JP2004175837A - 2,6-polyethylene naphthalate resin composition and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a 2,6-polyethylene naphthalate resin composition containing few foreign matters originating from a catalyst and excellent in transparency while retaining excellent characteristics of 2,6-polyethylene naphthalate. <P>SOLUTION: 2,6-Polyethylene naphthalate resin composition comprises a 2,6-polyethylene naphthalate resin, a specific phosphonate compound and a titanium compound soluble in the 2,6-polyethylene naphthalate resin, and contains at most 5 mmol% of the antimony element and the germanium element based on the 2,6-ethylene naphthalate component. A manufacturing method of the same is also provided. <P>COPYRIGHT: (C)2004,JPO

Description

【００１２】
（ここで、Ｚは−Ｃ_ｎＨ_２ｎ−ＯＨ（ｎは０〜４の整数）、ＡおよびＢはそれぞれ−Ｃ_ｎＨ_２ｎ＋１（ｎは０〜４の整数）または−Ｃ_ｎＨ_２ｎ−ＯＨ（ｎは１〜４の整数）、Ｘは−ＣＨ_２−または−ＣＨ（Ｙ）−、Ｙはフェニル基を示す。）
で示されるホスホネート化合物または該ホスホネート化合物と下記式（ＩＩＩ）
【００１３】
【化１０】

【００１４】
（ここで、式（ＩＩＩ）中のｎは２〜４の整数である。）
で示される芳香族多価カルボン酸との反応生成物および２，６−ポリエチレンナフタレート樹脂に可溶なチタン化合物を含有し、かつアンチモン元素およびゲルマニウム元素の含有量が、２，６−エチレンナフタレート成分に対して高々５ミリモル％である２，６−ポリエチレンナフタレート樹脂組成物によって達成できる。
【００１５】
また、本発明の２，６−ポリエチレンナフタレート樹脂組成物は、その好ましい態様として、チタン化合物およびホスホネート化合物の含有量が下記式（１）〜（３）
【００１６】
【数７】
４≦Ｔｉ≦１５ ・・・（１）
【００１７】
【数８】
２≦Ｐ／Ｔｉ≦１５ ・・・（２）
【００１８】
【数９】
１５≦Ｔｉ＋Ｐ≦１５０ ・・・（３）
（ここで、式（１）〜（３）中の、Ｔｉは該チタン化合物のチタン元素としてのモル数を、またＰはホスホネート化合物のリン元素としてのモル数を、樹脂組成物中の２，６−エチレンナフタレート成分のモル数で割った値（ミリモル％）である。）
を満足すること、またはチタン化合物が、下記式（ＩＩ）
【００１９】
【化１１】

【００２０】
（ここで、式（ＩＩ）中のＲ^１，Ｒ^２，Ｒ^３，Ｒ^４はアルキル基またはフェニル基である。）
で表わされる化合物および上記式（ＩＩ）で表わされる化合物と下記式（ＩＩＩ）
【００２１】
【化１２】

【００２２】
（ここで、式（ＩＩＩ）中のｎは２〜４の整数である。）
で表わされる芳香族多価カルボン酸との反応生成物とからなる群より選ばれた少なくとも１種であることのいずれかを具備する２，６−ポリエチレンナフタレート樹脂組成物も包含する。
【００２３】
また、本発明によれば、本発明の他の目的は、２，６−ジメチルナフタレートとエチレングリコールとをエステル交換反応させてから重縮合反応させる２，６−ポリエチレンナフタレート樹脂組成物の製造方法において、熱安定剤として下記式（Ｉ）
【００２４】
【化１３】

【００２５】
（ここで、Ｚは−Ｃ_ｎＨ_２ｎ−ＯＨ（ｎは０〜４の整数）、ＡおよびＢはそれぞれ−Ｃ_ｎＨ_２ｎ＋１（ｎは０〜４の整数）または−Ｃ_ｎＨ_２ｎ−ＯＨ（ｎは１〜４の整数）、Ｘは−ＣＨ_２−または−ＣＨ（Ｙ）−、Ｙはフェニル基を示す。）
で示されるホスホネート化合物または該ホスホネート化合物と下記式（ＩＩＩ）
【００２６】
【化１４】

【００２７】
（ここで、式（ＩＩＩ）中のｎは２〜４の整数である。）
で示される芳香族多価カルボン酸との反応性生物を使用し、かつ、主たる重合触媒として２，６−ポリエチレンナフタレート樹脂中に可溶なチタン化合物を用いる２，６−ポリエチレンナフタレート樹脂組成物の製造方法によって達成される。
【００２８】
さらにまた、本発明の２，６−ポリエチレンナフタレート樹脂組成物の製造方法は、その好ましい態様として、チタン化合物およびホスホネート化合物の添加量が、前記式（１）〜（３）を同時に具備すること、エステル交換反応させる前に、触媒であるチタン化合物を添加して、エステル交換反応触媒としても用いること、エステル交換反応が、０．０５〜０．２０ＭＰａの加圧下で行われること、および重合触媒であるチタン化合物が、前記式（ＩＩ）で表わされる化合物および前記式（ＩＩ）で表わされる化合物と前記式（ＩＩＩ）で表わされる芳香族多価カルボン酸との反応生成物からなる群より選ばれた少なくとも１種であることのいずれかを具備する２，６−ポリエチレンナフタレート化合物の製造方法も包含するものである。
【００２９】
【発明の実施の形態】
以下、本発明を更に詳しく説明する。
本発明の２，６−ポリエチレンナフタレート樹脂組成物は、８０重量％以上、好ましくは８５重量％以上が２，６−ポリエチレンナフタレート樹脂からなるものであり、２，６−ポリエチレンナフタレート樹脂以外の他の樹脂を、混合したものであっても良い。また、本発明における２，６−ポリエチレンナフタレート樹脂とは、２，６−エチレンナフタレート成分を主たる繰返し単位とするポリエステルである。ここでいう主たる繰り返し単位とは、全繰り返し単位の８０モル％以上、好ましくは８５モル％以上を意味する。２，６−ポリエチレンナフタレート樹脂が２，６−エチレンナフタレート成分以外の第３成分を共重合したものである場合、第３成分（共重合成分）としては、テレフタル酸、イソフタル酸、フタル酸等の如き２，６−ナフタレンジカルボン酸以外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如き脂肪族ジカルボン酸、シクロヘキサンジカルボン酸等の如き脂環族ジカルボン酸、トリメチレングリコール、ジエチレングリコール、テトラメチレングリコール、シクロヘキサンジメタノール等のグリコールが例示でき、これらは単独で使用しても二種以上を併用してもよい。
【００３０】
本発明の２，６−ポリエチレンナフタレート樹脂組成物を構成する２，６−ポリエチレンナフタレートは、２，６−ジメチルナフタレートとエチレングリコールとをエステル交換反応させ、その後重縮合反応させることで製造できる。 本発明の２，６−ポリエチレンナフタレート樹脂組成物は、下記式（Ｉ）で示されるホスホネート化合物または該ホスホネート化合物と下記式（ＩＩＩ）で示される芳香族多価カルボン酸との反応性生物を熱安定剤として含有することが必要であり、これらは単独で使用しても二種以上を併用してもよい。
【００３１】
【化１５】

【００３２】
（ここで、Ｚは−Ｃ_ｎＨ_２ｎ−ＯＨ（ｎは０〜４の整数）、ＡおよびＢはそれぞれ、−Ｃ_ｎＨ_２ｎ＋１（ｎは０〜４の整数）または−Ｃ_ｎＨ_２ｎ−ＯＨ（ｎは１〜４の整数）、Ｘは−ＣＨ_２−または−ＣＨ（Ｙ）−、Ｙはフェニル基を示す。）
特に好ましいホスホネート化合物としては、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、カルボブ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、カルボプロポキシ−ホスホノ−フェニル酢酸およびカルボブトキシ−ホスホノ−フェニル酢酸などの炭素数１〜４のグリコールエステルが挙げられる。ホスホネート化合物のグリコール置換体は、末端アルコキシ基の一部が置換されたものでも良く、ヒドロキシル基を含むすべてが置換されたものでもよい。
【００３３】
また本発明におけるホスホネート化合物と反応させる芳香族多価カルボン酸は下記式（ＩＩＩ）で表される。
【００３４】
【化１６】

【００３５】
（上記式中、ｎは２〜４の整数を表わす）
上記式（ＩＩＩ）で表される芳香族多価カルボン酸としては、フタル酸、トリメリット酸、ヘミメリット酸、ピロメリット酸が好ましい。なお、一般式（ＩＩＩ）で表される芳香族多価カルボン酸は、その無水物であっても良い。
【００３６】
本発明において、これらのホスホネート化合物が必要である理由は、通常安定剤として使用されているリン化合物に比べ、チタン化合物との反応が比較的緩やかに進行することから、重縮合反応中のチタン化合物の触媒活性の持続時間が長く、結果としてポリエステルへの触媒の添加量を少なくでき、触媒に対して多量の安定剤を添加してもポリエステルの熱安定性を損ないにくく、色調の低下を引き起こさないからである。さらに耐飛散姓に優れるため、より少ない添加量で熱安定剤としての効果が発現することも挙げられる。
【００３７】
本発明におけるホスホネート化合物の含有量は、２，６−エチレンナフタレート成分のモル数を基準として、リン元素量で８〜２２５ミリモル％であることが好ましく、更に１０〜５０ミリモル％が好ましく例示される。該リン元素量が下限未満だと、十分な熱安定性が得られにくい。一方リン元素量が上限を超えると、ポリマーの重合反応性が低下しやすい。
【００３８】
本発明において、ホスホネート化合物の添加時期は特に制限されることなく、エステル交換反応開始前でも良く、またエステル交換反応が実質的に終了した後、例えば、重縮合反応を開始する以前の大気圧下、重縮合反応を開始した後の減圧下、重縮合反応の末期または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。
【００３９】
本発明の２，６−ポリエチレンナフタレート樹脂組成物は、触媒起因の異物低減および透明性向上を目的にしていることから、実質的に触媒として、ポリマー中に可溶なチタン化合物を用いたものである。そのことから、２，６−ポリエチレンナフタレート樹脂組成物中のチタン化合物以外の触媒に起因するアンチモン元素およびゲルマニウム元素の含有量は、２，６−エチレンナフタレート成分のモル数を基準として、高々５ミリモル％である。アンチモン元素およびゲルマニウム元素の含有量が、５ミリモル％を超えると、これらの触媒に起因する異物の析出などの問題が惹起する。
【００４０】
本発明で触媒として用いるチタン化合物は、ポリマー中に可溶なものであれば特に限定されず、ポリエステルの重縮合触媒として一般的なチタン化合物、例えば、酢酸チタンやテトラ−ｎ−ブトキシチタンが挙げられる。これらの中でも、下記式（ＩＩ）で表わされる化合物、または下記式（ＩＩ）で表わされる化合物と下記式（ＩＩＩ）で表わされる芳香族多価カルボン酸またはその無水物とを反応させた生成物が好ましい。
【００４１】
【化１７】

【００４２】
（上記式中、Ｒ^１，Ｒ^２，Ｒ^３，Ｒ^４はアルキル基またはフェニル基を示す。）
【００４３】
【化１８】

【００４４】
（上記式中、ｎは２〜４の整数を表わす）
上記式（ＩＩ）で表わされるテトラアルコキサイドチタンとしては、Ｒ^１，Ｒ^２，Ｒ^３，Ｒ^４がそれぞれアルキル基またはフェニル基であれば特に限定されず、その中でも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が好ましい。また、上記式（ＩＩＩ）で表される芳香族多価カルボン酸としては、フタル酸、トリメリット酸、ヘミメリット酸、ピロメリット酸が好ましい。なお、一般式（ＩＩＩ）で表される芳香族多価カルボン酸は、その無水物であっても良い。上記チタン化合物と芳香族多価カルボン酸とを反応させるには、溶媒に芳香族多価カルボン酸またはその無水物の一部とを溶解し、これにチタン化合物を滴下し、０〜２００℃の温度で３０分以上反応させれば良い。
【００４５】
本発明の２，６−ポリエチレンナフタレート樹脂組成物は、前述のポリマー中に可溶なチタン化合物を、樹脂組成物中の２，６−エチレンナフタレート成分のモル数を基準として、チタン元素量で４〜１５ミリモル％含有することが好ましい。更に好ましい該チタン元素量は５〜１２ミリモル％、特に６〜１０ミリモル％である。該チタン元素量が下限未満だと、ポリエステルの生産性が低下し、所望の分子量を有するポリエステルが得られない。一方、該チタン元素量が上限を超えると、得られる２，６−ポリエチレンナフタレート樹脂組成物の熱安定性が低下し、フィルムなどへの成形加工時の分子量の低下が大きく、やはり所望の力学的特性を有する成形加工品が得られない。なお、ここで言うチタン金属元素とは、エステル交換反応による第一段階反応にも用いる場合は、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を示す。本発明におけるチタン化合物の添加時期は、２，６−ジメチルナフタレートを原料物質とする製造方法の中でも、チタン化合物の添加量を低減できることから、チタン化合物の少なくとも一部をエステル交換反応開始前に添加し、のこりのチタン化合物は重縮合工程で添加させることが好ましい。
【００４６】
本発明の２，６−ポリエチレンナフタレート樹脂組成物は、その製造段階で上述のチタン化合物を触媒として、また、ホスホネート化合物を安定剤として添加したものであり、チタン化合物とリン化合物の含有量は下記式（２）および（３）を満足することが好ましい。
【００４７】
【数１０】
２≦Ｐ／Ｔｉ≦１５ ・・・（２）
【００４８】
【数１１】
１５≦Ｔｉ＋Ｐ≦１５０ ・・・（３）
（ここで、式（２）および（３）中のＴｉは２，６−エチレンナフタレート成分に対するチタン化合物のチタン元素のモル比（ミリモル％）であり、Ｐは２，６−エチレンナフタレート成分に対するリン化合物のリン元素のモル比（ミリモル％）である。）
上記式（２）中の（Ｐ／Ｔｉ）の更に好ましい範囲は４〜１０の範囲、また、上記式（３）中の（Ｔｉ＋Ｐ）の更に好ましい範囲は３０〜７０である。
【００４９】
（Ｐ／Ｔｉ）が下限未満の場合、得られるポリマーの色相が黄味を帯びやすく、一方（Ｐ／Ｔｉ）が１５を超えるとポリエチレンテレフタレートの重合反応性が低下して、所望の分子量を有するポリエチレンテレフタレートを得ることが困難になる。（Ｐ／Ｔｉ）が２〜１５の範囲にあるとき、色相の優れた所望の分子量を有するポリマーを得ることができる。また、（Ｔｉ＋Ｐ）が下限に満たない場合は、例えばフィルムに成形加工する際に、静電印可法によるフィルム製膜プロセスにおける生産性が低下したり、フィルムの厚みが不均一化したりし、それらに起因して成形加工性の低下や耐衝撃性の低下が生じことがある。一方（Ｔｉ＋Ｐ）が１５０を超えると、触媒に起因する異物が発生しやすく、ポリマーの透明性が低下しやすい。
【００５０】
本発明のポリエステル樹脂組成物の固有粘度（ο−クロロフェノール、３５℃）は、０．５０〜０．８０の範囲にあることが好ましく、さらに０．５５〜０．７５、特に０．５５〜０．６５の範囲が好ましい。固有粘度が下限未満であると、成形加工品、例えばフィルムの耐衝撃性が不足しやすい。他方、固有粘度が上限を超えると、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。
【００５１】
本発明の２，６−ポリエチレンナフタレート樹脂組成物は、例えばフイルムへの成形用の場合、取扱い性を向上させるために、平均粒径０．０５〜５．０μｍの不活性粒子を滑剤として０．０５〜５．０重量％程度添加してもよい。この際、本発明の２，６−ポリエチレンナフタレート樹脂組成物の特徴である優れた透明性を維持する点からは、添加する不活性粒子は粒径の小さいものが、またその添加量はできる限り少ないことが好ましい。添加する不活性粒子としては、コロイダルシリカ、多孔質シリカ、酸化チタン、炭酸カルシウム、燐酸カルシウム、硫酸バリウム、アルミナ、ジルコニア、カオリン、複合酸化物粒子、架橋ポリスチレン、アクリル系架橋粒子、メタクリル系架橋粒子、シリコーン粒子などが挙げられる。また、フィルム、繊維、ボトルなど各成形品の要求に応じて、酸化防止剤、熱安定剤、粘度調整剤、可塑剤、色相改良剤、核剤、紫外線吸収剤などの各種機能剤を加えてもよい。
【００５２】
本発明の２，６−ポリエチレンナフタレート樹脂組成物の製造方法の一例について、さらに詳述する。エステル交換反応触媒であるポリマーに可溶なチタン化合物、熱安定剤であるホスホネート化合物、重合触媒であるポリマーに可溶性なチタン化合物の添加順序は、まずエステル交換反応開始前に２、６―ジメチルナフタレンジカルボン酸およびエチレングリコールとともにエステル交換反応触媒であるチタン化合物を存在させて添加して徐々に昇温し、発生するアルコールを除去させながらエステル交換反応を実施し、エステル交換反応後にホスホネート化合物を添加して実質的にエステル交換反応を完了させる。その後反応生成物を減圧装置が設けられた重合反応器に移し替え、高真空化下で重合反応を行う。この時必要であれば、チタン化合物を追添加しても良い。
【００５３】
本発明において、エステル交換反応時の反応系内の圧力は、０．０５〜０．２０ＭＰａの加圧下で行うのが好ましい。圧力を上限より高くすると、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増加して、ポリマーの熱安定性等の特性が低下しやすい。一方、圧力を下限未満とすると、著しく反応に時間が掛かり、工業的に経済性が伴わなくなる。
【００５４】
本発明のポリエステルフィルムの製造方法としては特に限定はなく、従来公知の技術を用いる事が出来る。例えば、重縮合反応により得られた２，６−ポリエチレンナフタレート樹脂組成物のチップを（Ｔｃ）〜（Ｔｃ＋４０）℃（ここで、Ｔｃは２，６−ポリエチレンナフタレート樹脂の昇温時の結晶化温度を示す）の温度範囲で１〜３時間乾燥した後、（Ｔｍ）〜（Ｔｍ＋７０）℃（ここで、Ｔｍは２，６−ポリエチレンナフタレート樹脂の融点を示す）の温度範囲内でシート状に溶融押出し、次いで表面温度２０〜４０℃の回転冷却ドラム上に密着固化させて、実質的に非晶質のポリエステルシート（未延伸フィルム）を得る。次いで未延伸フィルムを縦方向に延伸した後、横方向に延伸する、いわゆる縦・横逐次二軸延伸法、あるいは、この順序を逆にして延伸する方法などにより延伸する。延伸する際の温度（熱固定温度）は（Ｔｇ−１０）〜（Ｔｇ＋７０）℃（ ここで、Ｔｇは２，６−ポリエチレンナフタレート樹脂の二次転移点温度を示す）であって、延伸倍率は少なくとも一軸方向に２．５倍以上、さらには３倍以上で、かつ面積倍率が８倍以上、さらには１０〜３０倍の範囲から選ぶのが好ましい。使用するスリット状ダイの形状や、溶融温度、延伸倍率、熱固定温度等の条件について制限は無く、また単層フィルムや共押出し技術等を用いた積層フィルムのいずれも採用することができる。
【００５５】
【実施例】
以下、実施例により本発明をさらに説明する。なお、２，６−ポリエチレンナフタレート樹脂組成物の特性は、以下の方法で測定・評価した。
（１）極限粘度（ＩＶ）
ポリエステル０．６ｇをオルトクロロフェノール５０ｍｌ中に、加熱溶解した後、一旦冷却させ、その溶液をオストワルド式粘度管を用いて３５℃の温度条件で測定した溶液粘度から算出した。
（２）色相（Ｃｏｌ）
粒状のポリマーサンプルを１６０℃にて９０分乾燥機中で熱処理して結晶化させた後、カラーマシン社製ＣＭ―７５００型カラーマシンで測定した。Ｌ値は明度の指標であり、数値が大きいほど明度が高いことを、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。
（３）ヘーズ
粒状のポリマーサンプルを１５０℃にて６時間乾燥機中で熱処理して乾燥させた後、２９０℃にて１軸式の溶融押出し器から溶融滞留時間３０分で回転冷却ドラム上にシート状に溶融押出し、急冷固化して厚さ５００μｍの未延伸フィルム（シート）を作成する。得られた未延伸シートの表面に傷などが発生していない箇所をサンプリングし、日本電色工業社濁度計（ＨＤＨ−１００１ＤＰ）にて測定した。
（４）金属およびリン化合物含有濃度分析
チタン，リン原子濃度は、乾燥したサンプルを走査電子顕微鏡（ＳＥＭ，日立計測機器サービスＳ５７０型）にセットし、それに連結したエネルギー分散型Ｘ線マイクローアナライザー（ＸＭＡ，堀場ＥＭＡＸ−７０００）にて定量分析を実施した。
【００５６】
ポリエステル中の金属元素の濃度は、粒状のサンプルをアルミ板上で加熱溶融した後、圧縮プレス機で平面を有する成形体を作成し、蛍光Ｘ線装置（理学電機工業３２７０Ｅ型）にて、定量分析した。なお、滑剤を含む場合は、予め溶媒中で遠心分離処理により滑剤を除去した上で同様の測定を行った。
（５）熱安定性
ヘーズ測定のために作成した未延伸フイルム（シート）の極限粘度を前述の（１）記載の方法と同じ方法にて測定し、該測定値からシート作成に使用した粒状ポリマーの極限粘度を差し引いた値を算出し、該値より以下の基準で熱安定性を判定した。
熱安定性が特に優れる ・・・ −０．０３以上
熱安定性が優れる ・・・ −０．０４未満−０．０５以上
熱安定性が普通 ・・・ −０．０５未満〜−０．０７以上
熱安定性が劣る ・・・ −０．０７未満
（６）ジエチレングリコール量（ＤＥＧ）：
ポリエステルチップをＣＤＣｌ_３／ＣＦ_３ＣＯＯＤ混合溶媒にて溶解し、^１Ｈ−ＮＭＲにて測定した。
【００５７】
［実施例１］
２，６−ジメチルナフタレート１００部とエチレングリコール５６部の混合物に、テトラ−ｎ−ブチルチタネート（以下、ＴＢＴと称する。）０．０１１部を加圧反応が可能なＳＵＳ（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、下記式（ＩＶ）のホスホネート化合物（ジエトキシホスホノ酢酸ヒドロキシエチルエステル。以下、リン化合物１と略記する。）を表１に記載したモル量となるように添加し、エステル交換反応を終了させた。
【００５８】
【化１９】

【００５９】
その後反応生成物を重合容器に移し、２９０℃まで昇温し、１００Ｐａの高真空にて重縮合反応を行い、固有粘度０．６１、ジエチレングリコール量１．５モル％（２，６−エチレンナフタレート成分対比）の２，６−ポリエチレンナフタレート樹脂組成物を得た。
【００６０】
得られた２，６−ポリエチレンナフタレート樹脂組成物は、ペレットの状態で１８０℃の温度で充分に真空乾燥した。乾燥したペレットを２８０℃で溶融状態とし、回転しているキャスティングドラムに溶融状態の２，６−ポリエチレンナフタレート樹脂組成物を押出してシート状物を得た。なお、キャスティングドラムは溶融物がキャストされる直前の表面温度が３０℃で、その後表面温度は徐々に４０℃まで上がっており、またキャスティングドラムに溶融物がキャストされた直後に、シート状物の、キャスティングドラムが位置するのと反対側の面にワイヤー状の電極があり、該電極によってシート状物を静電印加させてキャスティングドラムに密着させ、厚さ５００μｍの未延伸２，６−ポリエチレンナフタレートフィルムを得た。
【００６１】
得られた２，６−ポリエチレンナフタレート樹脂組成物及びこれを使用して得られた未延伸フイルムの特性を表１に示す。
【００６２】
［実施例２］
チタン化合物を下記方法にて合成したトリメリット酸チタン（ＴＭＴと以下称する。）に変更する以外は実施例１と同様な操作を繰り返した。
【００６３】
得られた２，６−ポリエチレンナフタレート樹脂組成物及びこれを使用して得られた未延伸フイルムの特性を表１に示す。
【００６４】
トリメリット酸チタンの合成方法
無水トリメリット酸２重量部をエチレングリコール９８重量部に混ぜたエチレングリコール溶液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モル比が０．５となるように添加し、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。
【００６５】
［実施例３］
ホスホネート化合物を下記式（Ｖ）（以下、リン化合物２と略記する）で示されるホスホネート化合物に変更する以外は、実施例２と同様な操作を繰り返した。
【００６６】
得られた２，６−ポリエチレンナフタレート樹脂組成物およびこれを使用して得られた未延伸フィルムの特性を表１に示す。
【００６７】
【化２０】

【００６８】
［実施例４］
ホスホネート化合物を下記式（ＶＩ）（以下、リン化合物３と略記する）で示されるホスホネート化合物に変更する以外は、実施例２と同様な操作を繰り返した。
【００６９】
得られた２，６−ポリエチレンナフタレート樹脂組成物およびこれを使用して得られた未延伸フィルムの特性を表１に示す。
【００７０】
【化２１】

【００７１】
［実施例５］
ホスホネート化合物を、リン化合物１（５０モル％）、リン化合物２（３０モル％）、リン化合物３（２０モル％）からなる混合物（以下、リン化合物４と略記する）に変更する以外は、実施例２と同様な操作を繰り返した。
【００７２】
得られた２，６−ポリエチレンナフタレート樹脂組成物およびこれを使用して得られた未延伸フィルムの特性を表１に示す。
【００７３】
［実施例６〜１３］
チタン化合物の種類、チタン化合物とホスホネート化合物の量を表１に示すとおりに変更する以外は、実施例２と同様な操作を繰り返した。
【００７４】
得られた２，６−ポリエチレンナフタレート樹脂組成物およびこれを使用して得られた未延伸フィルムの特性を表１に示す。
【００７５】
［比較例１］
ホスホネート化合物の代わりに同モル量の正リン酸を用いた以外は、実施例２と同様な操作を繰り返した。
【００７６】
得られた２，６−ポリエチレンナフタレート樹脂組成物およびこれを使用して得られた未延伸フィルムの特性を表１に示す。
【００７７】
［比較例２］
ホスホネート化合物の代わりに同モル量のトリメチルホスフェイト（以下、ＴＭＰと称する。）を用いた以外は、実施例２と同様な操作を繰り返した。
【００７８】
得られた２，６−ポリエチレンナフタレート樹脂組成物およびこれを使用して得られた未延伸フィルムの特性を表１に示す。
【００７９】
［比較例３］
実施例１と同様にエステル交換反応させた後、その反応生成物に三酸化二アンチモンを０．０５３部添加し、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０．６０ｄｌ／ｇ、ジエチレングリコール量が１．５％である２，６−ポリエチレンナフタレート樹脂組成物を得た。未延伸フィルムは実施例１と同様の方法で得た。
【００８０】
得られた２，６−ポリエチレンナフタレート樹脂組成物及びこれを使用して得られた未延伸フイルムの特性を表１に示す。
【００８１】
【表１】

【００８２】
ここで、表１中の、ＴＢＴはテトラ−ｎ−ブトキシチタン、ＴＭＴはトリメリット酸チタン、ＴＭＰはトリメチルホスフェイトを示す。
【００８３】
表１からも明らかなように、特定のリン化合物を使用することで、透明性や色相、熱安定性などで良好な性能のポリエステル樹脂組成物が得られた。また、チタン化合物をチタン元素として４〜１５ミリモル％の範囲で含有し、（Ｐ／Ｔｉ）や（Ｔｉ＋Ｐ）が本発明の範囲にある２，６−ポリエチレンナフタレート樹脂組成物は、透明性や色相、熱安定性などでより良好な性能が得られた。これに対し、比較例１〜２に示したように、リン化合物としてホスホネート化合物以外のリン化合物を用いた場合、透明性、色相、特にｂ値、熱安定性のいずれも実施例と較べて不十分であった。なお、比較例３がアンチモン元素を７０ミリモル％含有する以外は、どれもアンチモン元素およびゲルマニウム元素は含有していなかった。
【００８４】
【発明の効果】
本発明によれば、エステル交換反応を経由する２，６−ポリエチレンナフタレート樹脂組成物において、特定のリン化合物を用いることによって、チタン化合物を触媒として使用する場合の従来技術の欠点であった色相の悪化を解消し、ポリエチレンテレフタレートが持つ優れた特性を保持しながら、触媒起因の異物が少なく、透明性および熱安定性に優れた２，６−ポリエチレンナフタレート樹脂を提供することができる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a 2,6-polyethylene naphthalate resin composition and a method for producing the same. More specifically, in a 2,6-polyethylene naphthalate resin composition using a titanium compound substantially as a polymerization catalyst via a transesterification reaction, excellent transparency with few foreign substances due to the polymerization catalyst in the polymer is obtained. The present invention relates to a 2,6-poly (ethylene naphthalate) resin composition which has practically no problem in melting heat stability and excellent polymer hue while maintaining the same, and a method for producing the same.
[0002]
[Prior art]
Since 2,6-polyethylene naphthalate has excellent mechanical properties, heat resistance, weather resistance, electrical insulation resistance, and chemical resistance, it is widely used as a molded article such as a film, a fiber or a bottle.
[0003]
In the production of such 2,6-polyethylene naphthalate, a polymerization catalyst is used in order to allow the polymerization reaction to proceed smoothly. Various metal compounds are known as the polymerization catalyst. Among them, an antimony (Sb) compound such as antimony trioxide is widely used because of its low cost and high polymerization activity. However, a part of the Sb compound is reduced during the reaction to generate metal Sb and other foreign substances, and as a result, the color of the polymer is darkened, and the production process is destabilized. Have the problem of deteriorating the quality of
[0004]
As a polycondensation catalyst other than the antimony compound, a titanium compound such as a germanium compound and tetra-n-butoxytitanium has been proposed. Germanium compounds are rather expensive and have the problem of increasing the cost of producing polyester. On the other hand, when a titanium compound is used as a polymerization catalyst, the above-mentioned generation of metal Sb and other foreign substances is suppressed, and the above-mentioned problem caused by the foreign substances is improved. However, 2,6-polyethylene naphthalate using a titanium compound as a polymerization catalyst itself has a problem specific to the titanium compound because it is itself colored yellow and has poor melting heat stability.
[0005]
Generally, in order to suppress the coloring of 2,6-polyethylene naphthalate, a cobalt compound is added to 2,6-polyethylene naphthalate to suppress the yellowish color. (B value) is improved. However, there is a problem that the addition of the cobalt compound further reduces the melting heat stability of the obtained 2,6-polyethylene naphthalate and promotes the decomposition of the polymer.
[0006]
On the other hand, as a catalyst for producing a polyester, a product obtained by reacting a titanium compound with a phosphite (JP-A-58-38722) or a complex of a titanium compound and a phosphorus compound (JP-A-Hei. Japanese Patent Application Laid-Open No. 7-138354) has also been proposed. According to these methods, the color tone of the obtained polymer can be improved while the melt heat stability of the obtained polyester is improved to some extent. However, the effect of improving the color tone of the polymer obtained by these methods is still insufficient, and further improvement in the color tone of the polymer is required.
[0007]
[Patent Document 1]
JP-A-58-38722
[Patent Document 2]
JP-A-7-138354
[0008]
[Problems to be solved by the invention]
An object of the present invention is to solve the problems of the prior art when a titanium compound is used as a catalyst, to maintain excellent transparency with few foreign substances caused by a polymerization catalyst in a polymer, and to stabilize the melting heat without a practical problem. TECHNICAL FIELD The present invention relates to a 2,6-polyethylene naphthalate resin composition having both excellent properties and a polymer hue, and a method for producing the same.
[0009]
[Means for Solving the Problems]
The present inventors have conducted intensive studies to achieve the above object, and as a result, by using a specific phosphorus compound, while maintaining excellent transparency, practically no problem with melting heat stability and excellent polymer hue. Have been found to be provided in a 2,6-polyethylene naphthalate resin composition, and have reached the present invention.
[0010]
According to the present invention, an object of the present invention is to provide a 2,6-polyethylene naphthalate resin represented by the following formula (I):
[0011]
Embedded image

[0012]
(Where Z is -C _n H _2n -OH (n is an integer of 0 to 4), A and B are each -C _n H _{2n + 1} (N is an integer of 0 to 4) or -C _n H _2n -OH (n is an integer of 1 to 4), X is -CH ₂ — Or —CH (Y) —, Y represents a phenyl group. )
Or a phosphonate compound represented by the following formula (III):
[0013]
Embedded image

[0014]
(Here, n in the formula (III) is an integer of 2 to 4.)
And a titanium compound soluble in a 2,6-polyethylene naphthalate resin and having an antimony element and a germanium element content of 2,6-ethylene naphthalene. This can be achieved by a 2,6-polyethylene naphthalate resin composition having a maximum of 5 mmol% based on the phthalate component.
[0015]
In a preferred embodiment, the content of the titanium compound and the phosphonate compound in the 2,6-polyethylene naphthalate resin composition of the present invention is represented by the following formulas (1) to (3).
[0016]
(Equation 7)
4 ≦ Ti ≦ 15 (1)
[0017]
(Equation 8)
2 ≦ P / Ti ≦ 15 (2)
[0018]
(Equation 9)
15 ≦ Ti + P ≦ 150 (3)
(Here, in the formulas (1) to (3), Ti represents the number of moles of the titanium compound as a titanium element, and P represents the number of moles of a phosphonate compound as a phosphorus element. It is a value (mmol%) divided by the number of moles of 6-ethylene naphthalate component.)
Or the titanium compound is represented by the following formula (II):
[0019]
Embedded image

[0020]
(Where R in the formula (II) ¹ , R ² , R ³ , R ⁴ Is an alkyl group or a phenyl group. )
And a compound represented by the above formula (II) and a compound represented by the following formula (III)
[0021]
Embedded image

[0022]
(Here, n in the formula (III) is an integer of 2 to 4.)
2,6-polyethylene naphthalate resin composition comprising at least one selected from the group consisting of a reaction product with an aromatic polycarboxylic acid represented by the formula:
[0023]
Further, according to the present invention, another object of the present invention is to produce a 2,6-polyethylene naphthalate resin composition in which 2,6-dimethylnaphthalate is subjected to a transesterification reaction with ethylene glycol followed by a polycondensation reaction. In the method, as a heat stabilizer, the following formula (I)
[0024]
Embedded image

[0025]
(Where Z is -C _n H _2n -OH (n is an integer of 0 to 4), A and B are each -C _n H _{2n + 1} (N is an integer of 0 to 4) or -C _n H _2n -OH (n is an integer of 1 to 4), X is -CH ₂ — Or —CH (Y) —, Y represents a phenyl group. )
Or a phosphonate compound represented by the following formula (III):
[0026]
Embedded image

[0027]
(Here, n in the formula (III) is an integer of 2 to 4.)
2,6-polyethylene naphthalate resin composition using a reactive product with an aromatic polycarboxylic acid represented by the formula: and using a titanium compound soluble in 2,6-polyethylene naphthalate resin as a main polymerization catalyst This is achieved by a method of manufacturing a product.
[0028]
Furthermore, in a preferred embodiment of the method for producing a 2,6-polyethylene naphthalate resin composition of the present invention, the addition amounts of the titanium compound and the phosphonate compound simultaneously satisfy the above formulas (1) to (3). Before a transesterification reaction, a titanium compound as a catalyst is added to be used as a transesterification catalyst, the transesterification reaction is performed under a pressure of 0.05 to 0.20 MPa, and a polymerization catalyst Is selected from the group consisting of the compound represented by the formula (II) and the reaction product of the compound represented by the formula (II) and the aromatic polycarboxylic acid represented by the formula (III). The present invention also encompasses a method for producing a 2,6-polyethylene naphthalate compound having any one of the above-mentioned at least one kind.
[0029]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in more detail.
The 2,6-polyethylene naphthalate resin composition of the present invention comprises at least 80% by weight, preferably at least 85% by weight, of a 2,6-polyethylene naphthalate resin. Other resins may be mixed. In the present invention, the 2,6-polyethylene naphthalate resin is a polyester having a 2,6-ethylene naphthalate component as a main repeating unit. Here, the main repeating unit means 80 mol% or more, preferably 85 mol% or more of all the repeating units. When the 2,6-polyethylene naphthalate resin is obtained by copolymerizing a third component other than the 2,6-ethylene naphthalate component, the third component (copolymer component) may be terephthalic acid, isophthalic acid, or phthalic acid. Aromatic dicarboxylic acids other than 2,6-naphthalenedicarboxylic acid such as adipic acid, azelaic acid, sebacic acid, aliphatic dicarboxylic acids such as decanedicarboxylic acid, etc .; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; Glycols such as methylene glycol, diethylene glycol, tetramethylene glycol, and cyclohexane dimethanol can be exemplified, and these may be used alone or in combination of two or more.
[0030]
The 2,6-polyethylene naphthalate constituting the 2,6-polyethylene naphthalate resin composition of the present invention is produced by subjecting 2,6-dimethyl naphthalate and ethylene glycol to a transesterification reaction and then a polycondensation reaction. it can. The 2,6-polyethylene naphthalate resin composition of the present invention comprises a phosphonate compound represented by the following formula (I) or a reaction product of the phosphonate compound and an aromatic polycarboxylic acid represented by the following formula (III): It is necessary to contain it as a heat stabilizer, and these may be used alone or in combination of two or more.
[0031]
Embedded image

[0032]
(Where Z is -C _n H _2n -OH (n is an integer of 0 to 4), A and B are each -C _n H _{2n + 1} (N is an integer of 0 to 4) or -C _n H _2n -OH (n is an integer of 1 to 4), X is -CH ₂ — Or —CH (Y) —, Y represents a phenyl group. )
Particularly preferred phosphonate compounds include carbomethoxymethanephosphonic acid, carboethoxymethanephosphonic acid, carbopropoxymethanephosphonic acid, carbobutoxymethanephosphonic acid, carbomethoxy-phosphono-phenylacetic acid, carboethoxy-phosphono-phenylacetic acid, and carbopropoxy- C1-C4 glycol esters, such as phosphono-phenylacetic acid and carbobutoxy-phosphono-phenylacetic acid, are mentioned. The glycol-substituted phosphonate compound may be one in which a part of the terminal alkoxy group has been substituted or one in which all of the terminal alkoxy groups including the hydroxyl group have been substituted.
[0033]
The aromatic polycarboxylic acid to be reacted with the phosphonate compound in the present invention is represented by the following formula (III).
[0034]
Embedded image

[0035]
(In the above formula, n represents an integer of 2 to 4.)
As the aromatic polycarboxylic acid represented by the above formula (III), phthalic acid, trimellitic acid, hemi-mellitic acid and pyromellitic acid are preferred. The aromatic polycarboxylic acid represented by the general formula (III) may be an anhydride thereof.
[0036]
In the present invention, the reason why these phosphonate compounds are necessary is that the reaction with the titanium compound proceeds relatively slowly as compared with the phosphorus compound which is usually used as a stabilizer. The duration of the catalytic activity of the polyester is long, and as a result, the amount of the catalyst added to the polyester can be reduced, and even if a large amount of a stabilizer is added to the catalyst, the thermal stability of the polyester is hardly impaired, and the color tone does not decrease. Because. In addition, since it is excellent in anti-scattering property, the effect as a heat stabilizer can be exhibited with a smaller amount of addition.
[0037]
The content of the phosphonate compound in the present invention is preferably from 8 to 225 mmol%, more preferably from 10 to 50 mmol% in terms of the amount of phosphorus element based on the number of moles of the 2,6-ethylenenaphthalate component. You. If the amount of the phosphorus element is less than the lower limit, it is difficult to obtain sufficient thermal stability. On the other hand, when the amount of the phosphorus element exceeds the upper limit, the polymerization reactivity of the polymer tends to decrease.
[0038]
In the present invention, the addition time of the phosphonate compound is not particularly limited and may be before the start of the transesterification reaction, or after the transesterification reaction is substantially completed, for example, under atmospheric pressure before the start of the polycondensation reaction. It may be added under reduced pressure after the polycondensation reaction is started, at the end of the polycondensation reaction or after the polycondensation reaction is completed, that is, after the polymer is obtained.
[0039]
Since the 2,6-polyethylene naphthalate resin composition of the present invention aims at reducing foreign matter caused by a catalyst and improving transparency, a titanium compound soluble in a polymer is substantially used as a catalyst. It is. Therefore, the content of the antimony element and the germanium element caused by the catalyst other than the titanium compound in the 2,6-polyethylene naphthalate resin composition is at most based on the number of moles of the 2,6-ethylene naphthalate component. 5 mmol%. If the contents of the antimony element and the germanium element exceed 5 mmol%, problems such as the deposition of foreign substances caused by these catalysts are caused.
[0040]
The titanium compound used as a catalyst in the present invention is not particularly limited as long as it is soluble in the polymer, and general titanium compounds as a polyester polycondensation catalyst, for example, titanium acetate and tetra-n-butoxytitanium include Can be Among them, a compound represented by the following formula (II) or a product obtained by reacting a compound represented by the following formula (II) with an aromatic polycarboxylic acid represented by the following formula (III) or an anhydride thereof: Is preferred.
[0041]
Embedded image

[0042]
(In the above formula, R ¹ , R ² , R ³ , R ⁴ Represents an alkyl group or a phenyl group. )
[0043]
Embedded image

[0044]
(In the above formula, n represents an integer of 2 to 4.)
The tetraalkoxide titanium represented by the above formula (II) includes R ¹ , R ² , R ³ , R ⁴ Is not particularly limited as long as each is an alkyl group or a phenyl group, and among them, tetraisopropoxytitanium, tetrapropoxytitanium, tetra-n-butoxytitanium, tetraethoxytitanium, and tetraphenoxytitanium are preferable. Further, as the aromatic polycarboxylic acid represented by the above formula (III), phthalic acid, trimellitic acid, hemimellitic acid and pyromellitic acid are preferable. The aromatic polycarboxylic acid represented by the general formula (III) may be an anhydride thereof. To react the titanium compound with the aromatic polycarboxylic acid, a part of the aromatic polycarboxylic acid or an anhydride thereof is dissolved in a solvent, and the titanium compound is added dropwise thereto. The reaction may be performed at the temperature for 30 minutes or more.
[0045]
The 2,6-polyethylene naphthalate resin composition of the present invention comprises a titanium compound soluble in the polymer described above, and a titanium element amount based on the number of moles of the 2,6-ethylene naphthalate component in the resin composition. Is preferably 4 to 15 mmol%. A more preferred amount of the titanium element is 5 to 12 mmol%, particularly 6 to 10 mmol%. If the amount of the titanium element is less than the lower limit, the productivity of the polyester decreases, and a polyester having a desired molecular weight cannot be obtained. On the other hand, when the amount of the titanium element exceeds the upper limit, the thermal stability of the obtained 2,6-polyethylene naphthalate resin composition decreases, and the molecular weight at the time of forming into a film or the like is large, and the desired dynamics Cannot obtain a molded product with proper characteristics. In addition, when the titanium metal element used here is also used in the first step reaction by transesterification, the total of the titanium compound used as the transesterification catalyst and the titanium compound used as the polycondensation reaction catalyst is used. Is shown. The addition time of the titanium compound in the present invention is that, among the production methods using 2,6-dimethylnaphthalate as a raw material, the addition amount of the titanium compound can be reduced. It is preferable to add the remaining titanium compound in the polycondensation step.
[0046]
The 2,6-polyethylene naphthalate resin composition of the present invention is obtained by adding the above-mentioned titanium compound as a catalyst and a phosphonate compound as a stabilizer at the production stage, and the content of the titanium compound and the phosphorus compound is It is preferable to satisfy the following expressions (2) and (3).
[0047]
(Equation 10)
2 ≦ P / Ti ≦ 15 (2)
[0048]
[Equation 11]
15 ≦ Ti + P ≦ 150 (3)
(Where Ti in the formulas (2) and (3) is the molar ratio (mmol%) of the titanium element of the titanium compound to the 2,6-ethylene naphthalate component, and P is the 2,6-ethylene naphthalate component Is the molar ratio (mmol%) of the phosphorus element of the phosphorus compound with respect to.
The more preferable range of (P / Ti) in the above formula (2) is 4 to 10, and the more preferable range of (Ti + P) in the above formula (3) is 30 to 70.
[0049]
When (P / Ti) is less than the lower limit, the hue of the obtained polymer tends to be yellowish, while when (P / Ti) exceeds 15, the polymerization reactivity of polyethylene terephthalate decreases, and the polymer has a desired molecular weight. It becomes difficult to obtain polyethylene terephthalate. When (P / Ti) is in the range of 2 to 15, it is possible to obtain a polymer having an excellent hue and a desired molecular weight. If (Ti + P) is less than the lower limit, for example, when forming into a film, the productivity in the film forming process by the electrostatic application method is reduced, or the thickness of the film becomes nonuniform. This may cause a reduction in molding workability and a reduction in impact resistance. On the other hand, when (Ti + P) exceeds 150, foreign matter due to the catalyst is likely to be generated, and the transparency of the polymer tends to be reduced.
[0050]
The intrinsic viscosity (o-chlorophenol, 35 ° C.) of the polyester resin composition of the present invention is preferably in the range of 0.50 to 0.80, more preferably 0.55 to 0.75, especially 0.55 to 0.75. A range of 0.65 is preferred. When the intrinsic viscosity is less than the lower limit, the impact resistance of a molded product, for example, a film tends to be insufficient. On the other hand, if the intrinsic viscosity exceeds the upper limit, it is necessary to increase the intrinsic viscosity of the raw material polymer excessively, which is uneconomical.
[0051]
When the 2,6-polyethylene naphthalate resin composition of the present invention is used for molding into a film, for example, in order to improve handleability, inert particles having an average particle diameter of 0.05 to 5.0 μm are used as a lubricant. You may add about 0.05-5.0 weight%. At this time, in order to maintain excellent transparency which is a feature of the 2,6-polyethylene naphthalate resin composition of the present invention, the inert particles to be added have a small particle size, and the amount of the added inert particles can be increased. Preferably, it is as small as possible. Examples of inert particles to be added include colloidal silica, porous silica, titanium oxide, calcium carbonate, calcium phosphate, barium sulfate, alumina, zirconia, kaolin, composite oxide particles, crosslinked polystyrene, acrylic crosslinked particles, and methacrylic crosslinked particles. And silicone particles. In addition, according to the requirements of each molded product such as films, fibers, bottles, etc., various functional agents such as antioxidants, heat stabilizers, viscosity modifiers, plasticizers, hue improvers, nucleating agents, and ultraviolet absorbers are added. Is also good.
[0052]
An example of the method for producing the 2,6-polyethylene naphthalate resin composition of the present invention will be described in more detail. The order of adding the titanium compound soluble in the polymer as the transesterification catalyst, the phosphonate compound as the heat stabilizer, and the titanium compound soluble in the polymer as the polymerization catalyst is as follows: 2,6-dimethylnaphthalene In the presence of a titanium compound as a transesterification reaction catalyst together with dicarboxylic acid and ethylene glycol, the mixture is gradually added, and the temperature is gradually increased to carry out a transesterification reaction while removing generated alcohol.After the transesterification reaction, a phosphonate compound is added. To substantially complete the transesterification reaction. Thereafter, the reaction product is transferred to a polymerization reactor provided with a decompression device, and the polymerization reaction is performed under high vacuum. At this time, if necessary, a titanium compound may be additionally added.
[0053]
In the present invention, the pressure in the reaction system during the transesterification reaction is preferably performed under a pressure of 0.05 to 0.20 MPa. When the pressure is higher than the upper limit, the content of diethylene glycol, which is generated as a by-product, in the polymer increases, and the properties such as the thermal stability of the polymer tend to decrease. On the other hand, when the pressure is lower than the lower limit, the reaction takes a considerable time, and industrially is not economical.
[0054]
The method for producing the polyester film of the present invention is not particularly limited, and a conventionally known technique can be used. For example, a chip of a 2,6-polyethylene naphthalate resin composition obtained by a polycondensation reaction is used to form a crystal of (Tc) to (Tc + 40) ° C. (where Tc is a crystal of the 2,6-polyethylene naphthalate resin when the temperature is raised). After drying in a temperature range of (Tm) to (Tm + 70) ° C. (where Tm indicates the melting point of 2,6-polyethylene naphthalate resin), the sheet is dried. Then, the mixture is melt-extruded into a shape and then solidified on a rotary cooling drum having a surface temperature of 20 to 40 ° C. to obtain a substantially amorphous polyester sheet (unstretched film). Next, after stretching the unstretched film in the longitudinal direction, it is stretched in the transverse direction, that is, by the so-called longitudinal and transverse sequential biaxial stretching method, or by stretching the film in the reverse order. The temperature at the time of stretching (heat setting temperature) is (Tg-10) to (Tg + 70) ° C. (where Tg indicates the secondary transition temperature of 2,6-polyethylene naphthalate resin), and the stretching ratio Is preferably at least 2.5 times or more, more preferably 3 times or more in the uniaxial direction, and the area magnification is preferably 8 times or more, more preferably 10 to 30 times. There are no restrictions on the shape of the slit die used, the melting temperature, the stretching ratio, the heat setting temperature, and other conditions, and any of a single-layer film and a laminated film using a co-extrusion technique can be employed.
[0055]
【Example】
Hereinafter, the present invention will be further described with reference to examples. The properties of the 2,6-polyethylene naphthalate resin composition were measured and evaluated by the following methods.
(1) Intrinsic viscosity (IV)
After heating and dissolving 0.6 g of polyester in 50 ml of orthochlorophenol, the solution was cooled once, and the solution was calculated from the solution viscosity measured at a temperature of 35 ° C. using an Ostwald viscometer.
(2) Hue (Col)
The granular polymer sample was heat-treated in a dryer at 160 ° C. for 90 minutes to be crystallized, and then measured using a color machine CM-7500 type color machine. The L value is an index of lightness. The larger the numerical value, the higher the lightness, and the larger the value, the greater the yellow coloration.
(3) Haze
The granular polymer sample is heat-treated in a dryer at 150 ° C. for 6 hours and dried, and then melted at 290 ° C. from a uniaxial melt extruder into a sheet on a rotary cooling drum with a melt residence time of 30 minutes. It is extruded, quenched and solidified to prepare an unstretched film (sheet) having a thickness of 500 μm. A portion of the surface of the obtained unstretched sheet where no scratch or the like was generated was sampled and measured by Nippon Denshoku Industries Co., Ltd. turbidimeter (HDH-1001DP).
(4) Analysis of metal and phosphorus compound content
The concentration of titanium and phosphorus atoms was determined by setting a dried sample on a scanning electron microscope (SEM, Hitachi Instrument Service S570) and connecting it to an energy dispersive X-ray microanalyzer (XMA, HORIBA EMAX-7000). The analysis was performed.
[0056]
The concentration of the metal element in the polyester is determined by heating and melting a granular sample on an aluminum plate, forming a molded body having a flat surface with a compression press, and using a fluorescent X-ray apparatus (Rigaku Denki Kogyo 3270E). analyzed. When a lubricant was contained, the same measurement was performed after removing the lubricant by centrifugation in a solvent in advance.
(5) Thermal stability
The intrinsic viscosity of the unstretched film (sheet) prepared for haze measurement was measured by the same method as described in the above (1), and the intrinsic viscosity of the granular polymer used for preparing the sheet was subtracted from the measured value. The value was calculated, and the thermal stability was determined from the value according to the following criteria.
Excellent thermal stability ... -0.03 or more
Excellent thermal stability-less than -0.04-0.05 or more
Normal thermal stability: less than -0.05 to -0.07 or more
Poor thermal stability-less than -0.07
(6) Diethylene glycol amount (DEG):
Polyester chips with CDCl ₃ / CF ₃ Dissolve in COOD mixed solvent, ¹ It was measured by H-NMR.
[0057]
[Example 1]
To a mixture of 100 parts of 2,6-dimethylnaphthalate and 56 parts of ethylene glycol, 0.011 part of tetra-n-butyl titanate (hereinafter referred to as TBT) is placed in a SUS (stainless steel) container capable of performing a pressure reaction. After charging and subjecting to transesterification while increasing the temperature from 140 ° C. to 240 ° C. under a pressure of 0.07 MPa, a phosphonate compound of the following formula (IV) (diethoxyphosphonoacetic acid hydroxyethyl ester; hereinafter, phosphorus compound 1) ) Was added to give the molar amount shown in Table 1 to terminate the transesterification reaction.
[0058]
Embedded image

[0059]
Thereafter, the reaction product was transferred to a polymerization vessel, the temperature was raised to 290 ° C., and a polycondensation reaction was performed under a high vacuum of 100 Pa, an intrinsic viscosity of 0.61, a diethylene glycol amount of 1.5 mol% (2,6-ethylene naphthalate). 2,6) polyethylene naphthalate resin composition (comparative to the components) was obtained.
[0060]
The obtained 2,6-polyethylene naphthalate resin composition was sufficiently dried in a pellet at a temperature of 180 ° C. under vacuum. The dried pellets were melted at 280 ° C., and the molten 2,6-polyethylene naphthalate resin composition was extruded on a rotating casting drum to obtain a sheet. The surface temperature of the casting drum was 30 ° C. immediately before the molten material was cast, and thereafter the surface temperature gradually increased to 40 ° C., and immediately after the molten material was cast on the casting drum, There is a wire-shaped electrode on the side opposite to the side where the casting drum is located, and the sheet-like material is electrostatically applied by the electrode to adhere to the casting drum, and a non-stretched 2,6-polyethylene film having a thickness of 500 μm is provided. A phthalate film was obtained.
[0061]
Table 1 shows the properties of the obtained 2,6-polyethylene naphthalate resin composition and the unstretched film obtained using the same.
[0062]
[Example 2]
The same operation as in Example 1 was repeated except that the titanium compound was changed to titanium trimellitate (hereinafter referred to as TMT) synthesized by the following method.
[0063]
Table 1 shows the properties of the obtained 2,6-polyethylene naphthalate resin composition and the unstretched film obtained using the same.
[0064]
Synthesis method of titanium trimellitate
Tetrabutoxytitanium is added to an ethylene glycol solution in which 2 parts by weight of trimellitic anhydride is mixed with 98 parts by weight of ethylene glycol so as to have a molar ratio of 0.5 with respect to trimellitic anhydride. And then allowed to react for 60 minutes, then cooled to room temperature, the resulting catalyst was recrystallized with 10 times the amount of acetone, the precipitate was filtered through filter paper, and dried at 100 ° C. for 2 hours to obtain the desired compound. Obtained.
[0065]
[Example 3]
The same operation as in Example 2 was repeated, except that the phosphonate compound was changed to a phosphonate compound represented by the following formula (V) (hereinafter abbreviated as phosphorus compound 2).
[0066]
Table 1 shows the properties of the obtained 2,6-polyethylene naphthalate resin composition and the unstretched film obtained by using the same.
[0067]
Embedded image

[0068]
[Example 4]
The same operation as in Example 2 was repeated except that the phosphonate compound was changed to a phosphonate compound represented by the following formula (VI) (hereinafter abbreviated as phosphorus compound 3).
[0069]
Table 1 shows the properties of the obtained 2,6-polyethylene naphthalate resin composition and the unstretched film obtained by using the same.
[0070]
Embedded image

[0071]
[Example 5]
Except that the phosphonate compound was changed to a mixture of phosphorus compound 1 (50 mol%), phosphorus compound 2 (30 mol%) and phosphorus compound 3 (20 mol%) (hereinafter abbreviated as phosphorus compound 4), The same operation as in Example 2 was repeated.
[0072]
Table 1 shows the properties of the obtained 2,6-polyethylene naphthalate resin composition and the unstretched film obtained by using the same.
[0073]
[Examples 6 to 13]
The same operation as in Example 2 was repeated, except that the type of the titanium compound and the amounts of the titanium compound and the phosphonate compound were changed as shown in Table 1.
[0074]
Table 1 shows the properties of the obtained 2,6-polyethylene naphthalate resin composition and the unstretched film obtained by using the same.
[0075]
[Comparative Example 1]
The same operation as in Example 2 was repeated except that the same molar amount of orthophosphoric acid was used instead of the phosphonate compound.
[0076]
Table 1 shows the properties of the obtained 2,6-polyethylene naphthalate resin composition and the unstretched film obtained by using the same.
[0077]
[Comparative Example 2]
The same operation as in Example 2 was repeated, except that the same molar amount of trimethyl phosphate (hereinafter, referred to as TMP) was used instead of the phosphonate compound.
[0078]
Table 1 shows the properties of the obtained 2,6-polyethylene naphthalate resin composition and the unstretched film obtained by using the same.
[0079]
[Comparative Example 3]
After the transesterification reaction was carried out in the same manner as in Example 1, 0.053 parts of diantimony trioxide was added to the reaction product, the mixture was transferred to a polymerization vessel, and the temperature was raised to 290 ° C. A polycondensation reaction was carried out in a vacuum to obtain a 2,6-polyethylene naphthalate resin composition having an intrinsic viscosity of 0.60 dl / g and a diethylene glycol content of 1.5%. An unstretched film was obtained in the same manner as in Example 1.
[0080]
Table 1 shows the properties of the obtained 2,6-polyethylene naphthalate resin composition and the unstretched film obtained using the same.
[0081]
[Table 1]

[0082]
Here, in Table 1, TBT indicates tetra-n-butoxytitanium, TMT indicates titanium trimellitate, and TMP indicates trimethyl phosphate.
[0083]
As is clear from Table 1, by using the specific phosphorus compound, a polyester resin composition having good performance in transparency, hue, heat stability, and the like was obtained. Further, a 2,6-polyethylene naphthalate resin composition containing a titanium compound as a titanium element in a range of 4 to 15 mmol% and having (P / Ti) or (Ti + P) within the range of the present invention has high transparency and transparency. Better performance was obtained in terms of hue, thermal stability and the like. On the other hand, as shown in Comparative Examples 1 and 2, when a phosphorus compound other than the phosphonate compound was used as the phosphorus compound, transparency, hue, particularly b value, and thermal stability were all lower than those of the Examples. Was enough. Except that Comparative Example 3 contained 70% by mole of antimony element, none of them contained antimony element and germanium element.
[0084]
【The invention's effect】
According to the present invention, by using a specific phosphorus compound in a 2,6-polyethylene naphthalate resin composition via a transesterification reaction, the hue which has been a disadvantage of the prior art when a titanium compound is used as a catalyst is used. The present invention can provide a 2,6-polyethylene naphthalate resin excellent in transparency and thermal stability, with less foreign matter due to a catalyst, while maintaining the excellent characteristics of polyethylene terephthalate, while maintaining the excellent properties of polyethylene terephthalate.

Claims (8)

2,6-polyethylene naphthalate resin, a phosphonate compound represented by the following formula (I) or a reaction product of the phosphonate compound with an aromatic polycarboxylic acid represented by the following formula (III): 2,6-polyethylene containing a titanium compound soluble in a phthalate resin and containing at most 5 mmol% of an antimony element and a germanium element based on a 2,6-ethylenenaphthalate component Naphthalate resin composition.

(Wherein, Z is _-C n _H 2n -OH (n is an integer of 0 to 4), A and B, respectively _-C n _{H 2n +} 1 (n is an integer from 0 to 4) or _-C n _H 2n -OH (n is an integer of 1 to 4), X is -CH ₂ - or -CH (Y) -, Y represents a phenyl group).

(Here, n in the formula (III) is an integer of 2 to 4.) The 2,6-polyethylene naphthalate resin composition according to claim 1, wherein the contents of the titanium compound and the phosphonate compound satisfy the following formulas (1) to (3).

(Here, in the formulas (1) to (3), Ti represents the number of moles of the titanium compound as a titanium element, and P represents the number of moles of a phosphonate compound as a phosphorus element. It is a value (mmol%) divided by the number of moles of 6-ethylene naphthalate component.) The titanium compound is selected from the group consisting of a compound represented by the following formula (II) and a reaction product of a compound represented by the following formula (II) and an aromatic polycarboxylic acid represented by the following formula (III): The 2,6-polyethylene naphthalate resin composition according to claim 1, which is at least one kind.

(Here, R ¹ , R ² , R ³ , and R ⁴ in the formula (II) are an alkyl group or a phenyl group.)

(Here, n in the formula (III) is an integer of 2 to 4.) In a method for producing a 2,6-polyethylene naphthalate resin composition in which a 2,6-dimethyl naphthalate and an ethylene glycol are subjected to a transesterification reaction and then a polycondensation reaction, a phosphonate represented by the following formula (I) is used as a heat stabilizer: Using a compound or a reaction product of the phosphonate compound with an aromatic polycarboxylic acid represented by the following formula (III), and using a titanium compound soluble in a 2,6-polyethylene naphthalate resin as a main polymerization catalyst: A method for producing a 2,6-polyethylene naphthalate resin composition, which is used.

(Wherein, Z is _-C n _H 2n -OH (n is an integer of 0 to 4), A and B, respectively _-C n _{H 2n +} 1 (n is an integer from 0 to 4) or _-C n _H 2n -OH (n is an integer of 1 to 4), X is -CH ₂ - or -CH (Y) -, Y represents a phenyl group).

(Here, n in the formula (III) is an integer of 2 to 4.) The method for producing a 2,6-poly (ethylene naphthalate) resin composition according to claim 4, wherein the added amounts of the titanium compound and the phosphonate compound simultaneously satisfy the following formulas (1) to (3).

(Here, in the formulas (1) to (3), Ti represents the number of moles of the titanium compound as a titanium element, and P represents the number of moles of a phosphonate compound as a phosphorus element. It is a value (mmol%) divided by the number of moles of the ethylene naphthalate component.) The method for producing a 2,6-poly (ethylene naphthalate) resin composition according to claim 4, wherein a titanium compound as a catalyst is added before the transesterification reaction to be used as a transesterification catalyst. The method for producing a 2,6-poly (ethylene naphthalate) resin composition according to claim 4, wherein the transesterification reaction is performed under a pressure of 0.05 to 0.20 MPa. A group consisting of a compound represented by the following formula (II) and a reaction product of a compound represented by the following formula (II) and an aromatic polycarboxylic acid represented by the following formula (III): The method for producing a 2,6-polyethylene naphthalate resin composition according to claim 4, which is at least one member selected from the group consisting of:

(Here, R ¹ , R ² , R ³ , and R ⁴ in the formula (II) are an alkyl group or a phenyl group.)

(Here, n in the formula (III) is an integer of 2 to 4.)