method of the present invention are measured by the following method. That is, a polyester sample was melted at 290 ° C. under vacuum for 10 minutes, formed on an aluminum plate into a plate having a thickness of 3.0 ± 1.0 mm, and the plate was immediately cooled in ice water. The plate is dried at 160 ° C. for 1 hour and then subjected to a crystallization treatment. After that, the plate is placed on a white standard plate for color difference meter adjustment, and the color of the test plate surface is changed to a Hunter type color difference meter CR manufactured by Minolta. Measured using -200.
[0053]
The polyester of the present invention is substantially free of cobalt atoms derived from the color-regulating cobalt compound. Polyesters containing cobalt atoms have the drawbacks of low thermal stability and easy decomposition. Here, “substantially free” means that a cobalt compound is not used as a color adjusting agent or a polycondensation catalyst, and therefore the resulting polyester does not contain a cobalt atom derived from the cobalt compound. To do. Therefore, the polyester of the present invention may contain a cobalt atom derived from a cobalt compound added for purposes other than the color adjusting agent and the catalyst.
[0054]
The intrinsic viscosity of the polyester in the present invention may be selected as appropriate, but is preferably in the range of 0.55 to 1.0. When the intrinsic viscosity is within this range, melt molding is easy and the strength of the molded product is high. A more preferable range of the intrinsic viscosity is 0.60 to 0.90, and particularly preferably 0.62 to 0.80.
[0055]
【Example】
The present invention will be further described in the following examples, but the scope of the present invention is not limited by these examples. However, as described above, the intrinsic viscosity, the hue, the titanium content, the number of foreign matters, the heat stability of fusion, and the layer of deposits generated on the spinneret were measured by the methods described below.
[0056]
(1) Intrinsic viscosity:
The intrinsic viscosity of the polyester polymer was determined from the viscosity value measured at 35 ° C. for the orthochlorophenol solution.
[0057]
(2) Color tone (L value and b value):
A polymer sample was melted at 290 ° C. under vacuum for 10 minutes, formed into a plate having a thickness of 3.0 ± 1.0 mm on an aluminum plate, and immediately cooled in ice water. The plate was dried at 160 ° C. for 1 hour. After the crystallization treatment, the plate was placed on a white standard plate for color difference adjustment, and the Hunter L value and b value on the plate surface were measured using a Hunter type color difference meter CR-200 manufactured by Minolta. The L value indicates the lightness, and the larger the value, the higher the lightness. The b value indicates the greater the degree of yellowing as the value increases.
[0058]
(3) Titanium content of the catalyst:
The titanium concentration in the catalyst compound was measured using a fluorescent X-ray measuring device 3270 manufactured by Rigaku Corporation.
[0059]
(4) Dynamic friction coefficient ratio measurement method:
A test cloth (weight W grams) 10 cm wide and 10 cm long is placed on a plate-shaped base (weight) on a cowhide stretched horizontally on a table placed in a box adjusted to a temperature of 20 ° C. and a relative humidity of 80%. 60 gram) is fixed to the bottom surface, and a 50 gram load is further applied on the plate-shaped pedestal. The string connected to the tip of the pedestal is guided from the horizontal direction to the strain gauge attached to the other end of the string vertically upward through a bearing, and the strain gauge is raised at a constant speed, so that the test cloth is moved at a speed of 10 mm / min. The tensile stress is automatically recorded by sliding on the cowhide, the average tensile stress F (gram) of stick-slip is read, and the dynamic friction coefficient μ is obtained by the following equation.
[0060]
[Equation 5]

A dynamic friction coefficient ratio is determined as a ratio of a dynamic friction coefficient in a wet state measured by the above method with a predetermined amount of water held in the test cloth and a dynamic friction coefficient in a dry state measured in the same manner after the test cloth is completely dried.
[0061]
FIG. 1 is a diagram showing an example of the relationship between the dynamic friction coefficient ratio measured by this method and the water retention rate. Curve A is a knitted fabric using polyester fibers produced by the method of the present invention (Example 1), and curve B is A knitted fabric using polytrimethylene terephthalate fibers not copolymerized in the present invention (Comparative Example 1), curve C is a fabric using 40th cotton yarn, curve D is a fabric using ordinary polyethylene terephthalate fibers (Comparative Example) The measurement result about 3) is shown.
[0062]
As is apparent from FIG. 1, the polyester fiber according to the method of the present invention has a smaller dynamic friction coefficient ratio value from 1.0 and a water retention rate of about 100% compared to normal polyester fiber and cotton. Even so, the level of the coefficient of dynamic friction at the time of absolutely dryness is maintained, and it can be seen that it has an excellent dry feeling surpassing that of cotton.
[0063]
In addition, the water retention rate said here is obtained from the following formula.
[0064]
[Formula 6]

[0065]
(5) Deposited layer generated in the spinneret:
Polyester is made into chips, melted at 290 ° C., discharged from a spinneret with a hole diameter of 0.15 mmφ and 12 holes, spun at 600 m / min for 2 days, and the deposits generated at the outer edge of the discharge port of the base The layer height was measured. As the height of the adhered layer increases, bending is more likely to occur in the filament flow of the discharged polyester melt, and the moldability of the polyester becomes lower. That is, the height of the deposit layer generated in the spinneret is an index of the moldability of the polyester.
[0066]
[ Reference Example 1]
194 parts by weight of dimethyl terephthalate, 124 parts by weight of ethylene glycol and 0.017 parts by weight of tetra-n-butyl titanate are put into a stainless steel container capable of pressure reaction, and transesterification is performed at 220 ° C. under a pressure of 0.07 MPa. After the reaction, 0.08 part of triethylphosphonoacetate was added to the reaction mixture to complete the first stage reaction.
[0067]
Next, the reaction mixture was put into a polycondensation flask equipped with a rectifying column, and 0.0002 part by weight of terazole blue, 3-hydroxycarbonyl / benzenesulfonic acid Na-5-carboxylate Na as a color adjusting agent was added to the reaction mixture. 7.7 parts of a 25% ethylene glycol solution and 2.9 parts of a 20% ethylene glycol slurry of titanium dioxide were added.
[0068]
Subsequently, the pressure was reduced from 101 kPa to 0.1 kPa over 1 hour, and at the same time, the temperature was raised from 230 ° C. to 280 ° C. over 1 hour 30 minutes. Under a reduced pressure of 0.1 kPa or less, polymerization was further carried out at a polymerization temperature of 280 ° C. for 3 hours, for a total of 4 hours and 30 minutes to obtain a polymer having an intrinsic viscosity of 0.640, and chipped according to a conventional method.
[0069]
This chip was dried by a conventional method, and a spinneret having 36 circular spinning holes having a hole diameter of 0.3 mm was used, and melt spinning was performed according to a conventional method to obtain a 340 dtex / 36 filament undrawn yarn. Next, this undrawn yarn was drawn 4.2 times according to a conventional method to obtain 81 dtex / 36 filament.
[0070]
The obtained multifilament is knitted into a 28G tricot half knitted fabric with a density of 52 / inch × 34 / inch, scoured and preset according to a conventional method, and then 1% water so that the weight loss rate becomes 20%. Treated with aqueous sodium oxide at boiling temperature. The relationship between the water retention rate and the dynamic friction coefficient ratio of this fabric was as shown by curve B in FIG. 1, and had an excellent dry feeling. The other results are shown in Table 1.
[0071]
[Example 2]
Polyester and fiber were obtained in the same manner as in Reference Example 1 except that the titanium compound was changed to 0.031 part of titanium trimellitic acid synthesized by the method of the following Reference Example. The results are shown in Table 1.
[0072]
[Reference example]
Synthesis method of titanium trimellitic acid:
Add 1/2 mol of tetrabutoxytitanium to trimellitic anhydride in ethylene glycol solution (0.2%) with respect to trimellitic anhydride, and keep it at 80 ° C. under atmospheric pressure for 60 minutes. The resulting catalyst was recrystallized with 10 times the amount of acetone, and the precipitate was filtered through filter paper and dried at 100 ° C. for 2 hours to obtain the desired compound.
[0073]
[Examples 3 to 5, Reference Examples 6 and 7, Comparative Examples 1 to 6]
A polyester and fiber were obtained by performing a polycondensation reaction in the same manner as in Reference Example 1 except that the titanium compound and the phosphorus compound were changed to the compounds and values shown in Table 1. The results are shown in Table 1.
[0074]
[Comparative Example 7]
A mixture of 194 parts by weight of dimethyl terephthalate and 124 parts by weight of ethylene glycol is charged with 0.017 parts by weight of tetra-n-butyl titanate in a stainless steel container capable of pressure reaction, and is pressurized to 0.07 MPa at 140 ° C. Then, the ester exchange reaction was carried out while raising the temperature to 240 ° C., and then 0.08 part of triethylphosphonoacetate was added to complete the ester exchange reaction.
[0075]
Thereafter, 0.101 part by weight of diantimony trioxide is added to the reaction product, the mixture is transferred to a polymerization vessel, heated to 290 ° C., and subjected to a polycondensation reaction at a high vacuum of 0.2 mmHg or less to obtain an intrinsic viscosity. A polyester having 0.640 and a diethylene glycol amount of 1.4% by weight was obtained.
[0076]
The obtained polyester was fiberized in the same manner as in Reference Example 1. The results are shown in Table 1.
[0077]
[Table 1]

[0078]
【The invention's effect】
According to the polyester fiber of the present invention and the method for producing the same, it has excellent color tone, has special fine pores, is excellent in hygroscopicity, water absorption, and dry feeling, and is further continuously spun through a spinneret. Even in this case, it is possible to provide a polyester fiber having a very small amount of deposits on the die and excellent in moldability and a method for producing the same.
[Brief description of the drawings]
FIG. 1 is a diagram showing a relationship between a dynamic friction coefficient ratio and a water retention rate measured by this method.
[Explanation of symbols]
A: A curve representing the relationship between the dynamic friction coefficient ratio and the water retention measured for a knitted fabric ( Reference Example 1) using polyester fibers produced by the method of the present invention.
B: A curve representing the relationship between the dynamic friction coefficient ratio and the water retention measured for a knitted fabric (Example 2) using the polyester fiber produced by the method of the present invention.
C: A curve representing the relationship between the dynamic friction coefficient ratio and the water retention measured for a fabric using 40th cotton yarn.
D: A curve representing the relationship between the dynamic friction coefficient ratio and the water retention measured for a knitted fabric using the polyester fiber produced according to Comparative Example 1.

Claims (4)

In producing a fiber comprising a polyester having ethylene terephthalate as a main repeating unit, the polyester contains a titanium compound soluble in the polyester and a phosphorus compound soluble in the polyester, and is soluble in the polyester. A phosphorus compound containing a phosphonate compound represented by the following general formula (II) as a phosphorus compound, and a titanium compound soluble in the polyester is represented by a compound represented by the following general formula (III) and the following general formula (IV) It is a product obtained by reacting an aromatic polyvalent carboxylic acid or its anhydride, and the titanium compound soluble in the polyester is 2 to 12 mmol as a titanium metal element based on the total dicarboxylic acid component constituting the polyester. % And a polyester polymer satisfying the following general formulas (1) and (2): Obtained by melt spinning after blending the sulfonic acid metal salt represented by the following general formula (I) in an amount of 0.1 to 25 mol% at an arbitrary stage until the melt spinning of the ester is completed. A method for producing a polyester fiber, wherein the fiber is treated with an aqueous solution of an alkali compound to remove at least a part of the sulfonic acid metal salt.

The titanium compound soluble in the polyester is added to the reaction system before the start of the transesterification reaction, and a part of the total addition amount and / or the total amount is used as both the transesterification reaction catalyst and the polycondensation reaction catalyst. Item 2. The production method according to Item 1.   The production method according to claim 1, wherein dimethyl terephthalate occupies 80 mol% or more of the starting material of the ethylene terephthalate unit.   The production method according to claim 1, wherein the transesterification reaction is carried out under a pressure of 0.05 to 0.20 MPa.

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