JP2004155994A - Polyester composition and molding composed of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a polyester composition that has excellent flavor retainability and high transparency and hardly causes mold deposition during the molding operation. <P>SOLUTION: The polyester composition is obtained by melt-mixing (A) 100 pts.wt. of a polyester that bears ethylene terephthalate as a main recurring unit with (B) 0.01-30 pts.wt. of an m-xylylene group-bearing polyamide. Thus, the maximum diameter of a dispersed phase is ≤ 400 nm in the polyester composition before drawing. <P>COPYRIGHT: (C)2004,JPO

Description

【００５９】
【化２】

【００６０】
【化３】

【００６１】
【化４】

【００６２】
（ただし、Ｒ_１〜Ｒ_７は水素、アルキル基、アリール基、シクロアルキル基またはアリールアルキル基、Ｘ_１〜Ｘ_５は水素、アルキル基、アリール基、シクロアルキル基、アリールアルキル基またはアルカリ金属、あるいは各式中のＸ_１〜Ｘ_５とＲ_１〜Ｒ_７のうちそれぞれ１個は互いに連結して環構造を形成してもよい）
【００６３】
化学式（Ｃ−１）で表されるホスフィン酸化合物としては、ジメチルホスフィン酸、フェニルメチルホスフィン酸、次亜リン酸、次亜リン酸ナトリウム、次亜リン酸カリウム、次亜リン酸リチウム、次亜リン酸エチル、
【００６４】
【化５】

または
【００６５】
【化６】

の化合物およびこれらの加水分解物、ならびに上記ホスフィン酸化合物の縮合物などがある。
【００６６】
化学式（Ｃ−２）で表される亜ホスホン酸化合物としては、フェニル亜ホスホン酸、フェニル亜ホスホン酸ナトリウム、フェニル亜ホスホン酸カリウム、フェニル亜ホスホン酸リチウム、フェニル亜ホスホン酸エチルなどがある。
化学式（Ｃ−３）で表されるホスホン酸化合物としてはフェニルホスホン酸、エチルホスホン酸、フェニルホスホン酸ナトリウム、フェニルホスホン酸カリウム、フェニルホスホン酸リチウム、フェニルホスホン酸ジエチル、エチルホスホン酸ナトリウム、エチルホスホン酸カリウムなどがある。
化学式（Ｃ−４）で表される亜リン酸化合物としては、亜リン酸、亜リン酸水素ナトリウム、亜リン酸ナトリウム、亜リン酸トリエチル、亜リン酸トリフェニル、ピロ亜リン酸などがある。
【００６７】
また、下記化学式（Ｄ）で表されるアルカリ化合物を添加すると、本発明のポリエステル組成物の熱安定性が更に向上することを見出した。
Ｚ−ＯＲ_８ （Ｄ）
（ただし、Ｚはアルカリ金属、Ｒ_８は水素、アルキル基、アリール基、シクロアルキル基、−Ｃ（Ｏ）ＣＨ_３または−Ｃ（Ｏ）ＯＺ’、（Ｚ’は水素、アルカリ金属））
【００６８】
化学式（Ｄ）で表されるアルカリ化合物としては、水酸化ナトリウム、ナトリウムメトキシド、ナトリウムエトキシド、ナトリウムプロポキシド、ナトリウムブトキシド、カリウムメトキシド、リチウムメトキシド、酢酸ナトリウム、炭酸ナトリウム、およびアルカリ土類金属を含むアルカリ土類化合物などが挙げられるが、いずれもこれらの化合物に限定されるものではない。
【００６９】
本発明に用いられるメタキシリレン基含有ポリアミド（Ｂ）中の前記アルカリ化合物の含有量は、リン原子含有量（Ｘ）の１．５〜６．０倍が好ましい。より好ましくは１．８〜５．５倍、更に好ましくは２．０〜５．０倍である。アルカリ化合物の含有量がリン原子含有量（Ｘ）の１．５倍より少ないと、ゲル化が促進されやすくなる。一方、アルカリ化合物の含有量がリン原子含有量（Ｘ）の６．０倍より多いと、重合速度が遅くなり、粘度も充分に上がらず、かつ特に減圧系ではゲル化が促進され不経済である。
【００７０】
本発明で使用する前記化学式（Ｃ−１）〜（Ｃ−４），及び化学式（Ｄ）で表される化合物はそれぞれ単独で用いてもよいが、特に併用して用いる方が、ポリエステル組成物の熱安定性が向上するので好ましい。なお、前述の化合物の他に、従来公知の酸化防止剤、紫外線吸収剤、耐候剤、艶消剤、滑剤、粘度安定剤などを中空成形体の香味保持性、ガスバリアー性、透明性を損なわない程度で併用してもよい。
【００７１】
本発明で用いられるメタキシリレン基含有ポリアミド（Ｂ）に前記、リン原子含有化合物およびアルカリ化合物を配合するには、ポリアミドの重合前の原料、重合中に添加するかあるいは該重合体に溶融混合してもよい。
【００７２】
本発明で用いられるメタキシリレン基含有ポリアミド（Ｂ）の三級窒素の含有量は好ましくは２．０モル％以下、より好ましくは１．５モル％以下、さらに好ましくは１．０モル％以下である。三級窒素の含有量が２．０モル％を超えるメタキシリレン基含有ポリアミド（Ｂ）を含むポリエステル組成物を用いて得た成形体は、ゲル化物による着色した異物状物を含み、また色も悪くなることがある。特に延伸成形して得た延伸フイルムや二軸延伸中空成形体では、ゲル状物の存在する個所は正常に延伸されずに肉厚となって、厚み斑の原因となり、商品価値のない成形体が多くなる場合がある。
【００７３】
また、３級窒素の含有量の下限は、製造上の理由から０．００１モル％、さらには０．０１モル％、特には０．０５モル％であることが好ましい。３級窒素の含有量が０．００１モル％以下のメタキシリレン基含有ポリアミドを製造しようとする際には、高度に精製した原料を用いる、劣化防止剤を大量に必要とする、重合温度を低く保つ必要がある等の生産性に問題が起こることがある。
【００７４】
なお，ここで言う三級窒素とは、イミノ化合物に基づく窒素と三級アミドに基づく窒素の両者であり、三級窒素の含有量は、二級アミド（−ＮＨＣＯ−：通常の主鎖を構成するアミド）に基づく窒素に対するモル比（モル％）で表わした含有量である。
【００７５】
本発明に用いられるメタキシリレン基含有ポリアミド（Ｂ）のチップの形状は、シリンダ−型、角型、球状または扁平な板状等の何れでもよい。その平均粒径は通常１．０〜５ｍｍ、好ましくは１．２〜４．５ｍｍ、さらに好ましくは１．５〜４．０ｍｍの範囲である。例えば、シリンダ−型の場合は、長さは１．０〜４ｍｍ、径は１．０〜４ｍｍ程度であるのが実用的である。球状粒子の場合は、最大粒子径が平均粒子径の１．１〜２．０倍、最小粒子径が平均粒子径の０．７倍以上であるのが実用的である。また、チップの重量は１０〜３０ｍｇ／個の範囲が実用的である。
【００７６】
本発明に用いられるメタキシリレン基含有ポリアミド（Ｂ）の密度は、１．２０〜１．２４ｍｇ／ｃｍ^３が好ましく、より好ましくは１．２０ｍｇ／ｃｍ^３以上であり、１．２３ｍｇ／ｃｍ^３以下である。
【００７７】
本発明のポリエステル組成物を構成するポリエステル（Ａ）とメタキシリレン基含有ポリアミド（Ｂ）との混合割合は、前記ポリエステル（Ａ）１００重量部に対して前記メタキシリレン基含有ポリアミド（Ｂ）０．０１重量部〜３０重量部であることが好ましい。前記のポリエステル組成物からＡＡ含有量が非常に少ない成形体を得たい場合のメタキシリレン基含有ポリアミド（Ｂ）の添加量は、前記ポリエステル（Ａ）１００重量部に対して０．０１〜５重量部が好ましく、より好ましい下限は０．１重量部、さらに好ましい下限は０．５重量部であり、より好ましい上限は４重量部、さらに好ましい上限は３重量部である。
【００７８】
またガスバリヤ−性が非常に優れ、かつ実用性を損なわない透明性を持つ成形体を得たい場合は、前記ポリエステル（Ａ）１００重量部に対して１〜３０重量部が好ましく、より好ましい下限は３重量部さらに好ましい下限は５重量部であり、より好ましい上限は２５重量部、さらに好ましい上限は２０重量部である。メタキシリレン基含有ポリアミド（Ｂ）の混合量が、ポリエステル（Ａ）１００重量部に対して０．０１重量部未満の場合は、得られた成形体のＡＡ含有量が低減されず、成形体内容物の香味保持性が非常に悪くなることがある。また、メタキシリレン基含有ポリアミド（Ｂ）の混合量が、ポリエステル（Ａ）１００重量部に対して３０重量部を超える場合は、得られた成形体の透明性が非常に悪くなることがあり、また成形体の機械的特性も低下することがある。
【００７９】
本発明のポリエステル組成物において、延伸前の分散相の最大径は４００ｎｍ以下であることが好ましい。より好ましくは３５０ｎｍ以下であり、さらに好ましくは３００ｎｍ以下である。延伸前のポリエステル組成物中における分散相の最大径が４００ｎｍより大きい場合、得られた成形体の透明性が悪くなることがある。特に、ポリエステル組成物を延伸して得られる成形体の透明性を非常に悪くすることがある。
【００８０】
延伸前の分散相の最大径を４００ｎｍ以下にする方法としては、それぞれの樹脂の溶融粘度及び溶融粘度比を適正に保つ、メタキシリレン基含有ポリアミド（Ｂ）のゲル化を防止すると共に、充分な剪断応力を加えることが必要である。
【００８１】
ポリエステル（Ａ）とメタキシリレン基含有ポリアミド（Ｂ）とからなる本発明のポリエステル組成物において、分散相の大きさは以下のようにして知ることができる。すなわち、ダイヤモンドナイフを用いて数十ｎｍ厚の切片を切り出し、四酸化ルテニウム蒸気中で染色処理を行った後、透過型電子顕微鏡を使用して撮影することにより分散相の大きさを測定することができる。ポリエステル（Ａ）相とメタキシリレン基含有ポリアミド（Ｂ）相との判別は、ポリエステル（Ａ）相の方がより濃く染色されるため容易に判別することができる。
【００８２】
本発明のポリエステル組成物において、ポリエステル（Ａ）とメタキシリレン基含有ポリアミド（Ｂ）の２９０℃における溶融粘度の比［メタキシリレン基含有ポリアミド（Ｂ）の溶融粘度／ポリエステル（Ａ）の溶融粘度］が０．００１以上であり、かつ０．３以下であることが好ましい。好ましい下限は０．００５、さらに好ましい下限は０．０１であり、好ましい上限は０．２８、さらに好ましい上限は０．２５である。溶融粘度の比が０．００１より小さい場合、本発明のポリエステル組成物より得られる成形体の性能が劣り、実用に供しえないことがある。溶融粘度の比が０．３より大きい場合、本発明の目的である透明性に優れた成形体が得られないことがある。
【００８３】
本発明でいう溶融粘度とは、上記ポリエステル組成物に用いるポリエステル（Ａ）とメタキシリレン基含有ポリアミド（Ｂ）をキャピログラフ（（株）東洋精機製作所製キャピログラフ１Ｂ）により直径１ｍｍ、長さ１０ｍｍのキャピラリーダイを用いて測定した、２９０℃、剪断速度１２００ｓｅｃ^−１における溶融粘度である。
【００８４】
本発明に用いられる主たる繰り返し単位がエチレンテレフタレートであるポリエステル（Ａ）の溶融粘度は、２９０℃おいて５０〜１０００Ｐａ・ｓの範囲であることが好ましい。より好ましい下限は１００Ｐａ・ｓであり、より好ましい上限は８００Ｐａ・ｓである。上記ポリエステル（Ａ）の２９０℃における溶融粘度が５０Ｐａ・ｓより小さい場合、本発明のポリエステル組成物から得られる成形体が十分な機械的物性を示さないことがある。２９０℃における溶融粘度が１０００Ｐａ・ｓより大きい場合、溶融粘度が高すぎるために、射出成形などの成形方法によっては流動性が悪くなり、非常に薄い成形体を得るのが困難になることがある。また、上記ポリエステル（Ａ）中の水分率は３００ｐｐｍ以下、好ましくは１００ｐｐｍ以下、さらに好ましくは５０ｐｐｍ以下に乾燥することが望ましい。
【００８５】
本発明に用いられるメタキシリレン基含有ポリアミド（Ｂ）の溶融粘度は、２９０℃において１〜３００Ｐａ・ｓの範囲であることが好ましい。より好ましい下限は５Ｐａ・ｓであり、より好ましい上限は２４０Ｐａ・ｓである。上記メタキシリレン基含有ポリアミド（Ｂ）の２９０における溶融粘度が１Ｐａ・ｓより小さい場合、本発明のポリエステル組成物から得られる成形体の機械的特性が低下することがある。２９０℃における溶融粘度が３００Ｐａ・ｓより大きい場合、本発明のポリエステル組成物から得られる成形体の透明性を悪化させることがある。また、上記メタキシリレン基含有ポリアミド（Ｂ）中の水分率は５００ｐｐｍ以下、さらに好ましくは３００ｐｐｍ以下、さらに好ましくは１００ｐｐｍ以下に乾燥することが好ましい。
【００８６】
また、本発明のポリエステル組成物は主たる繰り返し単位がエチレンテレフタレートであるポリエステル（Ａ）とメタキシリレン基含有ポリアミド（Ｂ）を従来公知の方法で溶融混合して得ることもできるし、ポリエステル（Ａ）とメタキシリレン基含有ポリアミド（Ｂ）をドライブレンドし、射出成形や押出成形などにより成形品に溶融加工される例えば、一軸又は二軸スクリュー押出機中で溶融混合することができる。溶融温度は少なくともポリエステル（Ａ）の融点と同じ温度でなければならず、代表的には２６０℃〜３１０℃である。好ましくは、溶融混合温度は前記範囲内でできるだけ低く保たれる。
【００８７】
本発明のポリエステル組成物を成形してなる成形体中のメタキシリレン基含有環状アミド１量体の含有量が０．５重量％以下、好ましくは０．４重量％以下、さらに好ましくは０．３重量％以下であることが望ましい。メタキシリレン基含有環状アミド１量体の含有量が０．５重量％を超える場合は、得られた成形体内容物の香味保持性が悪くなることがあり、また本発明のポリエステル組成物から耐熱性の中空成形体等を成形する場合には、成形体成形時の金型内面や金型のガスの排気口、排気管に異物が付着するために生じる金型汚れが非常に激しくなる場合があることが判った。なお、メタキシリレン基含有環状アミド１量体の含有量は経済的な製造の面から０．００１重量％以上が好ましく、より好ましくは０．０１重量％以上である。
【００８８】
ここで、メタキシリレン基含有ポリアミドがメタキシリレンジアミンとアジピン酸とから構成されるポリアミドである場合は、前記のメタキシリレン基含有環状アミド１量体の化学式は下記の式で表される。
【００８９】
【化７】

（上記式３中、ｎ＝１（整数）を表す。）
【００９０】
また、本発明に用いられるポリエステル組成物中のアセトアルデヒド含有量は好ましくは１５ｐｐｍ以下、より好ましくは１２ｐｐｍ以下、さらに好ましくは１０ｐｐｍ以下である。本発明のポリエステル組成物中のアセトアルデヒド含有量が１５ｐｐｍを超える場合には、得られた中空成形体等に充填された飲料の風味や臭いに影響を及ぼす場合がある。
【００９１】
また、本発明に用いられる主たる繰り返し単位がエチレンテレフタレ−トであるポリエステル（Ａ）の環状エステル３量体の含有量は好ましくは０．７０重量％以下、より好ましくは０．６０重量％以下、さらに好ましくは０．５０重量％以下、特に好ましくは０．４５重量％以下である。本発明のポリエステル組成物から耐熱性の中空成形体等を成形する場合、環状エステル３量体の含有量が０．７０重量％を超える含有量のポリエステルを使用すると、加熱処理条件によっては加熱金型表面へのオリゴマ−付着が急激に増加し、得られた中空成形体等の透明性が非常に悪化する場合がある。なお、環状エステル３量体の含有量の下限は経済的な製造の面から０．０１重量％が好ましく、より好ましくは０．１重量％である。
ここで、ＰＥＴの場合は、環状エステル３量体とは、テレフタル酸とエチレングリコールとから構成される環状３量体のことである。
【００９２】
また、本発明に用いられる主たる繰り返し単位がエチレンテレフタレ−トであるポリエステル（Ａ）を２９０℃の温度で６０分間溶融した時の環状エステル３量体の増加量が０．５０重量％以下であることが望ましい。環状エステル３量体の増加量は好ましくは０．４０重量％以下、より好ましくは０．３０重量％以下であることが望ましい。２９０℃の温度で６０分間溶融した時の環状エステル３量体の増加量が０．５０重量％を越えるポリエステルを用いると、ポリエステル組成物を成形する際の樹脂溶融時に環状エステル３量体量が増加し、加熱処理条件によっては加熱金型表面へのオリゴマ−付着が急激に増加し、得られた中空成形体等の透明性が非常に悪化することがある。
【００９３】
２９０℃の温度で６０分間溶融した時の環状エステル３量体の増加量が０．５０重量％以下である、本発明に用いられるポリエステル（Ａ）は、溶融重縮合後や固相重合後に得られたポリエステルに残存する重縮合触媒を失活処理することにより製造することができる。ポリエステル中の重縮合触媒を失活処理する方法としては、溶融重縮合後や固相重合後にポリエステルチップを水や水蒸気または水蒸気含有気体と接触処理する方法が挙げられる。
【００９４】
前記の目的を達成するためにポリエステルチップを水や水蒸気または水蒸気含有気体と接触処理する方法を次に述べる。
熱水処理方法としては、水中に浸ける方法やシャワ−でチップ上に水をかける方法等が挙げられる。処理時間としては５分〜２日間、好ましくは１０分〜１日間、さらに好ましくは３０分〜１０時間で、水の温度としては２０〜１８０℃、好ましくは４０〜１５０℃、さらに好ましくは５０〜１２０℃である。
また処理方法は連続方式、バッチ方式のいずれであっても差し支えないが、工業的に行うためには連続方式の方が好ましい。
【００９５】
ポリエステルのチップをバッチ方式で水処理する場合は、サイロタイプの処理槽が挙げられる。すなわちバッチ方式でポリエステルのチップをサイロへ受け入れ水処理を行う。ポリエステルのチップを連続方式で水処理する場合は、塔型の処理槽に継続的又は間欠的にポリエステルのチップを上部より受け入れ、水処理させることができる。
【００９６】
またポリエステルのチップと水蒸気または水蒸気含有ガスとを接触させて処理する場合は、５０〜１５０℃、好ましくは５０〜１１０℃の温度の水蒸気または水蒸気含有ガスあるいは水蒸気含有空気を好ましくは粒状ポリエチレンテレフタレ−ト１ｋｇ当り、水蒸気として０．５ｇ以上の量で供給させるか、または存在させて粒状ポリエチレンテレフタレ−トと水蒸気とを接触させる。
この、ポリエステルのチップと水蒸気との接触は、通常１０分間〜２日間、好ましくは２０分間〜１０時間行われる。
【００９７】
また処理方法は連続方式、バッチ方式のいずれであっても差し支えない。
ポリエステルのチップをバッチ方式で水蒸気と接触処理をする場合は、サイロタイプの処理装置が挙げられる。すなわちポリエステルのチップをサイロへ受け入れ、バッチ方式で、水蒸気または水蒸気含有ガスを供給し接触処理を行なう。
【００９８】
ポリエステルのチップを連続的に水蒸気と接触処理する場合は塔型の処理装置に連続で粒状ポリエチレンテレフタレ−トを上部より受け入れ、並流あるいは向流で水蒸気を連続供給し水蒸気と接触処理させることができる。
上記の如く、水又は水蒸気で処理した場合は、粒状ポリエチレンテレフタレ−トを必要に応じて振動篩機、シモンカ−タ−などの水切り装置で水切りし、コンベヤ−によって次の乾燥工程へ移送する。
【００９９】
水又は水蒸気と接触処理したポリエステルのチップの乾燥は、通常用いられるポリエステルの乾燥処理を用いることができる。連続的に乾燥する方法としては、上部よりポリエステルのチップを供給し、下部より乾燥ガスを通気するホッパ−型の通気乾燥機が通常使用される。
【０１００】
バッチ方式で乾燥する乾燥機としては大気圧下で乾燥ガスを通気しながら乾燥してもよい。
乾燥ガスとしては大気空気でも差し支えないが、ポリエステルの加水分解や熱酸化分解による分子量低下を防止する点からは乾燥窒素、除湿空気が好ましい。
【０１０１】
また、本発明に用いられる、主たる繰り返し単位がエチレンテレフタレ−トであるポリエステル（Ａ）は、ポリオレフィン樹脂、ポリアミド樹脂、ポリアセタ−ル樹脂、ポリブチレンテレフタレ−ト樹脂からなる群から選ばれた少なくとも一種の樹脂０．１ｐｐｂ〜１０００ｐｐｍを配合してなることを特徴とするポリエステルであることができる。本発明に用いられるポリエステル（Ａ）中での前記のポリオレフィン樹脂等の配合割合は、０．１ｐｐｂ〜１０００ｐｐｍ、好ましくは０．３ｐｐｂ〜１００ｐｐｍ、より好ましくは０．５ｐｐｂ〜１ｐｐｍ、さらに好ましくは０．５ｐｐｂ〜４５ｐｂｂである。
【０１０２】
配合量が０．１ｐｐｂ未満の場合は、結晶化速度が非常におそくなり、中空成形体の口栓部の結晶化が不十分となるため、サイクルタイムを短くすると口栓部の収縮量が規定値範囲内におさまらないためキャッピング不良となることがあったり、また、耐熱性中空成形体を成形する延伸熱固定金型の汚れが激しく、透明な中空成形体を得ようとすると頻繁に金型掃除をしなければならないことがある。また１０００ｐｐｍを超える場合は、結晶化速度が早くなり、中空成形体の口栓部の結晶化が過大となったり、このため口栓部の収縮収縮量が規定値範囲内におさまらないためキャッピング不良となり内容物の漏れが生じたり、また中空成形体用予備成形体が白化し、このため正常な延伸が不可能となることがある。また、シ−ト状物の場合、１０００ｐｐｍを越えると透明性が非常に悪くなり、また延伸性もわるくなって正常な延伸が不可能で、厚み斑の大きな、透明性の悪い延伸フイルムしか得られないことがある。
【０１０３】
本発明に用いられるポリエステル（Ａ）に配合されるポリオレフィン樹脂としては、ポリエチレン系樹脂、ポリプロピレン系樹脂、またはα−オレフィン系樹脂が挙げられる。
【０１０４】
本発明に用いられるポリエステル（Ａ）に配合されるポリエチレン系樹脂としては、例えば、エチレンの単独重合体、エチレンと、プロピレン、ブテン−１、３−メチルブテン−１、ペンテン−１、４−メチルペンテン−１、ヘキセン−１、オクテン−１、デセン−１等の炭素数２〜２０程度の他のα−オレフィンや、酢酸ビニル、塩化ビニル、アクリル酸、メタクリル酸、アクリル酸エステル、メタクリル酸エステル、スチレン等のビニル化合物との共重合体等が挙げられる。具体的には、例えば、低・中・高密度ポリエチレン等（分岐状又は直鎖状）のエチレン単独重合体、エチレン−プロピレン共重合体、エチレン−ブテン−１共重合体、エチレン−４−メチルペンテン−１共重合体、エチレン−ヘキセン−１共重合体、エチレン−オクテン−１共重合体、エチレン−酢酸ビニル共重合体、エチレン−アクリル酸共重合体、エチレン−メタクリル酸共重合体、エチレン−アクリル酸エチル共重合体等のエチレン系樹脂が挙げられる。
【０１０５】
また本発明に用いられるポリエステル（Ａ）に配合されるポリプロピレン系樹脂としては、例えば、プロピレンの単独重合体、プロピレンと、エチレン、ブテン−１、３−メチルブテン−１、ペンテン−１、４−メチルペンテン−１、ヘキセン−１、オクテン−１、デセン−１等の炭素数２〜２０程度の他のα−オレフィンや、酢酸ビニル、塩化ビニル、アクリル酸、メタクリル酸、アクリル酸エステル、メタクリル酸エステル、スチレン等のビニル化合物との共重合体等が挙げられる。具体的には、例えば、ブロピレン単独重合体、プロピレン−エチレン共重合体、プロピレン−エチレン−ブテン−１共重合体等のプロピレン系樹脂が挙げられる。
【０１０６】
また本発明に用いられるポリエステル（Ａ）に配合されるα−オレフィン系樹脂としては、４−メチルペンテン−１等の炭素数２〜８程度のα−オレフィンの単独重合体、それらのα−オレフィンと、エチレン、プロピレン、ブテン−１、３−メチルブテン−１、ペンテン−１、ヘキセン−１、オクテン−１、デセン−１等の炭素数２〜２０程度の他のα−オレフィンとの共重合体等が挙げられる。具体的には、例えば、ブテン−１単独重合体、４−メチルペンテン−１単独重合体、ブテン−１−エチレン共重合体、ブテン−１−プロピレン共重合体等のブテン−１系樹脂や４−メチルペンテン−１とＣ２〜Ｃ１８のα−オレフィンとの共重合体、等が挙げられる。
【０１０７】
また、本発明に用いられるポリエステル（Ａ）に配合されるポリアミド樹脂としては、例えば、ブチロラクタム、δ−バレロラクタム、ε−カプロラクタム、エナントラクタム、ω−ラウロラクタム等のラクタムの重合体、６−アミノカプロン酸、１１−アミノウンデカン酸、１２−アミノドデカン酸等のアミノカルボン酸の重合体、ヘキサメチレンジアミン、ノナメチレンジアミン、デカメチレンジアミン、ドデカメチレンジアミン、ウンデカメチレンジアミン、２，２，４−又は２，４，４−トリメチルヘキサメチレンジアミン等の脂肪族ジアミン、１，３−又は１，４−ビス（アミノメチル）シクロヘキサン、ビス（ｐ−アミノシクロヘキシルメタン）等の脂環式ジアミン、ｍ−又はｐ−キシリレンジアミン等の芳香族ジアミン等のジアミン単位と、グルタル酸、アジピン酸、スベリン酸、セバシ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、テレフタル酸、イソフタル酸等の芳香族ジカルボン酸等のジカルボン酸単位との重縮合体、及びこれらの共重合体等が挙げられ、具体的には、例えば、ナイロン４、ナイロン６、ナイロン７、ナイロン８、ナイロン９、ナイロン１１、ナイロン１２、ナイロン６６、ナイロン６９、ナイロン６１０、ナイロン６１１、ナイロン６１２、ナイロン６Ｔ、ナイロン６Ｉ、ナイロンＭＸＤ６、ナイロン６／６６、ナイロン６／６１０、ナイロン６／１２、ナイロン６／６Ｔ、ナイロン６Ｉ／６Ｔ等が挙げられる。
【０１０８】
また、本発明に用いられるポリエステル（Ａ）に配合されるポリアセタ−ル樹脂としては、例えばポリアセタ−ル単独重合体や共重合体が挙げられる。ポリアセタ−ル単独重合体としては、ＡＳＴＭ−Ｄ７９２の測定法により測定した密度が１．４０〜１．４２ｇ／ｃｍ^３、ＡＳＴＭＤ−１２３８の測定法により、１９０℃、荷重２１６０ｇで測定したメルトインデックス（ＭＩ）が０．５〜５０ｇ／１０分の範囲のポリアセタ−ルが好ましい。
【０１０９】
また、ポリアセタ−ル共重合体としては、ＡＳＴＭ−Ｄ７９２の測定法により測定した密度が１．３８〜１．４３ｇ／ｃｍ３、ＡＳＴＭＤ−１２３８の測定法により、１９０℃、荷重２１６０ｇで測定したメルトインデックス（ＭＩ）が０．４〜５０ｇ／１０分の範囲のポリアセタ−ル共重合体が好ましい。これらの共重合成分としては、エチレンオキサイドや環状エ−テルが挙げられる。
【０１１０】
また、本発明に用いられるポリエステル（Ａ）に配合されるでポリブチレンテレフタレ−ト樹脂としては、例えばテレフタル酸と１，４−ブタンジオ−ルからなるポリブチレンテレフタレ−ト単独重合体やこれにナフタレンジカルボン酸、ジエチレングリコ−ル、１，４−シクロヘキサンジメタノ−ル等を共重合した共重合体が挙げられる。
【０１１１】
また、本発明において用いられる前記のポリオレフィン樹脂等を配合したポリエステルは、前記ポリエステルに前記のポリオレフィン等の樹脂を、その含有量が前記範囲となるように、直接に添加し溶融混練する方法、または、マスタ−バッチとして添加し溶融混練する方法等の慣用の方法によるほか、前記のポリオレフィン等の樹脂を、前記ポリエステルの製造段階、例えば、溶融重縮合時、溶融重縮合直後、予備結晶化直後、固相重合時、固相重合直後等のいずれかの段階、または、製造段階を終えてから成形段階に到るまでの間に粉粒体として直接に添加するか、或いは、ポリエステルチップの流動条件下に前記のポリオレフィン等の樹脂製の部材に接触させる等の方法で混入させた後、溶融混練する方法等によることもできる。
【０１１２】
ここで、ポリエステルチップ状体を流動条件下に前記のポリオレフィン等の樹脂製の部材に接触させる方法としては、前記のポリオレフィン等の樹脂製の部材が存在する空問内で、ポリエステルチップを該部材に衝突接触させることが好ましく、具体的には、例えば、ポリエステルの溶融重縮合直後、予備結晶化直後、固相重合直後等の製造工程時、また、ポリエステルチップの製品としての輸送段階等での輸送容器充填・排出時、また、ポリエステルチップの成形段階での成形機投入時、等における気力輸送配管、重力輸送配管、サイロ、マグネットキャッチャ−のマグネット部等の一部を前記のポリオレフィン等の樹脂製とするか、または、前記のポリオレフィン等の樹脂をライニングするとか、或いは前記移送経路内に棒状又は網状体等の前記のポリオレフィン等の樹脂製部材を設置する等して、ポリエステルチップを移送する方法が挙げられる。ポリエステルチップの前記部材との接触時間は、通常、０．０１秒〜数分程度の極短時間であるが、ポリエステルに前記のポリオレフィン等の樹脂を微量混入させることができる。
【０１１３】
また、本発明に用いられる、主たる繰り返し単位がエチレンテレフタレ−トであるポリエステル（Ａ）のアセトアルデヒド含有量は１０ｐｐｍ以下、好ましくは８ｐｐｍ以下、より好ましくは６ｐｐｍ以下、さらに好ましくは４ｐｐｍ以下、ホルムアルデヒド含有量は６ｐｐｍ以下、好ましくは５ｐｐｍ以下、より好ましくは４ｐｐｍ以下であることが望ましい。アセトアルデヒド含有量が１０ｐｐｍを超え、およびホルムアルデヒド含有量が６ｐｐｍを超える場合は、このポリエステルから成形された成形体等の内容物の香味保持性の効果が悪くなる。
なお、アセトアルデヒド量、ホルムアルデヒド量の下限は０．１ｐｐｂであることが好ましい。
【０１１４】
また本発明に用いられる、主たる繰り返し単位がエチレンテレフタレ−トであるポリエステル（Ａ）中に共重合されたジエチレングリコ−ル量は前記ポリエステル（Ａ）を構成するグリコ−ル成分の下限は好ましくは１．０モル％、より好ましくは１．３モル％、さらに好ましくは１．５モル％であり、上限は好ましくは５．０モル％、より好ましくは４．５モル％、さらに好ましくは４．０モル％である。ジエチレングリコ−ル量が５．０モル％を越える場合は、熱安定性が悪くなり、成型時に分子量低下が大きくなったり、またアセトアルデヒド含有量やホルムアルデヒド含有量の増加量が大となることがあり好ましくない。またジエチレングリコ−ル含有量が１．０モル％未満の場合は、得られた成形体の透明性が悪くなることがある。
【０１１５】
本発明のポリエステル組成物は、従来公知の方法により前記のポリエステル（Ａ）と前記のメタキシリレン基含有ポリアミド（Ｂ）を混合して得ることができる。例えば、前記のポリアミドチップと前記のポリエステルチップとをタンブラー、Ｖ型ブレンダー、ヘンシェルミキサー等でドライブレンドしたもの、さらにドライブレンドした混合物を一軸押出機、二軸押出機、ニーダー等で１回以上溶融混合したもの、さらには必要に応じて溶融混合物を高真空下または不活性ガス雰囲気下で固相重合したものなどが挙げられる。また、あらかじめ前記のポリエステル（Ａ）と前記のメタキシリレン基含有ポリアミド（Ｂ）を溶融混合したものを、前記のポリエステル（Ａ）とドライブレンドしたもの、さらにドライブレンドした混合物を溶融混合したものが挙げられる。
【０１１６】
本発明のポリエステル組成物に飽和脂肪酸モノアミド、不飽和脂肪酸モノアミド、飽和脂肪酸ビスアミド、不飽和脂肪酸ビスアミド等を同時に併用することも可能である。
【０１１７】
飽和脂肪酸モノアミドの例としては、ラウリン酸アミド、パルミチン酸アミド、ステアリン酸アミド、ベヘン酸アミド等が挙げられる。不飽和脂肪酸モノアミドの例としては、オレイン酸アミド、エルカ酸アミドリシノ−ル酸アミド等が挙げられる。飽和脂肪酸ビスアミドの例としては、メチレンビスステアリン酸アミド、エチレンビスカプリン酸アミド、エチレンビスラウリン酸アミド、エチレンビスステアリン酸アミド、エチレンビスベヘン酸アミド、ヘキサメチレンビスステアリン酸アミド、ヘキサメチレンビスベヘン酸アミド等が挙げられる。また、不飽和脂肪酸ビスアミドの例としては、エチレンビスオレイン酸アミド、ヘキサメチレンビスオレイン酸アミド等が挙げられる。好ましいアミド系化合物は、飽和脂肪酸ビスアミド、不飽和脂肪酸ビスアミド等である。このようなアミド化合物の配合量は、１０ｐｐｂ〜１×１０^５ｐｐｍの範囲であることが好ましい。
【０１１８】
また炭素数８〜３３の脂肪族モノカルボン酸の金属塩化合物、例えばナフテン酸、カプリル酸、カプリン酸、ラウリン酸、ミリスチン酸、パルミチン酸、ステアリン酸、ベヘニン酸、モンタン酸、メリシン酸、オレイン酸、リノ−ル酸等の飽和及び不飽和脂肪酸のリチュウム塩、ナトリウム塩、カリウム塩、マグネシウム塩、カルシウム塩、及びコバルト塩等を同時に併用することも可能である。これらの化合物の配合量は、１０ｐｐｂ〜３００ｐｐｍの範囲であることが好ましい。
【０１１９】
本発明のポリエステル組成物には、必要に応じて他の添加剤、例えば、公知の紫外線吸収剤、酸化防止剤、酸素吸収剤、酸素捕獲剤、外部より添加する滑剤や反応中に内部析出させた滑剤、離型剤、核剤、安定剤、帯電防止剤、顔料などの各種の添加剤を配合してもよい。また、紫外線遮断性樹脂、耐熱性樹脂、使用済みポリエチレンテレフタレ−トボトルからの回収品等を適当な割合で混合することも可能である。
【０１２０】
無色透明の樹脂が望ましい用途においては、溶融加工の間に発生するかすかな黄色い色を青色着色剤の添加によって消すことができる。着色剤は重合の間、又は配合の間にブレンド物に直接添加することができる。配合の間に添加される場合には、着色剤はそのまま添加することもできるし、マスターバッチなどのような濃縮物として添加することもできる。また、あらかじめ前記のポリエステル（Ａ）と前記のメタキシリレン基含有ポリアミド（Ｂ）を溶融混合したものを、前記のポリエステル（Ａ）とドライブレンドする場合、さらにドライブレンドした混合物を溶融混合する場合には、前記のポリエステル（Ａ）と前記のメタキシリレン基含有ポリアミド（Ｂ）を溶融混合する際に、着色剤を添加することもできる。着色剤の量は、その吸光係数およびその用途に望ましい色で調整することができる。
【０１２１】
また、本発明のポリエステル組成物をフィルム用途に使用する場合には、滑り性、巻き性、耐ブロッキング性などのハンドリング性を改善するために、ポリエステル組成物中に炭酸カルシウム、炭酸マグネシウム、炭酸バリウム、硫酸カルシウム、硫酸バリウム、リン酸リチウム、リン酸カルシウム、リン酸マグネシウム等の無機粒子、蓚酸カルシウムやカルシウム、バリウム、亜鉛、マンガン、マグネシウム等のテレフタル酸塩等の有機塩粒子やジビニルベンゼン、スチレン、アクリル酸、メタクリル酸、アクリル酸またはメタクリル酸のビニル系モノマーの単独または共重合体等の架橋高分子粒子などの不活性粒子を含有させることが出来る。
【０１２２】
本発明のポリエステル組成物は、一般的に用いられる溶融成形法を用いてフィルム、シート、容器、その他の包装材料を成形することができる。本発明のポリエステル組成物からなる延伸フィルムは射出成形もしくは押出成形して得られたシート状物を、通常ＰＥＴの延伸に用いられる一軸延伸、逐次二軸延伸、同時二軸延伸のうちの任意の延伸方法を用いて成形される。また圧空成形、真空成形によリ、カップ状やトレイ状に成形することもできる。
【０１２３】
延伸フィルムを製造するに当たっては、延伸温度は通常は８０〜１３０℃である。延伸は一軸でも二軸でもよいが、好ましくはフィルム実用物性の点から二軸延伸である。延伸倍率は一軸の場合であれば通常１．１〜１０倍、好ましくは１．５〜８倍の範囲で行い、二軸延伸であれば縦方向および横方向ともそれぞれ通常１．１〜８倍、好ましくは１．５〜５倍の範囲で行えばよい。また、縦方向倍率／横方向倍率は通常０．５〜２、好ましくは０．７〜１．３である。得られた延伸フィルムは、さらに熱固定して、耐熱性、機械的強度を改善することもできる。熱固定は通常緊張下、１２０℃〜２４０、好ましくは１５０〜２３０℃で、通常数秒〜数時間、好ましくは数十秒〜数分間行われる。
【０１２４】
中空成形体を製造するにあたっては、本発明のポリエステル組成物から成形したブリフォームを延伸ブロー成形してなるもので、従来ＰＥＴのブロー成形で用いられている装置を用いることができる。具体的には例えば、射出成形または押出成形で一旦プリフォームを成形し、そのままあるいは口栓部、底部を加工後、それを再加熱し、ホットパリソン法あるいはコールドパリソン法などの二軸延伸ブロー成形法が適用される。この場合の成形温度、具体的には成形機のシリンダー各部およびノズルの温度は通常２６０〜２９０℃の範囲である。延伸温度は通常７０〜１２０℃、好ましくは９０〜１１０℃で、延伸倍率は通常縦方向に１．５〜３．５倍、円周方向に２〜５倍の範囲で行えばよい。得られた中空成形体は、そのまま使用できるが、特に果汁飲料、ウーロン茶などのように熱充填を必要とする飲料の場合には一般的に、さらにブロー金型内で熱固定処理を行い、耐熱性を付与して使用される。熱固定は通常、圧空などによる緊張下、１００〜２００℃、好ましくは１２０〜１８０℃で、数秒〜数時間、好ましくは数秒〜数分間行われる。
【０１２５】
また、口栓部に耐熱性を付与するために、射出成形または押出成形により得られたプリフォ−ムの口栓部を遠赤外線や近赤外線ヒ−タ設置オ−ブン内で結晶化させたり、あるいはボトル成形後に口栓部を前記のヒ−タで結晶化させる。
【０１２６】
また、本発明のポリエステル組成物は、積層成形体や積層フィルム等の一構成層としても用いることが出来る。特に、ＰＥＴとの積層体の形で容器等の製造に使用される。積層成形体の例としては、本発明のポリエステル組成物からなる外層とＰＥＴ内層との二層から構成される二層構造あるいは本発明のポリエステル組成物からなる内層とＰＥＴ外層との二層から構成される二層構造の成形体、本発明のポリエステル組成物を含む中間層とＰＥＴの外層および最内層から構成される三層構造あるいは本発明のポリエステル組成物を含む外層および最内層とＰＥＴの中間層から構成される三層構造の成形体、本発明のポリエステル組成物を含む中間層とＰＥＴの最内層、中心層および最内層から構成される五層構造の成形体等が挙げられる。ＰＥＴ層には、他のガスバリア−性樹脂、紫外線遮断性樹脂、耐熱性樹脂、使用済みポリエチレンテレフタレ−トボトルからの回収品等を適当な割合で混合使用することができる。
【０１２７】
また、その他の積層成形体の例としては、ポリオレフィン等のポリエステル以外の樹脂との積層成形体、紙や金属板等の異種の基材との積層成形体が挙げられる。
前記の積層成形体の厚み及び各層の厚みには特に制限は無い。また前記の積層成形体は、シ−ト状物、フィルム状物、板状物、中空体、容器等、種々の形状で使用可能である。
【０１２８】
前記の積層体の製造は、樹脂層の種類に対応した数の押出機と多層多種ダイスを使用して共押出しにより行うこともできるし、また樹脂層の種類に対応した数の射出機と共射出ランナ−および射出型を使用して共射出により行うこともできる。
本発明のポリエステル組成物は、中空成形体、トレ−、二軸延伸フィルム等の包装材、金属缶被覆用フィルム等として好ましく用いることが出来る。
また、本発明の組成物は、電子レンジおよび／またはオ−ブンレンジ等で食品を調理したり、あるいは冷凍食品を加熱するためのトレイ状容器の用途にも用いることができる。この場合は、ポリエステル組成物からのシ−ト状物をトレイ形状に成形後、熱結晶化させて耐熱性を向上させる。
なお、本発明における、主な特性値の測定法を以下に説明する。
【０１２９】
【実施例】
以下本発明を実施例により具体的に説明するが、本発明はこれらの実施例に限定させるものではない。なお、本明細書中における主な特性値の測定法を以下に説明する。
【０１３０】
（評価方法）
（１）ポリエステルの極限粘度（ＩＶ）
１，１，２，２−テトラクロルエタン／フェノ−ル（２：３重量比）混合溶媒中３０℃での溶液粘度から求めた。
【０１３１】
（２）ポリエステル中に共重合されたジエチレングリコ−ル含有量（以下［ＤＥＧ含有量」という）
メタノ−ルにより分解し、ガスクロマトグラフィ−によりＤＥＧ量を定量し、全グリコ−ル成分に対する割合（モル％）で表した。
【０１３２】
（３）環状エステル３量体の含有量（以下「ＣＴ含有量」という）
試料３００ｍｇをヘキサフルオロイソプロパノ−ル／クロロフォルム混合液（容量比＝２／３）３ｍｌに溶解し、さらにクロロフォルム３０ｍｌを加えて希釈する。これにメタノ−ル１５ｍｌを加えてポリマ−を沈殿させた後、濾過する。濾液を蒸発乾固し、ジメチルフォルムアミド１０ｍｌで定容とし、高速液体クロマトグラフ法により環状エステル３量体を定量した。
【０１３３】
（４）アセトアルデヒド含有量（以下「ＡＡ含有量」という）
試料／蒸留水＝１グラム／２ｃｃを窒素置換したガラスアンプルに入れた上部を溶封し、１６０℃で２時間抽出処理を行い、冷却後抽出液中のアセトアルデヒドを高感度ガスクロマトグラフィ−で測定し、濃度をｐｐｍで表示した。
【０１３４】
（５）ポリエステルの溶融時の環状エステル３量体増加量（△ＣＴ量）
乾燥したポリエステルチップ３ｇをガラス製試験管に入れ、窒素雰囲気下で２９０℃のオイルバスに６０分浸漬させ溶融させる。溶融時の環状エステル３量体増加量は、次式により求める。
溶融時の環状エステル３量体増加量（重量％）＝溶融後の環状エステル３量体含有量（重量％）−溶融前の環状エステル３量体含有量（重量％）
【０１３５】
（６）メタキシリレン基含有ポリアミドの相対粘度（ＲＶ）
試料０．２５ｇを９６％硫酸２５ｍｌに溶解し、この溶液１０ｍｌをオストワルド粘度管にて２０℃で測定、下式より求めた。
ＲＶ＝ｔ／ｔ_０
ｔ_０：溶媒の落下秒数
ｔ ：試料溶液の落下秒数
【０１３６】
（７）メタキシリレン基含有ポリアミドの重量平均分子量（Ｍｗ）、数平均分子量（Ｍｎ）
トリフルオロ酢酸ナトリウムを１０ｍＭの濃度で溶解させたヘキサフルオロイソプロパノール（ＨＦＩＰ）に試料を２ｍｇ／ｍｌの濃度で溶解させたものを測定溶液とし、ゲル浸透型クロマトグラフィー（ＧＰＣ）により測定を行った。測定装置には東ソー（株）製ＨＬＣ−８２２０、カラムにＴＳＫｇｅｌ Ｓｕｐｅｒ ＡＷＭ−Ｈ（６．０ｍｍＩＤ×１５ｃｍ、東ソー（株）製）×２本を用いた。移動相に上記と同一組成のトリフルオロ酢酸ナトリウムを含むＨＦＩＰを用い、注入量２０μｌ、カラム温度４０℃、流速０．３ｍｌ／ｍｉｎの条件で測定を行った。重量平均分子量、数平均分子量、分子量分布の算出は標準ポリメタクリル酸メチル（ＰＭＭＡ）を用いて、ＰＭＭＡ換算で算出した。この際、得られたクロマトグラムからのポリマー成分ピークのベースライン設定において、ベースラインの終点を、同条件で測定した分子量１６８０のＰＭＭＡの保持時間に設定した。
【０１３７】
（８）ポリエステル（Ａ）の溶融粘度（以下、ηＡと称する）、およびメタキシリレン基含有ポリアミド（Ｂ）の溶融粘度（以下、ηＢと称する）（Ｐａ・ｓ）
乾燥したレジンチップを（株）東洋精機製作所製キャピログラフ１Ｂ（キャピラリーダイ 直径１ｍｍ、長さ１０ｍｍ）を用いて、測定温度２９０℃、剪断速度５０〜４０００（ｓｅｃ^−１）の範囲で溶融粘度を測定した。本発明における溶融粘度とは、２９０℃、剪断速度１２００（ｓｅｃ^−１）における溶融粘度（Ｐａ・ｓ）を表す。
【０１３８】
（９）メタキシリレン基含有ポリアミドの末端アミノ基濃度（ＡＥＧ，μｍｏｌ／ｇ）
試料０．５ｇをフェノール／エタノール混合溶媒（容積比４／１）５０ｍｌに室温で溶解させた後、水／エタノール混合溶媒（容積比３／２）２０ｍｌを加え、撹拌する。その後、塩酸を用いて中和滴定を行い、末端アミノ基濃度を求めた。
【０１３９】
（１０）メタキシリレン基含有ポリアミドの末端カルボキシル基濃度（ＣＥＧ，μｍｏｌ／ｇ）
試料０．５ｇにベンジルアルコール２０ｍｌを加え、１７０〜１８０℃のオイルバス中で加熱溶解後、水酸化ナトリウム水溶液で中和滴定を行い、末端カルボキシル基濃度を求めた。
【０１４０】
（１１）メタキシリレン基含有環状アミド１量体の含有量（ＣＭ含有量）（重量％）
試料１００ｍｇをヘキサフルオロイソプロパノ−ル／クロロフォルム混合液（容量比＝２／３）３ｍｌに溶解し、さらにクロロフォルム２０ｍｌを加えて希釈し、メタノ−ル１０ｍｌを加える。これをエバポレ−タにより濃縮し、ジメチルフォルムアミド２０ｍｌに再溶解する。遠心濾過後、高速液体クロマトグラフ法により定量した。
【０１４１】
（１２）段付き成形板の成形
乾燥したポリエステル組成物を名機製作所製Ｍ−１５０Ｃ（ＤＭ）射出成形機により、シリンダー温度２９０℃において、１０℃に冷却した段付き平板金型を用い成形する（スクリュー回転数１２０ｒｐｍ、スクリュー背圧０．５ＭＰａ、冷却時間５０秒、１サイクル７２〜７３秒）。得られた段付き成形板は、２，３，４，５，６，７，８，９，１０，１１ｍｍの厚みの約３ｃｍ×約５ｃｍ角のプレートを階段状に備えたもので、段付き成形板１個の重量は約１４６ｇである。５ｍｍ厚みのプレートはヘイズ（霞度％）測定に使用する。
【０１４２】
（１３）ヘイズ（霞度％）
上記（１２）の成形体（肉厚５ｍｍ）を切り取り、日本電色（株）製ヘイズメーターで測定する。
【０１４３】
（１４）金型汚れの評価
窒素ガスを用いた乾燥機で乾燥したポリエステルの所定量および窒素ガスを用いた乾燥機で乾燥したメタキシリレン基含有ポリアミドチップの所定量を用いて、各機製作所製Ｍ−１５０Ｃ（ＤＭ）射出成型機により樹脂温度２９０℃でプリフォ−ムを成形した。このプリフォ−ムの口栓部を自家製の口栓部結晶化装置で加熱結晶化させた後、コ−ポプラスト社製ＬＢ−０１Ｅ延伸ブロ−成型機を用いて二軸延伸ブロ−成形し、引き続き約１４５℃に設定した金型内で約７秒間熱固定し、１５００ｃｃの中空成形体を得た。同様の条件で２０００本の中空成形体を連続的に延伸ブロ−成形し、その前後における金型表面の状態を目視で観察し、下記のように評価した。
○ ： 連続成形試験の前後において変化なし
△ ： 連続成形試験後にかなり付着物あり
× ： 連続成形試験後に付着物が非常に多い
【０１４４】
（１５）分散相の最大径
上記（１４）で成形して得られる二軸延伸ブロー前のプリフォームの胴部から切片を作成し、四酸化ルテニウム蒸気中で染色処理を行った後、カーボン蒸着を施した。その後、日本電子（株）製ＪＥＭ−２０１０透過型電子顕微鏡を用いて、加速電圧２００ｋＶ、直接倍率１００００倍で分散相を観察し、撮影した写真から分散相の粒径を測った。この際、分散相の観察は視野を替えて５回、異なる場所で観察を行い、その中で最も粒径の大きかった分散相の直径を最大径とした。（なお、延伸された成形体から測定する際は、未延伸部分である口栓部からサンプリングすることも可能である。
【０１４５】
（１６）中空成形体の透明性
（１４）の２０００本成形後に得られた中空成形体の外観を目視で観察し、下記のように評価した。
◎ ： 透明である
○ ： 実用的な範囲で透明であり、未溶融物は見られない
× ： 透明性に劣る、又は未溶融物が見られる
【０１４６】
（１７）官能試験
上記の中空成形体に沸騰した蒸留水を入れ密栓後３０分保持し、室温へ冷却し室温で１ヶ月間放置し、開栓後風味、臭いなどの試験を行った。比較用のブランクとして、蒸留水を使用。官能試験は１０人のパネラーにより次の基準により実施し、平均値で比較した。
（評価基準）
０：異味、臭いを感じない
１：ブランクとの差をわずかに感じる
２：ブランクとの差を感じる
３：ブランクとのかなりの差を感じる
４：ブランクとの非常に大きな差を感じる
【０１４７】
（１８）酸素透過量（ｃｃ／容器１本・２４ｈｒ・ａｔｍ）
Ｍｏｄｅｒｎ Ｃｏｎｔｒｏｌｓ社製酸素透過量測定器ＯＸ−ＴＲＡＮ１００により、１０００ｃｃのボトル１本当りの透過量として２０℃、０％ＲＨで測定した。
【０１４８】
（実施例および比較例に使用したポリエチレンテレフタレ−ト（ＰＥＴ））
試験に用いたＰＥＴ（Ｇｅ残存量＝約４０〜５０ｐｐｍ、リン残存量＝約３０〜３５ｐｐｍ）の特性を表１に示す。これらは、すべて連続溶融重縮合−固相重合装置で重合したものである。
ＰＥＴ（ａ）は、固相重合後イオン交換水中で約９０℃で３時間、熱水処理したものである。
なお、ＰＥＴ（ａ）〜ＰＥＴ（ｃ）のＤＥＧ含有量はすべて約２．７モル％である。
【０１４９】
【表１】

【０１５０】
（実施例および比較例に使用したメタキシリレン基含有ポリアミド（ＭＸＤ６））
【０１５１】
ＭＸＤ６（ｄ）の製造方法
攪拌機、分縮器、温度計、滴下ロートおよび窒素ガス導入管を備えた内容積２５０リットルの調製缶に、精秤したメタキシリレンジアミン２７．６６ｋｇ、アジピン酸２９．６５ｋｇ、を内温８５℃にて調合し、スラリー状の透明な溶液とした。缶内のＰＨ値を７．９５に調製した後、ゲル化抑制剤としてＮａＯＨ ３４．０９ｇ、ＮａＨ_２ＰＯ_２・Ｈ_２Ｏ ２５．８１ｇを投入して１５分攪拌した。その溶液を内容積２７０リットルの反応缶に移送し、缶内温度２６０℃、缶内圧１．０ＭＰａの条件下で攪拌して反応させた。留出する水を系外に除き、缶内温度が２３５℃になった時点で、缶内圧を６０分間かけて常圧に戻した。常圧で攪拌を行い、目標粘度に達した時点で攪拌を停止し、２０分間放置した。その後、反応缶下部の取り出し口より溶融樹脂を取り出し、冷却固化させてストランドカッターにて樹脂チップを得た。得られた樹脂の特性を表２に示す。
【０１５２】
ＭＸＤ６（ｅ）の製造方法
缶内のＰＨ値を７．２０に調製した以外は、ＭＸＤ６（ｄ）の製造方法と同様にして樹脂チップを得た。得られた樹脂の特性を表２に示す。
【０１５３】
ＭＸＤ６（ｆ）の製造方法
缶内のＰＨ値を７．０６に調製した以外は、ＭＸＤ６（ｄ）の製造方法と同様にして樹脂チップを得た。得られた樹脂の特性を表２に示す。
【０１５４】
ＭＸＤ６（ｇ）の製造方法
缶内のＰＨ値を６．９２に調製した以外は、ＭＸＤ６（ｄ）の製造方法と同様にして樹脂チップを得た。得られた樹脂の特性を表２に示す。
【０１５５】
ＭＸＤ６（ｈ）の製造方法
攪拌機、分縮器、温度計、滴下ロートおよび窒素ガス導入管を備えた内容積２５０リットルの調製缶に、精秤したメタキシリレンジアミン２７．６６ｋｇ、アジピン酸２９．６５ｋｇ、を内温９０℃にて調合し、スラリー状の透明な溶液とした。缶内のＰＨ値を７．０２に調製した後、ゲル化抑制剤としてＮａＯＨ ３４．０９ｇ、ＮａＨ_２ＰＯ_２・Ｈ_２Ｏ ２５．８１ｇを投入して１５分攪拌した。その溶液を内容積２７０リットルの反応缶に移送し、缶内温度２６５℃、缶内圧１．０ＭＰａの条件下で攪拌して反応させた。留出する水を系外に除き、缶内温度が２３５℃になった時点で、缶内圧を６０分間かけて常圧に戻した。常圧で攪拌を行い、目標粘度に達した時点で攪拌を停止し、２０分間放置した。その後、反応缶下部の取り出し口より溶融樹脂を取り出し、冷却固化させてストランドカッターにて樹脂チップを得た。得られた樹脂の特性を表２に示す。
【０１５６】
【表２】

【０１５７】
（実施例１）
ＰＥＴ（ａ）１００重量部に対してＭＸＤ６（ｄ）０．５重量部を用いて、評価方法（１４）の方法により中空成形体を成形し、その成形体のＣＴ含有量、ＣＭ含有量、ＡＡ含有量を測定した。また金型汚れ評価も行った。
得られた中空成形体の特性及び金型汚れ評価結果を表３に示す。
透過型電子顕微鏡による観察の結果、ＭＸＤ６が分散相を形成しており、その最大径は３００ｎｍであった。中空成形体のＡＡ含有量は８ｐｐｍ、官能試験評価は０．７、外観は実用的な範囲で透明であり、また金型汚れは認められなかった。
【０１５８】
（実施例２）
ＰＥＴ（ａ）１００重量部に対してＭＸＤ６（ｄ）３．０重量部を用いて、評価方法（１４）の方法により中空成形体を成形し、その成形体のＣＴ含有量、ＣＭ含有量、ＡＡ含有量を測定した。また金型汚れ評価も行った。
得られた中空成形体の特性及び金型汚れ評価結果を表３に示す。
透過型電子顕微鏡による観察の結果、ＭＸＤ６が分散相を形成しており、その最大径は３１０ｎｍであった。中空成形体のＡＡ含有量は７ｐｐｍ、官能試験評価は０．６、外観は実用的な範囲で透明であり、また金型汚れは認められなかった。
【０１５９】
（実施例３）
ＰＥＴ（ａ）１００重量部に対してＭＸＤ６（ｄ）２０．０重量部を用いて、評価方法（１４）の方法により中空成形体を成形し、その成形体のＣＴ含有量、ＣＭ含有量、ＡＡ含有量を測定した。また金型汚れ評価も行った。
得られた中空成形体の特性及び金型汚れ評価結果を表３に示す。
透過型電子顕微鏡による観察の結果、ＭＸＤ６が分散相を形成しており、その最大径は３００ｎｍであった。中空成形体のＡＡ含有量は６ｐｐｍ、官能試験評価は０．６、酸素透過量は０．２０ｃｃ／容器１本・２４ｈｒ・ａｔｍ、外観は実用的な範囲で透明であり、また金型汚れは認められなかった。
【０１６０】
（実施例４）
ＰＥＴ（ｃ）１００重量部に対してＭＸＤ６（ｅ）０．５重量部を用いて、評価方法（１４）の方法により中空成形体を成形し、その成形体のＣＴ含有量、ＣＭ含有量、ＡＡ含有量を測定した。また金型汚れ評価も行った。
得られた中空成形体の特性及び金型汚れ評価結果を表３に示す。
透過型電子顕微鏡による観察の結果、ＭＸＤ６が分散相を形成しており、その最大径は３５０ｎｍであった。中空成形体のＡＡ含有量は１０ｐｐｍ、官能試験評価は０．７、外観は実用的な範囲で透明であり、また金型汚れは認められなかった。
【０１６１】
（比較例１）
ＰＥＴ（ａ）１００重量部に対してＭＸＤ６（ｅ）１．０重量部を用いて、評価方法（１４）の方法により中空成形体を成形し、その成形体のＣＴ含有量、ＣＭ含有量、ＡＡ含有量を測定した。また金型汚れ評価も行った。
得られた中空成形体の特性及び金型汚れ評価結果を表３に示す。
透過型電子顕微鏡による観察の結果、ＭＸＤ６が分散相を形成しており、その最大径は５６０ｎｍであった。中空成形体のＡＡ含有量は９ｐｐｍと低く、官能試験評価は０．８、金型汚れも認められなかったが、透明性が悪く、実用性に乏しかった。
【０１６２】
（比較例２）
ＰＥＴ（ａ）１００重量部に対してＭＸＤ６（ｆ）１．０重量部を用いて、評価方法（１４）の方法により中空成形体を成形し、その成形体のＣＴ含有量、ＣＭ含有量、ＡＡ含有量を測定した。また金型汚れ評価も行った。
得られた中空成形体の特性及び金型汚れ評価結果を表３に示す。
透過型電子顕微鏡による観察の結果、ＭＸＤ６が分散相を形成しており、その最大径は６４０ｎｍであった。中空成形体の金型汚れは認められなかったが、ＡＡ含有量は１７ｐｐｍ、官能試験評価は２．１とブランクの蒸留水と差があった。また、透明性が悪く、実用性に乏しかった。
【０１６３】
（比較例３）
ＰＥＴ（ａ）１００重量部に対してＭＸＤ６（ｇ）０．５重量部を用いて、評価方法（１４）の方法により中空成形体を成形し、その成形体のＣＴ含有量、ＣＭ含有量、ＡＡ含有量を測定した。また金型汚れ評価も行った。
得られた中空成形体の特性及び金型汚れ評価結果を表３に示す。
透過型電子顕微鏡による観察の結果、ＭＸＤ６が分散相を形成しており、その最大径は５５０ｎｍであった。中空成形体の金型汚れは認められなかったが、ＡＡ含有量は１９ｐｐｍ、官能試験評価は２．３とブランクの蒸留水と差があった。また、透明性が悪く、実用性に乏しかった。
【０１６４】
（比較例４）
ＰＥＴ（ｂ）１００重量部に対してＭＸＤ６（ｄ）０．５重量部を用いて、評価方法（１４）の方法により中空成形体を成形し、その成形体のＣＴ含有量、ＣＭ含有量、ＡＡ含有量を測定した。また金型汚れ評価も行った。
得られた中空成形体の特性及び金型汚れ評価結果を表３に示す。
透過型電子顕微鏡による観察の結果、ＭＸＤ６が分散相を形成しており、その最大径は３４０ｎｍであった。中空成形体のＡＡ含有量は９ｐｐｍ、官能試験評価は０．９であったが、透明性が悪く、実用性に乏しかった。また、金型汚れにかなり付着物が認められた。
【０１６５】
（比較例５）
ＰＥＴ（ｂ）１００重量部に対してＭＸＤ６（ｇ）３．０重量部を用いて、評価方法（１４）の方法により中空成形体を成形し、その成形体のＣＴ含有量、ＣＭ含有量、ＡＡ含有量を測定した。また金型汚れ評価も行った。
得られた中空成形体の特性及び金型汚れ評価結果を表３に示す。
透過型電子顕微鏡による観察の結果、ＭＸＤ６が分散相を形成しており、その最大径は５８０ｎｍであった。中空成形体のＡＡ含有量は２３ｐｐｍ、官能試験評価は２．７とブランクの蒸留水と差があり、金型汚れにかなり付着物が認められた。また、透明性が悪く、実用性に乏しかった。
【０１６６】
（比較例６）
ＰＥＴ（ｃ）１００重量部に対してＭＸＤ６（ｆ）０．５重量部を用いて、評価方法（１４）の方法により中空成形体を成形し、その成形体のＣＴ含有量、ＣＭ含有量、ＡＡ含有量を測定した。また金型汚れ評価も行った。
得られた中空成形体の特性及び金型汚れ評価結果を表３に示す。
透過型電子顕微鏡による観察の結果、ＭＸＤ６が分散相を形成しており、その最大径は５４０ｎｍであった。中空成形体の金型汚れは認められなかったが、ＡＡ含有量は２０ｐｐｍと高く、官能試験評価は２．６とブランクの蒸留水と差があった。また、透明性が悪く、実用性に乏しかった。
【０１６７】
（比較例７）
ＰＥＴ（ｃ）１００重量部に対してＭＸＤ６（ｇ）１．０重量部を用いて、評価方法（１４）の方法により中空成形体を成形し、その成形体のＣＴ含有量、ＣＭ含有量、ＡＡ含有量を測定した。また金型汚れ評価も行った。
得られた中空成形体の特性及び金型汚れ評価結果を表３に示す。
透過型電子顕微鏡による観察の結果、ＭＸＤ６が分散相を形成しており、その最大径は３７０ｎｍであった。中空成形体の外観は実用的な範囲で透明であり、金型汚れも認められなかったが、ＡＡ含有量は２２ｐｐｍと高く、官能試験評価も２．７とブランクの蒸留水との差があった。
【０１６８】
（比較例８）
ＰＥＴ（ｃ）１００重量部に対してＭＸＤ６（ｈ）０．５重量部を用いて、評価方法（１４）の方法により中空成形体を成形し、その成形体のＣＴ含有量、ＣＭ含有量、ＡＡ含有量を測定した。また金型汚れ評価も行った。
得られた中空成形体の特性及び金型汚れ評価結果を表３に示す。
透過型電子顕微鏡による観察の結果、ＭＸＤ６が分散相を形成しており、その最大径は５６０ｎｍであった。中空成形体の金型汚れは認められなかったが、ＡＡ含有量は１９ｐｐｍと高く、官能試験評価は２．５とブランクの蒸留水と差があった。また、透明性が悪く、実用性に乏しかった。
【０１６９】
（比較例８）
ＰＥＴ（ａ）のみを用いて、評価方法（１４）の方法により中空成形体を成形し、また金型汚れ評価も行った。
得られた中空成形体の特性及び金型汚れ評価結果を表３に示す。
【０１７０】
【表３】

【０１７１】
【発明の効果】
本発明のポリエステル組成物によれば、香味保持性、および透明性に優れ、さらには成形時での金型汚れを発生させにくい中空成形体やシ−ト状物および延伸フィルムが得られる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a polyester composition suitably used as a material for molded articles such as hollow bottles such as beverage bottles, films, sheets and the like, and a flavor retaining property (flavor property) and transparency comprising the polyester composition. It relates to an excellent molded product. Further, the present invention provides a polyester composition with less mold stain when molding a hollow molded article.
[0002]
[Prior art]
Polyesters such as polyethylene terephthalate (hereinafter sometimes abbreviated as PET) are excellent in both mechanical properties and chemical properties, and therefore have high industrial value, and can be used as fibers, films, sheets and bottles. Widely used as such.
[0003]
Various resins are employed as materials for containers such as seasonings, oils, beverages, cosmetics, and detergents depending on the type of filling content and the purpose of use.
[0004]
Of these, polyester is excellent in mechanical strength, heat resistance, transparency and gas barrier properties, and is particularly suitable as a material for molded articles such as beverage filling containers such as juices, soft drinks, and carbonated drinks. .
[0005]
For example, such a polyester is supplied to a molding machine such as an injection molding machine to form a preform for a hollow molded body, and the preform is inserted into a mold having a predetermined shape, stretch-blown, and then bottled. Is generally heat-treated (heat-set) to form a hollow molded container, and if necessary, the plug portion of the bottle is heat-treated (plug portion crystallization).
[0006]
However, PET contains acetaldehyde (hereinafter sometimes abbreviated as AA) as a by-product during melt polycondensation. In addition, PET generates acetaldehyde by thermal decomposition during thermoforming of a molded article such as a hollow molded article, and the acetaldehyde content in the material of the obtained molded article increases, and the PET is filled in the hollow molded article or the like. Affects flavor and smell of beverages.
[0007]
Therefore, various measures have conventionally been taken to reduce the acetaldehyde content in the polyester molded article. Generally, a method of lowering the AA content by solid-state polymerization of a melt-polycondensed polyester, a method of lowering AA production during molding using a copolymerized polyester having a lower melting point, A method of reducing the molding temperature as much as possible and a method of reducing the shear stress at the time of thermoforming as much as possible have been adopted.
[0008]
In recent years, containers made of polyester, mainly polyethylene terephthalate, have come to be used as containers for low-flavor beverages such as mineral water and Wurong tea. In the case of such beverages, these beverages are generally heat-filled or sterilized by heating after filling, but the content of these containers is reduced only by reducing the AA content in the polyester molded material by the above-mentioned method. It has been found that the flavor and odor of the rice are not improved.
[0009]
Further, for example, a method of using a polyester composition in which a metaxylylene group-containing polyamide resin is added in an amount of 0.05 part by weight or more and less than 1 part by weight with respect to 100 parts by weight of a polyester resin (for example, see Patent Document 1), A polyester container made of a polyester composition containing a specific polyamide having a terminal amino group concentration controlled within a certain range (for example, see Patent Document 2) has been proposed. It has been found that in some cases, it is not sufficient as a material for containers for flavored beverages.
[0010]
For example, a method using a polyester composition in which a metaxylylene group-containing polyamide resin is added in an amount of 0.05 part by weight or more and less than 1 part by weight with respect to 100 parts by weight of a polyester resin is used (for example, see Patent Document 3). No particular mention is made of the relative viscosity and terminal group concentration of the metaxylylene group-containing polyamide, and it has been found that the polyamide is sometimes insufficient as a material for low-flavor beverage containers such as mineral water. .
[0011]
Further, a thermoplastic polyester, a polyester container comprising a polyester composition containing a specific polyamide whose terminal amino group concentration is regulated to a certain range, the relative viscosity of the polyamide as a range having a general film forming ability (For example, see Patent Document 4), but when a transparent beverage container such as a mineral water is formed using a polyamide having a relative viscosity actually applied within the range, a polyester obtained is obtained. In some cases, the composition has poor transparency and poor practicality.
[0012]
In order to solve such problems, for example, we have proposed a polyester hollow molded article containing 1 to 100 parts by weight of a metaxylylene group-containing polyamide resin with respect to 100 parts by weight of a polyester resin (for example, Patent Reference 5). However, when producing a heat-resistant hollow molded article using such a polyester composition, the monomer and oligomer components contained in the polyester composition migrate and accumulate on the mold surface, and the appearance of the hollow molded article is reduced. There was a problem of damage. In addition, troublesome cleaning of the mold must be frequently performed, and there is a problem that productivity is reduced.
[0013]
[Patent Document 1]
Japanese Patent Publication No. 6-6662
[Patent Document 2]
Japanese Patent Publication No. 4-71425
[Patent Document 3]
Japanese Patent Publication No. 6-6662
[Patent Document 4]
Japanese Patent Publication No. 4-71425
[Patent Document 5]
Japanese Patent Publication No. 4-54702
[0014]
[Problems to be solved by the invention]
An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a polyester composition having excellent flavor retention and transparency. Another object of the present invention is to provide a polyester composition that does not easily cause mold stains during molding.
[0015]
[Means for Solving the Problems]
The present inventors have conducted intensive studies to achieve the above object, and as a result, a polyester composition obtained by melt-mixing a polyester (A) whose main repeating unit is ethylene terephthalate and a polyamide containing a meta-xylylene group (B). It has been found that by setting the maximum diameter of the dispersed phase in the polyester composition before stretching to 400 nm or less, a polyester composition excellent in flavor retention and transparency can be obtained.
[0016]
In addition, when such different resins are melt-mixed, it is general theory that the closer the ratio of the melt viscosities to each other to 1, the easier it is to disperse. However, in the present invention, the polyester (A) and the metaxylylene group-containing polyamide ( It has been found that the maximum diameter of the dispersed phase in the polyester composition is easily reduced to 400 nm or less by setting the ratio of the melt viscosity of B) to a certain range apart from 1.
[0017]
That is, in the polyester composition of the present invention, 100 parts by weight of a polyester (A) whose main repeating unit is ethylene terephthalate and 0.01 to 30 parts by weight of a metaxylylene group-containing polyamide (B) are melt-mixed. The obtained polyester composition, wherein the maximum diameter of the dispersed phase in the polyester composition before stretching is 400 nm or less.
[0018]
In this case, the ratio of the melt viscosity of the polyester (A) and the meta-xylylene group-containing polyamide (B) at 290 ° C. [the melt viscosity of the meta-xylylene group-containing polyamide (B) / the melt viscosity of the polyester (A)] is 0.001. Or more and 0.3 or less.
[0019]
In this case, the meta-xylylene group-containing polyamide (B) can satisfy both of the following formulas (1) and (2).
AEG + CEG ≧ 150 (1)
AEG / CEG ≧ 2.0 (2)
(In the formulas (1) and (2), AEG represents the terminal amino group concentration (μmol / g) of the metaxylylene group-containing polyamide, and CEG represents the terminal carboxyl group concentration (μmol / g) of the metaxylylene group-containing polyamide.)
[0020]
In this case, the acetaldehyde content in the polyester composition can be 15 ppm or less.
[0021]
In this case, the content of the cyclic ester trimer contained in the polyester (A) whose main repeating unit is ethylene terephthalate can be 0.7% by weight or less.
[0022]
In this case, when the polyester (A) whose main repeating unit is ethylene terephthalate is melted at a temperature of 290 ° C. for 60 minutes, the cyclic ester trimer increases by 0.50% by weight or less. There can be.
[0023]
In this case, a molded article is obtained by molding the polyester composition according to any one of the above 1 to 6.
[0024]
In this case, the content of the meta-xylylene group-containing cyclic amide monomer in the molded product obtained by molding the polyester composition according to any one of the above 1 to 6 can be 0.5% by weight or less.
[0025]
In this case, the haze of a molded product having a thickness of 5 mm obtained by molding the polyester composition according to any one of the above 1 to 6 at 290 ° C. can be 20% or less.
[0026]
In this case, the molded article can be a hollow molded article.
In this case, the molded article may be a sheet.
In this case, the molded article may be a stretched film obtained by stretching the sheet-like material in at least one direction.
[0027]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the polyester composition of the present invention and a molded article made thereof will be described in detail.
The polyester (A) used in the present invention is a polyester whose main repeating unit is ethylene terephthalate, preferably a linear polyester containing at least 85 mol% of ethylene terephthalate units, more preferably It is a linear polyester containing at least 90 mol%, particularly preferably at least 95%.
[0028]
Examples of the dicarboxylic acid used as a copolymer component when the polyester is a copolymer include isophthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyl-4,4′-dicarboxylic acid, and diphenoxyethanedicarboxylic acid. Aromatic dicarboxylic acids such as acids and functional derivatives thereof, p-oxybenzoic acid, oxyacids such as oxycaproic acid and functional derivatives thereof, adipic acid, sebacic acid, succinic acid, aliphatic dicarboxylic acids such as glutaric acid and Examples thereof include functional derivatives thereof, aliphatic dicarboxylic acids such as cyclohexanedicarboxylic acid, and functional derivatives thereof.
[0029]
Examples of the glycol used as a copolymer component when the polyester is a copolymer include aliphatic glycols such as diethylene glycol, trimethylene glycol, tetramethylene glycol, and neopentyl glycol. And alicyclic glycols such as cyclohexanedimethanol, and aromatic glycols such as bisphenol A and alkylene oxide adducts of bisphenol A.
[0030]
Examples of the polyfunctional compound as a copolymer component used when the polyester is a copolymer include trimellitic acid and pyromellitic acid as acid components, and glycerin as a glycol component. And pentaerythritol. The amount of the above-mentioned copolymer component to be used must be such that the polyester maintains a substantially linear shape. Further, a monofunctional compound such as benzoic acid or naphthoic acid may be copolymerized.
[0031]
The above-mentioned polyester is obtained by directly reacting terephthalic acid with ethylene glycol and, if necessary, the above-mentioned copolymerization component to distill off water and esterify it, and then as an Sb compound, Ge compound, Ti compound or Al compound as a polycondensation catalyst. A direct esterification method in which one or more compounds selected from compounds are subjected to polycondensation under reduced pressure, or dimethyl terephthalate and ethylene glycol and, if necessary, the above copolymerization component in the presence of a transesterification catalyst After the methyl alcohol is distilled off and subjected to transesterification, one or more compounds selected from Sb compounds, Ge compounds, Ti compounds and Al compounds are used as polycondensation catalysts, mainly under reduced pressure. It is produced by a transesterification method of performing polycondensation on
Further, solid-state polymerization may be performed to increase the intrinsic viscosity of the polyester and reduce the acetaldehyde content.
[0032]
The above-mentioned esterification reaction, transesterification reaction, melt polycondensation reaction and solid-state polymerization reaction may be performed in a batch reactor or a continuous reactor. In any of these methods, the melt polycondensation reaction may be performed in one stage or may be performed in multiple stages. The solid-state polymerization reaction can be performed in a batch-type apparatus or a continuous-type apparatus as in the case of the melt polycondensation reaction. The melt polycondensation and the solid phase polymerization may be performed continuously or may be performed separately.
[0033]
The Sb compound used in the production of the polyester (A) used in the present invention includes antimony trioxide, antimony acetate, antimony tartrate, antimony potassium tartrate, antimony oxychloride, antimony glycolate, antimony pentoxide, triphenyl Antimony and the like. The Sb compound is added so that the residual amount of Sb in the produced polymer is in the range of 50 to 250 ppm.
[0034]
Examples of the Ge compound used for producing the polyester (A) used in the present invention include amorphous germanium dioxide, crystalline germanium dioxide, germanium chloride, germanium tetraethoxide, germanium tetra-n-butoxide, germanium phosphite and the like. Is mentioned. When a Ge compound is used, the amount of the Ge compound used is 5 to 150 ppm, preferably 10 to 100 ppm, more preferably 15 to 70 ppm as the amount of Ge remaining in the polyester.
[0035]
Examples of the Ti compound used for producing the polyester (A) used in the present invention include tetraethyl titanate, tetraisopropyl titanate, tetra-n-propyl titanate and tetra-n-butyl titanate. Tetraalkyl titanates and their partial hydrolysates, titanyl oxalate, titanyl ammonium oxalate, sodium titanyl oxalate, potassium titanyl oxalate, calcium titanyl oxalate, titanyl oxalate compounds such as strontium titanyl oxalate, titanium trimellitate, titanium sulfate, Titanium chloride and the like can be mentioned. The Ti compound is added so that the residual amount of Ti in the produced polymer is in the range of 0.1 to 10 ppm.
[0036]
Examples of the Al compound used in the production of the polyester (A) used in the present invention include carboxylic acid salts such as aluminum formate, aluminum acetate, aluminum propionate, and aluminum oxalate, oxides, aluminum hydroxide, aluminum chloride, and the like. Inorganic acid salts such as aluminum hydroxide chloride and aluminum carbonate; aluminum alkoxides such as aluminum methoxide and aluminum ethoxide; aluminum chelate compounds with aluminum acetylacetonate and aluminum acetyl acetate; trimethylaluminum And organoaluminum compounds such as triethylaluminum and partial hydrolysates thereof. Of these, aluminum acetate, aluminum chloride, aluminum hydroxide, aluminum hydroxide chloride, and aluminum acetylacetonate are particularly preferred. The Al compound is added so that the residual amount of Al in the produced polymer is in the range of 5 to 200 ppm.
[0037]
In the case of an Al compound, an alkali metal compound or an alkaline earth metal compound may be used in combination. The alkali metal compound or alkaline earth metal compound includes carboxylate such as acetate of these elements, alkoxide and the like, and is added to the reaction system as powder, aqueous solution, ethylene glycol solution and the like. The alkali metal compound or alkaline earth metal compound is added so that the residual amount of these elements in the resulting polymer is in the range of 1 to 50 ppm.
[0038]
The catalyst compound can be added at any stage of the polyester production reaction step.
Also, various phosphorus compounds can be used as stabilizers. Examples of the phosphorus compound used in the present invention include phosphoric acid, phosphorous acid, phosphonic acid and derivatives thereof. Specific examples include phosphoric acid, trimethyl phosphate, triethyl phosphate, tributyl phosphate, triphenyl phosphate, monomethyl phosphate, dimethyl phosphate, monobutyl phosphate, dibutyl phosphate, and dibutyl phosphate. Phosphoric acid, trimethyl phosphite, triethyl phosphite, tributyl phosphite, methyl phosphonic acid, methyl dimethyl phosphonate, dimethyl ethyl phosphonate, dimethyl phenyl phosphonate, diethyl phenyl phosphonate, diethyl phenyl -Diphosphonic acid diphenyl ester and the like, which may be used alone or in combination of two or more. The phosphorus compound is added at any stage of the polyester production reaction step so that the residual amount of phosphorus in the produced polymer is in the range of 5 to 100 ppm.
[0039]
The intrinsic viscosity of the polyester (A) used in the present invention is preferably 0.55 to 1.30 deciliter / gram, the lower limit is more preferably 0.58 deciliter / gram, and still more preferably 0.60 deciliter / gram, and the upper limit. Is more preferably 1.10 deciliter / gram, and even more preferably 0.90 deciliter / gram. If the intrinsic viscosity is less than 0.55 deciliter / gram, the obtained molded article may have poor mechanical properties. On the other hand, if it exceeds 1.30 deciliters / gram, the resin temperature may increase during melting by a molding machine or the like, resulting in intense thermal decomposition. Problems such as the molded article being colored yellow may occur.
[0040]
The shape of the polyester (A) chip used in the present invention may be any of a cylinder type, a square type, a spherical shape, a flat plate shape and the like. The average particle size is usually in the range of 1.3 to 5 mm, preferably 1.5 to 4.5 mm, and more preferably 1.6 to 4.0 mm. For example, in the case of a cylinder type, it is practical that the length is about 1.3 to 4 mm and the diameter is about 1.3 to 4 mm. In the case of spherical particles, it is practical that the maximum particle diameter is 1.1 to 2.0 times the average particle diameter and the minimum particle diameter is 0.7 times or more the average particle diameter. The practical weight of the chip is in the range of 10 to 30 mg / piece.
[0041]
The density of the polyester (A) used in the present invention is 1.33 to 1.43 mg / cm.³, Preferably 1.37 to 1.42 mg / cm³Range.
[0042]
In general, polyesters contain significant amounts of the co-components generated during the manufacturing process and the fines whose co-component content is the same as the polyester chips. Such fines have the property of accelerating the crystallization of polyester, and when present in a large amount, the transparency of a molded article molded from such polyester becomes extremely poor, and in the case of a bottle, However, the amount of shrinkage at the time of crystallization of the bottle stopper does not fall within the specified value range, and the bottle cannot be sealed with the cap.
[0043]
Therefore, the content of fines in the polyester (A) used in the present invention is desirably 500 ppm or less, preferably 300 ppm or less. If the content exceeds 500 ppm, the crystallization rate is increased, for example, the crystallization of the plug portion of the hollow molded container becomes excessively large, so that the shrinkage amount of the plug portion does not fall within the range of the specified value, Poor capping of the plug may result in leakage of the contents or whitening of the preform for hollow molding, which may make normal stretching impossible.
[0044]
Further, the metaxylylene group-containing polyamide (B) used in the present invention is produced from metaxylylenediamine or a mixed xylylenediamine containing metaxylylenediamine and 30% or less of the total amount of paraxylylenediamine and dicarboxylic acid. It is a polyamide resin containing at least 70 mol%, more preferably at least 75 mol%, particularly preferably at least 80 mol% in the molecular chain.
[0045]
Examples of the dicarboxylic acid as a copolymerization component include adipic acid, sebacic acid, malonic acid, succinic acid, glutaric acid, pimelic acid, stearic acid, azelaic acid, undecanoic acid, undecadionic acid, dodecandioic acid, and dimer acid. Alicyclic dicarboxylic acids such as aliphatic dicarboxylic acids and 1,4-cyclohexanedicarboxylic acid, and aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, xylylenedicarboxylic acid, and naphthalenedicarboxylic acid can be used.
[0046]
Further, as a diamine component as a copolymer component, ethylenediamine, 1-methylethylenediamine, 1,3-propylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, Aliphatic diamines such as decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, alicyclic diamines such as cyclohexanediamine, bis- (4,4'-aminohexyl) methane, para-bis- (2-amino Aromatic diamines such as ethyl) benzene and alicyclic diamines such as 1,3-bisaminomethylcyclohexane and 1,4-bisaminomethylcyclohexane can be used.
These dicarboxylic acids and diamines can be used alone or in combination of two or more kinds at an arbitrary ratio.
[0047]
In addition to diamines and dicarboxylic acids, lactams such as ε-caprolactam and laurolactam, aminocaproic acids, aminocarboxylic acids such as aminoundecanoic acid, and aromatic aminocarboxylic acids such as para-aminomethylbenzoic acid are also included. It can be used as a copolymer component. In particular, use of ε-caprolactam is desirable.
[0048]
Examples of these polymers include homopolymers such as polymetaxylylene adipamide, polymetaxylylene sebacamide, polymetaxylylene speramide, etc., and metaxylylenediamine / adipic / isophthalic acid copolymers, metaxylylene / P-xylylene adipamide copolymer, meta-xylylenediamine / adipic acid / terephthalic acid copolymer, meta-xylylene diamine / hexamethylenediamine / adipic acid copolymer, meta-xylylenediamine / hexamethylenediamine / terephthal An acid copolymer, a metaxylylenediamine / hexamethylenediamine / isophthalic acid copolymer, a metaxylylene / paraxylylenepiperamide copolymer, a metaxylylene / paraxylyleneazeramide copolymer, and the like can be given.
[0049]
The sodium atom content in the metaxylylene group-containing polyamide (B) used in the present invention is preferably in the range of 0.01 to 1000 ppm. The lower limit is more preferably 0.1 ppm, and still more preferably 1.0 ppm. The upper limit is more preferably 900 ppm, and even more preferably 800 ppm. When the sodium atom content in the meta-xylylene group-containing polyamide (B) is less than 0.01 ppm, gelation tends to proceed, as described later, when producing a heat-resistant hollow molded body using a polyester composition. Unmelted material is easily generated. Further, even if there is no undissolved material, the molecular weight distribution is easily widened and the melt viscosity is increased. Further, when the sodium atom content in the metaxylylene group-containing polyamide (B) is more than 1000 ppm, not only the transparency of the molded product obtained from the polyester composition becomes poor, but also the molecular weight of the polyester composition decreases, and the obtained product is obtained. In some cases, the mechanical strength of the molded body is reduced.
[0050]
The sodium atom content in the metaxylylene group-containing polyamide (B) used in the present invention is determined by atomic absorption spectrometry, emission spectrometry, inductively coupled plasma (hereinafter abbreviated as ICP) emission spectrometry, ICP mass spectrometry, fluorescence X It is determined by a line analysis method or the like, and can be used properly depending on the concentration of sodium atoms.
[0051]
The relative viscosity (RV) of the meta-xylylene group-containing polyamide (B) used in the present invention is preferably in the range of 1.3 to 2.1. The lower limit is more preferably 1.5, and the upper limit is more preferably 2.0. If the relative viscosity is less than 1.3, the molecular weight is too small, and the mechanical properties of a molded article made of the polyester composition of the present invention may be poor. Further, when the meta-xylylene group-containing polyamide (B) is taken out of the polymerization can, cooled and applied to a strand cutter, not only the resin chip size becomes non-uniform, but also a large amount of fines are generated, so that the production efficiency is poor, Not preferred. On the other hand, if the relative viscosity is larger than 2.1, the transparency of the hollow molded article obtained from the polyester composition of the present invention is poor, and the practical use may be poor.
[0052]
The molecular weight distribution of the meta-xylylene group-containing polyamide (B) used in the present invention (weight average molecular weight of meta-xylylene group-containing polyamide (B) / number average molecular weight of meta-xylylene group-containing polyamide (B)) is 1.7 to 2.5. Is preferably within the range. When the molecular weight distribution of the meta-xylylene group-containing polyamide (B) is less than 1.7, the decrease in melt viscosity at high shear is small, and the ratio of the melt viscosity at 290 ° C. of the polyester (A) and the meta-xylylene group-containing polyamide (B) is small. Therefore, the transparency of the hollow molded article obtained from the polyester composition of the present invention may be poor. When the molecular weight distribution is larger than 2.5, the crystallization behavior of a molded article obtained from the polyester composition of the present invention becomes unstable, and dimensional variations occur, which may lower the productivity. As described above, depending on the molecular weight distribution of the meta-xylylene group-containing polyamide (B), the ratio of the melt viscosity at the time of melt-mixing may be different. Therefore, to obtain the polyester composition of the present invention, the meta-xylylene group-containing polyamide (B ) May not be controlled only by the relative viscosity (RV).
[0053]
Further, the terminal group concentration of the metaxylylene group-containing polyamide (B) used in the present invention is represented by the following formula (3).
AEG + CEG ≧ 150 (3)
(In the formula (3), AEG represents the terminal amino group concentration (μmol / g) of the meta-xylylene group-containing polyamide, and CEG represents the terminal carboxyl group concentration (μmol / g) of the meta-xylylene group-containing polyamide.) preferable. More preferably, AEG + CEG ≧ 160, even more preferably AEG + CEG ≧ 180. When the total terminal group concentration (AEG + CEG) comprising the terminal carboxyl group concentration and the terminal amino group concentration in the meta-xylylene group-containing polyamide is smaller than 150 (μmol / g), the flavor retention of the hollow molded article obtained from the polyester composition of the present invention is maintained. In some cases, it becomes poor in practicality as a beverage container for low flavor.
[0054]
The terminal group concentration of the metaxylylene group-containing polyamide (B) used in the present invention is represented by the following formula (4).
AEG / CEG ≧ 2.0 (4)
(In the formula (4), AEG represents the terminal amino group concentration (μmol / g) of the metaxylylene group-containing polyamide, and CEG represents the terminal carboxyl group concentration (μmol / g) of the metaxylylene group-containing polyamide.)
Is preferably within the range. More preferably, AEG / CEG ≧ 3.0, and still more preferably, AEG / CEG ≧ 5.0. If the ratio of the terminal amino group concentration to the terminal carboxyl group concentration (AEG / CEG) in the metaxylylene group-containing polyamide is smaller than 2.0, the hollow molded article obtained from the polyester composition of the present invention has poor flavor retention, It may not be practical as a beverage container for low flavor.
[0055]
The meta-xylylene group-containing polyamide is obtained by heating and reacting an aqueous solution of an aminocarboxylic acid salt formed from a diamine and a dicarboxylic acid under pressure and normal pressure, or by directly reacting a diamine and a dicarboxylic acid by heating under normal pressure. Can be manufactured. In particular, the metaxylylene group-containing polyamide used in the present invention can adjust the terminal group concentration by adding an excess of diamine to dicarboxylic acid. In addition, by subjecting the polyamide chips obtained by the melt polycondensation reaction to solid-phase polymerization, it is possible to obtain a metaxylylene group-containing polyamide having a higher viscosity.
The polycondensation reaction of the above-mentioned meta-xylylene group-containing polyamide may be carried out in a batch reactor or a continuous reactor.
[0056]
Usually, in the production of a meta-xylylene group-containing polyamide (B), in order to prevent gelation due to thermal deterioration, polymerization is often performed by adding a phosphorus-based stabilizer.
Assuming that the phosphorus atom content in the meta-xylylene group-containing polyamide (B) used in the present invention is X, the content is preferably in the range of 0.01 ≦ X ≦ 400 ppm. The lower limit is more preferably 0.1 ppm, even more preferably 1 ppm, particularly preferably 3 ppm, and most preferably 5 ppm. The upper limit is preferably 380 ppm, more preferably 350 ppm. When X is less than 0.01 ppm, when producing a heat-resistant hollow molded article using the polyester composition, burn streaks and unmelted substances are likely to be generated. In addition, thermal deterioration during molding is large, and no effect as a stabilizer can be found. On the other hand, when X is more than 400 ppm, although the thermal stability is excellent, the transparency of the obtained hollow molded article may be deteriorated. In particular, when an Sb-based compound is added to PET used as a polymerization catalyst or an additive, blackening that is considered to be derived from metal Sb occurs, and the transparency may be significantly deteriorated.
[0057]
As the compound containing a phosphorus atom in the metaxylylene group-containing polyamide (B), it is preferable to use at least one selected from compounds represented by the following chemical formulas (C-1) to (C-4).
[0058]
Embedded image

[0059]
Embedded image

[0060]
Embedded image

[0061]
Embedded image

[0062]
(However, R₁~ R₇Is hydrogen, an alkyl group, an aryl group, a cycloalkyl group or an arylalkyl group, X₁~ X₅Is hydrogen, an alkyl group, an aryl group, a cycloalkyl group, an arylalkyl group or an alkali metal, or X in each formula₁~ X₅And R₁~ R₇One of each may be connected to each other to form a ring structure)
[0063]
Examples of the phosphinic acid compound represented by the chemical formula (C-1) include dimethylphosphinic acid, phenylmethylphosphinic acid, hypophosphorous acid, sodium hypophosphite, potassium hypophosphite, lithium hypophosphite, and hypophosphite. Ethyl phosphate,
[0064]
Embedded image

Or
[0065]
Embedded image

And hydrolysates thereof, and condensates of the above phosphinic acid compounds.
[0066]
Examples of the phosphonous acid compound represented by the chemical formula (C-2) include phenylphosphonous acid, sodium phenylphosphonite, potassium phenylphosphonite, lithium phenylphosphonite, and ethyl phenylphosphonite.
Examples of the phosphonic acid compound represented by the chemical formula (C-3) include phenylphosphonic acid, ethylphosphonic acid, sodium phenylphosphonate, potassium phenylphosphonate, lithium phenylphosphonate, diethyl phenylphosphonate, sodium ethylphosphonate, and ethylphosphonate. And potassium acid.
Examples of the phosphite compound represented by the chemical formula (C-4) include phosphorous acid, sodium hydrogen phosphite, sodium phosphite, triethyl phosphite, triphenyl phosphite, pyrophosphorous acid, and the like. .
[0067]
Further, they have found that the addition of an alkali compound represented by the following chemical formula (D) further improves the thermal stability of the polyester composition of the present invention.
Z-OR₈(D)
(However, Z is an alkali metal, R₈Is hydrogen, an alkyl group, an aryl group, a cycloalkyl group, -C (O) CH₃Or -C (O) OZ ', where Z' is hydrogen or an alkali metal.
[0068]
Examples of the alkali compound represented by the chemical formula (D) include sodium hydroxide, sodium methoxide, sodium ethoxide, sodium propoxide, sodium butoxide, potassium methoxide, lithium methoxide, sodium acetate, sodium carbonate, and alkaline earth Examples thereof include an alkaline earth compound containing a metal, but none of these compounds is limited to these compounds.
[0069]
The content of the alkali compound in the metaxylylene group-containing polyamide (B) used in the present invention is preferably 1.5 to 6.0 times the phosphorus atom content (X). It is more preferably 1.8 to 5.5 times, and still more preferably 2.0 to 5.0 times. When the content of the alkali compound is less than 1.5 times the phosphorus atom content (X), gelation is easily promoted. On the other hand, when the content of the alkali compound is more than 6.0 times the phosphorus atom content (X), the polymerization rate is slowed, the viscosity is not sufficiently increased, and gelation is promoted particularly in a reduced pressure system, which is uneconomical. is there.
[0070]
The compounds represented by the chemical formulas (C-1) to (C-4) and the chemical formula (D) used in the present invention may be used alone, but it is particularly preferable to use them in combination. Is preferred because of improving the thermal stability. In addition to the compounds described above, conventionally known antioxidants, ultraviolet absorbers, weathering agents, matting agents, lubricants, viscosity stabilizers, etc. impair the flavor retention, gas barrier properties, and transparency of the hollow molded article. It may be used together to the extent that it is not.
[0071]
In order to mix the phosphorus atom-containing compound and the alkali compound with the meta-xylylene group-containing polyamide (B) used in the present invention, the raw material before polymerization of the polyamide is added or added during the polymerization or melt-mixed with the polymer. Is also good.
[0072]
The tertiary nitrogen content of the metaxylylene group-containing polyamide (B) used in the present invention is preferably 2.0 mol% or less, more preferably 1.5 mol% or less, and further preferably 1.0 mol% or less. . A molded article obtained using a polyester composition containing a metaxylylene group-containing polyamide (B) having a tertiary nitrogen content of more than 2.0 mol% contains a colored foreign substance due to a gelled substance, and has a poor color. It can be. In particular, in the stretched film or the biaxially stretched hollow molded body obtained by stretch molding, the portion where the gel-like material is present is not normally stretched and becomes thick, causing unevenness in thickness, and a molded product having no commercial value. May increase.
[0073]
Further, the lower limit of the content of the tertiary nitrogen is preferably 0.001 mol%, more preferably 0.01 mol%, particularly preferably 0.05 mol% for production reasons. When producing a meta-xylylene group-containing polyamide having a tertiary nitrogen content of 0.001 mol% or less, a highly purified raw material is used, a large amount of a deterioration inhibitor is required, and the polymerization temperature is kept low. There may be a problem in productivity such as necessity.
[0074]
The term "tertiary nitrogen" used herein refers to both nitrogen based on imino compounds and nitrogen based on tertiary amides. The content of tertiary nitrogen is determined by secondary amides (-NHCO-: constituting a normal main chain). The content is represented by a molar ratio (mol%) to nitrogen based on the amide.
[0075]
The chip shape of the metaxylylene group-containing polyamide (B) used in the present invention may be any of a cylinder type, a square type, a spherical shape and a flat plate shape. The average particle size is usually in the range of 1.0 to 5 mm, preferably 1.2 to 4.5 mm, and more preferably 1.5 to 4.0 mm. For example, in the case of a cylinder type, it is practical that the length is about 1.0 to 4 mm and the diameter is about 1.0 to 4 mm. In the case of spherical particles, it is practical that the maximum particle diameter is 1.1 to 2.0 times the average particle diameter and the minimum particle diameter is 0.7 times or more the average particle diameter. The practical weight of the chip is in the range of 10 to 30 mg / piece.
[0076]
The density of the metaxylylene group-containing polyamide (B) used in the present invention is 1.20 to 1.24 mg / cm.³And more preferably 1.20 mg / cm³1.23 mg / cm³It is as follows.
[0077]
The mixing ratio of the polyester (A) and the meta-xylylene group-containing polyamide (B) constituting the polyester composition of the present invention is 0.01 part by weight of the meta-xylylene group-containing polyamide (B) per 100 parts by weight of the polyester (A). Parts to 30 parts by weight. When it is desired to obtain a molded article having a very low AA content from the polyester composition, the amount of the metaxylylene group-containing polyamide (B) is 0.01 to 5 parts by weight based on 100 parts by weight of the polyester (A). The lower limit is more preferably 0.1 part by weight, the still more preferred lower limit is 0.5 part by weight, the more preferred upper limit is 4 parts by weight, and the still more preferred upper limit is 3 parts by weight.
[0078]
When it is desired to obtain a molded article having excellent gas barrier properties and transparency without impairing the practicality, the amount is preferably 1 to 30 parts by weight based on 100 parts by weight of the polyester (A), and more preferably the lower limit is. 3 parts by weight, a more preferred lower limit is 5 parts by weight, a more preferred upper limit is 25 parts by weight, and a still more preferred upper limit is 20 parts by weight. When the mixing amount of the metaxylylene group-containing polyamide (B) is less than 0.01 part by weight based on 100 parts by weight of the polyester (A), the AA content of the obtained molded body is not reduced, and the content of the molded body is not reduced. May have a very poor flavor retention. When the mixing amount of the metaxylylene group-containing polyamide (B) exceeds 30 parts by weight with respect to 100 parts by weight of the polyester (A), the transparency of the obtained molded article may be extremely poor, The mechanical properties of the compact may also be reduced.
[0079]
In the polyester composition of the present invention, the maximum diameter of the dispersed phase before stretching is preferably 400 nm or less. The thickness is more preferably 350 nm or less, and still more preferably 300 nm or less. When the maximum diameter of the dispersed phase in the polyester composition before stretching is larger than 400 nm, the transparency of the obtained molded article may be deteriorated. In particular, the transparency of a molded product obtained by stretching the polyester composition may be extremely poor.
[0080]
As a method of setting the maximum diameter of the dispersed phase before stretching to 400 nm or less, the gelation of the meta-xylylene group-containing polyamide (B), which maintains the melt viscosity and the melt viscosity ratio of each resin appropriately, is performed while sufficient shearing is performed. It is necessary to apply stress.
[0081]
In the polyester composition of the present invention comprising the polyester (A) and the metaxylylene group-containing polyamide (B), the size of the dispersed phase can be known as follows. That is, a slice having a thickness of several tens of nm is cut out using a diamond knife, stained in ruthenium tetroxide vapor, and then photographed using a transmission electron microscope to measure the size of the dispersed phase. Can be. The polyester (A) phase can be easily distinguished from the metaxylylene group-containing polyamide (B) phase because the polyester (A) phase is dyed more intensely.
[0082]
In the polyester composition of the present invention, the ratio of the melt viscosity at 290 ° C. of the polyester (A) and the meta-xylylene group-containing polyamide (B) [the melt viscosity of the meta-xylylene group-containing polyamide (B) / the melt viscosity of the polyester (A)] is 0. It is preferably 0.001 or more and 0.3 or less. A preferred lower limit is 0.005, a more preferred lower limit is 0.01, a preferred upper limit is 0.28, and a more preferred upper limit is 0.25. When the ratio of the melt viscosities is less than 0.001, the performance of the molded article obtained from the polyester composition of the present invention is inferior and may not be practical. When the ratio of the melt viscosities is larger than 0.3, a molded article excellent in transparency which is the object of the present invention may not be obtained.
[0083]
The melt viscosity as referred to in the present invention means that the polyester (A) and the metaxylylene group-containing polyamide (B) used in the above polyester composition are capillary dies having a diameter of 1 mm and a length of 10 mm by Capillograph (Capillograph 1B manufactured by Toyo Seiki Seisaku-sho, Ltd.). 290 ° C., shear rate 1200 sec measured using^-1Is the melt viscosity at.
[0084]
The polyester (A) whose main repeating unit is ethylene terephthalate used in the present invention preferably has a melt viscosity in the range of 50 to 1000 Pa · s at 290 ° C. A more preferred lower limit is 100 Pa · s, and a more preferred upper limit is 800 Pa · s. When the melt viscosity at 290 ° C. of the polyester (A) is less than 50 Pa · s, a molded article obtained from the polyester composition of the present invention may not show sufficient mechanical properties. When the melt viscosity at 290 ° C. is higher than 1000 Pa · s, the melt viscosity is too high, and depending on a molding method such as injection molding, the fluidity becomes poor, and it may be difficult to obtain a very thin molded body. . It is desirable that the moisture content in the polyester (A) is dried to 300 ppm or less, preferably 100 ppm or less, more preferably 50 ppm or less.
[0085]
The melt viscosity of the metaxylylene group-containing polyamide (B) used in the present invention is preferably in the range of 1 to 300 Pa · s at 290 ° C. A more preferred lower limit is 5 Pa · s, and a more preferred upper limit is 240 Pa · s. When the melt viscosity at 290 of the metaxylylene group-containing polyamide (B) is less than 1 Pa · s, the mechanical properties of a molded article obtained from the polyester composition of the present invention may be reduced. When the melt viscosity at 290 ° C. is higher than 300 Pa · s, the transparency of a molded article obtained from the polyester composition of the present invention may be deteriorated. Further, the moisture content in the meta-xylylene group-containing polyamide (B) is preferably dried to 500 ppm or less, more preferably 300 ppm or less, more preferably 100 ppm or less.
[0086]
Further, the polyester composition of the present invention can be obtained by melt-mixing a polyester (A) whose main repeating unit is ethylene terephthalate and a polyamide containing a metaxylylene group (B) by a conventionally known method. The meta-xylylene group-containing polyamide (B) can be dry-blended and melt-processed into a molded product by injection molding or extrusion molding, for example, melt-mixed in a single-screw or twin-screw extruder. The melting temperature must be at least the same as the melting point of the polyester (A), typically between 260C and 310C. Preferably, the melt mixing temperature is kept as low as possible within said range.
[0087]
The content of the meta-xylylene group-containing cyclic amide monomer in the molded product obtained by molding the polyester composition of the present invention is 0.5% by weight or less, preferably 0.4% by weight or less, more preferably 0.3% by weight. % Is desirable. When the content of the meta-xylylene group-containing cyclic amide monomer exceeds 0.5% by weight, the flavor retention of the obtained molded article content may be deteriorated, and the polyester composition of the present invention may have poor heat resistance. When molding a hollow molded article of the type, there is a case where mold contamination caused by foreign matter adhering to the inner surface of the mold, the exhaust port of the gas of the mold, and the exhaust pipe at the time of molding the molded article may be extremely intense. It turns out. The content of the meta-xylylene group-containing cyclic amide monomer is preferably 0.001% by weight or more, more preferably 0.01% by weight or more, from the viewpoint of economical production.
[0088]
Here, when the meta-xylylene group-containing polyamide is a polyamide composed of meta-xylylenediamine and adipic acid, the chemical formula of the above-mentioned meta-xylylene group-containing cyclic amide monomer is represented by the following formula.
[0089]
Embedded image

(In the above formula 3, n = 1 (integer).)
[0090]
The acetaldehyde content in the polyester composition used in the present invention is preferably 15 ppm or less, more preferably 12 ppm or less, and still more preferably 10 ppm or less. When the acetaldehyde content in the polyester composition of the present invention exceeds 15 ppm, the flavor and odor of the beverage filled in the obtained hollow molded article or the like may be affected.
[0091]
The content of the cyclic ester trimer of the polyester (A) in which the main repeating unit used in the present invention is ethylene terephthalate is preferably 0.70% by weight or less, more preferably 0.60% by weight or less. More preferably, the content is 0.50% by weight or less, particularly preferably 0.45% by weight or less. When a heat-resistant hollow molded article or the like is molded from the polyester composition of the present invention, if a polyester having a cyclic ester trimer content of more than 0.70% by weight is used, depending on the heat treatment conditions, heating metal may be used. Oligomer adhesion to the mold surface may increase rapidly, and the transparency of the obtained hollow molded article or the like may be extremely deteriorated. The lower limit of the content of the cyclic ester trimer is preferably 0.01% by weight, more preferably 0.1% by weight, from the viewpoint of economical production.
Here, in the case of PET, the cyclic ester trimer is a cyclic trimer composed of terephthalic acid and ethylene glycol.
[0092]
Further, when the polyester (A) whose main repeating unit used in the present invention is ethylene terephthalate is melted at a temperature of 290 ° C. for 60 minutes, the cyclic ester trimer increases by 0.50% by weight or less. Desirably. The amount of the cyclic ester trimer increased is preferably 0.40% by weight or less, more preferably 0.30% by weight or less. When a polyester whose amount of increase of the cyclic ester trimer when melted at a temperature of 290 ° C. for 60 minutes exceeds 0.50% by weight is used, the amount of the cyclic ester trimer is reduced when the resin is melted at the time of molding the polyester composition. Depending on the heat treatment conditions, the adhesion of the oligomer to the surface of the heating mold may increase rapidly, and the transparency of the obtained hollow molded article or the like may be extremely deteriorated.
[0093]
The polyester (A) used in the present invention, in which the increase of the cyclic ester trimer when melted at a temperature of 290 ° C. for 60 minutes is 0.50% by weight or less, is obtained after melt polycondensation or after solid state polymerization. It can be produced by deactivating the polycondensation catalyst remaining in the obtained polyester. Examples of the method for deactivating the polycondensation catalyst in the polyester include a method in which a polyester chip is subjected to contact treatment with water, steam or a steam-containing gas after melt polycondensation or after solid-phase polymerization.
[0094]
A method for treating a polyester chip with water, steam or a steam-containing gas to achieve the above object will be described below.
Examples of the hot water treatment method include a method of immersing in water and a method of spraying water on a chip with a shower. The treatment time is 5 minutes to 2 days, preferably 10 minutes to 1 day, more preferably 30 minutes to 10 hours, and the water temperature is 20 to 180 ° C, preferably 40 to 150 ° C, more preferably 50 to 150 ° C. 120 ° C.
The treatment method may be either a continuous method or a batch method, but the continuous method is preferable for industrial use.
[0095]
In the case of treating the polyester chips with water in a batch system, a silo-type treatment tank may be used. That is, the chips of polyester are received in a silo in a batch system, and water treatment is performed. When the polyester chips are treated with water in a continuous manner, the polyester chips can be continuously or intermittently received in the tower-type treatment tank from above and subjected to water treatment.
[0096]
When the polyester chips are brought into contact with steam or a steam-containing gas for treatment, steam or a steam-containing gas or a steam-containing air at a temperature of 50 to 150 ° C., preferably 50 to 110 ° C. is preferably used as granular polyethylene terephthalate. The granular polyethylene terephthalate is brought into contact with steam in the amount of 0.5 g or more as steam or present in 1 kg of the steam.
The contact between the polyester chips and water vapor is usually performed for 10 minutes to 2 days, preferably for 20 minutes to 10 hours.
[0097]
The processing method may be either a continuous method or a batch method.
When a polyester chip is subjected to a contact treatment with steam in a batch system, a silo-type treatment device may be used. That is, a polyester chip is received in a silo, and steam or a steam-containing gas is supplied in a batch system to perform a contact treatment.
[0098]
If polyester chips are to be continuously contacted with steam, the granular polyethylene terephthalate should be continuously received in a tower-type treatment device from the top, and steam should be continuously supplied in parallel or countercurrent to contact with steam. Can be.
As described above, when treated with water or steam, the granular polyethylene terephthalate is drained by a draining device such as a vibrating sieve or a simmon cutter if necessary, and then transferred to the next drying step by a conveyor. .
[0099]
The drying of the polyester chips which have been subjected to the contact treatment with water or steam can be carried out by a commonly used polyester drying treatment. As a method of continuous drying, a hopper-type through-air dryer that supplies polyester chips from the upper portion and allows the drying gas to flow from the lower portion is usually used.
[0100]
As a dryer for drying by a batch method, drying may be performed under atmospheric pressure while passing a drying gas.
As the dry gas, atmospheric air may be used, but dry nitrogen and dehumidified air are preferred from the viewpoint of preventing molecular weight reduction due to hydrolysis or thermal oxidative decomposition of the polyester.
[0101]
The polyester (A) whose main repeating unit is ethylene terephthalate used in the present invention is selected from the group consisting of polyolefin resins, polyamide resins, polyacetal resins, and polybutylene terephthalate resins. It can be a polyester characterized by blending at least one resin of 0.1 ppb to 1000 ppm. The mixing ratio of the polyolefin resin and the like in the polyester (A) used in the present invention is 0.1 ppb to 1000 ppm, preferably 0.3 ppb to 100 ppm, more preferably 0.5 ppb to 1 ppm, and still more preferably 0.1 ppb to 1 ppm. It is 5 ppb to 45 pbb.
[0102]
If the compounding amount is less than 0.1 ppb, the crystallization speed becomes very slow, and the crystallization of the plug portion of the hollow molded article becomes insufficient. It may not be within the value range, and may result in poor capping.In addition, the stretch heat-fixing mold for forming the heat-resistant hollow molded article is heavily stained, and the mold is frequently used to obtain a transparent hollow molded article. You may need to clean it. If the concentration exceeds 1000 ppm, the crystallization speed is increased, the crystallization of the plug portion of the hollow molded article becomes excessive, or the shrinkage / shrinkage amount of the plug portion does not fall within the specified value range. As a result, the leakage of the contents may occur, and the preform for the hollow molded body may be whitened, so that normal stretching may not be possible. In the case of a sheet-like material, if the content exceeds 1000 ppm, the transparency becomes extremely poor, and the stretchability becomes poor, so that normal stretching is impossible, and only a stretched film having large unevenness of thickness and poor transparency is obtained. May not be possible.
[0103]
Examples of the polyolefin resin blended in the polyester (A) used in the present invention include a polyethylene resin, a polypropylene resin, and an α-olefin resin.
[0104]
Examples of the polyethylene resin blended in the polyester (A) used in the present invention include a homopolymer of ethylene, ethylene, propylene, butene-1, 3-methylbutene-1, pentene-1, and 4-methylpentene. -1, hexene-1, octene-1, decene-1 and other α-olefins having about 2 to 20 carbon atoms, vinyl acetate, vinyl chloride, acrylic acid, methacrylic acid, acrylate, methacrylate, A copolymer with a vinyl compound such as styrene is exemplified. Specifically, for example, ethylene homopolymer such as low / medium / high density polyethylene (branched or linear), ethylene-propylene copolymer, ethylene-butene-1 copolymer, ethylene-4-methyl Pentene-1 copolymer, ethylene-hexene-1 copolymer, ethylene-octene-1 copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene -Ethylene resins such as ethyl acrylate copolymer.
[0105]
Examples of the polypropylene resin blended in the polyester (A) used in the present invention include, for example, propylene homopolymer, propylene, ethylene, butene-1,3-methylbutene-1, pentene-1,4-methyl Other α-olefins having about 2 to 20 carbon atoms such as pentene-1, hexene-1, octene-1, decene-1, and the like, vinyl acetate, vinyl chloride, acrylic acid, methacrylic acid, acrylate, methacrylate And a copolymer with a vinyl compound such as styrene. Specifically, for example, propylene resins such as propylene homopolymer, propylene-ethylene copolymer, and propylene-ethylene-butene-1 copolymer are exemplified.
[0106]
Examples of the α-olefin resin blended in the polyester (A) used in the present invention include homopolymers of α-olefins having about 2 to 8 carbon atoms such as 4-methylpentene-1, and α-olefins thereof. And other α-olefins having about 2 to 20 carbon atoms such as ethylene, propylene, butene-1, 3-methylbutene-1, pentene-1, hexene-1, octene-1, and decene-1. And the like. Specifically, for example, butene-1 based resin such as butene-1 homopolymer, 4-methylpentene-1 homopolymer, butene-1-ethylene copolymer, butene-1-propylene copolymer, and the like; -Methylpentene-1 and a copolymer of C2-C18 α-olefin, and the like.
[0107]
Examples of the polyamide resin blended in the polyester (A) used in the present invention include lactam polymers such as butyrolactam, δ-valerolactam, ε-caprolactam, enantholactam, ω-laurolactam, and 6-aminocaprolene. Acid, 11-aminoundecanoic acid, polymers of aminocarboxylic acids such as 12-aminododecanoic acid, hexamethylenediamine, nonamethylenediamine, decamethylenediamine, dodecamethylenediamine, undecamethylenediamine, 2,2,4- or Aliphatic diamines such as 2,4,4-trimethylhexamethylenediamine, alicyclic diamines such as 1,3- or 1,4-bis (aminomethyl) cyclohexane, bis (p-aminocyclohexylmethane), m- or dia such as aromatic diamine such as p-xylylenediamine And dicarboxylic acid units such as aliphatic dicarboxylic acids such as glutaric acid, adipic acid, suberic acid, and sebacic acid; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; and aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid. And a copolymer thereof, and specifically, for example, nylon 4, nylon 6, nylon 7, nylon 8, nylon 9, nylon 11, nylon 12, nylon 66, nylon 69, and the like. Nylon 610, nylon 611, nylon 612, nylon 6T, nylon 6I, nylon MXD6, nylon 6/66, nylon 6/610, nylon 6/12, nylon 6 / 6T, nylon 6I / 6T, and the like.
[0108]
Examples of the polyacetal resin blended in the polyester (A) used in the present invention include a polyacetal homopolymer and a copolymer. As the polyacetal homopolymer, the density measured by the measuring method of ASTM-D792 is 1.40 to 1.42 g / cm.³Polyacetal having a melt index (MI) of 0.5 to 50 g / 10 minutes measured at 190 ° C. under a load of 2160 g according to ASTM D-1238 is preferred.
[0109]
The polyacetal copolymer has a density of 1.38 to 1.43 g / cm3 as measured by ASTM-D792 and a melt index of 190 ° C. under a load of 2160 g according to ASTM D-1238. A polyacetal copolymer having (MI) in the range of 0.4 to 50 g / 10 minutes is preferred. Examples of these copolymer components include ethylene oxide and cyclic ether.
[0110]
Examples of the polybutylene terephthalate resin blended in the polyester (A) used in the present invention include a polybutylene terephthalate homopolymer comprising terephthalic acid and 1,4-butanediol, And copolymers of naphthalenedicarboxylic acid, diethylene glycol, 1,4-cyclohexanedimethanol, and the like.
[0111]
Further, the polyester blended with the polyolefin resin and the like used in the present invention is a method of directly adding and melt-kneading the polyester and the resin such as the polyolefin so that the content is within the above range, or In addition to a conventional method such as a method of melt-kneading and adding as a master batch, the resin such as the polyolefin is produced at the polyester production stage, for example, during melt polycondensation, immediately after melt polycondensation, immediately after pre-crystallization, At the time of solid phase polymerization, any stage such as immediately after solid phase polymerization, or during the period from the end of the production stage to the molding stage, directly added as powders or the flow conditions of polyester chips It is also possible to adopt a method in which the mixture is mixed with the above-mentioned method by, for example, contacting with a resin member such as polyolefin, and then melt-kneaded.
[0112]
Here, as a method of bringing the polyester chip into contact with a resin-made member such as the above-mentioned polyolefin under flow conditions, the polyester chip is placed in a space where the resin-made member such as the above-mentioned polyolefin exists. Collision contact is preferred, specifically, for example, immediately after the melt polycondensation of polyester, immediately after pre-crystallization, during the production process such as immediately after solid-phase polymerization, or in the transportation stage of polyester chips as a product Part of the pneumatic transport pipe, gravity transport pipe, silo, magnet part of the magnet catcher, etc. at the time of filling / discharging of the transport container, or at the time of injection of the molding machine at the molding stage of polyester chips, and the resin such as polyolefin etc. Or a lining of the resin such as the polyolefin, or a rod-like or net-like body in the transfer path. By, for example placing the resin member such as the polyolefins, and a method of transferring the polyester chips. The contact time of the polyester chip with the member is usually very short, about 0.01 second to several minutes, but a small amount of the above-mentioned resin such as polyolefin can be mixed into the polyester.
[0113]
The polyester (A) whose main repeating unit is ethylene terephthalate used in the present invention has an acetaldehyde content of 10 ppm or less, preferably 8 ppm or less, more preferably 6 ppm or less, and still more preferably 4 ppm or less. The amount is desirably 6 ppm or less, preferably 5 ppm or less, more preferably 4 ppm or less. When the acetaldehyde content exceeds 10 ppm and the formaldehyde content exceeds 6 ppm, the effect of retaining the flavor of the contents such as a molded article molded from this polyester becomes poor.
The lower limit of the amount of acetaldehyde and the amount of formaldehyde are preferably 0.1 ppb.
[0114]
The amount of diethylene glycol copolymerized in the polyester (A) whose main repeating unit is ethylene terephthalate used in the present invention is preferably the lower limit of the glycol component constituting the polyester (A). 1.0 mol%, more preferably 1.3 mol%, further preferably 1.5 mol%, and the upper limit is preferably 5.0 mol%, more preferably 4.5 mol%, and still more preferably 4. 0 mol%. When the amount of diethylene glycol exceeds 5.0 mol%, the thermal stability becomes poor, the molecular weight decreases during molding, and the acetaldehyde content and the formaldehyde content increase in amount are preferably large. Absent. When the content of diethylene glycol is less than 1.0 mol%, the transparency of the obtained molded article may deteriorate.
[0115]
The polyester composition of the present invention can be obtained by mixing the above-mentioned polyester (A) and the above-mentioned metaxylylene group-containing polyamide (B) by a conventionally known method. For example, the polyamide chip and the polyester chip are dry-blended with a tumbler, a V-blender, a Henschel mixer, or the like, and the dry-blended mixture is melted at least once with a single-screw extruder, a twin-screw extruder, a kneader, or the like. Examples thereof include those obtained by mixing, and, if necessary, those obtained by subjecting a molten mixture to solid phase polymerization under a high vacuum or an inert gas atmosphere. Further, those obtained by melt-mixing the polyester (A) and the metaxylylene group-containing polyamide (B) in advance, dry-blending with the polyester (A), and further melt-mixing the dry-blended mixture. Can be
[0116]
It is also possible to simultaneously use a saturated fatty acid monoamide, an unsaturated fatty acid monoamide, a saturated fatty acid bisamide, an unsaturated fatty acid bisamide, and the like in the polyester composition of the present invention.
[0117]
Examples of the saturated fatty acid monoamide include lauric amide, palmitic amide, stearic amide, behenic amide and the like. Examples of unsaturated fatty acid monoamides include oleic acid amide, erucic acid amido ricinoleic acid amide, and the like. Examples of the saturated fatty acid bisamide include methylenebisstearic acid amide, ethylenebiscapric acid amide, ethylenebislauric acid amide, ethylenebisstearic acid amide, ethylenebisbehenic acid amide, hexamethylenebisstearic acid amide, hexamethylenebisbehenic acid Amides and the like. Examples of the unsaturated fatty acid bisamide include ethylene bisoleic acid amide and hexamethylene bisoleic acid amide. Preferred amide compounds are saturated fatty acid bisamides, unsaturated fatty acid bisamides, and the like. The compounding amount of such an amide compound is 10 ppb to 1 × 10⁵It is preferably in the ppm range.
[0118]
Metal salt compounds of aliphatic monocarboxylic acids having 8 to 33 carbon atoms, for example, naphthenic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, montanic acid, melisic acid, oleic acid It is also possible to simultaneously use lithium salts, sodium salts, potassium salts, magnesium salts, calcium salts, cobalt salts and the like of saturated and unsaturated fatty acids such as linoleic acid and the like. The compounding amount of these compounds is preferably in the range of 10 ppb to 300 ppm.
[0119]
The polyester composition of the present invention, if necessary, other additives, for example, known ultraviolet absorbers, antioxidants, oxygen absorbers, oxygen scavengers, lubricants added from the outside and internal precipitation during the reaction. Various additives such as a lubricant, a releasing agent, a nucleating agent, a stabilizer, an antistatic agent and a pigment may be blended. It is also possible to mix an ultraviolet-blocking resin, a heat-resistant resin, and a product recovered from a used polyethylene terephthalate bottle at an appropriate ratio.
[0120]
In applications where a clear, colorless resin is desired, the faint yellow color generated during melt processing can be eliminated by the addition of a blue colorant. Colorants can be added directly to the blend during polymerization or during compounding. When added during compounding, the colorant can be added as it is, or can be added as a concentrate such as a master batch. Further, when the polyester (A) and the metaxylylene group-containing polyamide (B) previously melt-mixed are dry-blended with the polyester (A), and when the dry-blended mixture is further melt-mixed, When the polyester (A) and the metaxylylene group-containing polyamide (B) are melt-mixed, a colorant may be added. The amount of colorant can be adjusted with its extinction coefficient and the color desired for its use.
[0121]
When the polyester composition of the present invention is used for film applications, calcium carbonate, magnesium carbonate, and barium carbonate are used in the polyester composition to improve handling properties such as slipperiness, winding property, and blocking resistance. Inorganic particles such as calcium sulfate, barium sulfate, lithium phosphate, calcium phosphate, and magnesium phosphate; organic salt particles such as terephthalate such as calcium and calcium oxalate, barium, zinc, manganese, and magnesium; divinylbenzene, styrene, and acrylic Inert particles such as cross-linked polymer particles such as homo- or copolymers of vinyl monomers of acid, methacrylic acid, acrylic acid or methacrylic acid can be contained.
[0122]
The polyester composition of the present invention can be used to form films, sheets, containers, and other packaging materials using commonly used melt molding methods. The stretched film made of the polyester composition of the present invention is a sheet-like product obtained by injection molding or extrusion molding, and is preferably any one of uniaxial stretching, sequential biaxial stretching, and simultaneous biaxial stretching usually used for PET stretching. It is formed using a stretching method. Further, it can be formed into a cup shape or a tray shape by pressure forming or vacuum forming.
[0123]
In producing a stretched film, the stretching temperature is usually from 80 to 130 ° C. The stretching may be uniaxial or biaxial, but is preferably biaxial in view of practical physical properties of the film. The stretching ratio is usually 1.1 to 10 times, preferably 1.5 to 8 times in the case of uniaxial stretching. In the case of biaxial stretching, it is usually 1.1 to 8 times in both the longitudinal and transverse directions. , Preferably in the range of 1.5 to 5 times. Further, the ratio of the vertical / horizontal magnification is usually 0.5 to 2, preferably 0.7 to 1.3. The obtained stretched film can be further heat-set to improve heat resistance and mechanical strength. The heat setting is usually performed under tension at 120 ° C. to 240 ° C., preferably 150 ° C. to 230 ° C., usually for several seconds to several hours, preferably for several tens seconds to several minutes.
[0124]
In producing the hollow molded article, a blow-form molded from the polyester composition of the present invention is formed by stretch blow molding, and an apparatus conventionally used for PET blow molding can be used. Specifically, for example, a preform is once molded by injection molding or extrusion molding, and after processing the plug portion and the bottom portion, it is reheated, and biaxial stretch blow molding such as hot parison method or cold parison method is performed. The law applies. In this case, the molding temperature, specifically, the temperature of each part of the cylinder and the nozzle of the molding machine is usually in the range of 260 to 290 ° C. The stretching temperature is usually from 70 to 120 ° C., preferably from 90 to 110 ° C., and the stretching ratio is usually from 1.5 to 3.5 times in the longitudinal direction and from 2 to 5 times in the circumferential direction. The obtained hollow molded body can be used as it is, but in particular, in the case of beverages requiring heat filling, such as fruit juice beverages, oolong tea, etc., in general, heat-setting treatment is further performed in a blow mold to obtain heat resistant It is used with imparting properties. The heat setting is usually performed at 100 to 200 ° C., preferably 120 to 180 ° C., for several seconds to several hours, preferably for several seconds to several minutes, under tension by compressed air or the like.
[0125]
Also, in order to impart heat resistance to the plug portion, the plug portion of the preform obtained by injection molding or extrusion molding is crystallized in a far infrared or near infrared heater installation oven, Alternatively, the plug portion is crystallized with the heater after the bottle is formed.
[0126]
Further, the polyester composition of the present invention can also be used as one constituent layer of a laminated molded article, a laminated film, or the like. In particular, it is used in the production of containers and the like in the form of a laminate with PET. Examples of the laminated molded article include a two-layer structure composed of an outer layer made of the polyester composition of the present invention and a PET inner layer or a two-layer structure composed of an inner layer made of the polyester composition of the present invention and a PET outer layer. Molded article having a two-layer structure, a three-layer structure composed of an intermediate layer containing the polyester composition of the present invention and an outer layer and innermost layer of PET, or an intermediate layer between the outer layer and the innermost layer containing the polyester composition of the present invention and PET. Examples include a molded article having a three-layer structure composed of layers, a molded article having a five-layer structure composed of an intermediate layer containing the polyester composition of the present invention, an innermost layer, a center layer, and an innermost layer of PET. In the PET layer, other gas barrier resins, ultraviolet shielding resins, heat-resistant resins, recovered products from used polyethylene terephthalate bottles, and the like can be mixed and used at an appropriate ratio.
[0127]
Examples of other laminated molded articles include a laminated molded article with a resin other than polyester such as polyolefin, and a laminated molded article with a different kind of base material such as paper or a metal plate.
There are no particular restrictions on the thickness of the laminate and the thickness of each layer. The laminated molded article can be used in various shapes such as a sheet, a film, a plate, a hollow body, and a container.
[0128]
The production of the laminate can be carried out by co-extrusion using a number of extruders corresponding to the type of resin layer and a multi-layered die, or a number of extruders corresponding to the type of resin layer. Co-injection can also be performed using an injection runner and an injection mold.
The polyester composition of the present invention can be preferably used as a packaging material such as a hollow molded article, a tray, a biaxially stretched film, and a film for covering a metal can.
Further, the composition of the present invention can be used for cooking foods in a microwave oven and / or an oven range or the like, or for use as a tray-shaped container for heating frozen foods. In this case, after the sheet-like material from the polyester composition is formed into a tray shape, it is thermally crystallized to improve heat resistance.
The main method of measuring characteristic values in the present invention will be described below.
[0129]
【Example】
Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to these Examples. In addition, the measuring method of the main characteristic value in this specification is demonstrated below.
[0130]
(Evaluation method)
(1) Intrinsic viscosity (IV) of polyester
It was determined from the solution viscosity at 30 ° C. in a 1,1,2,2-tetrachloroethane / phenol (2: 3 weight ratio) mixed solvent.
[0131]
(2) Diethylene glycol content copolymerized in the polyester (hereinafter referred to as [DEG content])
It was decomposed by methanol and the amount of DEG was quantified by gas chromatography and expressed as a ratio (mol%) to the total glycol components.
[0132]
(3) Content of cyclic ester trimer (hereinafter referred to as “CT content”)
300 mg of a sample is dissolved in 3 ml of a mixed solution of hexafluoroisopropanol / chloroform (volume ratio = 2/3), and further diluted with 30 ml of chloroform. To this, 15 ml of methanol was added to precipitate a polymer, followed by filtration. The filtrate was evaporated to dryness, the volume was adjusted to 10 ml with dimethylformamide, and the cyclic ester trimer was quantified by high performance liquid chromatography.
[0133]
(4) Acetaldehyde content (hereinafter referred to as "AA content")
A sample / distilled water = 1 g / 2 cc in a glass ampoule purged with nitrogen was sealed and subjected to extraction at 160 ° C. for 2 hours. After cooling, acetaldehyde in the extract was measured by high-sensitivity gas chromatography. The concentration was expressed in ppm.
[0134]
(5) Cyclic ester trimer increase during melting of polyester (ΔCT amount)
3 g of the dried polyester chip is placed in a glass test tube, and immersed in a 290 ° C. oil bath for 60 minutes in a nitrogen atmosphere to be melted. The amount of the cyclic ester trimer increased at the time of melting is determined by the following equation.
Cyclic ester trimer increase during melting (wt%) = cyclic ester trimer content after melting (wt%)-cyclic ester trimer content before melting (wt%)
[0135]
(6) Relative viscosity (RV) of metaxylylene group-containing polyamide
A sample (0.25 g) was dissolved in 96% sulfuric acid (25 ml), and the solution (10 ml) was measured at 20 ° C. using an Ostwald viscometer and determined by the following formula.
RV = t / t₀
t₀: Seconds of solvent falling
t : Number of seconds during which the sample solution falls
[0136]
(7) Weight average molecular weight (Mw), number average molecular weight (Mn) of metaxylylene group-containing polyamide
A solution obtained by dissolving a sample at a concentration of 2 mg / ml in hexafluoroisopropanol (HFIP) in which sodium trifluoroacetate was dissolved at a concentration of 10 mM was used as a measurement solution, and measurement was performed by gel permeation chromatography (GPC). The measuring apparatus used was HLC-8220 manufactured by Tosoh Corporation, and the column used was TSKgel Super AWM-H (6.0 mm ID × 15 cm, manufactured by Tosoh Corporation) × 2. The measurement was performed using HFIP containing sodium trifluoroacetate having the same composition as the above for the mobile phase under the conditions of an injection amount of 20 μl, a column temperature of 40 ° C., and a flow rate of 0.3 ml / min. The weight average molecular weight, number average molecular weight, and molecular weight distribution were calculated using standard polymethyl methacrylate (PMMA) in terms of PMMA. At this time, in setting the baseline of the polymer component peak from the obtained chromatogram, the end point of the baseline was set to the retention time of PMMA having a molecular weight of 1680 measured under the same conditions.
[0137]
(8) Melt viscosity of polyester (A) (hereinafter referred to as ηA) and melt viscosity of metaxylylene group-containing polyamide (B) (hereinafter referred to as ηB) (Pa · s)
Using a dried resin chip, Capillograph 1B (capillary die 1 mm in diameter, 10 mm in length) manufactured by Toyo Seiki Seisaku-sho, Ltd. at a measurement temperature of 290 ° C. and a shear rate of 50 to 4000 (sec)^-1) Was measured for the melt viscosity. The melt viscosity in the present invention refers to 290 ° C. and a shear rate of 1200 (sec).^-1) Represents the melt viscosity (Pa · s).
[0138]
(9) Terminal amino group concentration of metaxylylene group-containing polyamide (AEG, μmol / g)
After dissolving 0.5 g of the sample in 50 ml of a phenol / ethanol mixed solvent (4/1 by volume) at room temperature, 20 ml of a water / ethanol mixed solvent (3/2 by volume) is added and stirred. Thereafter, neutralization titration was performed using hydrochloric acid to determine the terminal amino group concentration.
[0139]
(10) Terminal carboxyl group concentration of metaxylylene group-containing polyamide (CEG, μmol / g)
20 ml of benzyl alcohol was added to 0.5 g of the sample, and dissolved by heating in an oil bath at 170 to 180 ° C., and neutralization titration was performed with an aqueous sodium hydroxide solution to determine the terminal carboxyl group concentration.
[0140]
(11) Content of metaxylylene group-containing cyclic amide monomer (CM content) (% by weight)
100 mg of a sample is dissolved in 3 ml of a mixed solution of hexafluoroisopropanol / chloroform (volume ratio = 2/3), further diluted with 20 ml of chloroform, and 10 ml of methanol is added. This is concentrated by an evaporator and redissolved in 20 ml of dimethylformamide. After centrifugal filtration, quantification was performed by high performance liquid chromatography.
[0141]
(12) Forming a stepped plate
The dried polyester composition is molded using an M-150C (DM) injection molding machine manufactured by Meiki Seisakusho at a cylinder temperature of 290 ° C. using a stepped plate mold cooled to 10 ° C. (screw rotation speed 120 rpm, screw back pressure). 0.5 MPa, cooling time 50 seconds, one cycle 72-73 seconds). The obtained stepped molded plate is provided with a plate of about 3 cm × about 5 cm square having a thickness of 2,3,4,5,6,7,8,9,10,11 mm in a stepwise manner. The weight of one molded plate is about 146 g. A plate having a thickness of 5 mm is used for measuring haze (% haze).
[0142]
(13) Haze (% haze)
The molded body (5 mm thick) of the above (12) is cut out and measured with a haze meter manufactured by Nippon Denshoku Co., Ltd.
[0143]
(14) Evaluation of mold contamination
Using a predetermined amount of polyester dried by a dryer using nitrogen gas and a predetermined amount of a meta-xylylene group-containing polyamide chip dried by a dryer using nitrogen gas, an M-150C (DM) injection molding machine manufactured by each machine manufacturer. To form a preform at a resin temperature of 290 ° C. After heating and crystallizing the plug portion of this preform with a home-made plug portion crystallizer, biaxial stretching blow molding was performed using an LB-01E stretching blow molding machine manufactured by Co-Poplast Co., Ltd. It was heat-set in a mold set at about 145 ° C. for about 7 seconds to obtain a 1500 cc hollow molded article. Under the same conditions, 2,000 hollow molded articles were continuously stretch blow-molded, and the state of the mold surface before and after the blow molding was visually observed and evaluated as follows.
○: No change before and after the continuous molding test
△: considerably adhered after continuous molding test
×: Very large amount of deposits after continuous molding test
[0144]
(15) Maximum diameter of dispersed phase
A section was prepared from the body of the preform before the biaxial stretching blow obtained by molding in the above (14), dyed in ruthenium tetroxide vapor, and then carbon deposited. Thereafter, using a JEM-2010 transmission electron microscope manufactured by JEOL Ltd., the disperse phase was directly observed at an acceleration voltage of 200 kV and a magnification of 10,000 times, and the particle size of the disperse phase was measured from a photograph taken. At this time, the observation of the dispersed phase was performed five times in different places while changing the visual field, and the diameter of the dispersed phase having the largest particle size among them was regarded as the maximum diameter. (When measuring from a stretched molded body, it is also possible to sample from a plug portion which is an unstretched portion.
[0145]
(16) Transparency of hollow molded body
The appearance of the hollow molded article obtained after the 2,000 molding of (14) was visually observed and evaluated as follows.
◎: transparent
：: Transparent in practical range, no unmelted material
×: Poor transparency or unmelted material
[0146]
(17) Sensory test
Boiling distilled water was put in the hollow molded body, sealed for 30 minutes after sealing, cooled to room temperature, allowed to stand at room temperature for one month, opened, and tested for flavor, smell and the like. Distilled water was used as a blank for comparison. The sensory test was carried out by 10 panelists according to the following criteria, and the average value was compared.
(Evaluation criteria)
0: No off-flavor or smell
1: Slight difference from blank
2: Feel the difference from the blank
3: I feel a considerable difference from the blank
4: I feel a very large difference from the blank
[0147]
(18) Oxygen permeability (cc / container / 24 hr.atm)
The permeation amount per bottle of 1000 cc was measured at 20 ° C. and 0% RH by an oxygen permeation measuring device OX-TRAN100 manufactured by Modern Controls.
[0148]
(Polyethylene terephthalate (PET) used in Examples and Comparative Examples)
Table 1 shows the characteristics of PET (remaining amount of Ge = about 40 to 50 ppm, remaining amount of phosphorus = about 30 to 35 ppm) used in the test. These are all polymerized by a continuous melt polycondensation-solid state polymerization apparatus.
PET (a) is obtained by subjecting the solid-phase polymerization to hot water treatment in ion-exchanged water at about 90 ° C. for 3 hours.
In addition, the PET content of PET (a) to PET (c) is about 2.7 mol%.
[0149]
[Table 1]

[0150]
(Metaxylylene group-containing polyamide (MXD6) used in Examples and Comparative Examples)
[0151]
Method for producing MXD6 (d)
27.66 kg of metaxylylenediamine and 29.65 kg of adipic acid were weighed into a 250-liter internal can equipped with a stirrer, a decomposer, a thermometer, a dropping funnel and a nitrogen gas inlet tube. To obtain a slurry-like transparent solution. After adjusting the PH value in the can to 7.95, 34.09 g of NaOH and NaH₂PO₂・ H₂25.81 g of O was added and stirred for 15 minutes. The solution was transferred to a reaction vessel having an inner volume of 270 liters, and reacted under stirring at a vessel temperature of 260 ° C. and a vessel pressure of 1.0 MPa. Distilled water was removed from the system, and when the temperature in the can reached 235 ° C, the internal pressure of the can was returned to normal pressure over 60 minutes. Stirring was performed at normal pressure. When the target viscosity was reached, the stirring was stopped, and the mixture was left for 20 minutes. Then, the molten resin was taken out from the outlet at the lower part of the reaction can, cooled and solidified, and a resin chip was obtained with a strand cutter. Table 2 shows the properties of the obtained resin.
[0152]
Method for producing MXD6 (e)
A resin chip was obtained in the same manner as in the method for producing MXD6 (d), except that the PH value in the can was adjusted to 7.20. Table 2 shows the properties of the obtained resin.
[0153]
Method for producing MXD6 (f)
A resin chip was obtained in the same manner as in the method for producing MXD6 (d), except that the PH value in the can was adjusted to 7.06. Table 2 shows the properties of the obtained resin.
[0154]
Method for producing MXD6 (g)
A resin chip was obtained in the same manner as in the method for producing MXD6 (d), except that the PH value in the can was adjusted to 6.92. Table 2 shows the properties of the obtained resin.
[0155]
Method for producing MXD6 (h)
27.66 kg of metaxylylenediamine and 29.65 kg of adipic acid, which were precisely weighed, were placed in a 250-liter internal can prepared with a stirrer, a decomposer, a thermometer, a dropping funnel, and a nitrogen gas inlet tube. To obtain a slurry-like transparent solution. After adjusting the PH value in the can to 7.02, 34.09 g of NaOH as a gelling inhibitor and NaH₂PO₂・ H₂25.81 g of O was added and stirred for 15 minutes. The solution was transferred to a reaction vessel having an inner volume of 270 liters, and reacted under stirring at a temperature of 265 ° C. and a pressure of 1.0 MPa in the vessel. Distilled water was removed from the system, and when the temperature in the can reached 235 ° C., the internal pressure of the can was returned to normal pressure over 60 minutes. Stirring was performed at normal pressure. When the target viscosity was reached, the stirring was stopped, and the mixture was left for 20 minutes. Then, the molten resin was taken out from the outlet at the lower part of the reaction can, cooled and solidified, and a resin chip was obtained with a strand cutter. Table 2 shows the properties of the obtained resin.
[0156]
[Table 2]

[0157]
(Example 1)
Using 0.5 parts by weight of MXD6 (d) with respect to 100 parts by weight of PET (a), a hollow molded body is molded by the method of evaluation method (14), and the CT content, CM content, The AA content was measured. In addition, mold stain evaluation was also performed.
Table 3 shows the properties of the obtained hollow molded body and the results of evaluation of mold contamination.
As a result of observation with a transmission electron microscope, MXD6 formed a dispersed phase, and had a maximum diameter of 300 nm. The AA content of the hollow molded body was 8 ppm, the sensory evaluation was 0.7, the appearance was transparent in a practical range, and no mold stain was observed.
[0158]
(Example 2)
Using 3.0 parts by weight of MXD6 (d) with respect to 100 parts by weight of PET (a), a hollow molded body was molded by the method of evaluation method (14), and the CT content, CM content, The AA content was measured. In addition, mold stain evaluation was also performed.
Table 3 shows the properties of the obtained hollow molded body and the results of evaluation of mold contamination.
As a result of observation with a transmission electron microscope, MXD6 formed a dispersed phase and had a maximum diameter of 310 nm. The AA content of the hollow molded article was 7 ppm, the sensory evaluation was 0.6, the appearance was transparent in a practical range, and no mold staining was observed.
[0159]
(Example 3)
Using 20.0 parts by weight of MXD6 (d) with respect to 100 parts by weight of PET (a), a hollow molded body was molded by the method of evaluation method (14), and the CT content, CM content, The AA content was measured. In addition, mold stain evaluation was also performed.
Table 3 shows the properties of the obtained hollow molded body and the results of evaluation of mold contamination.
As a result of observation with a transmission electron microscope, MXD6 formed a dispersed phase, and had a maximum diameter of 300 nm. The AA content of the hollow molded article is 6 ppm, the sensory test evaluation is 0.6, the oxygen permeation amount is 0.20 cc / one container, 24 hr.atm, the appearance is transparent within a practical range, and the mold stain is small. I was not able to admit.
[0160]
(Example 4)
Using 0.5 parts by weight of MXD6 (e) with respect to 100 parts by weight of PET (c), a hollow molded body is molded by the method of evaluation method (14), and the CT content, CM content, The AA content was measured. In addition, mold stain evaluation was also performed.
Table 3 shows the properties of the obtained hollow molded body and the results of evaluation of mold contamination.
As a result of observation with a transmission electron microscope, MXD6 formed a dispersed phase, and the maximum diameter was 350 nm. The AA content of the hollow molded article was 10 ppm, the sensory evaluation was 0.7, the appearance was transparent in a practical range, and no mold contamination was observed.
[0161]
(Comparative Example 1)
Using 1.0 part by weight of MXD6 (e) with respect to 100 parts by weight of PET (a), a hollow molded body was molded by the method of evaluation method (14), and the CT content, CM content, The AA content was measured. In addition, mold stain evaluation was also performed.
Table 3 shows the properties of the obtained hollow molded body and the results of evaluation of mold contamination.
As a result of observation with a transmission electron microscope, MXD6 formed a dispersed phase, and the maximum diameter was 560 nm. The AA content of the hollow molded article was as low as 9 ppm, and the organoleptic test evaluation was 0.8. No stain on the mold was observed, but the transparency was poor and the practicality was poor.
[0162]
(Comparative Example 2)
Using 1.0 part by weight of MXD6 (f) with respect to 100 parts by weight of PET (a), a hollow molded body was molded by the method of evaluation method (14), and the CT content, CM content, The AA content was measured. In addition, mold stain evaluation was also performed.
Table 3 shows the properties of the obtained hollow molded body and the results of evaluation of mold contamination.
As a result of observation with a transmission electron microscope, MXD6 formed a dispersed phase, and the maximum diameter was 640 nm. No mold contamination of the hollow molded body was observed, but the AA content was 17 ppm, and the sensory test evaluation was 2.1, which was different from that of blank distilled water. In addition, transparency was poor, and practicality was poor.
[0163]
(Comparative Example 3)
Using 0.5 part by weight of MXD6 (g) with respect to 100 parts by weight of PET (a), a hollow molded body was molded by the method of evaluation method (14), and the CT content, CM content, The AA content was measured. In addition, mold stain evaluation was also performed.
Table 3 shows the properties of the obtained hollow molded body and the results of evaluation of mold contamination.
As a result of observation with a transmission electron microscope, MXD6 formed a dispersed phase and had a maximum diameter of 550 nm. No mold contamination of the hollow molded body was observed, but the AA content was 19 ppm, and the sensory evaluation was 2.3, which was different from that of the blank distilled water. In addition, transparency was poor, and practicality was poor.
[0164]
(Comparative Example 4)
Using 0.5 part by weight of MXD6 (d) with respect to 100 parts by weight of PET (b), a hollow molded body was molded by the method of evaluation method (14), and the CT content, CM content, The AA content was measured. In addition, mold stain evaluation was also performed.
Table 3 shows the properties of the obtained hollow molded body and the results of evaluation of mold contamination.
As a result of observation with a transmission electron microscope, MXD6 formed a dispersed phase and had a maximum diameter of 340 nm. Although the AA content of the hollow molded article was 9 ppm and the sensory evaluation was 0.9, the transparency was poor and the practicality was poor. In addition, considerable deposits were observed on the mold stains.
[0165]
(Comparative Example 5)
Using 3.0 parts by weight of MXD6 (g) with respect to 100 parts by weight of PET (b), a hollow molded body was molded by the method of evaluation method (14), and the CT content, CM content, The AA content was measured. In addition, mold stain evaluation was also performed.
Table 3 shows the properties of the obtained hollow molded body and the results of evaluation of mold contamination.
As a result of observation with a transmission electron microscope, MXD6 formed a dispersed phase and had a maximum diameter of 580 nm. The AA content of the hollow molded body was 23 ppm, and the sensory evaluation was 2.7, which was different from that of the blank distilled water. In addition, transparency was poor, and practicality was poor.
[0166]
(Comparative Example 6)
Using 0.5 part by weight of MXD6 (f) with respect to 100 parts by weight of PET (c), a hollow molded body is molded by the method of evaluation method (14), and the CT content, CM content, The AA content was measured. In addition, mold stain evaluation was also performed.
Table 3 shows the properties of the obtained hollow molded body and the results of evaluation of mold contamination.
As a result of observation with a transmission electron microscope, MXD6 formed a dispersed phase and had a maximum diameter of 540 nm. No mold contamination of the hollow molded body was observed, but the AA content was as high as 20 ppm, and the sensory test evaluation was 2.6, which was different from that of blank distilled water. In addition, transparency was poor, and practicality was poor.
[0167]
(Comparative Example 7)
Using 1.0 part by weight of MXD6 (g) with respect to 100 parts by weight of PET (c), a hollow molded body was molded by the method of evaluation method (14), and the CT content, CM content, The AA content was measured. In addition, mold stain evaluation was also performed.
Table 3 shows the properties of the obtained hollow molded body and the results of evaluation of mold contamination.
As a result of observation with a transmission electron microscope, MXD6 formed a dispersed phase, and the maximum diameter was 370 nm. The appearance of the hollow molded article was transparent in a practical range, and no mold contamination was observed. However, the AA content was as high as 22 ppm, and the sensory evaluation was 2.7. Was.
[0168]
(Comparative Example 8)
Using 0.5 parts by weight of MXD6 (h) with respect to 100 parts by weight of PET (c), a hollow molded body is molded by the method of evaluation method (14), and the CT content, CM content, The AA content was measured. In addition, mold stain evaluation was also performed.
Table 3 shows the properties of the obtained hollow molded body and the results of evaluation of mold contamination.
As a result of observation with a transmission electron microscope, MXD6 formed a dispersed phase, and the maximum diameter was 560 nm. No mold contamination of the hollow molded body was observed, but the AA content was as high as 19 ppm, and the sensory test evaluation was 2.5, which was different from that of blank distilled water. In addition, transparency was poor, and practicality was poor.
[0169]
(Comparative Example 8)
Using only PET (a), a hollow molded body was formed by the method of evaluation method (14), and the mold contamination was also evaluated.
Table 3 shows the properties of the obtained hollow molded body and the results of evaluation of mold contamination.
[0170]
[Table 3]

[0171]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to the polyester composition of this invention, a hollow molded object, a sheet-like material, and a stretched film which are excellent in flavor retention and transparency, and hardly generate mold stains during molding can be obtained.

Claims (12)

A polyester composition obtained by melt-mixing 100 parts by weight of a polyester (A) whose main repeating unit is ethylene terephthalate and 0.01 to 30 parts by weight of a polyamide containing metaxylylene group (B), A polyester composition, wherein the maximum diameter of the dispersed phase in the polyester composition is 400 nm or less. A ratio of the melt viscosity of the polyester (A) and the meta-xylylene group-containing polyamide (B) at 290 ° C. [melt viscosity of the meta-xylylene group-containing polyamide (B) / melt viscosity of the polyester (A)] is 0.001 or more; The polyester composition according to claim 1, wherein the content is 0.3 or less. The polyester composition according to claim 1 or 2, wherein the metaxylylene group-containing polyamide (B) satisfies both of the following formulas (1) and (2).
AEG + CEG ≧ 150 (1)
AEG / CEG ≧ 2.0 (2)
(In the formulas (1) and (2), AEG represents the terminal amino group concentration (μmol / g) of the metaxylylene group-containing polyamide, and CEG represents the terminal carboxyl group concentration (μmol / g) of the metaxylylene group-containing polyamide.) The polyester composition according to any one of claims 1 to 3, wherein the acetaldehyde content in the polyester composition is 15 ppm or less. The content of the cyclic ester trimer contained in the polyester (A) whose main repeating unit is ethylene terephthalate is 0.7% by weight or less, according to any one of claims 1 to 4, wherein Polyester composition. When the polyester (A) whose main repeating unit is ethylene terephthalate is melted at a temperature of 290 ° C. for 60 minutes, the amount of the cyclic ester trimer increased by 0.50% by weight or less. The polyester composition according to any one of claims 1 to 5, wherein A molded article obtained by molding the polyester composition according to any one of claims 1 to 6. A molded article obtained by molding the polyester composition according to any one of claims 1 to 6, wherein the content of the metaxylylene group-containing cyclic amide monomer is 0.5% by weight or less. . A polyester composition, characterized in that the polyester composition according to any one of claims 1 to 6 has a haze of 20% or less in a molded article having a thickness of 5 mm at 290 ° C. A molded article according to claim 7, wherein the molded article is a hollow molded article. A molded article according to claim 7, wherein the molded article is a sheet. A molded article according to claim 7, wherein the molded article is a stretched film obtained by stretching the sheet-like article according to claim 11 in at least one direction.