JP3926438B2

JP3926438B2 - Molded product and laminate from saponified composition of ethylene-vinyl acetate copolymer

Info

Publication number: JP3926438B2
Application number: JP22566497A
Authority: JP
Inventors: 賢二仁宮
Original assignee: Nippon Synthetic Chemical Industry Co Ltd
Current assignee: Mitsubishi Chemical Corp
Priority date: 1997-08-06
Filing date: 1997-08-06
Publication date: 2007-06-06
Anticipated expiration: 2017-08-06
Also published as: JPH1149918A

Description

【０００１】
【発明の属する技術分野】
本発明は、エチレン−酢酸ビニル系共重合体ケン化物（以下、ＥＶＯＨと略記する）を主剤とするＥＶＯＨ組成物からの成形物、特にフィルム等の成形物に関する。また、本発明はその成形物を少なくとも一層とする積層体に関する。
【０００２】
【従来の技術】
従来より、ＥＶＯＨフィルムは、そのガスバリヤー性を生かして、各種包装用途に多用されている。
かかるＥＶＯＨフィルムの製造法としては、ＥＶＯＨ（ペレット）を溶融押出機等によりフィルム状に成形し、更に１軸或いは２軸に延伸するのが一般的であるが、該製造法によっては、得られたＥＶＯＨフィルムにダイラインやフィッシュアイ等が生じたり、或いは透明性に劣ったりすることも多く、又、製造中にゲルや目ヤニ等が発生しロングラン成形が困難となり、実用に供するのが難しくなる。
かかる対策として、本出願人は、ＥＶＯＨに水を含有せしめてなる樹脂組成物を用いることを提案した（特願平８−３１３０５０号）。
【０００３】
【発明が解決しようとする課題】
しかしながら、本発明者が詳細に検討した結果、上記技術ではフィッシュアイの低減は認められるものの、長時間の連続運転におけるＥＶＯＨ成形物の外観及び品質の安定性については改善の余地が残るものであり、技術の高度化と多様化に伴い、更にロングラン性に優れ、スジやフィッシュアイや着色のない、透明性に優れた外観の良好なＥＶＯＨ成形物（フィルム、シート、等）が望まれている。
【０００４】
【課題を解決するための手段】
そこで、本発明者はかかる事情に鑑みて鋭意研究を重ねた結果、エチレン含有量５〜６０モル％、ケン化度９０モル％以上のＥＶＯＨ（Ａ）、アルカリ土類金属の酢酸塩（Ｂ）、酢酸（Ｃ）、水（Ｄ）を含有してなり、かつ、アルカリ土類金属の酢酸塩（Ｂ）の含有量が該ＥＶＯＨ（Ａ）に対してアルカリ土類金属換算で５〜３００ｐｐｍ、酢酸（Ｃ）とアルカリ土類金属の酢酸塩（Ｂ）の重量比（（Ｃ）／（Ｂ））が０．０５〜１０、水（Ｄ）の含有量が該ＥＶＯＨ（Ａ）１００重量部に対して１０〜１４０重量部であるＥＶＯＨ組成物を溶融押出し、含水率５〜５０重量％で延伸し、熱固定してなる成形物が、上記の課題を解決するものであることを見出し本発明を完成するに至った。本発明において、上記ＥＶＯＨ組成物を溶融押出し、含水率５〜５０重量％で延伸し、熱固定して成形物、特にフィルム、シートとする。
【０００５】
又、本発明では、上記ＥＶＯＨ組成物を溶融押出して得られた成形物、特にフィルム、シートを含水率５〜５０重量％で延伸することも好ましく、フィルム外観の優れた成形物が得られるのである。
即ち、本発明は、膜厚が均一で透明性やガスバリヤー性、スジ、フィッシュアイの低減等に優れた外観の良好なＥＶＯＨ組成物の成形物（フィルム、シート等）を得ることができるのである。
【０００６】
【発明の実施の形態】
以下、本発明について具体的に説明する。
本発明のＥＶＯＨ（Ａ）としては、エチレン含量５〜６０モル％、好ましくは１０〜６０モル％、更に好ましくは２０〜５５モル％、酢酸ビニル成分のケン化度が９０モル％以上、好ましくは９５モル％以上のものが好適に用いられ、エチレン含量が５モル％未満では耐水性が不十分となり、一方６０モル％を越えるとガスバリヤー性が低下して好ましくない。又、ケン化度が９０モル％未満では耐水性が不十分となって好ましくない。
【０００７】
又、該ＥＶＯＨ（Ａ）は更に少量のプロピレン、イソブテン、α−オクテン、α−ドデセン、α−オクタデセン等のα−オレフィン、不飽和カルボン酸又はその塩・部分アルキルエステル・完全アルキルエステル・ニトリル・アミド・無水物、不飽和スルホン酸又はその塩、ビニルシラン化合物、塩化ビニル、スチレン等のコモノマーを含んでいても差し支えない。又、本発明の範囲で、ウレタン化、アセタール化、シアノエチル化等「後変性」にされても差し支えない。
【０００８】
アルカリ土類金属の酢酸塩（Β）としては、酢酸カルシウム、酢酸マグネシウム、酢酸バリウム、酢酸ベリリウム等が挙げられるが、好ましくは酢酸カルシウム、酢酸マグネシウムが採用される。又、これらは単独又は併用することもできる。
該アルカリ土類金属の酢酸塩（Β）の含有量は、ＥＶＯＨ（Α）に対してアルカリ土類金属換算で５〜３００ｐｐｍ、好ましくは１０〜２００ｐｐｍ、更に好ましくは１５〜１５０ｐｐｍである。アルカリ土類金属の酢酸塩（Β）の含有量が５ｐｐｍ未満では本発明の効果が得られず、一方、３００ｐｐｍを越えると組成物の熱分解が大きくなり臭気も大きくなる。
【０００９】
又、上記アルカリ土類金属の酢酸塩の他にアルカリ金属の酢酸塩、例えば酢酸ナトリウム、酢酸カリウム等をＥＶＯＨ（Ａ）に対してアルカリ金属換算で２０〜５００ｐｐｍ、好ましくは４０〜３００ｐｐｍを含有させることも可能である。
【００１０】
又、酢酸（Ｃ）の含有量は特に制限されないが、最終的に酢酸（Ｃ）とアルカリ土類金属の酢酸塩（Ｂ）の重量比（（Ｃ）／（Ｂ））が０．０５〜１０、好ましくは０．０８〜８、更に好ましくは０．１〜５であることが必要である。かかる重量比が０．０５未満では本発明の効果が得られず、一方１０を越えると成形物中にゲルが多発し、商品価値がなくなる。中でも特に酢酸（Ｃ）の含有量としては、ＥＶＯＨ（Ａ）に対して３０〜４０００ｐｐｍ、好ましくは５０〜２０００ｐｐｍが適当である。
【００１１】
本発明においては、上記の如くＥＶＯＨ（Ａ）、アルカリ土類金属の酢酸塩（Ｂ）、酢酸（Ｃ）及び水（Ｄ）を含有させてＥＶＯＨ組成物を得るが、かかる水（Ｄ）の含有量はＥＶＯＨ（Ａ）１００重量部に対して１０〜１４０重量部、好ましくは１５〜１２０重量部、更に好ましくは２０〜１００重量部である。水（Ｄ）の含有量が１０重量部未満では押出成形温度を上げる必要がありロングラン成形性が低下するばかりでなく、均一な延伸が困難となり、逆に１４０重量部を越えると押出機中で樹脂と水分の一部分離が起こり押出が不安定になる。
【００１２】
ＥＶＯＨ組成物の製造方法は特に制限はなく、要はＥＶＯＨ（Ａ）、アルカリ土類金属の酢酸塩（Ｂ）、酢酸（Ｃ）及び水（Ｄ）を上記の範囲内で含有されるようにすればよく、例えば、▲１▼ＥＶＯＨ（Ａ）の粉末、ペレット、粒状物にアルカリ土類金属の酢酸塩（Ｂ）及び酢酸（Ｃ）を任意の形態にして混合し、水（Ｄ）を混合する方法、▲２▼ＥＶＯＨ（Ａ）製造時の任意の段階、即ち重合時、ケン化時、後処理時、乾燥時の任意の段階でアルカリ土類金属の酢酸塩（Ｂ）及び酢酸（Ｃ）を所定量含有させ、ＥＶＯＨの製造後に水（Ｄ）を混合する方法、▲３▼ＥＶＯＨ（Ａ）と水（Ｄ）を混合撹拌してあるいは蒸気を吹き込んで吸水させた後アルカリ土類金属の酢酸塩（Ｂ）及び酢酸（Ｃ）を混合する方法、▲４▼ＥＶＯＨ（Ａ）の水／メタノール混合液を凝固液槽中に押出して多孔性の含水ＥＶＯＨ成形物を得た後、水中でアルカリ土類金属の酢酸塩（Ｂ）及び酢酸（Ｃ）を含浸させて、上記範囲の含水量まで乾燥する方法、等の方法が挙げられる。但し、これらに限定されることはない。
【００１３】
又、ＥＶＯＨ（Ａ）の製造時に若干のメタノール、イソプロピルアルコール等のアルコールとともに含水させておくことも可能である。
この際、少量のエチレングリコール、プロピレングリコール、グリセリン等の可塑剤を含んでいても差し支えない。エチレングリコール、プロピレングリコール、グリセリン等の可塑剤の含有量は０．２〜１０重量％程度が適当である。
又、酸化防止剤、滑剤、ハイドロタルサイト類、帯電防止剤、着色剤、紫外線吸収剤、無機・有機充填材、抗菌剤等を本発明の効果を阻害しない範囲で添加することができる。
【００１４】
かくして本発明のＥＶＯＨ組成物が得られる。該ＥＶＯＨ組成物は次いで溶融押出機に供されて成形物に溶融成形される。フィルムの場合、かかる成形時の条件としては、特に限定されないが、通常はノンベント、スクリュータイプ押出機を用い溶融温度４０〜１５０℃で押出製膜される。製膜されたフィルム中に均一な分布で水を残留させる為に、圧縮比２．０〜４．０のスクリューを用いることが好ましい。
【００１５】
上記の方法で得られたフィルム状のＥＶＯＨ組成物の成形物は、次いで延伸に供されるのであるが、かかる延伸時（延伸直前）のＥＶＯＨ組成物の成形物の含水率を５〜５０重量％、好ましくは７〜４５重量％、更に好ましくは１０〜４０重量％に調整することも重要で、かかる含水率が５重量％未満では延伸斑を生じやすく、破断の原因ともなり、逆に５０重量％を越えると充分な延伸配向によるガスバリヤー性と強度の改善効果が得られず、好ましくない。かかる含水率の調整方法としては、特に限定されず、製膜直後に調湿操作を加えることもできる。
【００１６】
延伸については、１軸延伸法、２軸延伸法（同時、逐次）等があり、特に限定されないが、本発明は、特に逐次２軸延伸法における第１次（ＭＤ方向）延伸に効果的であり、かかる延伸方法について詳細に説明する。
【００１７】
上記の含水率が調整されたフィルム状のＥＶＯＨ組成物の成形物は、第１次（ＭＤ方向）延伸工程に供される。かかる第１次（ＭＤ方向）延伸は、公知の方法を利用することができ、上記の成形物を４０〜１００℃の条件下で縦方向に１．５〜８倍に延伸するのである。かかる第１次（ＭＤ方向）延伸の処理後の含水率は０．５〜４５重量％、好ましくは１〜４０重量％にすることが望ましく、０．５重量％未満では第２次（ＴＤ方向）延伸での延伸斑が生じ、同時の延伸倍率まで延伸することが困難となり、逆に４５重量％を越えると第１次の延伸配向効果が期待できず、ガスバリヤー性、強度の改善効果が少なくなって好ましくない。かかる含水率の調整方法としては予熱ロールの温度と時間、第１次（ＭＤ方向）延伸の温度と延伸速度等により行うことができる。
【００１８】
上記の第１次（ＭＤ方向）延伸されたＥＶＯＨ組成物フィルムは、続いて第２次（ＴＤ方向）延伸工程で横方向の延伸に供されるのであるが、かかる工程においては、公知の方法を利用することができ、上記のＥＶＯＨ組成物フィルムを６０〜１４０℃の条件下で横方向に１．５〜８倍に延伸するのである。通常は、フィルム両耳部をクリップではさむテンター方式で行われる。本条件以外ではクリップ部、クリップ−クリップ間及びフイルム巾方向の中間部でのいずれかの破断が生じ、目標の延伸フィルムを得ることは極めて困難である。又、更に熱固定を行う。熱固定とは緊張下に温度１２０〜２００℃で数秒ないし数分間フィルムを加熱することで、更に熱固定後のフィルムに柔軟性と寸法安定性を付与するために、含水率が０．３〜３重量％程度になるまでフィルムを調湿してもよい。
【００１９】
かくしてＥＶＯＨ（Ａ）、アルカリ土類金属の酢酸塩（Ｂ）、酢酸（Ｃ）及び水（Ｄ）を特定量含有してなるＥＶＯＨ組成物は、溶融押出により、ロングラン性に優れ、スジやフィッシュアイ、着色のない、透明性に優れた外観の良好な成形物を得ることができるのである。
【００２０】
本発明で得られたＥＶＯＨ組成物の成形物（フィルム、シート等）は、単層のみならず、かかるフィルムを少なくとも一層とする積層体として実用に供せられることが多い。
該積層体の製造に当たっては、本発明の製造法により得られたフィルム、シート等の成形物の層の片面又は両面に他の基材をラミネートするのであるが、ラミネート方法としては、例えば、該成形物と他の基材のフィルム、シートとを有機チタン化合物、イソシアネート化合物、ポリエチレンイミン系化合物、ポリエステル系化合物、ポリウレタン系化合物等の公知の接着剤を用いてラミネートする方法等が挙げられる。
【００２１】
かかる他の基材フィルムとしては、直鎖状低密度ポリエチレン、低密度ポリエチレン、中密度ポリエチレン、高密度ポリエチレン、エチレン−酢酸ビニル共重合体、アイオノマー、エチレン−プロピレン共重合体、エチレン−アクリル酸エステル共重合体、ポリプロピレン、プロピレン−α−オレフィン（炭素数４〜２０のα−オレフィン）共重合体、ポリブテン、ポリペンテン等のオレフィンの単独又は共重合体、或いはこれらのオレフィンの単独又は共重合体を不飽和カルボン酸又はそのエステルでグラフト変性したもの等の広義のポリオレフィン系樹脂、ポリスチレン系樹脂、ポリエステル、ポリアミド、共重合ポリアミド、ポリ塩化ビニル、ポリ塩化ビニリデン、アクリル系樹脂、ビニルエステル系樹脂、ポリエステルエラストマー、ポリウレタンエラストマー、塩素化ポリエチレン、塩素化ポリプロピレン、ＥＶＯＨ等が挙げられ、更には、紙、金属箔、１軸又は２軸延伸プラスチックフイルム又はシート、織布、不織布、金属綿条、木質面なども使用可能である。
【００２２】
積層体の層構成としては、ＥＶＯＨフィルムの層をI（I1，I2，・・・）、他の基材、例えば熱可塑性樹脂層をII（II1，II2，・・・）とするとき、フィルム、シート状であれば、I／IIの二層構造のみならず、II／I／II、I／II／I、I1／I2／II、I／II1／II2、II2／II1／I／II1／II2など任意の組合せが可能である。
【００２３】
かくして、本発明のＥＶＯＨ組成物の成形物（フィルム、シート等）やその積層体は、その特性、即ち外観特性、ガスバリヤー性等に優れるため、食品や医薬品、農薬品、工業薬品包装用のフィルム、シート、チューブ、袋、容器等の用途に非常に有用である。
【００２４】
【実施例】
以下、実施例を挙げて本発明を具体的に説明する。
尚、例中、「部」、「％」とあるのは、特に断りのない限り重量基準を意味する。
実施例１
エチレン含量４０モル％のエチレン−酢酸ビニル共重合体の４０％メタノール溶液１０００部を耐圧反応器に入れ、撹拌しながら１１０℃に加熱した。続いて水酸化ナトリウムの６％メタノール溶液４０部及びメタノール２５００部を連続的に仕込むと共に副生する酢酸メチル及び余分のメタノールを系から留出させながら２．５時間ケン化反応を行い、酢酸ビニル成分のケン化度９９．０モル％のＥＶＯＨ（Ａ）を得た。
【００２５】
ケン化終了液に３０％含水メタノールを４５０部仕込みながら余分のメタノールを留去させ、水／メタノール溶液を製造した。
前記のＥＶＯＨ（Ａ）の水／メタノール混合液を水／メタノール（混合比９／１）凝固液槽（巾１００ｍｍ、長さ４０００ｍｍ、深さ１００ｍｍ）にストランド状に押出した。凝固終了後、凝固液槽の端部に付設された引き取りローラーを経て、ストランド状物をカッターで切り離し、白色、多孔性のペレットを製造した。
【００２６】
次に、該ペレット１００部を０．１％酢酸、３００部に浸漬し、３０℃で１時間撹拌して洗浄を２回繰り返した。該スラリーをろ別した後、得られたペレットを０．１％酢酸−０．２％酢酸カルシウム−０．１％酢酸マグネシウム水溶液３００部と混合し、３０℃で１時間撹拌した後、ろ別し、ＥＶＯＨ（Ａ）１００部に対して水７０部となるように乾燥した。
【００２７】
かくして得られたＥＶＯＨ組成物はエチレン含有量４０モル％、ケン化度９９．０％のＥＶＯＨ（Ａ）と該ＥＶＯＨ（Ａ）に対して酢酸カルシウムの含有量が２５０ｐｐｍ（カルシウム換算で６３ｐｐｍ）、酢酸マグネシウムの含有量が１２０ｐｐｍ（マグネシウム換算で２０ｐｐｍ）、酢酸とアルカリ土類金属の酢酸塩の重量比が０．５、水の含有量が該ＥＶＯＨ（Ａ）１００部に対して７０部の組成物であった。
【００２８】
尚、アルカリ土類金属の定量法は以下の通りであった。
（アルカリ土類金属）
乾燥した試料約８０ｇを精秤し、そのうちの約１０ｇを恒量化した白金蒸発皿に入れ、電熱器で炭化した。次にガスバーナーで加熱し、煙が出なくなる間で焼いた。
約４００℃の電気炉内に前記の白金蒸発皿を入れ、磁性ルツボ蓋で大半を覆い、７００℃まで徐々に昇温した。７００℃に３時間保持して完全灰下させた。白金ルツボに特級塩酸２ｍｌ及び純水３ｍｌを入れ、電熱器で加熱して溶解した。上記溶液を５０ｍｌメスフラスコに純水で流し込み、更に標線まで純水を追加して原子吸光分析用の試料とした。
【００２９】
別途、調製した標準液（アルカリ土類金属１ｐｐｍ、塩酸約０．５Ｎ）を対照液として原子吸光度の測定を行い、吸光度の比率からアルカリ土類金属の量を定量した。
測定条件は次の通りである。
装置：日立１８０ー３０形原子吸光／炎光分光光度計
フレーム：アセチレン−空気
【００３０】
そして、該ＥＶＯＨ組成物をＴダイを備えた単軸押出機に供給し、厚さ１２０μｍのＥＶＯＨ組成物フィルムの成形を行った。
単軸押出機による製膜条件は下記の通りとした。

【００３１】
長時間（４日間及び１０日間）連続運転時のＥＶＯＨ組成物フィルムの外観について下記の項目を評価した。
（フィルム外観）
▲１▼スジ
スジの有無を下記の基準で評価した。
○・・・スジは認められなかった。
△・・・スジが僅かに認められるが、実用上問題なし。
×・・・スジが多発し、実用上使用困難であった。
【００３２】
▲２▼フィッシュアイ
フィッシュアイの有無を下記の基準で評価した。
○・・・０〜３個／１００ｃｍ²（フィルムサイズ；１０ｃｍ×１０ｃｍ）
△・・・４〜２０個／１００ｃｍ²
×・・・２１個以上／１００ｃｍ²
【００３３】
▲３▼着色
着色の有無を下記の基準で評価した。
○・・・着色は認められなかった。
△・・・黄着色が僅かに認められた。
×・・・黄着色が大で実用上使用困難であった。
【００３４】
次いで、上記の成形で得られたＥＶＯＨ組成物フィルム（含水率３５％）を原反として、連続的に下記の条件で逐次２軸延伸、熱固定及び調湿を行って、ＥＶＯＨ組成物延伸フィルムを得た。
【００３５】
［第１次延伸（縦延伸）条件］
延伸機ロール式１次延伸機
延伸ロール温度７０℃
縦方向延伸倍率２．０倍
延伸後の膜厚６０μｍ
延伸後の含水率３０％
【００３６】
［第２次延伸（横延伸）条件］
延伸機テンター式２軸延伸機
延伸温度１１０℃
横方向延伸倍率３．０倍
延伸後の膜厚２０μｍ
延伸後の含水率２％
【００３７】
［熱固定条件］
温度１６０℃
時間３秒
［調湿条件］
２０℃、６５％ＲＨ下に７日放置
調湿後の含水率２．５％
得られたＥＶＯＨ組成物（２軸）延伸フィルムについて、上記と同様の評価を行った。
【００３８】
実施例２
実施例１において、エチレン含有量が３５モル％、ケン化度が９９．８モル％のＥＶＯＨ（Ａ）を用い、酢酸−酢酸カルシウム水溶液で処理し該ＥＶＯＨ（Ａ）に対して酢酸カルシウムを４７０ｐｐｍ（カルシウム換算で１２０ｐｐｍ）、、酢酸とアルカリ土類金属の酢酸塩の重量比を０．２、該ＥＶＯＨ（Ａ）１００部に対して水を３４部となるように含有せしめた以外は同様に行って、ＥＶＯＨ組成物フィルム及びＥＶＯＨ組成物延伸フィルムを得て、同様に評価を行った。この時のＥＶＯＨ組成物フィルムの含水率は２２％、第１次延伸後の水分率は２０％、第２次延伸後の水分率は０．６％、調湿後の含水率は２．５％であった。
【００３９】
実施例３
実施例１において、エチレン含有量が２８モル％、ケン化度が９８．６モル％のＥＶＯＨ（Ａ）を用い、酢酸−酢酸マグネシウム水溶液で処理し該ＥＶＯＨ（Ａ）に対して酢酸マグネシウムを２４０ｐｐｍ（マグネシウム換算で４０ｐｐｍ）、酢酸とアルカリ土類金属の酢酸塩の重量比を１．１、該ＥＶＯＨ（Ａ）１００部に対して水を５５部となるように含有せしめた以外は同様に行って、ＥＶＯＨ組成物フィルム及びＥＶＯＨ組成物延伸フィルムを得て、同様に評価を行った。この時のＥＶＯＨ組成物フィルムの含水率は３３％、第１次延伸後の水分率は２８％、第２次延伸後の水分率は１．５％、調湿後の含水率は２．８％であった。
【００４０】
実施例４
実施例１において、エチレン含有量が３５モル％、ケン化度が９９．８モル％のＥＶＯＨ（Ａ）を用い、酢酸、酢酸カルシウム、酢酸マグネシウム、酢酸ナトリウムを含む水溶液で処理し、該ＥＶＯＨ（Ａ）に対して酢酸カルシウムを１６０ｐｐｍ（カルシウム換算で４０ｐｐｍ）、酢酸マグネシウムを６０ｐｍｍ（マグネシウム換算で１０ｐｐｍ）、酢酸ナトリウムを１８０ｐｐｍ（ナトリウム換算で５０ｐｐｍ）、酢酸とアルカリ土類金属の酢酸塩の重量比を０．３５、該ＥＶＯＨ（Ａ）１００部に対して水を３４部となるように含有せしめた以外は同様に行って、ＥＶＯＨ組成物フィルム及びＥＶＯＨ組成物延伸フィルムを得て、同様に評価を行った。この時のＥＶＯＨ組成物フィルムの含水率は２２％、第１次延伸後の水分率は２０％、第２次延伸後の水分率は０．６％、調湿後の含水率は２．５％であった。
【００４１】
比較例１
実施例１において、ＥＶＯＨ（Ａ）を酢酸、酢酸カルシウム、酢酸マグネシウムを含む水溶液で処理することなく、ＥＶＯＨ（Ａ）１００部に対して水を７０部となるように含有せしめた以外は同様に行い、ＥＶＯＨ組成物フィルム及びＥＶＯＨ組成物延伸フィルムを得て、同様に評価を行った。この時のＥＶＯＨ組成物フィルムの含水率は３５％、第１次延伸後の水分率は３０％、第２次延伸後の水分率は２％、調湿後の含水率は２．５％であった。
【００４２】
比較例２
実施例１において、ＥＶＯＨ（Ａ）に対して酢酸カルシウムを８ｐｐｍ（カルシウム換算で２ｐｐｍ）、酢酸マグネシウムを６ｐｐｍ（マグネシウム換算で１ｐｐｍ）、酢酸とアルカリ土類金属の酢酸塩の重量比を２、ＥＶＯＨ（Ａ）１００部に対して水を７０部となるように含有せしめた以外は同様に行って、ＥＶＯＨ組成物フィルム及びＥＶＯＨ組成物延伸フィルムを得て、同様に評価を行った。この時のＥＶＯＨ組成物フィルムの含水率は３５％、第１次延伸後の水分率は３０％、第２次延伸後の水分率は２％、調湿後の含水率は２．５％であった。
【００４３】
比較例３
実施例１において、ＥＶＯＨ（Ａ）に対して酢酸カルシウムを９９０ｐｐｍ（カルシウム換算で２５０ｐｐｍ）、酢酸マグネシウムを８９０ｐｐｍ（マグネシウム換算で１５０ｐｐｍ）、酢酸とアルカリ土類金属の酢酸塩の重量比を０．２、ＥＶＯＨ（Ａ）１００部に対して水を７０部となるように含有せしめた以外は同様に行って、ＥＶＯＨ組成物フィルム及びＥＶＯＨ組成物延伸フィルムを得て、同様に評価を行った。この時のＥＶＯＨ組成物フィルムの含水率は３５％、第１次延伸後の水分率は３０％、第２次延伸後の水分率は２％、調湿後の含水率は２．５％であった。
【００４４】
比較例４
実施例１において、ＥＶＯＨ（Ａ）に対して酢酸カルシウムを２５０ｐｐｍ（カルシウム換算で６３ｐｐｍ）、酢酸マグネシウムを１２０ｐｐｍ（マグネシウム換算で２０ｐｐｍ）、酢酸とアルカリ土類金属の酢酸塩の重量比を０．０２、ＥＶＯＨ（Ａ）１００部に対して水を７０部となるように含有せしめた以外は同様に行って、ＥＶＯＨ組成物フィルム及びＥＶＯＨ組成物延伸フィルムを得て、同様に評価を行った。この時のＥＶＯＨ組成物フィルムの含水率は３５％、第１次延伸後の水分率は３０％、第２次延伸後の水分率は２％、調湿後の含水率は２．５％であった。
【００４５】
比較例５
実施例１において、ＥＶＯＨ（Ａ）に対して酢酸カルシウムを１６０ｐｐｍ（カルシウム換算で４０ｐｐｍ）、酢酸マグネシウムを６０ｐｐｍ（マグネシウム換算で１０ｐｐｍ）、酢酸とアルカリ土類金属の酢酸塩の重量比を１５、ＥＶＯＨ（Ａ）１００部に対して水を７０部となるように含有せしめた以外は同様に行って、ＥＶＯＨ組成物フィルム及びＥＶＯＨ組成物延伸フィルムを得て、同様に評価を行った。この時のＥＶＯＨ組成物フィルムの含水率は３５％、第１次延伸後の水分率は３０％、第２次延伸後の水分率は２％、調湿後の含水率は２．５％であった。
【００４６】
比較例６
実施例１において、水を５部とした以外は同様に行った。但し、１２０℃では樹脂が溶融せずに押出不可であったので、１９０℃で成形した。
又、延伸処理において、第２次延伸時にフィルムの破断が生じ、安定した延伸が不可能で、延伸フィルムを得ることができなかった。
【００４７】
比較例７
実施例１において、水を２００部とした以外は同様に行った。ＥＶＯＨ組成物フィルム（原反フィルム）の成形時において、バレルのフィールド部に水が析出し、吐出不安定となり、膜厚が不均一な延伸用原反フィルムしか得られなかったが、実施例１と同様に連続的に延伸処理を行った。
【００４８】
比較例８
実施例１において、水を含有させなかった以外は同様に行った。但し、１２０℃では樹脂が溶融せずに押出不可であったので、２１０℃で成形した。
又、延伸処理において、第２次延伸時にフィルムの破断が生じ、安定した延伸が不可能で、延伸フィルムを得ることができなかった。
実施例及び比較例の評価結果を表１、２に示す。
【００４９】
【表１】

【００５０】
【表２】

【００５１】
【発明の効果】
本発明は、ＥＶＯＨ（Ａ）、特定量のアルカリ土類金属の酢酸塩（Ｂ）及び酢酸（Ｃ）、特定量の水（Ｄ）を含有してなるため、溶融成形時のロングラン性に非常に優れ、更にガスバリヤー性はもとより、長時間の連続成形においてもスジ、フィッシュアイ、着色のないフィルム外観や透明性に優れた成形物を得ることができ、又、本発明の成形物（延伸フィルム等）を少なくとも１層とした多層積層体は、食品や医薬品、農薬品、工業薬品等の包装用材料として非常に有用である。[0001]
BACKGROUND OF THE INVENTION
The present invention is, ethylene - vinyl acetate copolymer saponified (hereinafter, abbreviated as EVOH) molding of the EVOH composition or we to main agent, more particularly molded product such as a film. The present invention also relates to a laminate comprising at least one layer of the molded product.
[0002]
[Prior art]
Conventionally, EVOH films have been widely used for various packaging applications by taking advantage of their gas barrier properties.
As a method for producing such an EVOH film, EVOH (pellet) is generally formed into a film shape by a melt extruder or the like, and further stretched uniaxially or biaxially. In addition, die lines, fish eyes, etc. are often produced on EVOH films, or are inferior in transparency. Also, gels and spears are produced during production, making long-run molding difficult and difficult to put to practical use. .
As a countermeasure against this, the present applicant has proposed to use a resin composition obtained by adding water to EVOH (Japanese Patent Application No. 8-313050).
[0003]
[Problems to be solved by the invention]
However, as a result of detailed studies by the present inventor, although the fish eye can be reduced in the above technique, there is still room for improvement in the appearance and the stability of the quality of the EVOH molded product in the continuous operation for a long time. With the sophistication and diversification of technology, EVOH molded products (films, sheets, etc.) with excellent long-running properties, no streaks, fish eyes and coloration and excellent transparency and good appearance are desired. .
[0004]
[Means for Solving the Problems]
Therefore, as a result of intensive studies in view of such circumstances, the present inventors have found that EVOH (A) having an ethylene content of 5 to 60 mol% and a saponification degree of 90 mol% or more, and an alkaline earth metal acetate (B). , Acetic acid (C), water (D), and the content of the alkaline earth metal acetate (B) is 5 to 300 ppm in terms of alkaline earth metal relative to the EVOH (A), The weight ratio of acetic acid (C) to alkaline earth metal acetate (B) ((C) / (B)) is 0.05 to 10 and the content of water (D) is 100 parts by weight of the EVOH (A). It is found that a molded product obtained by melt-extruding an EVOH composition of 10 to 140 parts by weight, stretched at a water content of 5 to 50% by weight , and heat-set can solve the above problems. The invention has been completed. In the present invention, the EVOH composition is melt-extruded, stretched at a water content of 5 to 50% by weight , and heat-set to form a molded product, particularly a film or sheet.
[0005]
In the present invention, it is also preferable to stretch a molded product obtained by melt extrusion of the EVOH composition, particularly a film or sheet at a moisture content of 5 to 50% by weight, and a molded product having an excellent film appearance can be obtained. is there.
That is, according to the present invention, a molded product (film, sheet, etc.) of an EVOH composition having a uniform film thickness and excellent appearance such as transparency, gas barrier properties, streaks, and reduction of fish eyes can be obtained. is there.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be specifically described.
The EVOH (A) of the present invention has an ethylene content of 5 to 60 mol%, preferably 10 to 60 mol%, more preferably 20 to 55 mol%, and a saponification degree of the vinyl acetate component of 90 mol% or more, preferably Those having a content of 95 mol% or more are preferably used. If the ethylene content is less than 5 mol%, the water resistance is insufficient. On the other hand, if it exceeds 60 mol%, the gas barrier property is lowered, which is not preferable. On the other hand, if the degree of saponification is less than 90 mol%, the water resistance is insufficient, which is not preferable.
[0007]
In addition, the EVOH (A) is a small amount of α-olefin such as propylene, isobutene, α-octene, α-dodecene, α-octadecene, unsaturated carboxylic acid or salt thereof, partial alkyl ester, complete alkyl ester, nitrile, A co-monomer such as amide / anhydride, unsaturated sulfonic acid or salt thereof, vinyl silane compound, vinyl chloride, styrene may be included. Further, within the scope of the present invention, “post-modification” such as urethanization, acetalization, cyanoethylation and the like may be performed.
[0008]
Examples of the alkaline earth metal acetate (Β) include calcium acetate, magnesium acetate, barium acetate, and beryllium acetate. Preferably, calcium acetate and magnesium acetate are used. These can be used alone or in combination.
The content of the alkaline earth metal acetate (Β) is 5 to 300 ppm, preferably 10 to 200 ppm, more preferably 15 to 150 ppm in terms of alkaline earth metal with respect to EVOH (Α). Content can not be obtained the effect of the present invention is less than 5ppm of alkaline earth metal acetates (beta), whereas, the larger the thermal decomposition is increased odor of the composition exceeds 300 ppm.
[0009]
In addition to the alkaline earth metal acetate, alkali metal acetate such as sodium acetate and potassium acetate is contained in EVOH (A) in an amount of 20 to 500 ppm, preferably 40 to 300 ppm in terms of alkali metal. It is also possible.
[0010]
Further, the content of acetic acid (C) is not particularly limited, but the weight ratio ((C) / (B)) of acetic acid (C) to alkaline earth metal acetate (B) is finally 0.05 to 10, preferably 0.08 to 8, more preferably 0.1 to 5. When the weight ratio is less than 0.05, the effect of the present invention cannot be obtained. On the other hand, when the weight ratio exceeds 10, gels frequently occur in the molded product, and the commercial value is lost. Especially, as content of acetic acid (C), 30-4000 ppm with respect to EVOH (A), Preferably 50-2000 ppm is suitable.
[0011]
In the present invention, as described above, EVOH (A), alkaline earth metal acetate (B), acetic acid (C) and water (D) are contained to obtain an EVOH composition. Content is 10-140 weight part with respect to 100 weight part of EVOH (A), Preferably it is 15-120 weight part, More preferably, it is 20-100 weight part. If the content of water (D) is less than 10 parts by weight, it is necessary to raise the extrusion molding temperature, not only lowering the long run moldability, but also making uniform stretching difficult. Extrusion becomes unstable due to partial separation of resin and moisture.
[0012]
The method for producing the EVOH composition is not particularly limited. In short, EVOH (A), alkaline earth metal acetate (B), acetic acid (C) and water (D) are contained within the above ranges. For example, (1) EVOH (A) powder, pellets and granules are mixed with alkaline earth metal acetate (B) and acetic acid (C) in any form, and water (D) is mixed. (2) EVOH (A) at any stage of production, that is, at any stage of polymerization, saponification, post-treatment or drying, alkaline earth metal acetate (B) and acetic acid ( A method of containing a predetermined amount of C) and mixing water (D) after producing EVOH; (3) mixing and stirring EVOH (A) and water (D) or absorbing water by blowing steam; Method of mixing metal acetate (B) and acetic acid (C), (4) EVOH (A) After extruding the methanol / liquid mixture into a coagulating liquid tank to obtain a porous hydrous EVOH molded product, it is impregnated with alkaline earth metal acetate (B) and acetic acid (C) in water, Examples thereof include a method of drying to the amount of water. However, it is not limited to these.
[0013]
In addition, it is possible to contain water together with some alcohol such as methanol and isopropyl alcohol during the production of EVOH (A).
At this time, a small amount of plasticizer such as ethylene glycol, propylene glycol, glycerin and the like may be included. The content of plasticizers such as ethylene glycol, propylene glycol and glycerin is suitably about 0.2 to 10% by weight.
Antioxidants, lubricants, hydrotalcites, antistatic agents, colorants, ultraviolet absorbers, inorganic / organic fillers, antibacterial agents and the like can be added within a range that does not impair the effects of the present invention.
[0014]
Thus, the EVOH composition of the present invention is obtained. The EVOH composition is then subjected to a melt extruder and melt molded into a molded product. In the case of a film, the conditions at the time of molding are not particularly limited, but are usually formed by extrusion using a non-vented, screw-type extruder at a melting temperature of 40 to 150 ° C. In order to leave water with a uniform distribution in the film formed, it is preferable to use a screw with a compression ratio of 2.0 to 4.0.
[0015]
Molding the obtained film-like EVOH composition method is of being subjected to stretching in the next doctor, the moisture content of the molding of the EVOH composition when such stretching (stretching immediately before) 5-50 It is also important to adjust the content to 7% by weight, preferably 7 to 45% by weight, and more preferably 10 to 40% by weight. If the water content is less than 5% by weight, stretch spots are likely to occur, which may cause breakage. If it exceeds 50% by weight, the effect of improving gas barrier properties and strength due to sufficient stretching orientation cannot be obtained, which is not preferable. The method for adjusting the moisture content is not particularly limited, and a humidity control operation can be added immediately after film formation.
[0016]
The stretching includes a uniaxial stretching method, a biaxial stretching method (simultaneous, sequential), and the like, and is not particularly limited. However, the present invention is particularly effective for primary (MD direction) stretching in the sequential biaxial stretching method. Yes, this stretching method will be described in detail.
[0017]
The molded product of the EVOH composition in the form of a film with the moisture content adjusted is subjected to a first (MD direction) stretching step. For such primary (MD direction) stretching, a known method can be used, and the above molded product is stretched 1.5 to 8 times in the longitudinal direction under the condition of 40 to 100 ° C. The water content after the primary (MD direction) stretching treatment is 0.5 to 45% by weight, preferably 1 to 40% by weight, and if it is less than 0.5% by weight, the secondary (TD direction) ) Stretch spots are generated during stretching, making it difficult to stretch to the same stretching ratio. Conversely, if it exceeds 45% by weight, the primary stretching orientation effect cannot be expected, and gas barrier properties and strength are improved. Less is not preferable. As a method for adjusting the water content, the temperature and time of the preheating roll, the temperature (first direction of MD) stretching, the stretching speed, and the like can be used.
[0018]
The primary (MD direction) stretched EVOH composition film is then subjected to a transverse direction stretching in a secondary (TD direction) stretching step. The EVOH composition film is stretched 1.5 to 8 times in the transverse direction under the condition of 60 to 140 ° C. Usually, it is performed by a tenter method in which both ears of a film are sandwiched between clips. Except for this condition, any breakage occurs at the clip portion, between the clip and the clip, or at the intermediate portion in the film width direction, and it is extremely difficult to obtain the target stretched film. Further, for heat fixed further. Heat setting means heating the film under tension at a temperature of 120 to 200 ° C. for several seconds to several minutes, and in order to further impart flexibility and dimensional stability to the film after heat setting, the moisture content is 0.3 to The film may be conditioned until it is about 3% by weight.
[0019]
Thus, the EVOH composition containing specific amounts of EVOH (A), alkaline earth metal acetate (B), acetic acid (C) and water (D) is excellent in long-running properties by melt extrusion, and is used for streaks and fish. It is possible to obtain a molded article having excellent appearance with no eye and coloring and excellent transparency.
[0020]
The molded product (film, sheet, etc.) of the EVOH composition obtained in the present invention is often put to practical use not only as a single layer but also as a laminate comprising such a film as at least one layer.
In the production of the laminate, another substrate is laminated on one side or both sides of a layer of a molded product such as a film or a sheet obtained by the production method of the present invention. Examples thereof include a method of laminating a molded product and another base film or sheet using a known adhesive such as an organic titanium compound, an isocyanate compound, a polyethyleneimine compound, a polyester compound, or a polyurethane compound.
[0021]
Such other base films include linear low density polyethylene, low density polyethylene, medium density polyethylene, high density polyethylene, ethylene-vinyl acetate copolymer, ionomer, ethylene-propylene copolymer, ethylene-acrylic acid ester. Copolymer, polypropylene, propylene-α-olefin (α-olefin having 4 to 20 carbon atoms) copolymer, polybutene, polypentene, and other olefins alone or copolymers, or these olefins alone or copolymers. Broadly defined polyolefin resins such as those graft-modified with unsaturated carboxylic acids or esters thereof, polystyrene resins, polyesters, polyamides, copolymerized polyamides, polyvinyl chloride, polyvinylidene chloride, acrylic resins, vinyl ester resins, polyesters Elastomer, Examples include polyurethane elastomer, chlorinated polyethylene, chlorinated polypropylene, EVOH, and paper, metal foil, uniaxial or biaxially stretched plastic film or sheet, woven fabric, non-woven fabric, metal cotton strip, wood surface, etc. Is possible.
[0022]
As the layer structure of the laminate, when the EVOH film layer is I (I1, I2,...) And another substrate, for example, the thermoplastic resin layer is II (II1, II2,...) In the case of a sheet, not only a two-layer structure of I / II, but also II / I / II, I / II / I, I1 / I2 / II, I / II1 / II2, II2 / II1 / I / II1 / Any combination such as II2 is possible.
[0023]
Thus, the molded product (film, sheet, etc.) and laminate thereof of the EVOH composition of the present invention are excellent in properties, that is, appearance properties, gas barrier properties, etc. It is very useful for applications such as films, sheets, tubes, bags and containers.
[0024]
【Example】
Hereinafter, the present invention will be specifically described with reference to examples.
In the examples, “parts” and “%” mean weight basis unless otherwise specified.
Example 1
1000 parts of a 40% methanol solution of an ethylene-vinyl acetate copolymer having an ethylene content of 40 mol% was placed in a pressure resistant reactor and heated to 110 ° C. with stirring. Subsequently, 40 parts of a 6% methanol solution of sodium hydroxide and 2500 parts of methanol were continuously added, and saponification reaction was carried out for 2.5 hours while distilling off by-produced methyl acetate and excess methanol from the system. EVOH (A) having a saponification degree of 99.0 mol% was obtained.
[0025]
While adding 450 parts of 30% aqueous methanol to the saponification finished solution, excess methanol was distilled off to produce a water / methanol solution.
The water / methanol mixture of EVOH (A) was extruded into a water / methanol (mixing ratio 9/1) coagulation liquid tank (width 100 mm, length 4000 mm, depth 100 mm) in a strand shape. After completion of the solidification, the strand-like material was cut with a cutter through a take-up roller attached to the end of the coagulation liquid tank to produce white and porous pellets.
[0026]
Next, 100 parts of the pellets were immersed in 300 parts of 0.1% acetic acid, stirred for 1 hour at 30 ° C., and washed twice. After the slurry was filtered, the obtained pellets were mixed with 300 parts of 0.1% acetic acid-0.2% calcium acetate-0.1% magnesium acetate aqueous solution and stirred at 30 ° C. for 1 hour, followed by filtration. And it dried so that it might become 70 parts of water with respect to 100 parts of EVOH (A).
[0027]
The EVOH composition thus obtained has an ethylene content of 40 mol%, EVOH (A) having a saponification degree of 99.0%, and a calcium acetate content of 250 ppm (63 ppm in terms of calcium) based on the EVOH (A), Composition with a magnesium acetate content of 120 ppm (20 ppm in terms of magnesium), a weight ratio of acetic acid to alkaline earth metal acetate of 0.5, and a water content of 70 parts per 100 parts of EVOH (A) It was a thing.
[0028]
The quantitative method for alkaline earth metals was as follows.
(Alkaline earth metal)
About 80 g of the dried sample was precisely weighed, and about 10 g of the sample was placed in a constant weight platinum evaporating dish and carbonized with an electric heater. Next, it was heated with a gas burner and baked while smoke did not come out.
The platinum evaporating dish was placed in an electric furnace at about 400 ° C., covered with a magnetic crucible lid, and gradually heated to 700 ° C. It was kept at 700 ° C. for 3 hours and completely ashed. A platinum crucible was charged with 2 ml of special grade hydrochloric acid and 3 ml of pure water, and dissolved by heating with an electric heater. The above solution was poured into a 50 ml volumetric flask with pure water, and pure water was further added up to the marked line to prepare a sample for atomic absorption analysis.
[0029]
Separately, atomic absorbance was measured using the prepared standard solution (alkaline earth metal 1 ppm, hydrochloric acid about 0.5 N) as a control solution, and the amount of alkaline earth metal was quantified from the ratio of absorbance.
The measurement conditions are as follows.
Equipment: Hitachi 180-30 atomic absorption / flame spectrophotometer Frame: acetylene-air
And this EVOH composition was supplied to the single screw extruder provided with T-die, and the 120-micrometer-thick EVOH composition film was shape | molded.
The film forming conditions using a single screw extruder were as follows.

[0031]
The following items were evaluated for the appearance of the EVOH composition film during long-term (4 days and 10 days) continuous operation.
(Film appearance)
(1) The presence or absence of streaks was evaluated according to the following criteria.
○ ... streaks were not recognized.
Δ: Slight streaks are recognized, but there is no practical problem.
X: Streaks occurred frequently, making it difficult to use practically.
[0032]
(2) Fish eye The presence or absence of fish eye was evaluated according to the following criteria.
○ ... 0-3 / 100 cm ² (film size; 10 cm × 10 cm)
△ 4-20 pieces / 100cm ²
× ・・・ 21 or more / 100cm ²
[0033]
(3) The presence or absence of coloring was evaluated according to the following criteria.
○: Coloring was not observed.
Δ: Slight yellowing was observed.
X: Yellow coloring was large and practical use was difficult.
[0034]
Next, using the EVOH composition film (moisture content 35%) obtained by the above molding as a raw fabric, the EVOH composition stretched film is continuously biaxially stretched, heat-set and humidity-controlled under the following conditions. Got.
[0035]
[First stretching (longitudinal stretching) conditions]
Stretcher Roll type primary stretcher Stretch roll temperature 70 ℃
Stretch ratio in the machine direction: Film thickness after stretching 2.0 times 60μm
30% moisture content after stretching
[0036]
[Secondary stretching (lateral stretching) conditions]
Stretcher Tenter type biaxial stretcher Stretching temperature 110 ° C
Stretch ratio in the transverse direction Film thickness after stretching 3.0 times 20 μm
Moisture content after stretching 2%
[0037]
[Heat setting conditions]
160 ° C
Time 3 seconds [humidity control conditions]
Moisture content 2.5% after humidity control at 20 ° C and 65% RH for 7 days
The obtained EVOH composition (biaxial) stretched film was evaluated in the same manner as described above.
[0038]
Example 2
In Example 1, EVOH (A) having an ethylene content of 35 mol% and a saponification degree of 99.8 mol% was treated with an acetic acid-calcium acetate aqueous solution and calcium acetate was 470 ppm with respect to the EVOH (A). (120 ppm in terms of calcium), except that the weight ratio of acetic acid and alkaline earth metal acetate is 0.2, and water is contained in 34 parts with respect to 100 parts of the EVOH (A). The EVOH composition film and the EVOH composition stretched film were obtained and evaluated in the same manner. At this time, the moisture content of the EVOH composition film was 22%, the moisture content after the first stretching was 20%, the moisture content after the second stretching was 0.6%, and the moisture content after humidity conditioning was 2.5%. %Met.
[0039]
Example 3
In Example 1, EVOH (A) having an ethylene content of 28 mol% and a saponification degree of 98.6 mol% was treated with an acetic acid-magnesium acetate aqueous solution to give 240 ppm of magnesium acetate with respect to the EVOH (A). (40 ppm in terms of magnesium), except that the weight ratio of acetic acid to alkaline earth metal acetate is 1.1 and water is 55 parts with respect to 100 parts of EVOH (A). The EVOH composition film and the EVOH composition stretched film were obtained and evaluated in the same manner. At this time, the moisture content of the EVOH composition film was 33%, the moisture content after the first stretching was 28%, the moisture content after the second stretching was 1.5%, and the moisture content after humidity conditioning was 2.8. %Met.
[0040]
Example 4
In Example 1, EVOH (A) having an ethylene content of 35 mol% and a saponification degree of 99.8 mol% was treated with an aqueous solution containing acetic acid, calcium acetate, magnesium acetate, and sodium acetate, and the EVOH ( A) Calcium acetate 160ppm (calcium conversion 40ppm), magnesium acetate 60pmm (magnesium conversion 10ppm), sodium acetate 180ppm (sodium conversion 50ppm), acetic acid and alkaline earth metal acetate weight ratio 0.35, EVOH (A) 100 parts EVOH (A) except that water was added to 34 parts in the same manner, EVOH composition film and EVOH composition stretched film were obtained and evaluated in the same manner Went. At this time, the moisture content of the EVOH composition film was 22%, the moisture content after the first stretching was 20%, the moisture content after the second stretching was 0.6%, and the moisture content after humidity conditioning was 2.5%. %Met.
[0041]
Comparative Example 1
In Example 1, EVOH (A) was similarly treated except that 70 parts of water was added to 100 parts of EVOH (A) without treatment with an aqueous solution containing acetic acid, calcium acetate, and magnesium acetate. The EVOH composition film and the EVOH composition stretched film were obtained and evaluated in the same manner. At this time, the moisture content of the EVOH composition film was 35%, the moisture content after the first stretching was 30%, the moisture content after the second stretching was 2%, and the moisture content after conditioning was 2.5%. there were.
[0042]
Comparative Example 2
In Example 1, with respect to EVOH (A), calcium acetate was 8 ppm (2 ppm in terms of calcium), magnesium acetate was 6 ppm (1 ppm in terms of magnesium), the weight ratio of acetic acid and alkaline earth metal acetate was 2, EVOH (A) An EVOH composition film and an EVOH composition stretched film were obtained in the same manner except that 70 parts of water was added to 100 parts, and evaluated in the same manner. At this time, the moisture content of the EVOH composition film was 35%, the moisture content after the first stretching was 30%, the moisture content after the second stretching was 2%, and the moisture content after conditioning was 2.5%. there were.
[0043]
Comparative Example 3
In Example 1, with respect to EVOH (A), calcium acetate was 990 ppm (250 ppm in terms of calcium), magnesium acetate was 890 ppm (150 ppm in terms of magnesium), and the weight ratio of acetic acid to alkaline earth metal acetate was 0.2. The EVOH composition film and the EVOH composition stretched film were obtained in the same manner except that 70 parts of water was added to 100 parts of EVOH (A), and evaluated in the same manner. At this time, the moisture content of the EVOH composition film was 35%, the moisture content after the first stretching was 30%, the moisture content after the second stretching was 2%, and the moisture content after conditioning was 2.5%. there were.
[0044]
Comparative Example 4
In Example 1, with respect to EVOH (A), calcium acetate is 250 ppm (63 ppm in terms of calcium), magnesium acetate is 120 ppm (20 ppm in terms of magnesium), and the weight ratio of acetic acid to alkaline earth metal acetate is 0.02 The EVOH composition film and the EVOH composition stretched film were obtained in the same manner except that 70 parts of water was added to 100 parts of EVOH (A), and evaluated in the same manner. At this time, the moisture content of the EVOH composition film was 35%, the moisture content after the first stretching was 30%, the moisture content after the second stretching was 2%, and the moisture content after conditioning was 2.5%. there were.
[0045]
Comparative Example 5
In Example 1, with respect to EVOH (A), calcium acetate is 160 ppm (40 ppm in terms of calcium), magnesium acetate is 60 ppm (10 ppm in terms of magnesium), the weight ratio of acetic acid to alkaline earth metal acetate is 15, EVOH (A) An EVOH composition film and an EVOH composition stretched film were obtained in the same manner except that 70 parts of water was added to 100 parts, and evaluated in the same manner. At this time, the moisture content of the EVOH composition film was 35%, the moisture content after the first stretching was 30%, the moisture content after the second stretching was 2%, and the moisture content after conditioning was 2.5%. there were.
[0046]
Comparative Example 6
In Example 1, it carried out similarly except water having been 5 parts. However, since the resin did not melt at 120 ° C. and could not be extruded, it was molded at 190 ° C.
Further, in the stretching treatment, the film was broken during the second stretching, and stable stretching was impossible, and a stretched film could not be obtained.
[0047]
Comparative Example 7
In Example 1, it carried out similarly except having made water 200 parts. At the time of forming the EVOH composition film (raw film), water was deposited on the field part of the barrel, the discharge became unstable, and only the original film for stretching having a non-uniform film thickness was obtained. In the same manner as described above, stretching was performed continuously.
[0048]
Comparative Example 8
In Example 1, it carried out similarly except not containing water. However, since the resin did not melt at 120 ° C. and could not be extruded, it was molded at 210 ° C.
Further, in the stretching treatment, the film was broken during the second stretching, and stable stretching was impossible, and a stretched film could not be obtained.
The evaluation results of Examples and Comparative Examples are shown in Tables 1 and 2.
[0049]
[Table 1]

[0050]
[Table 2]

[0051]
【The invention's effect】
The present invention contains EVOH (A), a specific amount of alkaline earth metal acetate (B) and acetic acid (C), and a specific amount of water (D). excellent, further gas barrier properties as well, also streaks, can be obtained fisheyes, the non-colored film appearance and excellent transparency molded product for a long time of continuous molding, and the molding product of the present invention (extension A multilayer laminate having at least one layer of stretched film or the like is very useful as a packaging material for foods, pharmaceuticals, agricultural chemicals, industrial chemicals and the like.

Claims

Saponified ethylene-vinyl acetate copolymer (A) having an ethylene content of 5 to 60 mol% and a saponification degree of 90 mol% or more, alkaline earth metal acetate (B), acetic acid (C), water (D ) And an alkaline earth metal acetate (B) content of 5 to 300 ppm in terms of alkaline earth metal with respect to the copolymer saponified product (A), acetic acid (C) and The alkaline earth metal acetate (B) weight ratio ((C) / (B)) is 0.05 to 10 and the water (D) content is 100 parts by weight of the copolymer saponified product (A). A molded product obtained by melt-extruding a saponified ethylene-vinyl acetate copolymer composition in an amount of 10 to 140 parts by weight, stretching at a water content of 5 to 50% by weight , and heat-setting.

A laminate comprising the molded product according to claim 1 as at least one layer.