JP2004196933A - Polyester with suppressed orientation crystallization, method for producing the same, and fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester favorable in color tone, very slight in spinneret deposition even if subjected to melt spinning continuously for a long period of time through a spinneret, having high performance of good formability, and giving polyester fibers of improved clearness. <P>SOLUTION: The polyester is produced by melt kneading a polyester obtained using, as a catalyst for the polycondensation reaction, a deposit obtained by heating a titanium compound and a phosphorus compound in a glycol, with an aqueous solution of an alkali metal salt soluble to the polyester. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００２１】
【化８】

【００２２】
【化９】

【００２３】
更に、本発明の第２の目的は、
重縮合反応の触媒として、下記一般式（Ｉ）で表されるチタン化合物、若しくは下記一般式（Ｉ）で表されるチタン化合物と下記一般式（ＩＩ）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と、下記一般式（ＩＩＩ）で表されるリン化合物とを、チタン元素のモル数に対するリン元素のモル数（Ｐ／Ｔｉ）が１〜４となる範囲でグリコール中で加熱することにより得られた析出物を、ポリエステルに含まれるチタン元素量が、該ポリエステルを構成する全ジカルボン酸成分を基準として２〜４０ミリモル％の範囲となるように用いて得た、全繰り返し単位の少なくとも８０モル％がエチレンテレフタレート単位であるポリエステルを、ベント付き溶融混練押出機へ供給しつつ、該押出機内に予め調製しておいたポリエステル可溶のアルカリ金属塩を水および／または沸点が５０〜２４０℃の範囲にある有機溶媒に溶解させた溶液を、該溶液中のアルカリ金属元素換算で該ポリエステルを構成する全ジカルボン酸成分を基準として２〜４０ミリモル％の範囲となるように、該押出機内へ添加し該混練機内で溶融混練する、ポリエステルの製造方法によって達成される。
【００２４】
【化１０】

【００２５】
【化１１】

【００２６】
【化１２】

【００２７】
【発明の実施の形態】
以下、本発明を詳しく説明する。
本発明におけるポリエステルは、芳香族ジカルボン酸のエステル形成性誘導体とアルキレングリコールとを、触媒の存在下にエステル交換反応、次いで重縮合反応させて得られるポリエステルであって、全繰り返し単位の８０モル％以上がエチレンテレフタレートであるポリエステルである。全繰り返し単位中のエチレンテレフタレート単位が８０モル％未満であると、ポリエスエステルの特徴である高強度、高弾性力といった基本特性が失われるため好ましくない。
【００２８】
本発明のポリエステルは、ポリエステルを構成する全ジカルボン酸成分を基準として、ポリエステル可溶性のアルカリ金属塩を２〜４０ミリモル％の範囲で含有する必要がある。ここで、アルカリ金属を例示すると、Ｌｉ、Ｎａ、Ｋを例示することができ、また塩根としてはポリエステルに使用されている公知の塩であれば特に問題はなく、酢酸根、リン酸根等が上げられるが、特に酢酸根が好ましく用いられる。アルカリ金属塩は一種を単独で用いても２種以上を併用してもどちらでもよい。該アルカリ金属塩は、２ミリモル％未満では、配向結晶抑制効果を示さず、４０ミリモル％を越えると、アルカリ性であることからポリエステルの分解、劣化を促進するようになるため好ましくない。
【００２９】
本発明におけるポリエステルは、その特性を失わない範囲でエチレンテレフタレート単位を構成する成分以外の第３成分を共重合した、共重合ポリエチレンテレフタレートであってもよい。第３成分（共重合成分）は、ジカルボン酸成分またはグリコール成分のいずれでもよい。第３成分として好ましく用いられるジカルボン酸成分としては、２，６−ナフタレンジカルボン酸、イソフタル酸、フタル酸等の芳香族ジカルボン酸、アジピン酸、アゼライン酸、セバシン酸、デカンジカルボン酸等の脂肪族ジカルボン酸、シクロヘキサンジカルボン酸等の脂環式ジカルボン酸、グリコール成分としては、トリメチレングリコール、テトラメチレングリコール、１，４−シクロヘキサンジメタノール等が例示でき、これらは一種を単独でまたは二種以上を併用して用いることができる。
【００３０】
本発明のポリエステルは、下記一般式（Ｉ）で表されるチタン化合物と下記一般式（ＩＩＩ）で表されるリン化合物とをチタン元素のモル数に対するリン元素のモル数（Ｐ／Ｔｉ）が１〜４となる範囲の組成で反応せしめたチタン／リン反応物を用いて重合されている必要がある。
【００３１】
【化１３】

【００３２】
【化１４】

【００３３】
ここでチタン元素のモル数に対するリン元素のモル数（Ｐ／Ｔｉ）が１より小さい場合、得られるポリエステルの色調が、不良になり、かつその耐熱性が低下することがあり好ましくなく、４より大きい場合、ポリエステル生成反応に対する触媒活性が不十分になり好ましくない。チタン元素のモル数に対するリン元素のモル数（Ｐ／Ｔｉ）は１．２〜３．５の範囲が好ましく、１．５〜３．０の範囲が更に好ましい。
【００３４】
また、チタン化合物成分（Ｉ）とリン化合物成分（ＩＩＩ）との触媒調製は、エチレングリコール中で加熱反応されている必要があるが、反応方法としては例えばリン化合物（ＩＩＩ）からなる成分とエチレングリコールとを混合して、リン化合物成分の一部又は全部を溶媒中に溶解し、この混合液にチタン化合物成分（Ｉ）を滴下し、反応系を０℃〜２００℃の温度に３０分間以上、好ましくは６０〜１５０℃の温度に４０〜９０分間、加熱することによって行われる。この反応において、反応圧力については格別の制限はなく、通常常圧下で行われる。
【００３５】
ここで上記式（Ｉ）で表されるチタン化合物としては例えば、チタンテトラブトキシド、チタンテトライソプロポキシド、チタンテトラプロポキシド、チタンテトラエトキシドなどのチタンテトラアルコキシドや、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、アルキルチタネート、酢酸チタン等を挙げることができる。
【００３６】
また上記式（ＩＩＩ）で表されるリン化合物としては式中のｐが０の場合は、例えば、フェニルホスホン酸、メチルホスホン酸、エチルホスホン酸、プロピルホスホン酸、イソプロピルホスホン酸、ブチルホスホン酸、トリルホスホン酸、キシリルホスホン酸、ビフェニルホスホン酸、ナフチルホスホン酸、アントリルホスホン酸、２−カルボキシフェニルホスホン酸、３−カルボキシフェニルホスホン酸、４−カルボキシフェニルホスホン酸、２，３−ジカルボキシフェニルホスホン酸、２，４−ジカルボキシフェニルホスホン酸、２，５−ジカルボキシフェニルホスホン酸、２，６−ジカルボキシフェニルホスホン酸、３，４−ジカルボキシフェニルホスホン酸、３，５−ジカルボキシフェニルホスホン酸、２，３，４−トリカルボキシフェニルホスホン酸、２，３，５−トリカルボキシフェニルホスホン酸、２，３，６−トリカルボキシフェニルホスホン酸、２，４，５−トリカルボキシフェニルホスホン酸、２，４，６−トリカルボキシフェニルホスホン酸等を挙げることができるが、中でもモノアリールホスホン酸が好ましい。
【００３７】
また、ｐが１の場合は例えば、モノメチルホスフェート、モノエチルホスフェート、モノトリメチルホスフェート、モノ−ｎ−ブチルホスフェート、モノヘキシルホスフェート、モノヘプチルホスフェート、モノノニルホスフェート、モノデシルホスフェート、モノドデシルホスフェート、モノフェニルホスフェート、モノベンジルホスフェート、モノ（４−ドデシル）フェニルホスフェート、モノ（４−メチルフェニル）ホスフェート、モノ（４−エチルフェニル）ホスフェート、モノ（４−プロピルフェニル）ホスフェート、モノ（４−ドデシルフェニル）ホスフェート、モノトリルホスフェート、モノキシリルホスフェート、モノビフェニルホスフェート、モノナフチルホスフェート、モノアントリルホスフェート等が挙げられる。
【００３８】
上記式（Ｉ）で表されるチタン化合物は予め下記式（ＩＩ）の多価カルボン酸及び／又はその無水物と反応させて使用する方法も好ましく用いられる。その場合、チタン化合物と多価カルボン酸及び／又はその無水物の反応モル比は（２：１）〜（２：５）の範囲が好ましい。特に好ましい範囲は（１：１）〜（１：２）である。
【００３９】
【化１５】

【００４０】
以下、本発明のポリエステルの製造方法について説明する。
【００４１】
本発明のポリエステルの製造方法において、チタン元素量は全ジカルボン酸成分に対し２〜４０ミリモル％の範囲にあるように添加することが好ましい。チタン元素量が２ミリモル％未満の場合は重合反応が遅くなり、４０ミリモル％を超える場合は得られるポリエステルの色調が、不良になり、かつその耐熱性が低下することがあり好ましくない。チタン元素量は３〜３０ミリモル％の範囲が好ましく、４〜２０ミリモル％の範囲が更に好ましい。
【００４２】
本発明の製造方法においては、チタン化合物、リン化合物、アルカリ金属塩を重合反応系内に一度に添加すると、アルカリ金属塩が重合反応を抑制するため、生産性が十分でないものとなるが、ポリエステル重合時の触媒としてチタン化合物とリン化合物とをチタン元素のモル数に対するリン元素のモル数（Ｐ／Ｔｉ）が１〜４となる範囲の組成でエチレングリコール中で加熱反応させたチタン／リン反応物を用い、且つ該ポリエステルに含まれるチタン元素量が全ジカルボン酸成分を基準として２〜４０ミリモル％の範囲にあるポリエステルプレチップをひとまず製造し、このチップをベント付き押出機に供給して、ポリエステルに可溶なアルカリ金属塩を水および／または沸点が５０〜２４０℃の範囲有機溶媒に溶解させ、該ポリエステルを構成する全ジカルボン酸成分を基準として２〜４０ミリモル％の範囲で含有するように供給し、混練させれば、生産性を損なうことなく、製造することができる。
【００４３】
上記のポリエステルプレチップの製造方法について説明すると、エステル交換反応触媒の存在下に、芳香族ジカルボン酸のエステル形成性誘導体とアルキレングリコールとをエステル交換反応させることによって製造するが、このエステル交換反応時の反応系内圧力については、通常は常圧で行われるが、必要に応じて加圧下での反応を実施してもよく、加圧下でのエステル交換反応を実施する場合、圧力を０．２０ＭＰａより高くすると、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為、０．２０ＭＰａ以下、好ましくは０．０６〜０．１０ＭＰａの範囲で実施することが好ましい。
【００４４】
次いで、得られたポリエステルプレチップはベント付き溶融混練押出機に供給し、更に、予め調整しておいた、ポリエステルに可溶なアルカリ金属塩を水および／または沸点５０〜２４０℃の範囲にある有機溶媒に溶解した溶液を添加する。
【００４５】
ここで、用いるベント式溶融混練押出機は、少なくとも一箇所のベント孔を備えた溶融混練押出機であればよく、該押出機の機能に特に制限はなく、１軸スクリュータイプ、２軸スクリュータイプのいずれも用いることができるが、不活性ガスの添加や減圧保持が可能であるように、ベント機能を２箇所以上有する溶融混練押出機であることが好ましい。また、混練性能が高く、短時間に反応が完結するように、２軸スクリュー型のベント付き溶融混練押出機を用いることが好ましい。尚、２軸スクリュー型ベント付き溶融混練押出機を用いる場合には、２軸の回転方向は同一でも逆方向でもよいが、同一方向の回転が、原料の熱劣化を抑える観点から好ましい。
【００４６】
また、その混練性能を高めるため、混練セグメントが具備されていることが好ましく、例えば、ニーディングディスク、ローターディスクが挙げられる。
【００４７】
ニーディングディスクとは、略楕円形のディスクを数枚、一定の位相でずらしながら組み合わせた混練用のスクリューセグメントであり、スクリューの回転にともなってポリエステルの混合物を狭いクリアランスへ強制的に通過させることで極めて高い剪断力を付与することができる。この結果、ポリオキシアルキレン系ポリエーテルのポリトリメチレンテレフタレートの分散効果が促進される。
【００４８】
一方、ローターディスクとは、多角形のディスクであり、その稜線を一定の角度でねじってあるスクリューセグメントであり、クリアランスがセグメントの全位置で一定であるという特徴がある。スクリュー軸に対する稜線のねじりの向きが順送りのものと逆送りのものとの二通りのセグメントがあり、これらのセグメントを組み合わせることで、高い剪断力を均一に付与することができ、剪断によるポリエステルの劣化を抑制しつつ、溶融混練を進めることが可能となる。
【００４９】
ニーディングディスクあるいはローターディスクは、目標とする組成物の物性により、適宜選択することができ特に制限はないが、これらの装着数を、ディスク又はセグメント長（Ｌ）及びスクリュー径（Ｄ）の比Ｌ／Ｄで表したとき、ニーディングディスク及びローターディスクの装着数はそれぞれ、Ｌ／Ｄ＝１〜３０の範囲とすることが好ましく、より好ましくはＬ／Ｄ＝２〜２０の範囲である。Ｌ／Ｄがこの範囲内にあるときには、更に良好な溶融混練を行うことができ、この時、該スクリューの回転数は、２０〜５００ｒｐｍ程度に設定すればよく、好ましくは５０〜３００ｒｐｍである。
【００５０】
尚、該押出機の温度は用いるポリマーの融点より１０〜４０℃高い温度、好ましくは用いるポリマーの融点より２０〜４０℃高い温度である。
【００５１】
また、ベント付き溶融混練押出機へ添加するためアルカリ金属塩溶液は、予め水および／または沸点が５０〜２５０℃の範囲にある有機溶媒に溶解させたものを用いる。ここで、有機溶媒を使用する場合、沸点が５０℃未満であると、揮発性が高くて添加溶媒として使用することが困難であり、２５０℃を越えると添加した後、ポリエステルからの留去が困難になる。該有機溶媒として好ましくは、メタノール、エタノール、エチレングリコール、トリメチレングリコール、１，４−ブタンジオール、ベンゼン、トルエン、キシレン、テトラヒドロフラン、１，３−ジオキソラン、２−メチル−１，３−ジオキソラン等の有機溶媒を挙げることができるが、安価であること、安全性が高いことから水が最も好ましく用いられる。
【００５２】
本発明の製造法方法において、ベント付き溶融混練押出機は、ベント孔の少なくとも１箇所は、真空ポンプ又はスチームエジェクターを用いて減圧下にすることが好ましく、通常は１０ｋＰａ以下、好ましくは５ｋＰａ以下、１ｋＰａ以下に設定することが更に好ましく、溶融混練操作において副次的に生成され得る水、メタノール等のアルコール、あるいは極少量の副生物等を留去することが好ましい。反応時間は１〜６０分間、特に５〜３０分間であることが好ましい。
【００５３】
本発明のようなベント付き押出機を用いれば、短時間で反応を完結することができ、結果として、副生成物を激減させ、同時に改善された色相を有するポリマーを得ることができる。
【００５４】
本発明において製造されるポリエステルの固有粘度（ｏ−クロロフェノール、３５℃）は、０．５０〜１．００の範囲にあることが好ましく、更に０．６０〜０．７０の範囲が好ましい。固有粘度が０．５０未満であると、繊維の強度が不足するため好ましくない。他方、固有粘度が１．００を超えると、原料ポリマーの固有粘度を過剰に引き上げる必要があり不経済である。
【００５５】
本発明において、必要に応じて少量の添加剤、例えば滑剤、顔料、染料、酸化防止剤、固相重合促進剤、蛍光増白剤、帯電防止剤、抗菌剤、紫外線吸収剤、光安定剤、熱安定剤、遮光剤、艶消剤等を含んでいてもよい。特に艶消剤としての酸化チタンは好ましく添加され、その場合平均粒径が０．０１〜２μｍの酸化チタンを最終的に得られるポリエステル組成物中に０．０１〜１０重量％含有させるよう添加することが好ましい。
【００５６】
尚、上述したような溶融混練操作を経てベント付き溶融混練押出機から出たポリエステル組成物は、水冷バス等の冷却工程を通過後、チップカッターを用いてチップ化されるか、あるいは、冷却・チップ化をすること無く、そのまま紡糸機に供してもよい。
【００５７】
本発明のポリエステル繊維を製造する時の製造方法としては特に限定はなく、従来公知の溶融紡糸方法が用いられるが、例えばポリエステルを２７０〜３００℃の範囲で溶融紡糸して製造することが好ましく、溶融紡糸の速度は４００〜５０００ｍ／分で紡糸することが好ましい。紡糸速度がこの範囲にあると、得られる繊維の強度も十分なものであると共に、安定して巻き取りを行うこともできる。また延伸はポリエステル繊維を巻き取ってから、あるいは一旦巻き取ることなく連続的に延伸処理することによって、延伸糸を得ることができる。更に本発明のポリエステル繊維は風合いを高める為に、公知の方法によるアルカリ減量処理も好ましく実施される。
【００５８】
本発明のポリエステル繊維を製造する際において、紡糸時に使用する口金の形状について制限は無く、円形、異形、中実、中空等のいずれも採用することができる。
【００５９】
【実施例】
本発明を更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。尚、固有粘度、色相、チタン、リン、カルシウム、マグネシウム含有量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した。
【００６０】
（１）固有粘度：
ポリエステルポリマーの固有粘度は、ｏ−クロロフェノール溶液中、３５℃において測定した粘度の値から求めた。
【００６１】
（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−３００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。
【００６２】
（３）ポリマー中のチタン、リン及びアンチモン含有量：
ポリマー試料を加熱溶融して円形ディスクを作成し、リガク社製蛍光Ｘ線測定装置３２７０を用いて測定した。ただし、艶消し剤として酸化チタンを添加したもののチタン元素量については、ポリマー試料をヘキサフルオロイソプロパノールに溶解し、遠心分離機で酸化チタン粒子を沈降させ、傾斜法により上澄み液のみを回収し、溶剤を蒸発させた後に測定した。
【００６３】
（４）引張強度、引張伸度：
ＪＩＳ Ｌ１０１３記載の方法に準拠して測定を行った。
【００６４】
（５）熱水収縮率：
孔径０．３ｍｍの円形紡糸孔を３６個備えた紡糸口金を有する押出紡糸機を用いて２８７℃で溶融し、紡糸紡糸温度２９２℃、紡糸速度４０００ｍ／分で紡糸サンプルを採取、沸水で３０分保持したときの収縮率を測定した。収縮率が高いほど配向結晶が抑制されていることを示す。
【００６５】
（６）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］触媒の調整：
エチレングリコール１３１重量部中にフェニルホスホン酸３．６重量部を１２０℃に１０分間加熱して溶解した。このエチレングリコール溶液１３４．５重量部に、更にエチレングリコール４０重量部を加えた後、これにチタンテトラブトキシド３．８重量部を溶解させた。得られた反応系を１２０℃で６０分間撹拌し、チタン化合物とフェニルホスホン酸とを反応させ、反応生成物を含む触媒の白色スラリーを得た。この触媒スラリーのチタン含量は０．３重量％、チタン元素のリン元素に対するモル比（Ｐ／Ｔｉ）は２．０であった。
【００６７】
［参考例２］触媒の調整：
エチレングリコール２．５重量部に無水トリメリット酸０．８重量部を溶解し、この溶液にチタンテトラブトキシド０．７重量部（無水トリメリット酸のモル量を基準として０．５ｍｏｌ％）を滴下し、この反応系を空気中、常圧下、８０℃に６０分間保持してチタンテトラブトキシドと無水トリメリット酸とを反応させ、反応生成物を熟成させた。その後反応系を常温に冷却し、これにアセトン１５重量部を加え、析出物をＮｏ．５濾紙で濾過し、採取し、これを１００℃の温度で２時間乾燥した。得られた反応生成物のチタン含有量は１１．２重量％であった。 次に、エチレングリコール１３１重量部中にフェニルホスホン酸３．６重量部を１２０℃に１０分間加熱して溶解した。このエチレングリコール溶液１３４．５重量部に、更にエチレングリコール４０重量部を加えた後、これに上記チタン化合物５．０重量部を溶解させた。得られた反応系を１２０℃で６０分間撹拌し、チタン化合物とフェニルホスホン酸とを反応させ、反応生成物を含む触媒の白色スラリーを得た。この触媒スラリーのチタン含量は０．３重量％、チタン元素のリン元素に対するモル比（Ｐ／Ｔｉ）は２．０であった。
【００６８】
［参考例３］触媒の調整：
エチレングリコール１３１重量部中にモノ−ｎ−ブチルホスフェート３．５重量部を１２０℃に１０分間加熱して溶解した。このエチレングリコール溶液１３４．５重量部に、更にエチレングリコール４０重量部を加えた後、これにチタンテトラブトキシド３．８重量部を溶解させた。得られた反応系を１２０℃で６０分間撹拌し、チタン化合物とモノ−ｎ−ブチルホスフェートとを反応させ、反応生成物を含む触媒の白色スラリーを得た。この触媒スラリーのチタン含量は０．３重量％、チタン元素のリン元素に対するモル比（Ｐ／Ｔｉ）は２．０であった。
【００６９】
［参考例４］触媒の調整：
エチレングリコール２．５重量部に無水トリメリット酸０．８重量部を溶解し、この溶液にチタンテトラブトキシド０．７重量部（後記ポリエステルの製造に用いられる無水トリメリット酸のモル量を基準として０．５ｍｏｌ％）を滴下し、この反応系を空気中、常圧下、８０℃に６０分間保持してチタンテトラブトキシドと無水トリメリット酸とを反応させ、反応生成物を熟成させた。その後反応系を常温に冷却し、これにアセトン１５重量部を加え、析出物をＮｏ．５濾紙で濾過し、採取し、これを１００℃の温度で２時間乾燥した。得られた反応生成物のチタン含有量は１１．２重量％であった。
【００７０】
次に、エチレングリコール１３１重量部中にモノ−ｎ−ブチルホスフェート３．５重量部を１２０℃に１０分間加熱して溶解した。このエチレングリコール溶液１３４．５重量部に、更にエチレングリコール４０重量部を加えた後、これに上記チタン化合物５．０重量部を溶解させた。得られた反応系を１２０℃で６０分間撹拌し、チタン化合物とモノ−ｎ−ブチルホスフェートとを反応させ、反応生成物を含む触媒の白色スラリーを得た。この触媒スラリーのチタン含量は０．３重量％、チタン元素のリン元素に対するモル比（Ｐ／Ｔｉ）は２．０であった。
【００７１】
［実施例１］
テレフタル酸ジメチル１００部とエチレングリコール７０部の混合物に重合触媒として参考例１で調製したチタン触媒０．８２部を添加して撹拌機、精留塔及びメタノール留出コンデンサーを設けた反応器に仕込み、１４０℃から２４０℃まで徐々に昇温しつつ、反応の結果生成するメタノールを系外に留出させながら、エステル交換反応を行った。その後、５６重量％濃度のリン酸水溶液０．０５０５部を添加し、エステル交換反応を終了させた。
【００７２】
このエステル交換反応物を撹拌装置、窒素導入口、減圧口、蒸留装置を備えた反応容器に移し、２８５℃まで昇温し、３０Ｐａ以下の高真空にて重縮合反応を行って、固有粘度０．６５、ジエチレングリコール量が１．０％であるポリエステルプレチップを得た。
【００７３】
このプレチップをロス・イン・ウェート式計量フィーダーで計量し、チップ投入口から下流へ向けてオープンベントを２箇所、真空ベント２箇所を備え、かつニーディングディスクをＬ／Ｄ換算で５、ローターディスクをＬ／Ｄ換算で５、有する同方向回転型二軸押出機へ供給し、２８０℃で溶融させた。
【００７４】
さらに、酢酸ナトリウムの１０ｗｔ％水溶液を調製し、最終ポリマー中での含有量がポリエステルの重量に対して１５ｍｍｏｌ％になるように設定し、プランジャーポンプを用いて押出機のポリマー溶融部へ注入した。ポリエステル総重量に対して、２７℃、大気圧で１倍に相当する体積の窒素をオープンベントより吹き込み、他方のオープンベントより排出させた。
【００７５】
その後、押出機に備え付けられた真空ベント孔から２０Ｐａの圧力で減圧し、滞留時間１５分、回転数は２００ｒｐｍで溶融混練した。混練後、ポリマーをストランド状に押し出して水冷バスで固化した後、チップカッターでチップ化した。
【００７６】
得られたチップを常法により乾燥した後、孔径０．３ｍｍの円形紡糸孔を３６個備えた紡糸口金を有する押出紡糸機を用いて２８７℃で溶融し、引取速度１４００ｍ／分で紡糸し、３３３ｄｔｅｘ／３６ｆｉｌの未延伸糸を作り、次いで８５℃の加熱ローラーと１６０℃のプレートヒーターとを有する延伸処理機に供し、４．０倍で延伸処理し、８３ｄｔｅｘ／３６ｆｉｌの延伸糸を得た。結果を表１に示す。
【００７７】
［実施例２〜４］
実施例１において、チタン化合物とリン化合物とを表１記載の通りに変更したこと以外は同様の操作を行った。結果を表１に示す。
【００７８】
［実施例５］
テレフタル酸ジメチル１００部とエチレングリコール７０部の混合物に重合触媒として参考例１で調製したチタン触媒０．８２部を添加して撹拌機、精留塔及びメタノール留出コンデンサーを設けた反応器に仕込み、１４０℃から２４０℃まで徐々に昇温しつつ、反応の結果生成するメタノールを系外に留出させながら、エステル交換反応を行った。その後、２０％の二酸化チタンエチレングリコールスラリー１４．５重量部を添加し、エステル交換反応を終了させた。
【００７９】
このエステル交換反応物を撹拌装置、窒素導入口、減圧口、蒸留装置を備えた反応容器に移し、２８５℃まで昇温した後、３０Ｐａ以下の高真空にて重縮合反応を行って、固有粘度０．６５、ジエチレングリコール量が１．０％であるポリエステルプレチップを得た。
【００８０】
実施例１と同様に、プレポリマー溶融体を３４５ｋｇ／ｈで放流できるラインを設け、このラインに圧入できるよう、オープンベントを２箇所、真空ベント２箇所を備え、かつニーディングディスクをＬ／Ｄ換算で５、ローターディスクをＬ／Ｄ換算で５、有する同方向回転型二軸押出機の先端を繋ぎ込んだ。上記で製造した二酸化チタン含有ポリエステルプレチップをロス・イン・ウェート式計量フィーダーで１０ｋｇ／ｈ計量し、チップ投入口から下流へ向けて、２８０℃で溶融させた。酢酸ナトリウムの１０ｗｔ％水溶液を調製し、最終ポリマー中での含有量がポリエステルの重量に対して１５ｍｍｏｌ％になるように設定し、プランジャーポンプを用いて押出機のポリマー溶融部へ注入した。ポリエステル総重量に対して、２７℃、大気圧で１倍に相当する体積の窒素をオープンベントより吹き込み、他方のオープンベントより排出させた。
【００８１】
その後、押出機に備え付けられた真空ベント孔から２０Ｐａの圧力で減圧させた。滞留時間は１５分、回転数は２００ｒｐｍであった。混練後、ポリマーはストランド状に押し出され、水冷バスで固化された後、チップカッターでチップ化し得られたチップを常法により乾燥した後、孔径０．３ｍｍの円形紡糸孔を３６個備えた紡糸口金を有する押出紡糸機を用いて２８７℃で溶融し、引取速度１４００ｍ／分で紡糸し、３３３ｄｔｅｘ／３６ｆｉｌの未延伸糸を作り、ついで８５℃の加熱ローラーと１６０℃のプレートヒーターとを有する延伸処理機に供し、４．０倍で延伸処理し、８３ｄｔｅｘ／３６ｆｉｌの延伸糸を得た。結果を表１に示す。
【００８２】
［比較例１］
実施例１においてプレチップを溶融混練すること無く、そのまま使用した。
【００８３】
［比較例２］
テレフタル酸ジメチル１００部とエチレングリコール７０部の混合物にエステル交換触媒として酢酸カルシウム０．０５部を添加して撹拌機、精留塔及びメタノール留出コンデンサーを設けた反応器に仕込み、１４０℃から２４０℃まで徐々に昇温しつつ、反応の結果生成するメタノールを系外に留出させながら、エステル交換反応を行った。その後、５６重量％濃度のリン酸水溶液０．０５０５部を添加し、エステル交換反応を終了させた。
【００８４】
このエステル交換反応物を撹拌装置、窒素導入口、減圧口、蒸留装置を備えた反応容器に移し、二酸化アンチモン０．０３５部を添加し、２８５℃まで昇温、３０Ｐａ以下の高真空下にて重縮合反応を行って、固有粘度０．６５、ジエチレングリコール量が１．０％であるポリエステルチップを得た。
【００８５】
【表１】

【００８６】
【発明の効果】
本発明によれば、Ｔｉ触媒を使用し従来技術の欠点であった色相の悪化を解消し、ポリエステルが持つ、優れた特性を保持しながら、配向結晶抑制性に優れ、色相が優れたポリエステル繊維を提供することができる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention has an extremely small amount of deposits attached to a spinneret even when continuously spun through a spinneret for a long time, and particularly has an excellent performance of being excellent in suppressing the oriented crystal when processed into a film, and The present invention relates to a polyester, a method for producing the same, and a fiber which can provide a fiber having a dull color and an improved hue.
[0002]
[Prior art]
Polyester, 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 properties. I have.
[0003]
For example, polyethylene terephthalate is usually subjected to a direct esterification reaction between terephthalic acid and ethylene glycol, a transesterification reaction between a lower alkyl ester of terephthalic acid such as dimethyl terephthalate and ethylene glycol, or a reaction between terephthalic acid and ethylene oxide. The reaction is carried out to produce an ethylene glycol ester of terephthalic acid and / or a low polymer thereof, and then the reaction product is heated under reduced pressure in the presence of a polymerization catalyst to cause a polycondensation reaction until a predetermined degree of polymerization is reached. Have been.
[0004]
It is well known that the type of catalyst used in these polycondensation reaction steps greatly affects the reaction rate and the quality of the resulting polyester. As a polycondensation catalyst for 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 the antimony compound is used as a polycondensation catalyst, when the polyester is continuously melt-spun over a long period of time, foreign substances (hereinafter, sometimes simply referred to as foreign matters of the die) adhere to and accumulate around the hole of the die, and the molten polymer is deposited. A flow bending phenomenon (bending) occurs, which causes a problem of moldability such as generation of fluff and / or breakage in the spinning and drawing steps. In recent years, for example, in a spinning process, production has been started at a speed exceeding 6000 m / min, and a demand for a reduction in product yield and a need for production performance have been more and more increased. In a conventional antimony-based catalyst, the oriented portion is crystallized during high-speed molding, causing unevenness in internal stress, and there is a limit in quality and performance. As an index for improving the moldability, further suppression of oriented crystals has been required.
[0006]
As a polycondensation catalyst other than the antimony compound, it has been proposed to use a titanium compound such as titanium tetrabutoxide. However, a new problem arises in that the obtained polyester itself is colored yellow and the melt heat stability is poor.
[0007]
In order to solve the above-mentioned coloring problem, it is common practice to add a cobalt compound to polyester to suppress yellowing. Certainly, the color tone (b value) of the polyester can be improved by adding the cobalt compound, but the problem that the addition of the cobalt compound lowers the melt heat stability of the polyester and the polymer is easily decomposed. There is.
[0008]
As other titanium compounds, use of titanium hydroxide as a catalyst for polyester production (for example, see Patent Document 1) and use of α-titanic acid as a catalyst for polyester production (for example, see Patent Document 2). It has been disclosed. 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 deteriorated, so that its storage and handling are not easy. In addition, it is difficult to obtain a polymer having a good color tone (b value).
[0009]
Further, a product obtained by reacting a titanium compound with trimellitic acid is used as a catalyst for producing a polyester (for example, see Patent Document 3), or a reaction between a titanium compound and a phosphite is performed. It is disclosed that the obtained product is used as a polyester production catalyst (for example, see Patent Document 4).
[0010]
Certainly, according to these methods, although the melt heat stability of the polyester is improved to some extent, the color tone of the obtained polymer is not sufficient, and thus further improvement of the polymer color tone is desired.
[0011]
Further, as described above, it is effective to use no antimony as a catalyst in order to suppress foreign matter in a die. However, in a method using no antimony, the hue of the yarn deteriorates. Could not be offered.
[0012]
Accordingly, there has been a demand for a polyester fiber which does not use antimony as a catalyst, is excellent in the ability to suppress oriented crystals, and exhibits a good hue.
[0013]
[Patent Document 1]
Japanese Patent Publication No. 48-2229
[Patent Document 2]
Japanese Patent Publication No. 47-26597
[Patent Document 3]
Japanese Patent Publication No. 59-46258
[Patent Document 4]
JP-A-58-38722
[Problems to be solved by the invention]
The first object of the present invention is to provide an excellent performance in which the amount of deposits attached to a spinneret is extremely small even when spinning continuously through a spinneret for a long period of time, and in particular, it is excellent in suppressing oriented crystals when processing a fiber or film. And to provide a polyester having a dullness and an improved hue. A second object of the present invention is to provide a method for producing a polyester.
[0018]
[Means for Solving the Problems]
The present inventors have conducted intensive studies in view of the above-mentioned conventional technology, and as a result, completed the present invention.
[0019]
That is, the first object of the present invention is to
As the polycondensation reaction catalyst, a titanium compound represented by the following general formula (I), or a titanium compound represented by the following general formula (I) and an aromatic polycarboxylic acid represented by the following general formula (II) or A product obtained by reacting the anhydride with a phosphorus compound represented by the following general formula (III) is mixed with a phosphorus element in a molar ratio (P / Ti) of 1 to 4 with respect to the titanium element. The precipitate obtained by heating in glycol with the above is used so that the amount of titanium element contained in the polyester is in the range of 2 to 40 mmol% based on all dicarboxylic acid components constituting the polyester. In addition, the polyester is a polyester in which ethylene terephthalate units occupy 80 mol% or more based on all repeating units, and the polyester is soluble in an alkali metal salt. Containing 2 to 40 mmol% of the dicarboxylic acid component as a reference, it is achieved by polyesters with suppressed oriented crystals.
[0020]
Embedded image

[0021]
Embedded image

[0022]
Embedded image

[0023]
Further, a second object of the present invention is that
As a catalyst for the polycondensation reaction, a titanium compound represented by the following general formula (I), or a titanium compound represented by the following general formula (I) and an aromatic polycarboxylic acid represented by the following general formula (II) Alternatively, a product obtained by reacting the anhydride with an anhydride thereof and a phosphorus compound represented by the following general formula (III) have a molar number of phosphorus element (P / Ti) of 1 to 4 with respect to a molar number of titanium element. The precipitate obtained by heating in the glycol in the above range is used so that the amount of titanium element contained in the polyester is in the range of 2 to 40 mmol% based on all dicarboxylic acid components constituting the polyester. The obtained polyester in which at least 80 mol% of the total repeating units are ethylene terephthalate units is fed to a vented melt-kneading extruder, and the polyester prepared in advance in the extruder is supplied. A solution obtained by dissolving a stell-soluble alkali metal salt in water and / or an organic solvent having a boiling point in the range of 50 to 240 ° C. is obtained by converting all dicarboxylic acid components constituting the polyester in terms of an alkali metal element in the solution. This is achieved by a method for producing a polyester, which is added into the extruder and melt-kneaded in the kneader so as to be in a range of 2 to 40 mmol% as a standard.
[0024]
Embedded image

[0025]
Embedded image

[0026]
Embedded image

[0027]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail.
The polyester in the present invention is a polyester obtained by subjecting an ester-forming derivative of an aromatic dicarboxylic acid and an alkylene glycol to a transesterification reaction and then a polycondensation reaction in the presence of a catalyst, and comprising 80 mol% of all repeating units. The above is the polyester which is ethylene terephthalate. If the amount of the ethylene terephthalate unit in all the repeating units is less than 80 mol%, it is not preferable because basic characteristics such as high strength and high elasticity characteristic of the polyester ester are lost.
[0028]
The polyester of the present invention needs to contain a polyester-soluble alkali metal salt in the range of 2 to 40 mmol% based on all dicarboxylic acid components constituting the polyester. Here, when an alkali metal is exemplified, Li, Na, and K can be exemplified. Further, as the salt root, there is no particular problem as long as it is a known salt used for polyester, and an acetate group, a phosphate group, and the like can be used. In particular, acetate is preferably used. The alkali metal salt may be used alone or in combination of two or more. If the alkali metal salt is less than 2 mmol%, it does not exhibit the effect of suppressing the orientational crystallization, and if it exceeds 40 mmol%, it is unfavorable because it is alkaline and accelerates the decomposition and deterioration of the polyester.
[0029]
The polyester in the present invention may be a copolymerized polyethylene terephthalate obtained by copolymerizing a third component other than the component constituting the ethylene terephthalate unit as long as its properties are not lost. The third component (copolymer component) may be either a dicarboxylic acid component or a glycol component. Examples of the dicarboxylic acid component preferably used as the third component include aromatic dicarboxylic acids such as 2,6-naphthalenedicarboxylic acid, isophthalic acid and phthalic acid, and aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid and decanedicarboxylic acid. Acids, alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, and the glycol component include trimethylene glycol, tetramethylene glycol, 1,4-cyclohexanedimethanol, and the like. These may be used alone or in combination of two or more. Can be used.
[0030]
The polyester of the present invention comprises a titanium compound represented by the following general formula (I) and a phosphorus compound represented by the following general formula (III) in which the number of moles of phosphorus element (P / Ti) relative to the number of moles of titanium element is obtained. It must be polymerized using a titanium / phosphorus reactant reacted with a composition in the range of 1-4.
[0031]
Embedded image

[0032]
Embedded image

[0033]
Here, when the number of moles of the phosphorus element relative to the number of moles of the titanium element (P / Ti) is less than 1, the color tone of the obtained polyester may be poor, and the heat resistance thereof may be reduced. If it is large, the catalytic activity for the polyester formation reaction becomes insufficient, which is not preferable. The number of moles of phosphorus (P / Ti) relative to the number of moles of titanium is preferably in the range of 1.2 to 3.5, more preferably in the range of 1.5 to 3.0.
[0034]
The catalyst preparation of the titanium compound component (I) and the phosphorus compound component (III) needs to be heat-reacted in ethylene glycol. Glycol is mixed, and part or all of the phosphorus compound component is dissolved in a solvent. The titanium compound component (I) is added dropwise to the mixture, and the reaction system is heated to a temperature of 0 ° C to 200 ° C for 30 minutes or more. It is preferably carried out by heating to a temperature of 60 to 150 ° C. for 40 to 90 minutes. In this reaction, there is no particular limitation on the reaction pressure, and the reaction is usually performed under normal pressure.
[0035]
Here, as the titanium compound represented by the above formula (I), for example, titanium tetraalkoxide such as titanium tetrabutoxide, titanium tetraisopropoxide, titanium tetrapropoxide, titanium tetraethoxide, octaalkyltrititanate, hexaalkyl Examples thereof include dititanate, alkyl titanate, and titanium acetate.
[0036]
When p in the formula (III) is 0, examples of the phosphorus compound represented by the above formula (III) include, for example, phenylphosphonic acid, methylphosphonic acid, ethylphosphonic acid, propylphosphonic acid, isopropylphosphonic acid, butylphosphonic acid, tolyl Phosphonic acid, xylylphosphonic acid, biphenylphosphonic acid, naphthylphosphonic acid, anthrylphosphonic acid, 2-carboxyphenylphosphonic acid, 3-carboxyphenylphosphonic acid, 4-carboxyphenylphosphonic acid, 2,3-dicarboxyphenylphosphonic Acid, 2,4-dicarboxyphenylphosphonic acid, 2,5-dicarboxyphenylphosphonic acid, 2,6-dicarboxyphenylphosphonic acid, 3,4-dicarboxyphenylphosphonic acid, 3,5-dicarboxyphenylphosphonic acid Acid, 2,3,4-tricarboxy Phenylphosphonic acid, 2,3,5-tricarboxyphenylphosphonic acid, 2,3,6-tricarboxyphenylphosphonic acid, 2,4,5-tricarboxyphenylphosphonic acid, 2,4,6-tricarboxyphenylphosphonic acid And the like, and among them, monoarylphosphonic acid is preferred.
[0037]
When p is 1, for example, monomethyl phosphate, monoethyl phosphate, monotrimethyl phosphate, mono-n-butyl phosphate, monohexyl phosphate, monoheptyl phosphate, monononyl phosphate, monodecyl phosphate, monododecyl phosphate, monophenyl Phosphate, monobenzyl phosphate, mono (4-dodecyl) phenyl phosphate, mono (4-methylphenyl) phosphate, mono (4-ethylphenyl) phosphate, mono (4-propylphenyl) phosphate, mono (4-dodecylphenyl) phosphate , Monotolyl phosphate, monoxylyl phosphate, monobiphenyl phosphate, mononaphthyl phosphate, monoanthryl phosphate and the like.
[0038]
A method in which the titanium compound represented by the above formula (I) is previously reacted with a polyvalent carboxylic acid of the following formula (II) and / or an anhydride thereof and used is also preferably used. In that case, the reaction molar ratio of the titanium compound to the polyvalent carboxylic acid and / or its anhydride is preferably in the range of (2: 1) to (2: 5). A particularly preferred range is from (1: 1) to (1: 2).
[0039]
Embedded image

[0040]
Hereinafter, the method for producing the polyester of the present invention will be described.
[0041]
In the method for producing a polyester of the present invention, it is preferable to add titanium so that the amount of titanium element is in the range of 2 to 40 mmol% based on all dicarboxylic acid components. When the amount of titanium element is less than 2 mmol%, the polymerization reaction becomes slow, and when it exceeds 40 mmol%, the color tone of the obtained polyester becomes poor, and the heat resistance thereof is undesirably reduced. The amount of titanium element is preferably in the range of 3 to 30 mmol%, more preferably in the range of 4 to 20 mmol%.
[0042]
In the production method of the present invention, when a titanium compound, a phosphorus compound, and an alkali metal salt are added at once to the polymerization reaction system, the alkali metal salt suppresses the polymerization reaction, so that the productivity is not sufficient. A titanium / phosphorus reaction in which a titanium compound and a phosphorus compound are heat-reacted in ethylene glycol at a composition in which the number of moles of phosphorus element (P / Ti) to the number of moles of titanium element (P / Ti) is 1 to 4 as a catalyst during polymerization. A polyester pre-chip, in which the amount of titanium element contained in the polyester is in the range of 2 to 40 mmol% based on the total dicarboxylic acid component, is first produced, and the chip is supplied to a vented extruder. An alkali metal salt soluble in polyester is dissolved in water and / or an organic solvent having a boiling point of 50 to 240 ° C. It was supplied to contain in the range of 2 to 40 mmol% based on the total dicarboxylic acid component constituting the, if kneaded without impairing the productivity can be produced.
[0043]
The method for producing the polyester prechip will be described. The polyester prechip is produced by subjecting an ester-forming derivative of an aromatic dicarboxylic acid and an alkylene glycol to a transesterification reaction in the presence of a transesterification catalyst. The pressure in the reaction system is usually carried out at normal pressure, but if necessary, the reaction may be carried out under pressure.If the transesterification reaction is carried out under pressure, the pressure may be 0.20 MPa. If it is higher, the content of diethylene glycol generated as a by-product in the polymer is significantly increased, and properties such as thermal stability of the polymer are deteriorated. Therefore, 0.20 MPa or less, preferably 0.06 to 0.10 MPa. It is preferable to carry out within the range.
[0044]
Next, the obtained polyester pre-chip is supplied to a vented melt-kneading extruder, and further, a preliminarily prepared polyester-soluble alkali metal salt is dissolved in water and / or a boiling point of 50 to 240 ° C. A solution dissolved in an organic solvent is added.
[0045]
Here, the vent-type melt-kneading extruder to be used may be a melt-kneading extruder having at least one vent hole, and the function of the extruder is not particularly limited, and a single screw type, a twin screw type Any of these can be used, but a melt-kneading extruder having two or more vent functions so as to be able to add an inert gas and maintain a reduced pressure is preferable. Further, it is preferable to use a twin screw type vented melt kneading extruder so that the kneading performance is high and the reaction is completed in a short time. In the case of using a melt-kneading extruder with a twin-screw vent, the rotation directions of the two shafts may be the same or opposite, but rotation in the same direction is preferable from the viewpoint of suppressing thermal deterioration of the raw material.
[0046]
In order to enhance the kneading performance, a kneading segment is preferably provided, and examples thereof include a kneading disk and a rotor disk.
[0047]
A kneading disc is a kneading screw segment that combines several elliptical discs while shifting them at a constant phase, and forcibly passes the polyester mixture to a narrow clearance with the rotation of the screw. Can give an extremely high shearing force. As a result, the dispersion effect of polytrimethylene terephthalate of the polyoxyalkylene-based polyether is promoted.
[0048]
On the other hand, the rotor disk is a polygonal disk, which is a screw segment whose ridge is twisted at a fixed angle, and characterized in that the clearance is constant at all positions of the segment. There are two types of segments in which the direction of the ridge torsion with respect to the screw axis is forward and reverse, and by combining these segments, a high shearing force can be applied uniformly, and the polyester by shearing Melt kneading can be advanced while suppressing deterioration.
[0049]
The kneading disk or the rotor disk can be appropriately selected depending on the physical properties of the target composition, and is not particularly limited. The number of these disks to be mounted is determined by the ratio of the disk or segment length (L) to the screw diameter (D). When represented by L / D, the number of kneading disks and the number of rotor disks to be mounted is preferably in the range of L / D = 1 to 30, more preferably in the range of L / D = 2 to 20, respectively. When L / D is within this range, more favorable melt-kneading can be performed, and at this time, the rotation speed of the screw may be set to about 20 to 500 rpm, and preferably 50 to 300 rpm.
[0050]
The temperature of the extruder is 10 to 40 ° C higher than the melting point of the polymer used, preferably 20 to 40 ° C higher than the melting point of the polymer used.
[0051]
As the alkali metal salt solution to be added to the vented melt-kneading extruder, a solution previously dissolved in water and / or an organic solvent having a boiling point in the range of 50 to 250 ° C. is used. Here, when an organic solvent is used, if the boiling point is less than 50 ° C., it is difficult to use it as an additional solvent because of high volatility. It becomes difficult. Preferred examples of the organic solvent include methanol, ethanol, ethylene glycol, trimethylene glycol, 1,4-butanediol, benzene, toluene, xylene, tetrahydrofuran, 1,3-dioxolan, and 2-methyl-1,3-dioxolan. Organic solvents can be mentioned, but water is most preferably used because of its low cost and high safety.
[0052]
In the production method of the present invention, the vented melt-kneading extruder preferably has at least one vent hole under reduced pressure using a vacuum pump or a steam ejector, and usually has a pressure of 10 kPa or less, preferably 5 kPa or less. It is more preferable to set the pressure to 1 kPa or less, and it is preferable to distill off water, alcohol such as methanol, or a very small amount of by-products which may be produced as a by-product in the melt-kneading operation. The reaction time is preferably 1 to 60 minutes, particularly preferably 5 to 30 minutes.
[0053]
When a vented extruder such as the present invention is used, the reaction can be completed in a short time, and as a result, by-products can be drastically reduced, and at the same time, a polymer having an improved hue can be obtained.
[0054]
The intrinsic viscosity (o-chlorophenol, 35 ° C.) of the polyester produced in the present invention is preferably in the range of 0.50 to 1.00, more preferably 0.60 to 0.70. If the intrinsic viscosity is less than 0.50, the strength of the fiber becomes insufficient, which is not preferable. On the other hand, if the intrinsic viscosity exceeds 1.00, it is necessary to raise the intrinsic viscosity of the raw material polymer excessively, which is uneconomical.
[0055]
In the present invention, if necessary, a small amount of additives such as a lubricant, a pigment, a dye, an antioxidant, a solid-state polymerization accelerator, a fluorescent brightener, an antistatic agent, an antibacterial agent, an ultraviolet absorber, a light stabilizer, It may contain a heat stabilizer, a light shielding agent, a matting agent and the like. In particular, titanium oxide as a matting agent is preferably added. In this case, titanium oxide having an average particle size of 0.01 to 2 μm is added so as to be contained in the finally obtained polyester composition in an amount of 0.01 to 10% by weight. Is preferred.
[0056]
In addition, the polyester composition which came out of the ventilated melt-kneading extruder through the melt-kneading operation as described above is passed through a cooling step such as a water-cooled bath, and then formed into chips using a chip cutter, or cooled or cooled. It may be directly supplied to a spinning machine without chipping.
[0057]
The method for producing the polyester fiber of the present invention is not particularly limited, and a conventionally known melt spinning method is used.For example, it is preferable that the polyester fiber is produced by melt spinning in the range of 270 to 300 ° C, It is preferable to spin at a melt spinning speed of 400 to 5000 m / min. When the spinning speed is in this range, the strength of the obtained fiber is sufficient, and the winding can be performed stably. In the drawing, a drawn yarn can be obtained by winding the polyester fiber or by continuously drawing without once winding. Further, in the polyester fiber of the present invention, an alkali weight reduction treatment by a known method is preferably carried out in order to enhance the feeling.
[0058]
In producing the polyester fiber of the present invention, there is no limitation on the shape of the die used at the time of spinning, and any of a circular shape, a deformed shape, a solid shape, a hollow shape and the like can be adopted.
[0059]
【Example】
The present invention will be further specifically described with reference to the following Examples, but the scope of the present invention is not limited by these Examples. The intrinsic viscosity, hue, content of titanium, phosphorus, calcium, and magnesium, and the layer of deposits generated on the spinneret were measured by the following methods.
[0060]
(1) Intrinsic viscosity:
The intrinsic viscosity of the polyester polymer was determined from the value of the viscosity measured at 35 ° C. in an o-chlorophenol solution.
[0061]
(2) Color tone (L value and b value):
The polymer sample was melted under vacuum at 290 ° C. for 10 minutes, immediately formed into a plate having a thickness of 3.0 ± 1.0 mm on an aluminum plate, immediately cooled in ice water, and dried at 160 ° C. for 1 hour. After the crystallization treatment, the plate was placed on a white standard plate for adjusting a color difference meter, and the Hunter L value and the b value on the plate surface were measured using a Hunter type color difference meter CR-300 manufactured by Minolta. The L value indicates lightness, and the larger the numerical value, the higher the lightness. The larger the value, the greater the yellow coloration.
[0062]
(3) Titanium, phosphorus and antimony content in the polymer:
The polymer sample was heated and melted to form a circular disk, and the measurement was performed using a fluorescent X-ray measuring apparatus 3270 manufactured by Rigaku Corporation. However, regarding the titanium element content of titanium oxide added as a matting agent, the polymer sample was dissolved in hexafluoroisopropanol, the titanium oxide particles were sedimented by a centrifugal separator, and only the supernatant was recovered by a gradient method. Was measured after evaporation.
[0063]
(4) Tensile strength, tensile elongation:
The measurement was performed according to the method described in JIS L1013.
[0064]
(5) Hot water shrinkage:
Melting was performed at 287 ° C. using an extrusion spinning machine having a spinneret having 36 circular spinning holes having a hole diameter of 0.3 mm, and a spinning sample was collected at a spinning temperature of 292 ° C. and a spinning speed of 4000 m / min. The shrinkage rate when held was measured. The higher the shrinkage, the more the oriented crystals are suppressed.
[0065]
(6) Layer of deposits generated on spinneret:
Polyester is made into a chip, which is melted at 290 ° C., discharged from a spinneret having a hole diameter of 0.15 mmφ and 12 holes, and spun at 600 m / min for 2 days. The layer height was measured. As the height of the deposit layer increases, bending tends to occur in the filamentary flow of the discharged polyester melt, and the moldability of the polyester decreases. That is, the height of the deposit layer generated on the spinneret is an index of the moldability of the polyester.
[0066]
[Reference Example 1] Preparation of catalyst:
3.6 parts by weight of phenylphosphonic acid was dissolved in 131 parts by weight of ethylene glycol by heating to 120 ° C. for 10 minutes. After further adding 40 parts by weight of ethylene glycol to 134.5 parts by weight of this ethylene glycol solution, 3.8 parts by weight of titanium tetrabutoxide was dissolved therein. The obtained reaction system was stirred at 120 ° C. for 60 minutes to react the titanium compound with phenylphosphonic acid, thereby obtaining a white slurry of a catalyst containing a reaction product. The titanium content of this catalyst slurry was 0.3% by weight, and the molar ratio of titanium element to phosphorus element (P / Ti) was 2.0.
[0067]
[Reference Example 2] Preparation of catalyst:
0.8 part by weight of trimellitic anhydride is dissolved in 2.5 parts by weight of ethylene glycol, and 0.7 part by weight of titanium tetrabutoxide (0.5 mol% based on the molar amount of trimellitic anhydride) is dropped into this solution. Then, the reaction system was kept at 80 ° C. for 60 minutes in the air under normal pressure to cause the reaction between titanium tetrabutoxide and trimellitic anhydride to mature the reaction product. Thereafter, the reaction system was cooled to room temperature, and 15 parts by weight of acetone was added thereto. 5 was filtered through filter paper, collected and dried at a temperature of 100 ° C. for 2 hours. The titanium content of the obtained reaction product was 11.2% by weight. Next, 3.6 parts by weight of phenylphosphonic acid was dissolved in 131 parts by weight of ethylene glycol by heating to 120 ° C. for 10 minutes. After further adding 40 parts by weight of ethylene glycol to 134.5 parts by weight of this ethylene glycol solution, 5.0 parts by weight of the above titanium compound was dissolved therein. The obtained reaction system was stirred at 120 ° C. for 60 minutes to react the titanium compound with phenylphosphonic acid, thereby obtaining a white slurry of a catalyst containing a reaction product. The titanium content of this catalyst slurry was 0.3% by weight, and the molar ratio of titanium element to phosphorus element (P / Ti) was 2.0.
[0068]
[Reference Example 3] Preparation of catalyst:
3.5 parts by weight of mono-n-butyl phosphate was dissolved in 131 parts by weight of ethylene glycol by heating to 120 ° C. for 10 minutes. After further adding 40 parts by weight of ethylene glycol to 134.5 parts by weight of this ethylene glycol solution, 3.8 parts by weight of titanium tetrabutoxide was dissolved therein. The obtained reaction system was stirred at 120 ° C. for 60 minutes to cause a reaction between the titanium compound and mono-n-butyl phosphate to obtain a white slurry of a catalyst containing a reaction product. The titanium content of this catalyst slurry was 0.3% by weight, and the molar ratio of titanium element to phosphorus element (P / Ti) was 2.0.
[0069]
[Reference Example 4] Preparation of catalyst:
Dissolve 0.8 parts by weight of trimellitic anhydride in 2.5 parts by weight of ethylene glycol, and add 0.7 parts by weight of titanium tetrabutoxide (based on the molar amount of trimellitic anhydride used in the production of the polyester described below). 0.5 mol%) was added dropwise, and the reaction system was kept at 80 ° C. for 60 minutes in the air under normal pressure to allow titanium tetrabutoxide to react with trimellitic anhydride to mature the reaction product. Thereafter, the reaction system was cooled to room temperature, and 15 parts by weight of acetone was added thereto. 5 was filtered through filter paper, collected and dried at a temperature of 100 ° C. for 2 hours. The titanium content of the obtained reaction product was 11.2% by weight.
[0070]
Next, 3.5 parts by weight of mono-n-butyl phosphate was dissolved in 131 parts by weight of ethylene glycol by heating to 120 ° C. for 10 minutes. After further adding 40 parts by weight of ethylene glycol to 134.5 parts by weight of this ethylene glycol solution, 5.0 parts by weight of the above titanium compound was dissolved therein. The obtained reaction system was stirred at 120 ° C. for 60 minutes to cause a reaction between the titanium compound and mono-n-butyl phosphate to obtain a white slurry of a catalyst containing a reaction product. The titanium content of this catalyst slurry was 0.3% by weight, and the molar ratio of titanium element to phosphorus element (P / Ti) was 2.0.
[0071]
[Example 1]
0.82 parts of the titanium catalyst prepared in Reference Example 1 was added as a polymerization catalyst to a mixture of 100 parts of dimethyl terephthalate and 70 parts of ethylene glycol, and the mixture was charged into a reactor equipped with a stirrer, a rectification column, and a methanol distillation condenser. The transesterification reaction was performed while gradually increasing the temperature from 140 ° C. to 240 ° C. while distilling the methanol generated as a result of the reaction out of the system. Thereafter, 0.0505 parts of a 56% by weight phosphoric acid aqueous solution was added to terminate the transesterification reaction.
[0072]
This transesterification product was transferred to a reaction vessel equipped with a stirrer, a nitrogen inlet, a vacuum port, and a distillation apparatus, heated to 285 ° C., and subjected to a polycondensation reaction under a high vacuum of 30 Pa or less to give an intrinsic viscosity of 0. .65, and a polyester prechip having a diethylene glycol content of 1.0% was obtained.
[0073]
This pre-tip is weighed with a loss-in-weight weighing feeder, and two open vents and two vacuum vents are provided downstream from the tip inlet, and the kneading disk is 5 in L / D conversion and the rotor disk is Was supplied to a co-rotating twin-screw extruder having an L / D conversion of 5, and melted at 280 ° C.
[0074]
Further, a 10 wt% aqueous solution of sodium acetate was prepared, the content in the final polymer was set to be 15 mmol% with respect to the weight of the polyester, and the solution was injected into the polymer melting portion of the extruder using a plunger pump. . Nitrogen was blown from the open vent at a volume equivalent to one time at 27 ° C. and atmospheric pressure with respect to the total weight of the polyester, and discharged from the other open vent.
[0075]
Thereafter, the pressure was reduced at a pressure of 20 Pa from a vacuum vent hole provided in the extruder, and the mixture was melt-kneaded at a residence time of 15 minutes and a rotation speed of 200 rpm. After kneading, the polymer was extruded into a strand, solidified in a water-cooled bath, and then formed into chips by a chip cutter.
[0076]
After drying the obtained chip by a conventional method, it was melted at 287 ° C. using an extrusion spinning machine having a spinneret having 36 circular spinning holes having a diameter of 0.3 mm, and spun at a take-up speed of 1,400 m / min. An undrawn yarn of 333 dtex / 36 fill was prepared, and then subjected to a drawing machine having a heating roller at 85 ° C. and a plate heater at 160 ° C., and drawn at 4.0 times to obtain a drawn yarn of 83 dtex / 36 fill. Table 1 shows the results.
[0077]
[Examples 2 to 4]
The same operation was performed as in Example 1, except that the titanium compound and the phosphorus compound were changed as shown in Table 1. Table 1 shows the results.
[0078]
[Example 5]
0.82 parts of the titanium catalyst prepared in Reference Example 1 was added as a polymerization catalyst to a mixture of 100 parts of dimethyl terephthalate and 70 parts of ethylene glycol, and the mixture was charged into a reactor equipped with a stirrer, a rectification column, and a methanol distillation condenser. The transesterification reaction was performed while gradually increasing the temperature from 140 ° C. to 240 ° C. while distilling the methanol generated as a result of the reaction out of the system. Thereafter, 14.5 parts by weight of a 20% titanium dioxide ethylene glycol slurry was added to terminate the transesterification reaction.
[0079]
The transesterified product was transferred to a reaction vessel equipped with a stirrer, a nitrogen inlet, a vacuum port, and a distillation apparatus, heated to 285 ° C., and then subjected to a polycondensation reaction under a high vacuum of 30 Pa or less to obtain an intrinsic viscosity. A polyester pre-chip having 0.65 and a diethylene glycol content of 1.0% was obtained.
[0080]
In the same manner as in Example 1, a line capable of discharging the prepolymer melt at 345 kg / h was provided, and two open vents and two vacuum vents were provided so that the prepolymer melt could be press-fitted into the line. The tip of a co-rotating twin-screw extruder having 5 in terms of conversion and 5 in terms of L / D in rotor disk was connected. The above-prepared titanium dioxide-containing polyester pre-tip was weighed at 10 kg / h with a loss-in-weight type measuring feeder, and was melted at 280 ° C. from the chip input port to the downstream. A 10 wt% aqueous solution of sodium acetate was prepared, the content in the final polymer was set to be 15 mmol% based on the weight of the polyester, and the solution was injected into the polymer melt portion of the extruder using a plunger pump. Nitrogen was blown from the open vent at a volume equivalent to one time at 27 ° C. and atmospheric pressure with respect to the total weight of the polyester, and discharged from the other open vent.
[0081]
Thereafter, the pressure was reduced at a pressure of 20 Pa from a vacuum vent hole provided in the extruder. The residence time was 15 minutes and the number of revolutions was 200 rpm. After kneading, the polymer is extruded into strands, solidified in a water-cooled bath, chipped with a chip cutter, and the obtained chips are dried by a conventional method. It is melted at 287 ° C. using an extrusion spinning machine having a spinneret, spun at a take-up speed of 1400 m / min to make an undrawn yarn of 333 dtex / 36 fill, and then drawn with a heating roller at 85 ° C. and a plate heater at 160 ° C. It was provided to a processor and stretched at a ratio of 4.0 to obtain a drawn yarn of 83 dtex / 36fil. Table 1 shows the results.
[0082]
[Comparative Example 1]
In Example 1, the pre-chip was used as it was without melt-kneading.
[0083]
[Comparative Example 2]
To a mixture of 100 parts of dimethyl terephthalate and 70 parts of ethylene glycol, 0.05 parts of calcium acetate was added as a transesterification catalyst, and the mixture was charged into a reactor equipped with a stirrer, a rectification column and a methanol distillation condenser, and heated at 140 ° C to 240 ° C. The transesterification reaction was performed while gradually raising the temperature to ° C. and distilling the methanol generated as a result of the reaction out of the system. Thereafter, 0.0505 parts of a 56% by weight phosphoric acid aqueous solution was added to terminate the transesterification reaction.
[0084]
This transesterification reaction product was transferred to a reaction vessel equipped with a stirrer, a nitrogen inlet, a vacuum port, and a distillation apparatus, and 0.035 parts of antimony dioxide was added. The temperature was raised to 285 ° C., and under a high vacuum of 30 Pa or less. A polycondensation reaction was performed to obtain a polyester chip having an intrinsic viscosity of 0.65 and a diethylene glycol content of 1.0%.
[0085]
[Table 1]

[0086]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the deterioration of the hue which was the defect of the prior art using a Ti catalyst is eliminated, and the polyester fiber which is excellent in the orientation crystal suppression property and the hue is excellent, maintaining the excellent property which polyester has. Can be provided.

Claims (12)

As the polycondensation reaction catalyst, a titanium compound represented by the following general formula (I), or a titanium compound represented by the following general formula (I) and an aromatic polycarboxylic acid represented by the following general formula (II) or A product obtained by reacting the anhydride with a phosphorus compound represented by the following general formula (III) is mixed with a phosphorus element in a molar ratio (P / Ti) of 1 to 4 with respect to the titanium element. The precipitate obtained by heating in glycol with the above is used so that the amount of titanium element contained in the polyester is in the range of 2 to 40 mmol% based on all dicarboxylic acid components constituting the polyester. In addition, the polyester is a polyester in which ethylene terephthalate units occupy 80 mol% or more based on all repeating units, and the polyester is soluble in an alkali metal salt. Containing 2 to 40 mmol% of the dicarboxylic acid component as a reference, the orientation crystallinity of inhibition polyester.

The polyester according to claim 1, wherein the polyester-soluble alkali metal salt is at least one compound selected from the group consisting of lithium acetate, sodium acetate, and potassium acetate. The polyester according to claim 1, wherein p in the formula (III) is 0. The polyester according to claim 3, wherein the phosphorus compound represented by the formula (III) is a monoarylphosphonic acid. The polyester according to claim 1, wherein p in the formula (III) is 1. The polyester according to claim 5, wherein the phosphorus compound represented by the formula (III) is a monoalkyl phosphate. The polyester according to claim 1, wherein the titanium compound represented by the formula (I) is at least one compound selected from the group consisting of titanium tetraalkoxides, hexaalkyldititanates, and octaalkyltrititanates. . Polyester fiber obtained by melt-spinning the polyester according to any one of claims 1 to 7. As a catalyst for the polycondensation reaction, a titanium compound represented by the following general formula (I), or a titanium compound represented by the following general formula (I) and an aromatic polycarboxylic acid represented by the following general formula (II) Alternatively, a product obtained by reacting the anhydride with an anhydride thereof and a phosphorus compound represented by the following general formula (III) have a molar number of phosphorus element (P / Ti) of 1 to 4 with respect to a molar number of titanium element. The precipitate obtained by heating in the glycol in the above range is used so that the amount of titanium element contained in the polyester is in the range of 2 to 40 mmol% based on all dicarboxylic acid components constituting the polyester. The obtained polyester in which at least 80 mol% of the total repeating units are ethylene terephthalate units is fed to a vented melt-kneading extruder, and the polyester prepared in advance in the extruder is supplied. A solution obtained by dissolving a stell-soluble alkali metal salt in water and / or an organic solvent having a boiling point in the range of 50 to 240 ° C. is obtained by converting all dicarboxylic acid components constituting the polyester in terms of an alkali metal element in the solution. A method for producing a polyester, wherein the polyester is added to the extruder and melt-kneaded in the kneader so as to be in the range of 2 to 40 mmol% as a standard.

The titanium compound of the formula (I) is previously reacted with a polyvalent carboxylic acid of the following general formula (II) and / or an acid anhydride thereof in a composition in a reaction molar ratio (2: 1) to (2: 5). The production method according to claim 9, wherein the reaction is carried out with the phosphorus compound of formula (III). The production method according to claim 9, wherein the vented melt-kneading extruder is a twin-screw vented melt-kneading extruder having at least a kneading disk. The production method according to claim 9, wherein the vented melt-kneading extruder is a twin-screw vented melt-kneading extruder having at least a rotor disk.