JP2004059908A - Polyester composition and polyester wrapping material comprising the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester composition excellent in transparency, heat stability and flavor retention or transparency, heat stability, flavor retention and gas barrier properties, and scarcely pollutes a mold during molding, and to provide a polyester wrapping material comprising the same. <P>SOLUTION: The polyester composition comprising 100 pts.wt. of a thermoplastic polyester and 0.1-50 pts.wt. of a partial aromatic polyamide, characteristically contains 0.1-300 ppm of an alkali metal atom in the polyester composition. <P>COPYRIGHT: (C)2004,JPO

Description

【００９４】
【化２】

【００９５】
【化３】

【００９６】
【化４】

【００９７】
（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）
【００９８】
化学式（Ｂ−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、
【００９９】
【化５】

または
【０１００】
【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。
【０１０１】
化学式（Ｂ−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。
【０１０２】
化学式（Ｂ−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（Ｂ−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。
【０１０３】
本発明に用いられる部分芳香族ポリアミド中の全アルカリ金属の含有量（前記リン系安定剤に含まれるアルカリ金属原子の量と前記アルカリ金属化合物に含まれるアルカリ金属原子の量との合計量）が、同ポリアミド中のリン原子の含有量の１．０〜６．０倍モルであることが好ましい。下限はより好ましくは１．５倍モル、さらに好ましくは２．０倍モル、特に好ましくは２．３倍モル、最も好ましくは２．５倍モルであり、上限はより好ましくは、５．５倍モル、更に好ましくは５．０倍モルである。全アルカリ金属の含有量がリン原子含有量の１．０倍モルより少ないと、ゲル化が促進されやすくなる。一方、全アルカリ金属の含有量がリン原子含有量の６．０倍モルより多いと、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かえってゲル化が促進され不経済である。
【０１０４】
本発明で使用する前記化学式（Ａ）および化学式（Ｂ−１）〜（Ｂ−４）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。
【０１０５】
本発明で用いられる部分芳香族ポリアミドに前記リン化合物や前記アルカリ金属含有化合物を配合するには、ポリアミドの重合前の原料、重合中にこれらを添加するかあるいは前記重合体に溶融混合してもよい。
またこれらの化合物は同時に添加してもよいし、別々に添加してもよい。
【０１０６】
本発明に用いられる部分芳香族ポリアミドの相対粘度は、１．３〜４．０、好ましくは１．５〜３．０、より好ましくは１．７〜２．５、さらに好ましくは１．８〜２．０の範囲である。相対粘度が１．３以下では分子量が小さすぎて、本発明のポリエステル組成物からなる包装材料の機械的性質に劣ることがある。逆に相対粘度が４．０以上では、前記ポリアミドの重合に長時間を要し、ポリマーの劣化や好ましくない着色の原因となる場合があるだけでなく、生産性が低下しコストアップ要因となることがある。
【０１０７】
また、本発明に用いられる部分芳香族ポリアミドの末端アミノ基濃度（μｍｏｌ／ｇ）をＡＥＧ、また部分芳香族ポリアミドの末端カルボキシル基濃度（μｍｏｌ／ｇ）をＣＥＧとした場合、ＣＥＧに対するＡＥＧの比（ＡＥＧ／ＣＥＧ）が、１．０以上であることが好ましい。部分芳香族ポリアミド中の末端カルボキシル基濃度に対する末端アミノ基濃度の比（ＡＥＧ／ＣＥＧ）が１．０より小さい場合は、本発明のポリエステル包装材料の風味保持性が乏しくなり、このようなポリエステル包装材料は低フレーバー飲料用の容器としては実用性に乏しい場合がある。また、部分芳香族ポリアミド中の末端カルボキシル基濃度に対する末端アミノ基濃度の比（ＡＥＧ／ＣＥＧ）が２０を超える場合は、得られたポリエステル包装材料の着色が激しくなり商品価値がなくなるので好ましくない。
【０１０８】
本発明に用いられる部分芳香族ポリアミドのチップの形状は、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５〜３０ｍｇ／個の範囲が実用的である。
【０１０９】
本発明のポリエステル組成物を下記の測定法（５）に記載した方法で射出成形して得られた成形体のアセトアルデヒド含有量（Ａ_ｔ）（ｐｐｍ）と、射出成形前のポリエステル組成物のアセトアルデヒド含有量（Ａ_０）（ｐｐｍ）との差（Ａ_ｔ−Ａ_０）が、２０ｐｐｍ以下、好ましくは１５ｐｐｍ以下、さらに好ましくは１０ｐｐｍ以下、最も好ましくは５ｐｐｍ以下であることが好ましい。射出成形前後のアセトアルデヒド含有量の差　（Ａ_ｔ−Ａ_０）が２０ｐｐｍを超える場合には、得られたポリエステル包装材料の香味保持性が悪くなる。また、射出成形前後のアセトアルデヒド含有量の差（Ａ_ｔ−Ａ_０）の下限は１ｐｐｍであり、これ以下に低減するにはポリエステル包装材料の生産条件を非生産的な条件にしなければならず、不経済である。
【０１１０】
射出成形後のアセトアルデヒド含有量（Ａ_ｔ）と射出成形前のアセトアルデヒド含有量（Ａ_０）との差（Ａ_ｔ−Ａ_０）が２０ｐｐｍ以下のポリエステル組成物は、アセトアルデヒド含有量が５ｐｐｍ以下の熱可塑性ポリエステルか、あるいはアセトアルデヒド含有量が１０ｐｐｍ以下で、かつ残存する重縮合触媒を失活処理した熱可塑性ポリエステルを構成成分として用いることによって得ることができる。熱可塑性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熱可塑性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。また重縮合触媒を失活させる別の手段として、リン化合物を溶融重縮合後または固相重合後のポリエステルの溶融物に添加、混合して重合触媒を不活性化する方法が挙げられる。
【０１１１】
また、前記の差（Ａ_ｔ−Ａ_０）が２０ｐｐｍ以下のポリエステル組成物は、アセトアルデヒド含有量が１０ｐｐｍ以下の熱可塑性ポリエステルと部分芳香族ポリアミドとからなるポリエステル組成物を水や水蒸気または水蒸気含有気体と接触処理することによっても得ることが出来る。
【０１１２】
本発明のポリエステル包装材料は、前記ポリエステル包装材料中のアルカリ金属原子含有量が、０．１〜３００ｐｐｍの範囲内にあることを特徴とする。
【０１１３】
前記ポリエステル包装材料中のアルカリ金属原子含有量の下限は、好ましくは１ｐｐｍであり、より好ましく５ｐｐｍであることが好ましい。また前記ポリエステル包装材料中のアルカリ金属原子含有量の上限は、好ましくは２７０ｐｐｍであり、より好ましくは２５０ｐｐｍであり、さらに好ましくは２００ｐｐｍであることが好ましい。
【０１１４】
前記ポリエステル包装材料中のアルカリ金属原子含有量が０．１ｐｐｍ未満の場合は、着色が激しかったり、焼けすじや未溶融物が発生しやすくなり、その結果、ポリエステル包装材料の外観が悪くなる。一方、前記ポリエステル包装材料中のアルカリ金属原子含有量が３００ｐｐｍより多い場合は、焼けすじや未溶融物の発生はほとんどみられないが、透明性や香味保持性が悪くなる。
【０１１５】
本発明のポリエステル包装材料中のアセトアルデヒド含有量は２０ｐｐｍ以下、好ましくは１５ｐｐｍ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包装材料中のアセトアルデヒド含有量が２０ｐｐｍを超える場合には、ポリエステル包装材料の香味保持性が悪くなる。また、ポリエステル包装材料中のアセトアルデヒド含有量の下限値は３ｐｐｍであり、これ以下に低減するには採算を度外視した成形となり問題である。
【０１１６】
本発明のポリエステル包装材料は、これを２９０℃で３０分間溶融処理した時のアセトアルデヒド含有量の増加量（△ＡＡ）（ｐｐｍ）が、２０ｐｐｍ以下、好ましくは１５ｐｐｍ以下、さらに好ましくは１３ｐｐｍ以下、である。溶融処理した時のアセトアルデヒド含有量の増加量（△ＡＡ）（ｐｐｍ）が２０ｐｐｍを超える場合は、使用済み後のＰＥＴボトルなどのリサイクル回収品を一部用いてポリエステル包装材料を成形する際、得られたポリエステル包装材料のＡＡ含有量を目的の値に低下させることが非常に困難となったり、またバージンＰＥＴ樹脂へのリサイクル回収品の混合比率を極端に低下させなければならなくなる。
【０１１７】
ポリエステル包装材料を２９０℃で３０分間溶融処理した時の前記環状エステル３量体の増加量（△ＣＴ_２）を０．４０重量％以下に維持するためには、２９０℃の温度で３０分間溶融処理した時の環状エステル３量体の増加量（△ＣＴ_１）が０．４０重量％以下、好ましくは０．３５重量％以下、さらに好ましくは０．３０重量％以下の熱可塑性ポリエステルを用いることが必要である。２９０℃の温度で３０分間溶融処理した時の環状エステル３量体の増加量（△ＣＴ_１）が０．４０重量％を越える熱可塑性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。
【０１１８】
２９０℃の温度で３０分間溶融処理した時の環状エステル３量体の増加量（△ＣＴ_１）が０．４０重量％以下である熱可塑性ポリエステルは、溶融重縮合後や固相重合後に得られた熱可塑性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。熱可塑性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、前記したと同じ方法を用いることができる。
【０１１９】
なお、熱可塑性ポリエステルが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。
本発明のポリエステル包装材料中の熱可塑性ポリエステル由来の環状エステル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０．５０重量％以下、さらに好ましくは０．４０重量％以下であることが好ましい。ポリエステル包装材料中の熱可塑性ポリエステル由来の環状エステル３量体の含有量が０．７０重量％を超える場合には、加熱金型表面へのオリゴマ−付着が急激に増加し、これが原因で得られた中空成形体の透明性が非常に悪化するとともに、香味保持性も悪くなり問題である。
【０１２０】
ポリエステル包装材料中の熱可塑性ポリエステル由来の環状エステル３量体の含有量を０．７０重量％以下に維持するためには、ポリエステル組成物中の前記環状エステル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０．５０重量％以下、さらに好ましくは０．４０重量％以下であることが必要である。ポリエステル包装材料が耐熱性中空成形体の場合には、成形に用いるポリエステル組成物中の環状エステル３量体の含有量が０．７０重量％を超える場合には、加熱金型表面への環状エステル３量体等のポリエステル由来のオリゴマ−付着が経時的に増加し、金型清浄化のための掃除に多大な労力がかると同時に成形中断による経済的な損失をこうむることになる。下限値は０．１０重量％であり、これ以下に低減するには採算を度外視したポリエステルの製造条件を採用せねばならず、問題である。
【０１２１】
本発明のポリエステル包装材料中のメタキシリレン基含有環状アミド１量体の含有量は０．３重量％以下、好ましくは０．２８重量％以下、さらに好ましくは０．２５重量％以下であることが好ましい。ポリエステル包装材料中の前記環状アミド１量体の含有量が０．３重量％を超える場合には、ポリエステル包装材料に充填された内容物の香味保持性が悪くなり問題である。
【０１２２】
これを達成するためには、本発明のポリエステル組成物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０．３重量％以下、好ましくは０．２８重量％以下、さらに好ましくは０．２５重量％以下であることが好ましい。
【０１２３】
ポリエステル組成物中の環状アミド１量体の含有量が０．３重量％を超える場合には、耐熱性が向上したポリエステル包装材料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。前記ポリエステル組成物中または前記ポリエステル包装材料中の、前記環状アミド１量体の含有量の下限は、経済的な理由などから、０．００１ｐｐｍであることが好ましい。環状アミド１量体は下記に記載する高速液体クロマトグラフ法によって測定する。
【０１２４】
なお、前記メタキシリレン基含有ポリアミドには、出発物質として使用するジアミンとジカルボン酸とから構成される環状アミド１量体、環状アミド２量体、環状アミド３量体及び環状アミド４量体等の環状オリゴマ−、前記ジカルボン酸および前記ジアミン等の未反応モノマ−、および前記ジアミンと前記ジカルボン酸とからなる線状２量体、線状３量体等の線状オリゴマ−が含まれている。重縮合方法や重縮合条件、あるいは生成ポリアミドの分子量等によってもそれらの含有量は異なるが、一例として環状アミド１量体は０．２〜２．０重量％、環状アミド２量体は０．１〜２．０重量％、環状アミド３量体は０．１〜１．０重量％、環状アミド４量体は０．００５〜０．５重量％、線状オリゴマー類は１〜５０００ｐｐｍのオーダー、また未反応モノマ−類は０．１〜２０００ｐｐｍのオーダーである。
【０１２５】
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、環状オリゴマーの化学式は下記の式で表され、ｎ＝１の場合が環状アミド１量体である。
【０１２６】
【化７】

（上記式１中、ｎは１〜４の整数を表す。）
【０１２７】
本発明のポリエステル組成物やポリエステル包装材料中の環状アミド１量体の含有量を前記の値に調整する方法は、特に制限はなく、例えば下記のようにして製造することができる。すなわち、熱可塑性ポリエステルに対するメタキシリレン基含有ポリアミドの配合量に応じて、前記ポリエステル組成物中やポリエステル包装材料中の環状アミド１量体の含有量が本発明の請求範囲の値を満足するように、環状アミド１量体含有量を減少させたメタキシリレン基含有ポリアミドを用いることによって達成することができる。また、メタキシリレン基含有ポリアミドを含むポリエステル組成物、あるいは前記ポリエステル組成物から得られたポリエステル包装材料を水や有機溶剤などによって、前記の環状体を抽出除去することによっても達成することができる。前記環状アミド１量体含有量の少ないメタキシリレン基含有ポリアミドを製造する方法も何ら制限はなく、水や有機溶剤による抽出、重縮合条件の変更、減圧加熱処理およびこれらの方法を組合わせた方法等を挙げることができる
【０１２８】
本発明のポリエステル包装材料の極限粘度は、好ましくは０．５５〜１．００デシリットル／グラム、より好ましくは０．５８〜０．９５デシリットル／グラム、さらに好ましくは０．６０〜０．９０デシリットル／グラムの範囲である。
【０１２９】
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、染料や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。
【０１３０】
また、本発明のポリエステル包装材料がフイルムの場合には、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配合させることができる。
本発明のポリエステル包装材料は、公知の製造方法によって得ることができる。
【０１３１】
以下には、代表例として、熱可塑性ポリエステルがポリエチレンテレフタレート（ＰＥＴ）の場合、種々のポリエステル包装材料の簡単な製法を説明する。　本発明のポリエステル包装材料用の樹脂組成物は、従来公知の方法により前記の熱可塑性ポリエステルと前記のポリアミド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熱可塑性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。
【０１３２】
さらに、前記ポリアミドを粉砕して用いてもよい。特に前記ポリアミドを少量用いる組成物の場合は好都合である。粉砕した場合の粒径は約１０メッシュ以下が好ましい。また前記ポリアミドをヘキサフロロイソプロパノールなどの溶剤に溶解させた溶液を熱可塑性ポリエステルのチップの表面に付着させる方法、前記ポリアミド製の部材が存在する空間内で、前記熱可塑性ポリエステルを前記部材に衝突接触させて前記熱可塑性ポリエステルチップ表面に前記ポリアミドを付着させる方法などが挙げられる。
【０１３３】
本発明のポリエステル包装材料がシート状物である場合は、例えば、押出機とダイを備えた一般的なシート成形機を用いて製造することができる。
またこのシート状物は、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。また、本発明のポリエステル包装材料は、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、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。
【０１３４】
本発明のポリエステル包装材料が延伸フィルムである場合は、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。
【０１３５】
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。
【０１３６】
中空成形体を製造するにあたっては、本発明のＰＥＴ組成物から成形したプ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２６０〜３１０℃の範囲である。延伸温度ば通常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。
【０１３７】
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。
【０１３８】
また、本発明のポリエステル包装材料は、積層成形体や積層フイルム等の一構成層であることができる。特に、ＰＥＴとの積層体の形で容器等に使用される。積層成形体の例としては、本発明のポリエステル包装材料からなる外層と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包装材料からなる内層と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包装材料を含む中間層と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包装材料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包装材料を含む中間層と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。
【０１３９】
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熱可塑性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。
【０１４０】
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、フイルム状物、板状物、中空体、容器等、種々の形状で使用可能である。
【０１４１】
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。
【０１４２】
本発明のポリエステル包装材料は、ラミネート金属板の片面あるいは両面にラミネートするフィルムであることができる。用いられる金属板としては、ブリキ、ティンフリースチール、アルミニウム等が挙げられる。
【０１４３】
ラミネート法としては、従来公知の方法が適用でき、特に限定されないが、有機溶剤フリーが達成でき、残留溶剤による食料品の味や臭いに対する悪影響が回避できるサーマルラミネート法で行うことが好ましい。なかでも、金属板の通電加工によるサーマルラミネート法が特に推奨される。また、両面ラミネートの場合は、同時にラミネートしてもよいし、逐次でラミネートしてもよい。
なお、接着剤を用いてフィルムを金属板にラミネートできることはいうまでもない。
【０１４４】
また、金属容器は、前記ラミネート金属板を用いて成形することによって得られる。前記金属容器の成形方法は特に限定されるものではない。また、金属容器の形状も特に限定されるものではないが、絞り成型、絞りしごき成型、ストレッチドロー成型等の成型加工により製缶されるいわゆる２ピース缶への適用が好ましいが、例えばレトルト食品やコーヒー飲料等の食料品を充填するのに好適な天地蓋を巻締めて内容物を充填する、いわゆる３ピース缶へも適用可能である。
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。
【０１４５】
【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。
【０１４６】
（評価方法）
（１）ポリエステル、ポリエステル組成物およびポリエステル包装材料の極限粘度（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。（単位はデシリットル／グラム）
【０１４７】
（２）ポリエステル中に共重合されたジアルキレングリコ−ル含有量
メタノ−ルにより分解し、ガスクロマトグラフィ−によりジアルキレングリコ−ル量を定量し、全グリコ−ル成分に対する割合（モル％）で表した。ＰＥＴの場合はＤＥＧ含有量、ＰＴＴの場合はＤＰＧ含有量である。
【０１４８】
（３）ポリエステル、ポリエステル組成物およびポリエステル包装材料の環状エステルオリゴマーの含有量（重量％）
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オリゴマーを定量した。ＰＥＴの場合は環状３量体（ＣＴ含有量）、ＰＴＴの場合は環状２量体（ＣＤ含有量）である。
【０１４９】
（４）ポリエステル、ポリエステル組成物およびポリエステル包装材料のアセトアルデヒド含有量（以下「ＡＡ含有量」という）（ｐｐｍ）
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あと、窒素シール下にアンプル上部を溶封し、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。
【０１５０】
（５）ポリエステル組成物の射出成形前後のアセトアルデヒド含有量の差（以下「Ａ_ｔ−Ａ_０」という）（ｐｐｍ）
窒素気流下で５０〜１００℃で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℃の水で冷却した段付平板金型（表面温度約２２℃）を用いて段付成形板を射出成形する。得られた段付成形板は、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、１個の重量は約１４６ｇである。２ｍｍ厚みのプレートより試料を採取し、（４）の測定方法によってアセトアルデヒド含有量（Ａ_ｔ）を求め、下記の式より射出成形前後のアセトアルデヒド含有量の差を求める。
射出成形前後のアセトアルデヒド含有量の差（Ａ_ｔ−Ａ_０）（ｐｐｍ）＝
射出成形後の段付成形板のアセトアルデヒド含有量（Ａ_ｔ）（ｐｐｍ）−射出成形前の乾燥したポリエステル組成物のアセトアルデヒド含有量（Ａ_０）（ｐｐｍ）
【０１５１】
（６）ポリエステル包装材料の溶融処理時のアセトアルデヒド含有量の増加量（以下「△ＡＡ」という）（ｐｐｍ）
ポリエステル包装材料より約１〜３ｍｍ角の試料３ｇを採取し、これをガラス製試験管に入れて約５０〜７０℃で真空乾燥したあと常圧窒素雰囲気下で２９０℃のオイルバスに３０分浸漬させて溶融処理する。溶融処理時のアセトアルデヒド含有量の増加量は、次式により求める。
融処理時のアセトアルデヒド含有量の増加量（ｐｐｍ）＝
溶融処理後のアセトアルデヒド含有量（ｐｐｍ）−溶融処理前の乾燥後のアセトアルデヒド含有量（ｐｐｍ）
【０１５２】
（７）ポリエステルの溶融処理時の環状エステル３量体増加量（以下「△ＣＴ_１量」という）（重量％）およびポリエステル包装材料の溶融処理時の環状エステル３量体増加量（以下「△ＣＴ_２量」という）（重量％）
【０１５３】
乾燥したポリエステルチップあるいはポリエステル包装材料、３ｇをガラス製試験管に入れ、常圧窒素雰囲気下で２９０℃のオイルバスに３０分浸漬させ溶融処理する。ポリエステル包装材料は約１〜３ｍｍ角の大きさにカットして測定に供する。
【０１５４】
ポリエステル溶融処理時の環状エステル３量体増加量（△ＣＴ_１量）およびポリエステル包装材料の溶融処理時の環状エステル３量体増加量（△ＣＴ_２量）は、次式により求める。
溶融処理時の環状エステル３量体増加量（重量％）＝
溶融処理後の環状エステル３量体含有量（重量％）−　溶融処理前の環状エステル３量体含有量（重量％）
【０１５５】
（８）部分芳香族ポリアミドの相対粘度（以下「Ｒｖ」という）
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
【０１５６】
（９）部分芳香族ポリアミド、ポリエステル組成物およびポリエステル包装材料のナトリウム原子含有量（以下「Ｎａ含有量」という）
試料を白金るつぼにて灰化分解し、６ｍｏｌ／Ｌ塩酸を加えて蒸発乾固する。１．２ｍｏｌ／Ｌ塩酸で溶解し、原子吸光で定量して求めた。
【０１５７】
（１０）ファインの含有量の測定
樹脂約０．５ｋｇを、ＪＩＳ−Ｚ８８０１による呼び寸法１．７ｍｍの金網をはった篩（直径３０ｃｍ）の上に乗せ、テラオカ社製揺動型篩い振トウ機ＳＮＦ−７で１８００ｒｐｍで１分間篩った。この操作を繰り返し、樹脂を合計２０ｋｇ篩った。
篩の下にふるい落とされたファインは、イオン交換水で洗浄し岩城硝子社製Ｇ１ガラスフィルターで濾過して集めた。これらをガラスフィルターごと乾燥器内で１００℃で２時間乾燥後、冷却して秤量した。再度、イオン交換水で洗浄、乾燥の同一操作を繰り返し、恒量になったことを確認し、この重量からガラスフィルターの重量を引き、ファイン重量を求めた。ファイン含有量は、ファイン重量／篩いにかけた全樹脂重量、である。
【０１５８】
（１１）金型汚れの評価
窒素ガスを用いた乾燥機で乾燥した熱可塑性ポリエステルチップの所定量および窒素ガスを用いた乾燥機で乾燥した部分芳香族ポリアミドの所定量をドライブレンドし、これを用いて名機製作所製Ｍ−１５０Ｃ（ＤＭ）射出成型機により樹脂温度２８５℃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熱固定し、１０００ｃｃ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
○　：　連続成形試験後にわずかに付着物あり
△　：　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
【０１５９】
（１２）中空成形体の透明性
ａ）非耐熱中空成形体：実施例１において記載した方法で成形した中空成形体の外観を目視で観察し、下記の評価基準によって評価した。
ｂ）耐熱中空成形体：（１３）の成形後に得られた中空成形体の外観を目視で観察し、下記の評価基準によって評価した。短期透明性は１０本成形後、連続成形透明性は２０００本後で評価した。
（評価基準）
◎　：　透明である
○　：　実用的な範囲で透明であり、未溶融物等の異物は見られない
△　：　実用的な範囲で透明であるが、未溶融物等の異物が認められる。
×　：　透明性に劣る、着色が認められる、又は未溶融物が見られる
【０１６０】
（１３）官能試験
ａ）非耐熱中空成形体：沸騰した蒸留水を５０℃に冷却後、中空成形体に入れ密栓後３０分保持し、その後５０℃で１０日間放置し、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。
ｂ）耐熱中空成形体：中空成形体に沸騰した蒸留水を入れ密栓後３０分保持し、その後５０℃で５日間放置し、開栓後前記と同様に風味、臭いなどの試験を行った。
（評価基準）
◎　　：　異味、臭いを感じない
○　　：　ブランクとの差をわずかに感じる
△　　：　ブランクとの差を感じる
×　　：　ブランクとのかなりの差を感じる
××　：　ブランクとの非常に大きな差を感じる
【０１６１】
（１４）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。
（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））
中空成形体の評価試験に用いたＰＥＴ（Ａ）〜（Ｅ）の特性を表１に示す。これらのＰＥＴは、Ｇｅ系触媒を用いて連続溶融重縮合−固相重合装置で重合したものである。
なお、これらのＰＥＴのＤＥＧ含有量は約２．８モル％、ＰＥＴ（Ａ）〜（Ｃ）のファイン含有量は約７０ｐｐｍ以下、またＰＥＴ（Ｄ）、（Ｅ）のファイン含有量は約５００ｐｐｍであった。
【０１６２】
【表１】

【０１６３】
（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（Ｎｙ−ＭＸＤ６））
試験に使用したＮｙ−ＭＸＤ６（Ｆ）〜Ｎｙ−ＭＸＤ６（Ｉ）の特性を表２に示す。
Ｎｙ−ＭＸＤ６（Ｆ）〜Ｎｙ−ＭＸＤ６（Ｈ）は、耐圧重縮合釜中でメタキシリレンジアミンとアジピン酸をＮａＯＨやＮａＨ_２ＰＯ_２・Ｈ_２Ｏの存在下において加圧下および常圧下に加熱して重縮合する回分式方法により得たものである。ナトリウム量としては次亜リン酸ナトリウムと水酸化ナトリウムのナトリウム原子の合計量としてリン原子の３．０倍モルになるようにした。
Ｎｙ−ＭＸＤ６（Ｉ）も、Ｎｙ−ＭＸＤ６（Ｈ）と同様の重合方法により得たものである。上記のリン原子含有化合物、およびアルカリ化合物は添加しなかった。これらのＮｙ−ＭＸＤ６の二次転移点は約６５℃である。
【０１６４】
【表２】

【０１６５】
（実施例１）
ＰＥＴ（Ｃ）１００重量部に対してＮｙ−ＭＸＤ６（Ｇ）２重量部を用い、これらをそれぞれ評価方法（１２）に記した乾燥方法により乾燥後ドライブレンドし、これを用いて名機製作所製Ｍ−１５０Ｃ（ＤＭ）射出成型機により樹脂温度２８５℃でプリフォ−ムを成形した。このプリフォ−ムをコ−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、２０００ｃｃの非耐熱中空成形体を得た。
【０１６６】
得られた中空成形体の特性の評価結果を表３に示す。
ポリエステル組成物のナトリウム含有量は２ｐｐｍ、射出成形前後のアセトアルデヒド含有量の差（Ａ_ｔ−Ａ_０）は８ｐｐｍであり、中空成形体のＡＡ含有量は１０ｐｐｍ、官能試験評価は「◎」、透明性は「◎」であり、透明性および香味保持性に非常に優れた中空成形体を得ることができた。
【０１６７】
（実施例２）
ＰＥＴ（Ｃ）１００重量部に対してＮｙ−ＭＸＤ６（Ｆ）１０重量部を用いて、実施例１と同様にして２０００ｃｃの中空成形体を成形し、評価を行った。
得られた中空成形体の特性の評価結果を表３に示す。
ポリエステル組成物のナトリウム含有量は５９ｐｐｍ、射出成形前後のアセトアルデヒド含有量の差（Ａ_ｔ−Ａ_０）は６ｐｐｍであり、中空成形体のＡＡ含有量は８ｐｐｍ、官能試験評価は「○」、透明性は「◎」であり問題なかった。また酸素バリヤー性も改善されている。
【０１６８】
（実施例３）
ＰＥＴ（Ｃ）１００重量部に対してＮｙ−ＭＸＤ６（Ｆ）３０重量部を用いて、実施例１と同様にして中空成形体を成形し、評価を行った。
得られた中空成形体の特性の価結果を表３に示す。
ポリエステル組成物のナトリウム含有量は１５０ｐｐｍ、射出成形前後のアセトアルデヒド含有量の差（Ａ_ｔ−Ａ_０）は５ｐｐｍであり、中空成形体のＡＡ含有量は６ｐｐｍ、官能試験評価は「○」、透明性は「○」であり問題なかった。
【０１６９】
（比較例１）
ＰＥＴ（Ｄ）１００重量部に対してＮｙ−ＭＸＤ６（Ｉ）１０重量部を用いて、実施例１と同様にして中空成形体を成形し、評価を行った。
得られた中空成形体の特性の評価結果を表３に示す。
ポリエステル組成物のナトリウム含有量は０ｐｐｍ、射出成形前後のアセトアルデヒド含有量の差（Ａ_ｔ−Ａ_０）は１８ｐｐｍであり、中空成形体のＡＡ含有量は２２ｐｐｍ、透明性は「×（着色未溶融物が見られる）」、官能試験評価は「×」と悪く、実用性がないものであった。
【０１７０】
（比較例２）
ＰＥＴ（Ｅ）１００重量部に対してＮｙ−ＭＸＤ６（Ｈ）３０重量部を用いて、実施例１と同様にして中空成形体を成形し、評価を行った。
得られた中空成形体の特性の評価結果を表３に示す。
ポリエステル組成物のナトリウム含有量は３４６ｐｐｍ、射出成形前後のアセトアルデヒド含有量の差（Ａ_ｔ−Ａ_０）は１１ｐｐｍであり、中空成形体のＡＡ含有量は１５ｐｐｍであったが、透明性は「×（透明性に劣る）」、官能試験評価は「××」と悪く、実用性がないものであった。
【０１７１】
（比較例３）
ＰＥＴ（Ｄ）１００重量部を用いて、実施例１と同様にして中空成形体を成形し、評価を行った。
得られた中空成形体の特性の評価結果を表３に示す。
【０１７２】
【表３】

【０１７３】
（実施例４）
ＰＥＴ（Ａ）１００重量部に対してＮｙ−ＭＸＤ６（Ｇ）１０重量部を用いて、評価方法（１２）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４に示す。
ポリエステル組成物の射出成形前後のアセトアルデヒド含有量の差（Ａ_ｔ−Ａ_０）は５ｐｐｍであり、中空成形体のナトリウム含有量は１１ｐｐｍ、中空成形体のＡＡ含有量は９ｐｐｍ、△ＡＡ含有量は１０ｐｐｍ、環状エステル３量体含有量は０．３２重量％、環状エステル３量体含有量の増加量（△ＣＴ_２量）は０．０４重量％、ＣＭ含有量は５３０ｐｐｍ、官能試験評価は「○」、透明性は「○」であり、また金型付着物は認められなかった。
【０１７４】
（実施例５）
ＰＥＴ（Ｂ）１００重量部に対してＮｙ−ＭＸＤ６（Ｆ）２０重量部を用いて、評価方法（１２）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４に示す。
ポリエステル組成物の射出成形前後のアセトアルデヒド含有量の差（Ａ_ｔ−Ａ_０）は５ｐｐｍであり、中空成形体のナトリウム含有量は１０８ｐｐｍ、中空成形体のＡＡ含有量は７ｐｐｍ、△ＡＡ含有量は１０ｐｐｍ、環状エステル３量体含有量は０．３４重量％、環状エステル３量体含有量の増加量（△ＣＴ_２量）は０．０９重量％、ＣＭ含有量は１１００ｐｐｍ、官能試験評価は「○」、透明性は「○」であり、また金型付着物は認められなかった。
【０１７５】
（実施例６）
ＰＥＴ（Ａ）１００重量部に対してＮｙ−ＭＸＤ６（Ｆ）３０重量部を用いて、評価方法（１２）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４に示す。
ポリエステル組成物の射出成形前後のアセトアルデヒド含有量の差（Ａ_ｔ−Ａ_０）は４ｐｐｍであり、中空成形体のナトリウム含有量は１５０ｐｐｍ、中空成形体のＡＡ含有量は５ｐｐｍ、△ＡＡ含有量は８ｐｐｍ、環状エステル３量体含有量は０．３１重量％、環状エステル３量体含有量の増加量（△ＣＴ_２量）は０．０５重量％、ＣＭ含有量は１４００ｐｐｍ、官能試験評価は「○」、透明性は「○」であり、また金型付着物は認められなかった。
【０１７６】
（比較例４）
ＰＥＴ（Ｄ）１００重量部に対してＮｙ−ＭＸＤ６（Ｉ）０．０５重量部を用いて、評価方法（１２）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４に示す。
ポリエステル組成物の射出成形前後のアセトアルデヒド含有量の差（Ａ_ｔ−Ａ_０）は２７ｐｐｍであり、中空成形体のリン含有量は０ｐｐｍ、中空成形体のＡＡ含有量は４１ｐｐｍ、△ＡＡ含有量は３５ｐｐｍ、環状エステル３量体含有量は０．７６重量％、環状エステル３量体含有量の増加量（△ＣＴ_２量）は０．５０重量％、官能試験評価は「××」、透明性は「×」と悪く、また金型汚れもひどかった。
【０１７７】
（比較例５）
ＰＥＴ（Ｅ）１００重量部に対してＮｙ−ＭＸＤ６（Ｈ）３０重量部を用いて、評価方法（１２）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４に示す。
ポリエステル組成物の射出成形前後のアセトアルデヒド含有量の差（Ａ_ｔ−Ａ_０）は７ｐｐｍであり、中空成形体のナトリウム含有量は３４６ｐｐｍ、中空成形体のＡＡ含有量は１３ｐｐｍ、△ＡＡ含有量は１８ｐｐｍ、環状エステル３量体含有量は０．７９重量％、環状エステル３量体含有量の増加量（△ＣＴ_２量）は０．５２重量％、ＣＭ含有量は３８００ｐｐｍ、官能試験評価は「××」、透明性は「×」と悪く、また金型汚れもひどかった。
【０１７８】
【表４】

【０１７９】
【発明の効果】
本発明のポリエステル組成物によれば、透明性、熱安定性および香味保持性、あるいは透明性、熱安定性、香味保持性およびガスバリヤ−性に優れたポリエステル包装材料が得られ、また本発明のポリエステル包装材料は、上述したように、清涼飲料などの飲料用包装材料として非常に好適である。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention is a hollow molded container including a beverage bottle, a film, a polyester composition suitably used as a material of a molded article such as a sheet and a transparent composition comprising the same, excellent in heat stability and flavor retention, The invention also relates to a polyester packaging material having excellent gas barrier properties.
[0002]
[Prior art]
Thermoplastic polyesters such as polyethylene terephthalate (hereinafter sometimes abbreviated as PET) have high industrial value because of their excellent mechanical properties and chemical properties, and thus have high industrial value, such as fibers, films and sheets. Widely used as bottles. Further, thermoplastic polyesters are excellent in heat resistance, transparency and gas barrier properties, and therefore are particularly suitable as a material for packaging materials for beverage filling containers such as juices, soft drinks and carbonated drinks.
[0003]
Such a thermoplastic 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 and stretch blow molded. Generally, the body of the bottle is heat-treated (heat-set) to be formed into a hollow molded container, and the plug of the bottle is generally heat-treated (crystallized of the plug) as necessary.
[0004]
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.
[0005]
In order to solve such a problem, various measures have conventionally been taken to reduce the acetaldehyde content in the thermoplastic polyester molded article. Generally, a method of using a thermoplastic polyester having a reduced AA content by solid-state polymerization of a melt-polycondensed prepolymer, and a method of producing AA during molding using a copolymerized thermoplastic polyester having a lower melting point. Are known, such as a method of lowering the molding temperature during thermoforming and a method of minimizing the shear stress during thermoforming.
[0006]
[Problems to be solved by the invention]
In recent years, containers made of thermoplastic polyesters, mainly polyethylene terephthalate, have come to be used as containers for low-flavor beverages such as mineral water and walon tea. In the case of such beverages, these beverages are generally heat-filled or sterilized by heating after filling, but these containers can be used only by reducing the AA content in the thermoplastic polyester molding material by the method described above. It has been found that the flavor and odor of the contents have not been improved, and improvements are required.
[0007]
As a technique for solving such a problem, a method of using a polyester composition in which a metaxylylene group-containing polyamide resin is added in an amount of 0.05 to less than 1 part by weight based on 100 parts by weight of a thermoplastic polyester resin (Japanese Patent Publication No. No. 6-6662) and a polyester container comprising a polyester composition containing a thermoplastic polyamide and a specific polyamide in which the terminal amino group concentration is regulated within a certain range (Japanese Patent Publication No. 4-71425). However, it has been found that there are still cases where the flavor and odor of beverages are insufficient for containers for low-flavor beverages such as mineral water.
[0008]
On the other hand, a thermoplastic polyester packaging material mainly composed of PET is excellent in gas barrier properties as described above, but is a hollow molded article for contents containing a compound very sensitive to oxygen such as vitamin C. It turned out to be unsatisfactory, and improvements are required.
[0009]
As a technique for solving such a problem, we have proposed a thermoplastic polyester hollow molded article (Japanese Patent Publication No. 4-54702) in which 1 to 100 parts by weight of a metaxylylene group-containing polyamide resin is contained with respect to 100 parts by weight of a thermoplastic polyester resin. No. Gazette). However, it has been found that the flavor and odor of beverages, particularly low-flavor beverages, filled in hollow molded articles made of such a polyester composition are problematic.
[0010]
Further, when the heat-resistant hollow molded body is manufactured using the polyester composition, the body of the hollow molded body is subjected to heat treatment. There is a problem that mold contamination in which foreign matter adheres to the tube is much more likely to occur than in the case of molding using only a thermoplastic polyester resin. This point is still unsolved and needs improvement.
[0011]
In addition, it has been studied to laminate a thermoplastic polyester film having good heat resistance on a metal plate, and to use the laminated metal plate mainly for metal cans for food containers such as soft drinks, beer, and cans. In such applications, a thermoplastic polyester film for laminating metal plates (JP-A-5-339393) having an acetaldehyde content of 20 ppm or less has been proposed in order to improve flavor retention. It has been found that the solution does not completely solve the problem, and improvement is required.
[0012]
An object of the present invention is to solve the above-mentioned problems of the prior art, and is excellent in transparency, heat stability and flavor retention, or transparency, heat stability, flavor retention and gas barrier properties. An object of the present invention is to provide a polyester composition which does not easily cause mold stains at the time and a polyester packaging material comprising the same.
[0013]
[Means for Solving the Problems]
The present inventors use a polyester composition comprising 100 parts by weight of a thermoplastic polyester and 0.1 to 50 parts by weight of a partially aromatic polyamide to obtain transparency and flavor retention, or transparency, flavor retention and As a result of examining a polyester packaging material having excellent gas barrier properties and its production, it was found that the content of alkali metal atoms in the polyester composition or the content of alkali metal atoms in the polyester packaging material was related to transparency and flavor retention. The inventors have found that the present invention has been completed.
[0014]
That is, the polyester composition of the present invention is a polyester composition comprising 100 parts by weight of a thermoplastic polyester and 0.1 to 50 parts by weight of a partially aromatic polyamide, wherein the alkali metal atom content in the polyester composition is It is characterized by being within the range of 0.1 to 300 ppm.
[0015]
The lower limit of the alkali metal atom content in the polyester composition is preferably 1 ppm, and more preferably 5 ppm. The upper limit of the alkali metal atom content in the polyester composition is preferably 270 ppm, and more preferably 250 ppm.
[0016]
When the content of the alkali metal atom in the polyester composition is less than 0.1 ppm, when producing a polyester packaging material using such a polyester composition, the coloring becomes intense, and the gelation easily proceeds. As a result, burn streaks and unmelted materials are easily generated. On the other hand, when the alkali metal atom content in the polyester composition is more than 300 ppm, although the generation of burn streaks and unmelted substances is almost eliminated, the transparency and flavor retention of the obtained polyester packaging material are deteriorated, and The molecular weight decreases, and the mechanical strength decreases.
[0017]
As a method for adjusting the alkali metal atom content in the polyester composition to the range of 0.1 to 300 ppm, the alkali metal content contained in the partially aromatic polyamide is adjusted according to the amount of the partially aromatic polyamide used. For example, a method of adjusting the amount of alkali metal contained in the polyester can be used.
[0018]
The alkali metal atom content in the partially aromatic polyamide 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, fluorescent X-ray It is determined by an analytical method or the like, and can be used properly depending on the concentration of an alkali metal atom.
[0019]
In this case, it is preferable that the thermoplastic polyester is a polyester having ethylene terephthalate as a main repeating unit.
[0020]
In this case, the partially aromatic polyamide is preferably a polyamide containing at least 20 mol% of a structural unit derived from meta-xylylenediamine and dicarboxylic acid in a molecular chain.
[0021]
In this case, it is preferable that the secondary transition point of the partially aromatic polyamide measured by DSC (differential scanning calorimeter) is 50 to 120 ° C.
[0022]
In this case, the acetaldehyde content (A) of a molded product obtained by injection molding the polyester composition_t) (Ppm) and the acetaldehyde content (A) of the polyester composition before injection molding.₀) (Ppm) (A)_t-A₀) Is preferably 20 ppm or less.
[0023]
Here, the acetaldehyde content (A) of the molded product obtained by injection molding the polyester composition_t) Means a stepped plate mold in which a polyester composition dried at 100 ° C. under a nitrogen stream is cooled with water at 10 ° C. at a cylinder temperature of 290 ° C. using an M-150C (DM) injection molding machine manufactured by Meiki Seisakusho. (Surface temperature of about 22 ° C.) means the acetaldehyde content of the resin collected from a 2 mm-thick plate of a stepped molding plate obtained by injection molding using a mold, and the acetaldehyde content of the polyester composition before injection molding. (A₀) Means the acetaldehyde content of the dried polyester composition before injection molding. Then, the difference (A_t-A₀) Is determined by the following equation as described in the section of the measurement method (5) below.
[0024]
Difference in acetaldehyde content before and after injection molding (A_t-A₀) (Ppm)
= Acetaldehyde content of the stepped plate after injection molding (A_t) (Ppm)
-Acetaldehyde content of the dried polyester composition before injection molding (A₀) (Ppm)
[0025]
The polyester packaging material of the present invention is obtained by molding the above-mentioned polyester composition.
In this case, it is preferable that the alkali metal atom content in the polyester packaging material is in the range of 0.1 to 300 ppm.
In this case, it is preferable that the acetaldehyde content in the polyester packaging material is 20 ppm or less.
[0026]
In this case, the amount of increase in acetaldehyde content (ΔAA) (ppm) and the amount of increase in cyclic ester trimer derived from thermoplastic polyester when the polyester packaging material is melted at 290 ° C. for 30 minutes.
(△ CT₂) (% By weight) is preferably 20 ppm or less and 0.40% by weight, respectively.
[0027]
Here, when the polyester packaging material was melted at 290 ° C. for 30 minutes, the increase in acetaldehyde content (ΔAA) (ppm) and the increase in the cyclic ester trimer derived from thermoplastic polyester (ΔCT)₂) (% By weight) is determined by the following equation, as described in the sections of the measuring methods (6) and (7) below.
Increase in acetaldehyde content during melt processing (ΔAA) (ppm) =
Acetaldehyde content after melt treatment (ppm)-Acetaldehyde content after drying before melt treatment (ppm)
[0028]
Cyclic ester trimer increase during melt processing (ΔCT₂) (% By weight) =
Cyclic ester trimer content after melt treatment (wt%)-cyclic ester trimer content before melt treatment (wt%)
[0029]
In this case, the content of the cyclic ester trimer derived from the thermoplastic polyester in the polyester packaging material is preferably 0.70% by weight or less.
[0030]
In this case, the content of the meta-xylylene group-containing cyclic amide monomer in the polyester packaging material is preferably 0.3% by weight or less.
The polyester packaging material of the present invention can be any one of a hollow molded article, a sheet-like material, and a stretched film obtained by stretching the sheet-like material in at least one direction.
[0031]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the polyester composition of the present invention and a polyester packaging material comprising the same will be specifically described.
The thermoplastic polyester used in the present invention is a crystalline thermoplastic polyester mainly obtained from an aromatic dicarboxylic acid component and a glycol component, and more preferably, the aromatic dicarboxylic acid unit has at least 85 mol% of the acid component. It is a thermoplastic polyester containing 90 mol% or more, most preferably a thermoplastic polyester containing an aromatic dicarboxylic acid unit of 95 mol% or more of the acid component.
[0032]
Examples of the aromatic dicarboxylic acid component constituting the thermoplastic polyester used in the present invention include terephthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyl-4,4'-dicarboxylic acid, and diphenoxyethanedicarboxylic acid. Group dicarboxylic acids and functional derivatives thereof.
[0033]
Examples of the glycol component constituting the thermoplastic polyester used in the present invention include alicyclic groups such as ethylene glycol, 1,3-trimethylene glycol, tetramethylene glycol, and cyclohexanedimethanol. And glycol.
Acid components used as a copolymer component in the thermoplastic polyester include terephthalic acid, 2,6-naphthalenedicarboxylic acid, isophthalic acid, diphenyl-4,4'-dicarboxylic acid, diphenoxyethanedicarboxylic acid, and the like. Oxyacids such as aromatic dicarboxylic acid, p-oxybenzoic acid and oxycaproic acid and functional derivatives thereof; adipic acid, sebacic acid, succinic acid, glutaric acid, and dimer acid; Derivatives, alicyclic dicarboxylic acids such as hexahydroterephthalic acid, hexahydroisophthalic acid, and cyclohexanedicarboxylic acid, and functional derivatives thereof, and the like.
[0034]
Examples of the glycol component used as a copolymer component in the thermoplastic polyester include ethylene glycol, 1,3-trimethylene glycol, tetramethylene glycol, diethylene glycol, and neopentyl glycol. Aliphatic glycols such as cyclohexanedimethanol, alicyclic glycols such as cyclohexanedimethanol, 1,3-bis (2-hydroxyethoxy) benzene, bisphenol A, alkylene oxide adducts of bisphenol A, etc. And polyalkylene glycols such as polyethylene glycol and polybutylene glycol.
[0035]
Further, a polyfunctional compound such as trimellitic acid, trimesic acid, pyromellitic acid, tricarballylic acid, glycerin, pentaerythritol, and trimethylolpropane may be used in a range where the thermoplastic polyester is substantially linear. It may be polymerized, or a monofunctional compound such as benzoic acid or naphthoic acid may be copolymerized.
[0036]
As the thermoplastic polyester according to the present invention, a polyester containing 70 mol% or more of a structural unit derived from an aromatic dicarboxylic acid and at least one glycol selected from aliphatic glycols having 2 to 4 carbon atoms is preferable.
[0037]
One preferred example of the thermoplastic polyester used in the present invention is a thermoplastic polyester whose main repeating unit is composed of ethylene terephthalate, and more preferably contains 85 mol% or more of ethylene terephthalate unit, A linear copolymerized thermoplastic polyester containing isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,4-cyclohexanedimethanol, etc. as a component, particularly preferably a line containing 95 mol% or more of ethylene terephthalate units. Thermoplastic polyester.
[0038]
Examples of these linear thermoplastic polyesters include polyethylene terephthalate (hereinafter abbreviated as PET), poly (ethylene terephthalate-ethylene isophthalate) copolymer, poly (ethylene terephthalate-ethylene isophthalate-ethylene-2,6-naphthalate) ) Copolymer, poly (ethylene terephthalate-1,4-cyclohexane dimethylene terephthalate) copolymer, poly (ethylene terephthalate-ethylene-2,6-naphthalate) copolymer, poly (ethylene terephthalate-dioxyethylene terephthalate) Copolymers, poly (ethylene terephthalate-1,3-propylene terephthalate) copolymers, poly (ethylene terephthalate-ethylene cyclohexylene dicarboxylate) copolymers and the like can be mentioned.
[0039]
Another preferable example of the thermoplastic polyester used in the present invention is a thermoplastic polyester whose main repeating unit is composed of ethylene-2,6-naphthalate, and more preferably ethylene-2,6-naphthalate. Is a linear thermoplastic polyester containing 85 mol% or more of styrene units, and particularly preferable is a linear thermoplastic polyester containing 95 mol% or more of ethylene-2,6-naphthalate units.
[0040]
Examples of these linear thermoplastic polyesters include polyethylene-2,6-naphthalate, poly (ethylene-2,6-naphthalate-ethylene terephthalate) copolymer, and poly (ethylene-2,6-naphthalate-ethylene isophthalate). And copolymers such as poly (ethylene-2,6-naphthalate-dioxyethylene-2,6-naphthalate).
[0041]
Another preferred example of the thermoplastic polyester according to the present invention is a thermoplastic polyester whose main structural unit is composed of 1,3-propylene terephthalate, and more preferably 1,3-propylene terephthalate. Is a linear thermoplastic polyester containing 70 mol% or more of terephthalic acid units, and particularly preferable is a linear thermoplastic polyester containing 90 mol% or more of 1,3-propylene terephthalate units.
[0042]
Examples of these linear thermoplastic polyesters include polypropylene terephthalate (PTT), poly (1,3-propylene terephthalate-1,3-propylene isophthalate) copolymer, and poly (1,3-propylene terephthalate-1,4). -Cyclohexane dimethylene terephthalate) copolymer, poly (1,3-propylene terephthalate-1,3-propylene-2,6-naphthalate) copolymer and the like.
[0043]
Still another preferred example of the thermoplastic polyester according to the present invention is a thermoplastic polyester whose main constituent unit is butylene terephthalate, more preferably 70 mol% or more of butylene terephthalate unit. And particularly preferred is a linear thermoplastic polyester containing 90 mol% or more of butylene terephthalate units.
[0044]
Examples of these linear thermoplastic polyesters include polybutylene terephthalate (PBT), poly (butylene terephthalate-butylene isophthalate) copolymer, poly (butylene terephthalate-1,4-cyclohexanedimethylene terephthalate) copolymer, (Butylene terephthalate-butylene-2,6-naphthalate) copolymer, poly (butylene terephthalate-1,3-propylene terephthalate) copolymer, poly (butylene terephthalate-butylene cyclohexylene dicarboxylate) copolymer and the like. Can be
[0045]
Other preferred examples of the thermoplastic polyester according to the present invention other than the above include a thermoplastic polyester whose main structural unit is composed of 1,3-propylene-ethylene-2,6-naphthalate, and a main structural unit whose butylene is Thermoplastic polyesters composed of -ethylene-2,6-naphthalate.
[0046]
The thermoplastic polyester can be manufactured by a conventionally known manufacturing method. That is, in the case of PET, terephthalic acid and ethylene glycol and, if necessary, the above-mentioned copolymerization component are directly reacted to distill water and esterify, and then a Sb compound, Ge compound, Ti A direct esterification method in which polycondensation is performed under reduced pressure using one or more compounds selected from a compound or an Al compound, or a transesterification catalyst for dimethyl terephthalate and ethylene glycol and, if necessary, the above copolymerization component And then transesterification by distilling off methyl alcohol, using one or more compounds selected from Sb compounds, Ge compounds, Ti compounds or Al compounds as polycondensation catalysts. It is mainly produced by a transesterification method in which polycondensation is carried out under reduced pressure.
Further, solid-state polymerization may be carried out in order to increase the intrinsic viscosity of the thermoplastic polyester and to reduce the acetaldehyde content and the cyclic ester trimer content.
[0047]
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 melt polycondensation reaction. The melt polycondensation and the solid phase polymerization may be performed continuously or may be performed separately.
[0048]
Examples of the starting materials such as aromatic dicarboxylic acid dimethyl ester, aromatic dicarboxylic acid and glycols such as ethylene glycol include dimethyl terephthalate of virgin derived from para-xylene, ethylene glycol derived from terephthalic acid or ethylene. That is, recovered materials such as dimethyl terephthalate, terephthalic acid, bishydroxyethyl terephthalate or ethylene glycol recovered from used PET bottles by chemical recycling methods such as methanol decomposition and ethylene glycol decomposition are also used as at least a part of the starting materials. I can do it. It goes without saying that the quality of the recovered material must be purified to a purity and quality according to the purpose of use.
[0049]
Examples of the Sb compound used in the production of the thermoplastic polyester used in the present invention include antimony trioxide, antimony acetate, antimony tartrate, antimony tartrate, antimony oxychloride, antimony glycolate, antimony pentoxide, and triphenylantimony. 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.
[0050]
Examples of the Ge compound used for producing the thermoplastic polyester used in the present invention include amorphous germanium dioxide, crystalline germanium dioxide, germanium chloride, germanium tetraethoxide, germanium tetra-n-butoxide, and germanium phosphite. No. 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 thermoplastic polyester.
[0051]
Examples of the Ti compound used for producing the thermoplastic polyester used in the present invention include tetraethyl titanate, tetraisopropyl titanate, tetra-n-propyl titanate and tetra-n-butyl titanate. Alkyl titanates and their partial hydrolysates, titanium acetate, titanyl oxalate, titanyl ammonium oxalate, sodium titanyl oxalate, potassium titanyl oxalate, calcium titanyl oxalate, titanyl oxalate compounds such as titanyl strontium oxalate, titanium trimellitate, sulfuric acid Titanium, titanium chloride, hydrolyzate of titanium halide, titanium oxalate, titanium fluoride, potassium hexafluorotitanate, ammonium hexafluorotitanate, cobalt hexafluorotitanate, manganese hexafluorotitanate, titanium Acetylacetonate etc. It is below. 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.
[0052]
Examples of the Al compound used for producing the thermoplastic polyester used in the present invention include aluminum formate, aluminum acetate, basic aluminum acetate, aluminum propionate, aluminum oxalate, aluminum acrylate, and lauric acid. Carboxylates such as aluminum, aluminum stearate, aluminum benzoate, aluminum trichloroacetate, aluminum lactate, aluminum citrate, aluminum salicylate, aluminum chloride, aluminum hydroxide, aluminum hydroxide chloride, polyaluminum chloride, aluminum nitrate, aluminum sulfate , Aluminum carbonate, aluminum phosphate, inorganic acid salts such as aluminum phosphonate, aluminum methoxide, aluminum ethoxide, aluminum n Aluminum chelates such as propoxide, aluminum iso-propoxide, aluminum n-butoxide, aluminum t-butoxide, aluminum alkoxide, aluminum acetylacetonate, aluminum acetyl acetate, aluminum ethyl acetoacetate, aluminum ethyl acetoacetate di-iso-propoxide, Examples thereof include organoaluminum compounds such as trimethylaluminum and triethylaluminum, and partial hydrolysates thereof, and aluminum oxide. Of these, carboxylate, inorganic acid salt and chelate compound are preferable, and among these, basic aluminum acetate, aluminum chloride, aluminum hydroxide, aluminum hydroxide chloride, polyaluminum chloride and aluminum acetylacetonate are particularly preferable. 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.
[0053]
These catalyst compounds can be used, for example, as an ethylene glycol solution during the transesterification step or at any stage from the end of the transesterification reaction to the start of the polycondensation reaction, or during the esterification step or after the end of the esterification reaction to the start of the polycondensation reaction. It can be added at any stage.
[0054]
In the production of the thermoplastic polyester used in the present invention, 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.
The catalyst compound can be added at any stage of the thermoplastic polyester production reaction step.
[0055]
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 above-mentioned thermoplastic polyester production reaction step so that the amount of phosphorus remaining in the produced polymer is in the range of 5 to 100 ppm.
[0056]
Further, in the production of the thermoplastic polyester according to the present invention, it is preferable to use a basic nitrogen compound in order to suppress the production of dialkylene glycol produced as a by-product from glycol. The basic nitrogen compound may be any of aliphatic, alicyclic, aromatic and heterocyclic nitrogen compounds. Specific examples include triethylamine, tributylamine, dimethylaniline, dimethylaniline, pyridine, quinoline, dimethylbenzylamine, piperidine, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, triethylbenzylammonium hydroxide, imidazole, imidazoline and the like. . These compounds may be used in a free form or as a salt of a lower fatty acid or TPA. The addition of these basic nitrogen compounds to the reaction system can be appropriately selected at any stage until the end of the initial polycondensation reaction, and may be used alone or in combination of two or more. Good.
[0057]
The compounding amount of these basic nitrogen compounds is 0.01 to 1 mol%, preferably 0.05 to 0.7 mol%, more preferably 0.1 to 0.5 mol%, based on polyester. If the amount of the basic nitrogen compound is less than 0.01 mol%, the transparency of the hollow molded article made of the obtained polyester, particularly the stretched heat-fixed hollow molded article, becomes extremely poor. On the other hand, if it exceeds 1 mol%, the color tone of the polyester deteriorates.
[0058]
Further, in order to suppress a decrease in viscosity of the polyester composition of the present invention at the time of melting or to suppress by-products of low molecular weight generated by thermal decomposition of a strong irritating odor such as acetaldehyde or allyl aldehyde during drying or heat treatment before molding. It is also preferable to add a hindered phenolic antioxidant. As such a hindered phenol-based antioxidant, known ones may be used. For example, pentaerythritol-tetraextract [3- (3,5-di-tert-butyl-4-hydrid-3-) (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5- Trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, 3,9-bis {2- [3- (3-tert-butyl-4-hydroxy-5) -Methyl 3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl} -2,4,8,10-tetraoxaspiro [ , 5] undecane, 1,3,5-tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzene) isophthalic acid, triethylglycol-bis [3- (3-tert-butyl-5-methyl) -4-hydroxy 3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3,3- (3,5-di-tert- Butyl-4-hydroxyphenyl) propionate], 2,2-thio-diethylene-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl-3- (3,5-di-tert-butyl- 4-hydroxyphenyl) propionate] and octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate]. Above all, pentaerythritol-tetraextract [3- (3,5-di-tert-butyl-4-hydroxy [3- (3,5-di-tert-butyl-4-hydroxyph-3- (3,5- Di-tert-butyl-4-hydroxyphenyl) propionate), etc. In this case, the hindered phenol-based oxidation stabilizer may be bonded to a thermoplastic polyester, and the polyester composition of the hindered phenol-based oxidation stabilizer The amount in the product is preferably 1% by weight or less based on the weight of the polyester composition, because if it exceeds 1% by weight, coloring may occur, and even if 1% by weight or more is added, it is melt-stable. This is because the ability to improve the properties is saturated, preferably from 0.02 to 0.5% by weight.
[0059]
The intrinsic viscosity of the thermoplastic polyester used in the present invention, particularly the thermoplastic polyester whose main repeating unit is composed of ethylene terephthalate, is preferably 0.55 to 1.50 deciliter / gram, more preferably 0.1 to 0.5 deciliter / gram. The range is from 58 to 1.30 deciliters / gram, more preferably from 0.60 to 0.90 deciliters / gram. When the intrinsic viscosity is less than 0.55 deciliter / gram, the mechanical properties of the obtained packaging material and the like are poor. If it exceeds 1.50 deciliters / gram, the resin temperature rises during melting by a molding machine or the like, and the thermal decomposition becomes severe, free low-molecular-weight compounds that affect the fragrance retention increase, or the packaging material becomes Problems such as yellowing occur.
[0060]
The intrinsic viscosity of the thermoplastic polyester used in the present invention, particularly, the thermoplastic polyester whose main repeating unit is composed of ethylene-2,6-naphthalate has an intrinsic viscosity of 0.40 to 1.00 deciliter / gram, preferably 0. 0.42 to 0.95 deciliter / gram, more preferably 0.45 to 0.90 deciliter / gram. When the intrinsic viscosity is less than 0.40 deciliter / gram, the mechanical properties of the obtained packaging material and the like are poor. On the other hand, if it exceeds 1.00 deciliter / gram, the resin temperature rises during melting by a molding machine or the like, and thermal decomposition becomes severe, so that free low-molecular-weight compounds that affect fragrance retention increase, Causes problems such as coloring of yellow.
[0061]
The limiting viscosity of the thermoplastic polyester according to the present invention, particularly the thermoplastic polyester whose main structural unit is composed of 1,3-propylene terephthalate, is 0.50 to 2.00 deciliter / gram, preferably 0.1 to 2.0 deciliter / gram. It is in the range of 55 to 1.50 deciliter / gram, more preferably 0.60 to 1.00 deciliter / gram. When the intrinsic viscosity is less than 0.50 deciliter / gram, the mechanical properties of the obtained packaging material and the like deteriorate, which is a problem. In addition, the upper limit of the intrinsic viscosity is 2.00 deciliters / gram, and if it exceeds this, the resin temperature rises during melting by a molding machine or the like, the thermal decomposition becomes severe, the molecular weight decreases drastically, and the yellow color is increased. Problems such as coloring occur.
[0062]
The content of the dialkylene glycol copolymerized in the thermoplastic polyester according to the present invention is preferably 0.5 to 5.0 mol%, more preferably 1.50 mol%, of the glycol component constituting the thermoplastic polyester. It is 0 to 4.0 mol%, and more preferably 1.5 to 3.0 mol%. If the amount of the dialkylene glycol exceeds 5.0 mol%, the thermal stability is deteriorated, the molecular weight is greatly reduced at the time of molding, and the content of aldehydes is undesirably increased. In order to produce a thermoplastic polyester having a dialkylene glycol content of less than 0.5 mol%, it is necessary to select uneconomic production conditions as transesterification conditions, esterification conditions or polymerization conditions, Costs do not match. Here, the dialkylene glycol copolymerized in the thermoplastic polyester means, for example, in the case of a polyester whose main structural unit is ethylene terephthalate, diethylene glycol by-produced during production from ethylene glycol which is a glycol. Among them, diethylene glycol (hereinafter abbreviated as DEG) copolymerized with the thermoplastic polyester, and in the case of a polyester having 1,3-propylene terephthalate as a main structural unit, Among di (1,3-propylene glycol) (or bis (3-hydroxypropyl) ether) by-produced from 1,3-propylene glycol which is a glycol, a copolymer copolymerized with the thermoplastic polyester is used. (1,3-propylene glycol (hereinafter referred to as DPG)) .
[0063]
The content of aldehydes such as acetaldehyde in the thermoplastic polyester according to the present invention is desirably 50 ppm or less, preferably 30 ppm or less, and more preferably 10 ppm or less. In particular, when the polyester composition of the present invention is used as a material for containers for low-flavor beverages such as mineral water, the content of aldehydes in the thermoplastic polyester is 8 ppm or less, preferably 5 ppm or less, more preferably Is desirably 4 ppm or less. When the aldehyde content exceeds 50 ppm, the effect of retaining the flavor of contents such as a molded article molded from the thermoplastic polyester becomes poor. Further, these lower limits are preferably 0.1 ppb in view of manufacturing problems. Here, the aldehydes are acetaldehyde when the thermoplastic polyester is a polyester having ethylene terephthalate as a main constituent unit, and an aldehyde is a polyester having 1,3-propylene terephthalate as a main constituent unit. Allyl aldehyde.
[0064]
Further, the content of the cyclic ester oligomer of the thermoplastic polyester according to the present invention is 70% or less, preferably 60% or less, more preferably 70% or less of the content of the cyclic ester oligomer contained in the melt polycondensate of the thermoplastic polyester. It is preferably at most 50%, particularly preferably at most 35%.
Here, the thermoplastic polyester generally contains cyclic ester oligomers having various degrees of polymerization, and the cyclic ester oligomer in the present invention is the most contained cyclic ester oligomer among the thermoplastic ester oligomers contained in the thermoplastic polyester. It means a cyclic ester oligomer having a high amount. For example, in the case of a polyester containing ethylene terephthalate as a main repeating unit, it means a cyclic trimer.
In the case where the thermoplastic polyester is PET, which is a typical polyester having ethylene terephthalate as a main constituent unit, the content of the cyclic trimer of the melt polycondensed polyester is about 1.0% by weight. The content of the cyclic trimer of the thermoplastic polyester according to the present invention is 0.70% by weight or less, preferably 0.60% by weight or less, more preferably 0.50% by weight or less, and particularly preferably 0.35% by weight. The following is preferred.
[0065]
Such a polyester having a reduced content of the cyclic ester oligomer can be obtained by a method such as solid-state polymerization of a melt polycondensed polyester or heat treatment at a temperature lower than the melting point under an inert gas.
[0066]
Further, when the thermoplastic polyester according to the present invention is melted at 290 ° C. for 60 minutes, the amount of the cyclic ester oligomer to increase is desirably 0.50% by weight or less. The increase in the amount of the cyclic ester oligomer is preferably 0.40% by weight or less, more preferably 0.30% by weight or less, further preferably 0.20% by weight or less, and particularly preferably 0.10% by weight or less. .
When the content of the cyclic ester oligomer exceeds 0.70% by weight or the increase amount exceeds 0.50% by weight, the amount of the cyclic ester oligomer increases when the resin for molding is melted, and the oligomer on the surface of the heating mold is increased. -Adhesion sharply increases, and the transparency of the obtained hollow molded article or the like is extremely deteriorated. In the case of a film, oligomers are formed near the exit of a die or at the surface of a stretching roll at the time of film formation or stretching. This is a problem because it adheres and accumulates inside the heat fixing chamber, and these adhere to the film surface and become foreign substances. Further, these lower limits are preferably 0.1% by weight and 0.05% by weight, respectively, from the viewpoints of manufacturing and production costs.
[0067]
The thermoplastic polyester according to the present invention, in which the cyclic ester oligomer increase amount is 0.50% by weight or less, is produced by deactivating a polyester polycondensation catalyst obtained after melt polycondensation or after solid state polymerization. be able to.
[0068]
Examples of the method for deactivating the polyester polycondensation catalyst include a method of subjecting a polyester chip to contact treatment with water, steam or a steam-containing gas after melt polycondensation or after solid-phase polymerization. Examples of the hot water treatment method include a method in which a polyester chip is immersed in water at 20 to 180 ° C. for about 5 minutes to 2 days, a method in which water is applied to the chip with a shower, and the like. In addition, there is a method in which a polyester chip is brought into contact with steam or a steam-containing gas at 50 to 150 ° C. for 10 minutes to 2 days for treatment.
[0069]
As another means for deactivating the polycondensation catalyst, a method of inactivating the polymerization catalyst by adding and mixing a phosphorus compound to a melt of the polyester after the melt polycondensation or after the solid phase polymerization is used.
In the case of the melt polycondensation polyester, the polyester after the completion of the melt polycondensation reaction and the polyester resin containing the phosphorus compound are mixed in a device such as a line mixer capable of mixing in a molten state to inactivate the polycondensation catalyst. Method.
As a method of blending a phosphorus compound into a solid-phase polymerized polyester, a method of dry blending a phosphorus compound with a solid-phase polymerized polyester or a method of mixing a polyester master-batch chip blended by melting and kneading a phosphorus compound with a solid-phase polymerized polyester chip are used. After a predetermined amount of the phosphorus compound is blended into the polyester by the above method, the mixture is melted in an extruder or a molding machine to deactivate the polycondensation catalyst.
Examples of the phosphorus compound to be used include the above-described phosphoric acid, phosphorous acid, phosphonic acid, and derivatives thereof, which have been described as being usable as a stabilizer during the production of the thermoplastic polyester according to the present invention. These may be used alone or in combination of two or more.
[0070]
The shape of the thermoplastic polyester chip used in the present invention may be any of a cylinder type, a square type, a spherical shape or a flat plate shape. 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.
[0071]
In general, thermoplastic polyesters contain a significant amount of fines, i.e., fines, which are generated during the manufacturing process and whose copolymer component content is the same as the chips of the thermoplastic polyester. Such fines have the property of accelerating the crystallization of thermoplastic polyester, and when present in large amounts, the transparency of the polyester packaging material formed from the polyester composition containing such fines is very high. In the case of a bottle, there is a problem that the amount of shrinkage at the time of crystallization of the bottle plug portion does not fall within a specified value range and the bottle cannot be sealed with a cap. Therefore, the content of fines in the thermoplastic polyester used in the present invention is desirably 1000 ppm or less, preferably 500 ppm or less, more preferably 300 ppm or less, and particularly preferably 100 ppm or less.
[0072]
The partially aromatic polyamide according to the present invention has a polyamide mainly composed of a unit derived from an aliphatic dicarboxylic acid and an aromatic diamine, or a polyamide mainly composed of a unit derived from an aromatic dicarboxylic acid and an aliphatic diamine. It is a polyamide as a unit.
[0073]
The aromatic dicarboxylic acid component constituting the partially aromatic polyamide according to the present invention includes terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyl-4,4′-dicarboxylic acid, diphenoxy Ethanedicarboxylic acid and its functional derivatives;
[0074]
As the aliphatic dicarboxylic acid component constituting the partially aromatic polyamide according to the present invention, a linear aliphatic dicarboxylic acid is preferable, and a linear aliphatic dicarboxylic acid having an alkylene group having 4 to 12 carbon atoms is particularly preferable. preferable. Examples of such linear aliphatic dicarboxylic acids include adipic acid, sebacic acid, malonic acid, succinic acid, glutaric acid, pimelic acid, stearic acid, azelaic acid, undecanoic acid, undecadionic acid, dodecandioic acid , Dimer acids and their functional derivatives.
[0075]
Examples of the aromatic diamine component constituting the partially aromatic polyamide according to the present invention include metaxylylenediamine, paraxylylenediamine, and para-bis- (2-aminoethyl) benzene.
[0076]
The aliphatic diamine component constituting the partially aromatic polyamide according to the present invention is an aliphatic diamine having 2 to 12 carbon atoms or a functional derivative thereof. The aliphatic diamine may be a linear aliphatic diamine or a branched aliphatic diamine. Specific examples of such a linear aliphatic diamine include ethylenediamine, 1-methylethylenediamine, 1,3-propylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, Aliphatic diamines such as nonamethylenediamine, decamethylenediamine, undecamethylenediamine, and dodecamethylenediamine are exemplified.
[0077]
Further, as the dicarboxylic acid component constituting the partially aromatic polyamide according to the present invention, an alicyclic dicarboxylic acid can be used in addition to the above-mentioned aromatic dicarboxylic acid and aliphatic dicarboxylic acid. Examples of the alicyclic dicarboxylic acid include alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid, hexahydroterephthalic acid, and hexahydroisophthalic acid.
[0078]
Further, as the diamine component constituting the partially aromatic polyamide according to the present invention, an alicyclic diamine can be used in addition to the above-described aromatic diamine and aliphatic diamine. Examples of the alicyclic diamine include alicyclic diamines such as cyclohexanediamine and bis- (4,4'-aminohexyl) methane.
[0079]
In addition to the 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.
[0080]
Preferable examples of the partially aromatic polyamide according to the present invention include metaxylylenediamine, or a mixture of metaxylylenediamine and paraxylylenediamine containing not more than 30% of the total amount thereof, and an aliphatic dicarboxylic acid. A meta-xylylene group-containing polyamide containing at least 20 mol%, more preferably at least 30 mol%, and particularly preferably at least 40 mol% of a structural unit in a molecular chain.
[0081]
Further, the partially aromatic polyamide according to the present invention may contain a structural unit derived from a polycarboxylic acid having three or more bases such as trimellitic acid and pyromellitic acid within a substantially linear range. Good.
[0082]
Examples of these polyamides include homopolymers such as polymetaxylylene adipamide, polymetaxylylene sebacamide, polymetaxylyleneperamide, etc., and metaxylylenediamine / adipic / isophthalic acid copolymers, metaxylylene / Para-xylylene adipamide copolymer, meta-xylylene / para-xylylene piperamide copolymer, meta-xylylene / para-xylylene azeramide copolymer, meta-xylylenediamine / adipic acid / isophthalic acid / ε-caprolactam copolymer And meta-xylylenediamine / adipic acid / isophthalic acid / ω-aminocaproic acid copolymer.
[0083]
Further, as another preferable example of the partially aromatic polyamide according to the present invention, a structural unit derived from an aliphatic diamine and at least one acid selected from terephthalic acid or isophthalic acid is included in a molecular chain in at least 20 mol%. It is a polyamide containing at least 30 mol%, particularly preferably at least 40 mol%, more preferably.
[0084]
Examples of these polyamides include polyhexamethylene terephthalamide, polyhexamethylene isophthalamide, hexamethylene diamine / terephthalic acid / isophthalic acid copolymer, polynonamethylene terephthalamide, polynonamethylene isophthalamide, nonamethylene diamine / terephthalic acid / Isophthalic acid copolymer, nonamethylenediamine / terephthalic acid / adipic acid copolymer and the like.
[0085]
Other preferable examples of the partially aromatic polyamide according to the present invention include, in addition to aliphatic diamine and at least one acid selected from terephthalic acid or isophthalic acid, lactams such as ε-caprolactam and laurolactam, and aminocaproic acid. An aminocarboxylic acid such as aminoundecanoic acid, obtained using an aromatic aminocarboxylic acid such as para-aminomethylbenzoic acid as a copolymerization component, and at least one selected from aliphatic diamines and terephthalic acid or isophthalic acid. Polyamide containing at least 20 mol% or more, more preferably 30 mol% or more, particularly preferably 40 mol% or more of a structural unit derived from one kind of acid in a molecular chain.
[0086]
Examples of these polyamides include hexamethylenediamine / terephthalic acid / ε-caprolactam copolymer, hexamethylenediamine / isophthalic acid / ε-caprolactam copolymer, and hexamethylenediamine / terephthalic acid / adipic acid / ε-caprolactam copolymer. Coalescence and the like.
[0087]
The partially aromatic polyamide according to the present invention is obtained by heating an aqueous solution of an aminocarboxylic acid salt formed from a diamine and a dicarboxylic acid under pressure and at normal pressure, and removing water and water generated by a polycondensation reaction in a molten state. It can be produced by a method of polycondensation, or a method of heating a diamine and a dicarboxylic acid and directly reacting them in a molten state under normal pressure or under vacuum to perform polycondensation. In addition, by subjecting the polyamide chips obtained by these melt polycondensation reactions to solid-phase polymerization, a partially aromatic polyamide having a higher viscosity can be obtained.
The polycondensation reaction of the partially aromatic polyamide may be performed in a batch reactor or a continuous reactor.
[0088]
In producing the partially aromatic polyamide used in the present invention, an alkali metal-containing compound represented by the following chemical formula (A) is added to improve thermal stability and prevent gelation. The alkali metal atom content in the partially aromatic polyamide is preferably in the range of 1 to 1000 ppm.
[0089]
Z-OR₈(A)
(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.
[0090]
Examples of the alkali compound represented by the chemical formula (A) 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.
[0091]
In the production of the partially aromatic polyamide, it is preferable to polymerize by adding a phosphorus compound as a stabilizer for preventing gelation due to thermal degradation.
[0092]
Assuming that the phosphorus atom content derived from the phosphorus compound in the partially aromatic polyamide used in the present invention is X, the range is 0 <X ≦ 500 ppm. The lower limit is preferably 0.1 ppm, more preferably 1 ppm, and even more preferably 5 pm. The upper limit is preferably 400 ppm, more preferably 300 ppm, and even more preferably 250 ppm. If X is 0, that is, if no phosphorus atom is contained, the effect of preventing gelation during polycondensation is inferior. On the other hand, if X is more than 500 ppm, the gelation preventing effect is limited and uneconomical.
As the phosphorus compound to be added to the partially aromatic polyamide, it is preferable to use at least one selected from compounds represented by the following chemical formulas (B-1) to (B-4).
[0093]
Embedded image

[0094]
Embedded image

[0095]
Embedded image

[0096]
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[0097]
(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)
[0098]
Examples of the phosphinic acid compound represented by the chemical formula (B-1) include dimethylphosphinic acid, phenylmethylphosphinic acid, hypophosphorous acid, sodium hypophosphite, potassium hypophosphite, lithium hypophosphite, and hypophosphite. Ethyl phosphate,
[0099]
Embedded image

Or
[0100]
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And hydrolysates thereof, and condensates of the above phosphinic acid compounds.
[0101]
Examples of the phosphonous acid compound represented by the chemical formula (B-2) include phenylphosphonous acid, sodium phenylphosphonite, potassium phenylphosphonite, lithium phenylphosphonite, and ethyl phenylphosphonite.
[0102]
Phosphonic acid compounds represented by the chemical formula (B-3) include phenylphosphonic acid, ethylphosphonic acid, sodium phenylphosphonate, potassium phenylphosphonate, lithium phenylphosphonate, diethyl phenylphosphonate, sodium ethylphosphonate, and ethylphosphonate. And potassium acid.
Examples of the phosphorous acid compound represented by the chemical formula (B-4) include phosphorous acid, sodium hydrogen phosphite, sodium phosphite, triethyl phosphite, triphenyl phosphite, pyrophosphorous acid, and the like. .
[0103]
The content of the total alkali metal in the partially aromatic polyamide used in the present invention (the total amount of the amount of the alkali metal atom contained in the phosphorus-based stabilizer and the amount of the alkali metal atom contained in the alkali metal compound) is It is preferably 1.0 to 6.0 times the phosphorus atom content in the polyamide. The lower limit is more preferably 1.5 times, more preferably 2.0 times, particularly preferably 2.3 times, and most preferably 2.5 times, and the upper limit is more preferably 5.5 times. Mole, more preferably 5.0 times mole. When the content of all alkali metals is less than 1.0 times the phosphorus atom content, gelation is easily promoted. On the other hand, if the total alkali metal content is more than 6.0 times the phosphorus atom content, the polymerization rate will be slow, the viscosity will not be sufficiently increased, and gelation will be promoted, especially in a reduced pressure system, which is uneconomical. is there.
[0104]
The compounds represented by the chemical formula (A) and the chemical formulas (B-1) to (B-4) used in the present invention may be used alone. It is preferable because the thermal stability is improved.
[0105]
In order to blend the phosphorus compound or the alkali metal-containing compound into the partially aromatic polyamide used in the present invention, a raw material before polymerization of the polyamide, these may be added during the polymerization, or may be melt-mixed with the polymer. Good.
These compounds may be added simultaneously or separately.
[0106]
The relative viscosity of the partially aromatic polyamide used in the present invention is 1.3 to 4.0, preferably 1.5 to 3.0, more preferably 1.7 to 2.5, and further preferably 1.8 to 1.8. 2.0. If the relative viscosity is less than 1.3, the molecular weight is too small, and the mechanical properties of the packaging material comprising the polyester composition of the present invention may be poor. On the other hand, if the relative viscosity is 4.0 or more, it takes a long time to polymerize the polyamide, which may not only cause deterioration of the polymer or undesired coloring, but also decrease productivity and increase cost. Sometimes.
[0107]
When the terminal amino group concentration (μmol / g) of the partially aromatic polyamide used in the present invention is AEG and the terminal carboxyl group concentration (μmol / g) of the partially aromatic polyamide is CEG, the ratio of AEG to CEG (AEG / CEG) is preferably 1.0 or more. When the ratio of the terminal amino group concentration to the terminal carboxyl group concentration (AEG / CEG) in the partially aromatic polyamide is less than 1.0, the polyester packaging material of the present invention has poor flavor retention, and such polyester packaging is poor. The material may be less useful as a container for low flavor beverages. On the other hand, if the ratio of the terminal amino group concentration to the terminal carboxyl group concentration (AEG / CEG) in the partially aromatic polyamide is more than 20, the obtained polyester packaging material is undesirably colored and loses commercial value.
[0108]
The shape of the tip of the partially aromatic polyamide 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 1.0 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 5 to 30 mg / piece.
[0109]
The acetaldehyde content (A) of a molded product obtained by injection molding the polyester composition of the present invention by the method described in the following measurement method (5)_t) (Ppm) and the acetaldehyde content (A) of the polyester composition before injection molding.₀) (Ppm) (A)_t-A₀) Is 20 ppm or less, preferably 15 ppm or less, more preferably 10 ppm or less, and most preferably 5 ppm or less. Difference in acetaldehyde content before and after injection molding Δ (A_t-A₀) Exceeds 20 ppm, the resulting polyester packaging material has poor flavor retention. Also, the difference in acetaldehyde content before and after injection molding (A_t-A₀The lower limit of 1) is 1 ppm. To reduce the lower limit to 1 ppm or less, the production conditions of the polyester packaging material must be unproductive, which is uneconomical.
[0110]
Acetaldehyde content after injection molding (A_t) And acetaldehyde content before injection molding (A₀) And the difference (A_t-A₀) Is 20 ppm or less, a thermoplastic polyester having an acetaldehyde content of 5 ppm or less, or a thermoplastic polyester having an acetaldehyde content of 10 ppm or less and deactivating the remaining polycondensation catalyst is used as a component. Can be obtained by: Examples of the method of deactivating the polycondensation catalyst in the thermoplastic polyester include a method of subjecting the thermoplastic polyester chip to contact treatment with water, steam or a steam-containing gas after melt polycondensation or after solid-phase polymerization. As another means for deactivating the polycondensation catalyst, a method of inactivating the polymerization catalyst by adding and mixing a phosphorus compound to a melt of the polyester after the melt polycondensation or after the solid phase polymerization is used.
[0111]
In addition, the difference (A_t-A₀) Can also be obtained by subjecting a polyester composition comprising a thermoplastic polyester having an acetaldehyde content of 10 ppm or less and a partially aromatic polyamide to contact treatment with water, steam or a steam-containing gas. .
[0112]
The polyester packaging material of the present invention is characterized in that the content of alkali metal atoms in the polyester packaging material is in the range of 0.1 to 300 ppm.
[0113]
The lower limit of the alkali metal atom content in the polyester packaging material is preferably 1 ppm, and more preferably 5 ppm. The upper limit of the alkali metal atom content in the polyester packaging material is preferably 270 ppm, more preferably 250 ppm, and further preferably 200 ppm.
[0114]
When the content of the alkali metal atom in the polyester packaging material is less than 0.1 ppm, the polyester coloring material is intensely colored, burns streaks or unmelted substances are easily generated, and as a result, the appearance of the polyester packaging material is deteriorated. On the other hand, when the alkali metal atom content in the polyester packaging material is more than 300 ppm, burn streaks and unmelted matter are hardly generated, but transparency and flavor retention are deteriorated.
[0115]
The acetaldehyde content in the polyester packaging material of the present invention is 20 ppm or less, preferably 15 ppm or less, more preferably 10 ppm or less. When the acetaldehyde content in the polyester packaging material of the present invention exceeds 20 ppm, the flavor retention of the polyester packaging material is deteriorated. In addition, the lower limit of the acetaldehyde content in the polyester packaging material is 3 ppm, and if the content is reduced to less than 3 ppm, the molding is not considered profitable, which is a problem.
[0116]
The polyester packaging material of the present invention has an acetaldehyde content increase (ΔAA) (ppm) of 20 ppm or less, preferably 15 ppm or less, more preferably 13 ppm or less when the polyester packaging material is melted at 290 ° C. for 30 minutes. is there. If the increase in acetaldehyde content (時 AA) (ppm) at the time of the melt treatment exceeds 20 ppm, it may be difficult to obtain a polyester packaging material by partially using a recycled product such as a used PET bottle. It becomes very difficult to reduce the AA content of the obtained polyester packaging material to the target value, and the mixing ratio of the recycled and collected product to the virgin PET resin must be extremely reduced.
[0117]
The amount of the cyclic ester trimer increased when the polyester packaging material was melted at 290 ° C. for 30 minutes (ΔCT₂) Is maintained at 0.40% by weight or less in order to increase the amount of the cyclic ester trimer (ΔCT) when melt-processed at a temperature of 290 ° C. for 30 minutes.₁) Of 0.40% by weight or less, preferably 0.35% by weight or less, more preferably 0.30% by weight or less. Increase in amount of cyclic ester trimer when melted at 290 ° C. for 30 minutes (ΔCT₁) Exceeds 0.40% by weight, the amount of the cyclic ester trimer increases when the resin is melted during molding of the polyester composition, and depending on the heat treatment conditions, the oligomer on the surface of the heated mold may be reduced. The adhesion sharply increases, and the transparency of the obtained hollow molded article or the like is extremely deteriorated.
[0118]
Increase in amount of cyclic ester trimer when melted at 290 ° C. for 30 minutes (ΔCT₁Is 0.40% by weight or less can be produced by deactivating the polycondensation catalyst remaining in the thermoplastic polyester obtained after the melt polycondensation or after the solid phase polymerization. As the method for deactivating the polycondensation catalyst in the thermoplastic polyester, the same method as described above can be used.
[0119]
In addition, when the thermoplastic polyester is PET, the cyclic ester trimer is a cyclic trimer composed of terephthalic acid and ethylene glycol.
The content of the cyclic ester trimer derived from the thermoplastic polyester in the polyester packaging material of the present invention is preferably 0.70% by weight or less, more preferably 0.50% by weight or less, and still more preferably 0.40% by weight. The following is preferred. When the content of the cyclic ester trimer derived from the thermoplastic polyester in the polyester packaging material exceeds 0.70% by weight, the adhesion of the oligomer to the surface of the heating mold rapidly increases, and this is obtained. The resulting hollow molded article has a problem that the transparency of the molded article is extremely deteriorated and the flavor retention is also deteriorated.
[0120]
In order to maintain the content of the cyclic ester trimer derived from thermoplastic polyester in the polyester packaging material at 0.70% by weight or less, the content of the cyclic ester trimer in the polyester composition is preferably It is necessary to be 0.70% by weight or less, more preferably 0.50% by weight or less, further preferably 0.40% by weight or less. When the polyester packaging material is a heat-resistant hollow molded article, when the content of the cyclic ester trimer in the polyester composition used for molding exceeds 0.70% by weight, the cyclic ester on the heating mold surface is added. Adhesion of oligomers derived from polyesters such as trimers increases over time, resulting in considerable labor for cleaning for mold cleaning and economical loss due to molding interruption. The lower limit is 0.10% by weight. To reduce the amount to less than 0.10% by weight, it is necessary to adopt the production conditions of polyester, which is not considered profitable, which is a problem.
[0121]
The content of the meta-xylylene group-containing cyclic amide monomer in the polyester packaging material of the present invention is 0.3% by weight or less, preferably 0.28% by weight or less, more preferably 0.25% by weight or less. . When the content of the cyclic amide monomer in the polyester packaging material exceeds 0.3% by weight, there is a problem in that the content of the content filled in the polyester packaging material has poor flavor retention.
[0122]
In order to achieve this, the content of the meta-xylylene group-containing cyclic amide monomer in the polyester composition of the present invention is 0.3% by weight or less, preferably 0.28% by weight or less, more preferably 0.25% by weight or less. It is preferable that the content is not more than weight%.
[0123]
When the content of the cyclic amide monomer in the polyester composition exceeds 0.3% by weight, the inner surface of the mold, the gas outlet of the mold gas, and the exhaust pipe when molding a polyester packaging material having improved heat resistance. Mold stains caused by foreign matter adhering to the surface become extremely intense. The lower limit of the content of the cyclic amide monomer in the polyester composition or the polyester packaging material is preferably 0.001 ppm for economic reasons and the like. Cyclic amide monomer is measured by the high performance liquid chromatography method described below.
[0124]
The above-mentioned meta-xylylene group-containing polyamide includes cyclic amides such as a cyclic amide monomer, a cyclic amide dimer, a cyclic amide trimer and a cyclic amide tetramer composed of diamine and dicarboxylic acid used as starting materials. Oligomers, unreacted monomers such as the dicarboxylic acids and the diamines, and linear oligomers such as linear dimers and linear trimers composed of the diamines and the dicarboxylic acids. The content thereof varies depending on the polycondensation method and the polycondensation conditions, the molecular weight of the produced polyamide, and the like. 1 to 2.0% by weight, cyclic amide trimer 0.1 to 1.0% by weight, cyclic amide tetramer 0.005 to 0.5% by weight, linear oligomers 1 to 5000 ppm The unreacted monomers are on the order of 0.1 to 2000 ppm.
[0125]
Here, when the meta-xylylene group-containing polyamide is a polyamide composed of meta-xylylenediamine and adipic acid, the chemical formula of the cyclic oligomer is represented by the following formula, and the case where n = 1 is a cyclic amide monomer. is there.
[0126]
Embedded image

(In the above formula 1, n represents an integer of 1 to 4.)
[0127]
The method for adjusting the content of the cyclic amide monomer in the polyester composition or the polyester packaging material of the present invention to the above-mentioned value is not particularly limited, and can be produced, for example, as follows. That is, depending on the amount of the metaxylylene group-containing polyamide relative to the thermoplastic polyester, the content of the cyclic amide monomer in the polyester composition or the polyester packaging material satisfies the value of the claims of the present invention, This can be achieved by using a metaxylylene group-containing polyamide having a reduced cyclic amide monomer content. Further, it can also be achieved by extracting and removing the above-mentioned cyclic substance from a polyester composition containing a meta-xylylene group-containing polyamide or a polyester packaging material obtained from the polyester composition with water or an organic solvent. The method for producing the metaxylylene group-containing polyamide having a low content of the cyclic amide monomer is not limited at all, and the method includes extraction with water or an organic solvent, changes in polycondensation conditions, heat treatment under reduced pressure, and a method combining these methods. Can be mentioned
[0128]
The intrinsic viscosity of the polyester packaging material of the present invention is preferably 0.55 to 1.00 deciliter / gram, more preferably 0.58 to 0.95 deciliter / gram, and still more preferably 0.60 to 0.90 deciliter / gram. In the range of grams.
[0129]
In the polyester composition of the present invention, other additives as necessary, for example, known ultraviolet absorbers, antioxidants, oxygen absorbers, oxygen scavengers, lubricants added from the outside and precipitated inside during the reaction. Various additives such as a lubricant, a releasing agent, a nucleating agent, a stabilizer, an antistatic agent, a dye 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.
[0130]
Further, when the polyester packaging material of the present invention is a film, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate are contained in the polyester composition in order to improve handling properties such as slipperiness, winding property, and blocking resistance. And inorganic particles such as 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; and divinylbenzene, styrene, acrylic acid, and methacrylic acid. Inert particles such as crosslinked polymer particles such as homo- or copolymers of vinyl monomers of acid, acrylic acid or methacrylic acid can be blended.
The polyester packaging material of the present invention can be obtained by a known production method.
[0131]
Hereinafter, as a typical example, when the thermoplastic polyester is polyethylene terephthalate (PET), a simple method for producing various polyester packaging materials will be described.樹脂 The resin composition for a polyester packaging material of the present invention can be obtained by mixing the above-mentioned thermoplastic polyester and the above-mentioned polyamide by a conventionally known method. For example, the polyamide chips and the thermoplastic polyester chips are dry-blended with a tumbler, a V-type blender, a Henschel mixer, or the like, and the dry-blended mixture is once processed with a single screw extruder, a twin screw extruder, a kneader, or the like. Examples thereof include those obtained by melt mixing as described above, and those obtained by subjecting the molten mixture to solid phase polymerization under a high vacuum or an inert gas atmosphere, if necessary.
[0132]
Further, the polyamide may be pulverized and used. Particularly, a composition using a small amount of the polyamide is advantageous. The particle size when pulverized is preferably about 10 mesh or less. Also, a method in which a solution obtained by dissolving the polyamide in a solvent such as hexafluoroisopropanol is attached to the surface of the thermoplastic polyester chip, and the thermoplastic polyester is brought into contact with the member in a space where the polyamide member is present. A method of causing the polyamide to adhere to the surface of the thermoplastic polyester chip.
[0133]
When the polyester packaging material of the present invention is in the form of a sheet, it can be produced, for example, using a general sheet forming machine equipped with an extruder and a die.
Further, the sheet-like material can be formed into a recup shape or a tray shape by pressure forming or vacuum forming. Further, the polyester packaging material of the present invention can be used for cooking food in a microwave oven and / or an oven range or the like, or for use as a tray-shaped container for heating frozen food. In this case, after the sheet-like material is formed into a tray shape, it is thermally crystallized to improve heat resistance.
[0134]
When the polyester packaging material of the present invention is a stretched film, the sheet-like material obtained by injection molding or extrusion molding may be used for uniaxial stretching, sequential biaxial stretching, and simultaneous biaxial stretching which are usually used for PET stretching. Is formed by using an arbitrary stretching method described above.
[0135]
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.
[0136]
In producing the hollow molded article, a preform molded from the PET composition of the present invention is obtained by stretch blow molding, and an apparatus conventionally used in 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 310C. The stretching temperature is usually 70 to 120 ° C., preferably 90 to 110 ° C., and the stretching ratio is usually 1.5 to 3.5 times in the longitudinal direction and 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.
[0137]
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.
[0138]
Further, the polyester packaging material of the present invention can be one constituent layer such as a laminated molded product or a laminated film. In particular, it is used for 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 two layers of an outer layer composed of the polyester packaging material of the present invention and an inner layer of PET, or a two-layer structure composed of an inner layer composed of the polyester packaging material of the present invention and a PET outer layer. Molded article having a two-layer structure, a three-layer structure comprising an intermediate layer containing the polyester packaging material 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 packaging material of the present invention and PET. 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 packaging material of the present invention, an innermost layer, a center layer and an innermost layer of PET, and the like can be given. 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.
[0139]
Examples of other laminated molded articles include a laminated molded article with a resin other than thermoplastic polyester such as polyolefin, and a laminated molded article with a different kind of base material such as paper or a metal plate.
[0140]
There are no particular restrictions on the thickness of the laminate and the thickness of each layer. Further, the laminated molded article can be used in various shapes such as a sheet, a film, a plate, a hollow body, a container and the like.
[0141]
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.
[0142]
The polyester packaging material of the present invention can be a film laminated on one side or both sides of a laminated metal plate. Examples of the metal plate used include tin, tin-free steel, and aluminum.
[0143]
As the laminating method, a conventionally known method can be applied, and it is not particularly limited. However, it is preferable to perform the laminating method by a thermal laminating method which can achieve an organic solvent-free process and can avoid adverse effects on the taste and odor of foodstuffs due to a residual solvent. Above all, a thermal lamination method by energizing a metal plate is particularly recommended. In the case of double-sided lamination, they may be laminated simultaneously or sequentially.
Needless to say, the film can be laminated to the metal plate using an adhesive.
[0144]
Further, the metal container is obtained by molding using the laminated metal plate. The method for forming the metal container is not particularly limited. Also, the shape of the metal container is not particularly limited, but it is preferably applied to a so-called two-piece can made by molding such as drawing, drawing and ironing, and stretch draw molding. The present invention is also applicable to a so-called three-piece can in which the contents are filled by winding a top cover suitable for filling a food product such as a coffee beverage.
The main method of measuring characteristic values in the present invention will be described below.
[0145]
【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.
[0146]
(Evaluation method)
(1) Intrinsic viscosity (IV) of polyester, polyester composition and polyester packaging material
It was determined from the solution viscosity at 30 ° C. in a 1,1,2,2-tetrachloroethane / phenol (2: 3 weight ratio) mixed solvent. (Unit is deciliter / gram)
[0147]
(2) Content of dialkylene glycol copolymerized in polyester
It was decomposed with methanol, and the amount of dialkylene glycol was quantified by gas chromatography and expressed as a ratio (mol%) to the total glycol components. The PET content is the DEG content, and the PTT content is the DPG content.
[0148]
(3) Content of polyester, polyester composition and cyclic ester oligomer of polyester packaging material (% by weight)
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 amount of cyclic ester oligomer was determined by high performance liquid chromatography. PET is a cyclic trimer (CT content), and PTT is a cyclic dimer (CD content).
[0149]
(4) Acetaldehyde content of polyester, polyester composition and polyester packaging material (hereinafter referred to as "AA content") (ppm)
A sample / distilled water = 1 g / 2 cc was put into a glass ampoule with a nitrogen purge, the upper part of the ampoule was sealed under a nitrogen seal, an extraction treatment was performed at 160 ° C. for 2 hours, and after cooling, the acetaldehyde in the extract was increased. The sensitivity was measured by gas chromatography, and the concentration was expressed in ppm.
[0150]
(5) Difference in acetaldehyde content before and after injection molding of the polyester composition (hereinafter referred to as “A_t-A₀") (Ppm)
The polyester composition dried at 50 to 100 ° C. under a nitrogen stream was cooled with 10 ° C. water at a cylinder temperature of 290 ° C. using a M-150C (DM) injection molding machine manufactured by Meiki Seisakusho (surface). (Temperature: about 22 ° C.) to injection-mold the stepped plate. The obtained stepped 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. Weighs about 146 g. A sample was collected from a 2 mm thick plate, and the acetaldehyde content (A_t) Is determined, and the difference in acetaldehyde content before and after injection molding is determined from the following equation.
Difference in acetaldehyde content before and after injection molding (A_t-A₀) (Ppm) =
Acetaldehyde content of the step-formed plate after injection molding (A_t) (Ppm)-acetaldehyde content of dried polyester composition before injection molding (A₀) (Ppm)
[0151]
(6) Increase in acetaldehyde content during melt processing of polyester packaging material (hereinafter referred to as “ΔAA”) (ppm)
A 3 g sample of about 1-3 mm square is collected from the polyester packaging material, placed in a glass test tube, vacuum dried at about 50-70 ° C., and then immersed in a 290 ° C. oil bath for 30 minutes under a normal pressure nitrogen atmosphere. And melted. The increase in the acetaldehyde content during the melting treatment is determined by the following equation.
Increase in acetaldehyde content during melting (ppm) =
Acetaldehyde content after melt treatment (ppm)-Acetaldehyde content after drying before melt treatment (ppm)
[0152]
(7) Increase in cyclic ester trimer during melt processing of polyester (hereinafter referred to as “ΔCT₁Amount) (% by weight) and the amount of cyclic ester trimer increased during melt processing of polyester packaging material (hereinafter referred to as “ΔCT”).₂Amount)) (% by weight)
[0153]
3 g of the dried polyester chip or polyester packaging material is placed in a glass test tube and immersed in an oil bath at 290 ° C. for 30 minutes under a nitrogen atmosphere at normal pressure to perform a melting treatment. The polyester packaging material is cut into a size of about 1 to 3 mm square and used for measurement.
[0154]
Cyclic ester trimer increase during polyester melt treatment (ΔCT₁Amount) and cyclic ester trimer increase during melt processing of polyester packaging material (ΔCT₂Is determined by the following equation.
Increase in cyclic ester trimer during melt processing (% by weight) =
Cyclic ester trimer content after melt treatment (wt%)-{cyclic ester trimer content before melt treatment (wt%)
[0155]
(8) Relative viscosity of partially aromatic polyamide (hereinafter referred to as “Rv”)
A sample (0.25 g) was dissolved in 96% sulfuric acid (25 ml), and this solution (10 ml) was measured at 20 ° C. using an Ostwald viscometer and determined by the following equation.
Rv = t / t₀
t₀: Seconds of solvent falling
t: Sample solution falling seconds
[0156]
(9) Content of sodium atom in partially aromatic polyamide, polyester composition and polyester packaging material (hereinafter referred to as “Na content”)
The sample is incinerated and decomposed in a platinum crucible, and 6 mol / L hydrochloric acid is added to evaporate to dryness. It was dissolved in 1.2 mol / L hydrochloric acid and quantitatively determined by atomic absorption.
[0157]
(10) Measurement of fine content
About 0.5 kg of the resin is put on a sieve (diameter: 30 cm) with a wire mesh having a nominal size of 1.7 mm according to JIS-Z8801, and a rocking sieve tow machine SNF-7 manufactured by Teraoka Co., Ltd. for 1 minute at 1800 rpm. Sieved. This operation was repeated to sieve a total of 20 kg of the resin.
The fines sieved under the sieve were washed with ion-exchanged water and collected by filtration through a G1 glass filter manufactured by Iwaki Glass Co., Ltd. These were dried together with the glass filter in a dryer at 100 ° C. for 2 hours, cooled, and weighed. The same operation of washing and drying with ion-exchanged water was repeated again to confirm that the weight became constant, and the weight of the glass filter was subtracted from this weight to obtain a fine weight. Fine content is the fine weight / the total resin weight sieved.
[0158]
(11) Evaluation of mold contamination
A predetermined amount of a thermoplastic polyester chip dried by a dryer using nitrogen gas and a predetermined amount of a partially aromatic polyamide dried by a dryer using nitrogen gas are dry-blended, and the resulting mixture is used to produce M-M-M-M. A preform was molded at a resin temperature of 285 ° C. using a 150C (DM) injection molding machine. 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. to obtain a hollow molded body of 1000 cc. Under the same conditions, 2,000 hollow moldings were continuously stretch blow-molded, and the state of the mold surface before and after the molding was visually observed and evaluated as follows.
◎ ： No change before and after the continuous molding test
○ ： Slight deposits after continuous molding test
△ △: △ There is considerable adhesion after continuous molding test
×: Very much deposits after continuous molding test
[0159]
(12) Transparency of hollow molded body
a) Non-heat-resistant hollow molded article: The appearance of a hollow molded article molded by the method described in Example 1 was visually observed and evaluated according to the following evaluation criteria.
b) Heat-resistant hollow molded article: The appearance of the hollow molded article obtained after the molding of (13) was visually observed and evaluated according to the following evaluation criteria. The short-term transparency was evaluated after 10 moldings, and the continuous molding transparency was evaluated after 2000 moldings.
(Evaluation criteria)
◎: transparent
○: Transparent in practical range, no foreign matter such as unmelted matter
Δ: △ Transparent in a practical range, but foreign matters such as unmelted matter are observed.
X: Poor transparency, coloring, or unmelted material
[0160]
(13) Sensory test
a) Non-heat-resistant hollow molded article: After boiling distilled water is cooled to 50 ° C., put in a hollow molded article, sealed and kept for 30 minutes, then allowed to stand at 50 ° C. for 10 days, opened, and then tested for flavor, smell, etc. went. 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.
b) Heat-resistant hollow molded body: Boiling distilled water was put into the hollow molded body, kept for 30 minutes after sealing, then allowed to stand at 50 ° C. for 5 days. After opening, the flavor, smell and the like were tested as described above.
(Evaluation criteria)
◎ ： No off-flavor or smell
○: slight difference from blank
△: Feel the difference from the blank
×: I feel a considerable difference from the blank
××: I feel a very large difference from the blank
[0161]
(14) Oxygen permeation amount (cc / one container / 24 hr · atm)
The permeation amount per bottle of 1000 cc was measured at 20 ° C. and 0% RH using an oxygen permeation measuring device OX-TRAN100 manufactured by Modern @ Controls.
(Polyethylene terephthalate (PET) used in Examples and Comparative Examples)
Table 1 shows the properties of PET (A) to (E) used in the evaluation test of the hollow molded article. These PET are polymerized by a continuous melt polycondensation-solid state polymerization apparatus using a Ge catalyst.
The DEG content of these PET is about 2.8 mol%, the fine content of PET (A) to (C) is about 70 ppm or less, and the fine content of PET (D) and (E) is about 500 ppm. Met.
[0162]
[Table 1]

[0163]
(Metaxylylene group-containing polyamide (Ny-MXD6) used in Examples and Comparative Examples)
Table 2 shows the characteristics of Ny-MXD6 (F) to Ny-MXD6 (I) used in the test.
Ny-MXD6 (F) to Ny-MXD6 (H) convert meta-xylylenediamine and adipic acid into NaOH or NaH in a pressure-resistant polycondensation kettle.₂PO₂・ H₂It is obtained by a batch method in which polycondensation is performed by heating under pressure and normal pressure in the presence of O. The amount of sodium was adjusted so that the total amount of sodium atoms of sodium hypophosphite and sodium hydroxide was 3.0 times mol of phosphorus atoms.
Ny-MXD6 (I) was also obtained by the same polymerization method as Ny-MXD6 (H). The phosphorus atom-containing compound and the alkali compound were not added. The secondary transition point of these Ny-MXD6 is about 65 ° C.
[0164]
[Table 2]

[0165]
(Example 1)
2 parts by weight of Ny-MXD6 (G) were used with respect to 100 parts by weight of PET (C), these were dried by the drying method described in the evaluation method (12), and then dry-blended. A preform was molded at a resin temperature of 285 ° C. using an M-150C (DM) injection molding machine. The preform was biaxially stretched and blow-molded using an LB-01E stretch blow molding machine manufactured by Co-Poplast to obtain a 2000 cc non-heat-resistant hollow molded body.
[0166]
Table 3 shows the evaluation results of the properties of the obtained hollow molded body.
The sodium content of the polyester composition was 2 ppm, and the difference in acetaldehyde content before and after injection molding (A_t-A₀) Is 8 ppm, the AA content of the hollow molded article is 10 ppm, the sensory test evaluation is “◎”, the transparency is “◎”, and a hollow molded article having extremely excellent transparency and flavor retention is obtained. Was completed.
[0167]
(Example 2)
A 2000 cc hollow molded body was molded in the same manner as in Example 1 using 10 parts by weight of Ny-MXD6 (F) with respect to 100 parts by weight of PET (C) and evaluated.
Table 3 shows the evaluation results of the properties of the obtained hollow molded body.
The sodium content of the polyester composition was 59 ppm, and the difference in the acetaldehyde content before and after injection molding (A_t-A₀) Was 6 ppm, the AA content of the hollow molded article was 8 ppm, the sensory test evaluation was “「 ”, and the transparency was“ ◎ ”. The oxygen barrier properties are also improved.
[0168]
(Example 3)
Using 30 parts by weight of Ny-MXD6 (F) with respect to 100 parts by weight of PET (C), a hollow molded body was molded in the same manner as in Example 1 and evaluated.
Table 3 shows the value results of the properties of the obtained hollow molded body.
The sodium content of the polyester composition was 150 ppm, and the difference in acetaldehyde content before and after injection molding (A_t-A₀) Was 5 ppm, the AA content of the hollow molded article was 6 ppm, the sensory test evaluation was “」 ”, and the transparency was“ ○ ”, which was no problem.
[0169]
(Comparative Example 1)
Using 10 parts by weight of Ny-MXD6 (I) with respect to 100 parts by weight of PET (D), a hollow molded body was molded in the same manner as in Example 1 and evaluated.
Table 3 shows the evaluation results of the properties of the obtained hollow molded body.
The sodium content of the polyester composition was 0 ppm, and the difference in acetaldehyde content before and after injection molding (A_t-A₀) Was 18 ppm, the AA content of the hollow molded article was 22 ppm, the transparency was "x" (colored unmelted material was observed), and the sensory evaluation was "x". .
[0170]
(Comparative Example 2)
Using 30 parts by weight of Ny-MXD6 (H) with respect to 100 parts by weight of PET (E), a hollow molded body was molded in the same manner as in Example 1 and evaluated.
Table 3 shows the evaluation results of the properties of the obtained hollow molded body.
The sodium content of the polyester composition was 346 ppm, and the difference in acetaldehyde content before and after injection molding (A_t-A₀) Was 11 ppm, and the AA content of the hollow molded article was 15 ppm. However, the transparency was "× (poor in transparency)", and the sensory test evaluation was "XX", which was poor and not practical. there were.
[0171]
(Comparative Example 3)
Using 100 parts by weight of PET (D), a hollow molded body was molded in the same manner as in Example 1 and evaluated.
Table 3 shows the evaluation results of the properties of the obtained hollow molded body.
[0172]
[Table 3]

[0173]
(Example 4)
Using 10 parts by weight of Ny-MXD6 (G) with respect to 100 parts by weight of PET (A), a hollow molded body was molded by the method of evaluation method (12), and the evaluation of mold contamination was also performed.
Table 4 shows the properties of the obtained hollow molded body and the results of evaluation of mold contamination.
Difference in acetaldehyde content before and after injection molding of the polyester composition (A_t-A₀) Is 5 ppm, the sodium content of the hollow molded article is 11 ppm, the AA content of the hollow molded article is 9 ppm, the ΔAA content is 10 ppm, the cyclic ester trimer content is 0.32% by weight, the cyclic ester 3 Increase in monomer content (△ CT₂Amount) was 0.04% by weight, the CM content was 530 ppm, the organoleptic test evaluation was “○”, the transparency was “○”, and no adhesion to the mold was observed.
[0174]
(Example 5)
Using 20 parts by weight of Ny-MXD6 (F) with respect to 100 parts by weight of PET (B), a hollow molded article was molded by the method of the evaluation method (12), and mold stain evaluation was also performed.
Table 4 shows the properties of the obtained hollow molded body and the results of evaluation of mold contamination.
Difference in acetaldehyde content before and after injection molding of the polyester composition (A_t-A₀) Is 5 ppm, the sodium content of the hollow molded article is 108 ppm, the AA content of the hollow molded article is 7 ppm, the ΔAA content is 10 ppm, the cyclic ester trimer content is 0.34% by weight, the cyclic ester 3 Increase in monomer content (△ CT₂Amount) was 0.09% by weight, the CM content was 1100 ppm, the organoleptic test evaluation was “○”, the transparency was “○”, and no adhesion to the mold was observed.
[0175]
(Example 6)
Using 30 parts by weight of Ny-MXD6 (F) with respect to 100 parts by weight of PET (A), a hollow molded body was molded by the method of the evaluation method (12), and mold stain evaluation was also performed.
Table 4 shows the properties of the obtained hollow molded body and the results of evaluation of mold contamination.
Difference in acetaldehyde content before and after injection molding of the polyester composition (A_t-A₀) Is 4 ppm, the sodium content of the hollow molded article is 150 ppm, the AA content of the hollow molded article is 5 ppm, the ΔAA content is 8 ppm, the cyclic ester trimer content is 0.31% by weight, the cyclic ester 3 Increase in monomer content (△ CT₂Amount) was 0.05% by weight, the CM content was 1400 ppm, the organoleptic test evaluation was “○”, the transparency was “○”, and no adhesion to the mold was observed.
[0176]
(Comparative Example 4)
Using 100 parts by weight of PET (D) and 0.05 part by weight of Ny-MXD6 (I), a hollow molded body was molded by the method of evaluation method (12), and the evaluation of mold contamination was also performed.
Table 4 shows the properties of the obtained hollow molded body and the results of evaluation of mold contamination.
Difference in acetaldehyde content before and after injection molding of the polyester composition (A_t-A₀) Is 27 ppm, the phosphorus content of the hollow molded article is 0 ppm, the AA content of the hollow molded article is 41 ppm, the ΔAA content is 35 ppm, the cyclic ester trimer content is 0.76% by weight, and the cyclic ester 3 is Increase in monomer content (△ CT₂Amount) was 0.50% by weight, the sensory evaluation was "XX", the transparency was "X", and the mold stain was severe.
[0177]
(Comparative Example 5)
Using 30 parts by weight of Ny-MXD6 (H) with respect to 100 parts by weight of PET (E), a hollow molded body was molded by the method of the evaluation method (12), and mold contamination was also evaluated.
Table 4 shows the properties of the obtained hollow molded body and the results of evaluation of mold contamination.
Difference in acetaldehyde content before and after injection molding of the polyester composition (A_t-A₀) Is 7 ppm, the sodium content of the hollow molded body is 346 ppm, the AA content of the hollow molded body is 13 ppm, the ΔAA content is 18 ppm, the cyclic ester trimer content is 0.79% by weight, and the cyclic ester 3 is Increase in monomer content (△ CT₂Amount) was 0.52% by weight, the CM content was 3800 ppm, the sensory evaluation was "XX", the transparency was "X", and the mold stain was severe.
[0178]
[Table 4]

[0179]
【The invention's effect】
According to the polyester composition of the present invention, a polyester packaging material excellent in transparency, heat stability and flavor retention, or transparency, heat stability, flavor retention and gas barrier properties can be obtained. As described above, the polyester packaging material is very suitable as a packaging material for beverages such as soft drinks.

Claims (4)

A polyester composition comprising 100 parts by weight of a thermoplastic polyester and 0.1 to 50 parts by weight of a partially aromatic polyamide, wherein an alkali metal atom content in the polyester composition is in a range of 0.1 to 300 ppm. A polyester composition, characterized in that: 2. The polyester composition according to claim 1, wherein a secondary transition point of the partially aromatic polyamide measured by DSC (differential scanning calorimeter) is 50 to 120 ° C. 3. A polyester packaging material obtained by molding the polyester composition according to claim 1 or 2. 4. The polyester packaging material according to claim 3, wherein the polyester packaging material is any one of a hollow molded article, a sheet-like material, and a stretched film obtained by stretching this sheet-like material in at least one direction.