JP4679702B2 - Gas barrier film and method for producing the same - Google Patents

Description

【００２４】
本実施形態のガスバリア性フィルムは、下記の実験によって、例えば、ＰＶＡの透明性を維持したままで、ガスバリア性と高湿度下での密着性が維持されることが判った。
【００２５】
（実施形態２）
本実施形態におけるガスバリア性フィルムの製造方法について説明する。本実施形態において、ガスバリア性フィルムの基材としては、プラスチックフィルムが飽和ポリエステルであるポリエチレンテレフタレート（以下、ＰＥＴと称する）が用いられる。ＰＥＴにガスバリア性を付与するための塗布液として、ガスバリア性の優れたＰＶＡを、イソプロピルアルコール（以下、ＩＰＡと称する）等の有機溶剤と水との溶媒に溶解する。この溶液に、上記のアジリジン官能基を有するアジリジン化合物を、ＰＶＡとアジリジン化合物との固形分比が配合比で、１００／１乃至１００／８となるように添加する。なお、アジリジン化合物は、ＰＶＡの架橋剤である。続いて、ＰＶＡとアジリジン化合物との組成物の塗布剤を、ＰＥＴフィルムに塗布して乾燥させる。この積層体を４０℃にて所定時間エージングして、ＰＥＴフィルムによるガスバリア性フィルムを形成する。
【００２６】
なお、実施形態１，２において、ＰＶＡは、変性されていない分子構造のものより、有機酸による変性した変性ＰＶＡが好ましい。
【００２７】
（実施形態３）
本実施形態におけるガスバリア性フィルムの製造方法について、以下の製造工程で説明する。
（１）ＰＶＡを、ＩＰＡ等の有機溶剤と水との配合比が、ＩＰＡ／水＝２０／８０である溶媒に溶解して、６％溶液を調整する第１の工程と、
（２）ＰＶＡと架橋剤であるアジリジン化合物との固形分の配合比が１００／１乃至１００／８となるように、第１の工程で得られた溶液にアジリジン化合物を添加する第２の工程と、
（３）第２の工程で調整されたＰＶＡ塗布液（ＰＶＡとアジリジン化合物の組成物）をプラスチックフィルムの基材に塗布して乾燥させた積層体を形成する第３の工程と、
（４）前記積層体をエージングする第４の工程と、
を有するガスバリア性フィルムの製造方法である。
【００２８】
なお、実施形態３において、ＰＶＡは、変性されていない分子構造のものより、有機酸により変性した変性ＰＶＡが好ましい。
【００２９】
（実施形態４）
本実施形態におけるガスバリア性フィルムの製造方法について、以下の製造工程で説明する。
（１）ＰＶＡ（（株）クラレ製、ポバール１０５）を、ＩＰＡ等の有機溶剤と水の配合比が、ＩＰＡ／水＝２０／８０である溶媒に溶解して、ＰＶＡの６％溶液を調整する第１の工程と、
（２）ＰＶＡと架橋剤であるアジリジン化合物との固形分の配合比が１００／１乃至１００／８となる前記溶液にアジリジン化合物を添加して、ＰＶＡ塗布液を調整する第２の工程と、
（３）第２の工程で調整されたＰＶＡ塗布液（ＰＶＡとアジリジン化合物との組成物）を、ポリエステルフィルム（以下、ＰＥＴと称する）（東洋紡績（株）製、Ｅ５１００、厚さが１２μｍ）の基材上にワイヤーバーにて塗布し、乾燥状態で約１μｍの厚さの塗膜を形成する第３の工程と、
（４）第３の工程によるＰＶＡ塗布液を乾燥させた積層体を、４０℃にてエージングする第４の工程と、
を有するガスバリア性フィルムの製造方法である。
【００３０】
（実施形態５）
本実施形態におけるガスバリア性フィルムの製造方法について、以下の製造工程で実施することができる。
（１）変性ＰＶＡ（（株）クラレ製、ポバール、ＫＭ−１１８Ｍ）を、ＩＰＡ等の有機溶剤と水との配合比が、ＩＰＡ／水＝２０／８０である溶媒に溶解して、ＰＶＡの６％溶液を調整する第１の工程と、
（２）変性ＰＶＡと架橋剤であるアジリジン化合物との固形分の配合比が１００／１乃至１００／８となる前記溶液に、アジリジン化合物を添加してＰＶＡ塗布液を調整する第２の工程と、
（３）第２の工程のＰＶＡ塗布液（変性ＰＶＡとアジリジン化合物との組成物）をＰＥＴ（東洋紡績（株）製、Ｅ５１００、厚さが１２μｍ）の基材上にワイヤーバーにて塗布し、乾燥状態で約１μｍの厚さの塗膜を形成する第３の工程と、
（４）第３の工程によるＰＶＡ塗布液を乾燥させた積層体を、４０℃にてエージングする第４の工程と、
を有するガスバリア性フィルムの製造方法である。
【００３１】
なお、上記実施形態において、アジリジン化合物は、下記に示す多官能アジリジン化合物（相互薬工（株）製のＴＡＺＭ、又は日本触媒（株）製ケミタイトＰＺ−３３）が好ましい。さらに、ＰＶＡは、カルボン酸変性ＰＶＡ（（株）クラレ製、ポバールＫＭ−１１８）が好ましい。
【００３２】
【化２】

【００３３】
上記実施形態では、例えば、実施形態１〜５のガスバリア性フィルムを形成した後、このガスバリア性フィルムの片面または両面に他の基材をラミネート加工してもよい。このラミネート加工方法としては、熱可塑性樹脂を溶融押出しラミネートする方法、他のフィルムまたはシートを公知の接着剤を用いてドライラミネートする方法等が挙げられる。ラミネートする相手側の樹脂またはフィルムあるいはシートとしては、ヒートシール性を有するものがよく、例えば、溶融押出しする樹脂としては、低密度ポリエチレン（ＬＤＰＥ）、線状低密度ポリエチレン（ＬＬＤＰＥ）、エチレン酢酸ポリエチレン（ＥＶＡ）、アイオノマーが挙げられ、ドライラミネートするフィルムまたはシートとしては、無延伸ポリプロピレン（ＣＰＰ）、低密度ポリエチレン（ＬＤＰＥ）、線状低密度ポリエチレン（ＬＬＤＰＥ）等のフィルムまたはシートが挙げられる。また、本実施形態のガスバリア性フィルムは、三方袋、ピロー包装、ＰＴＰ包装等の各種包装材料に用いることができる。
【００３４】
（実施形態６）
本発明のガスバリア性組成物（塗布剤）の実施形態は、上記実施形態から明らかであるが、ポリビニールアルコール、アジリジン化合物、および水または水とアルコールの混合溶媒とを含むガスバリア性組成物である。ＰＶＡを主体とするガスバリア性組成物は、その溶媒として、水を使用することができる。また、この溶媒の乾燥性を向上させるためには、水にアルコールを加えた混合溶媒とするとよい。なお、アルコール含有量が多すぎるとＰＶＡの溶解性が低下するため、水とアルコールとの混合割合としては、水／アルコール＝１０／９０乃至３０／７０程度とし、特に水／アルコール＝２０／８０程度の割合で混合した溶媒が好ましい。アルコールとしては、メタノール、エタノール、イソプロパノール、ブタノール等が挙げられる。アジリジン化合物としては、上記に示した多官能アジリジン化合物が好ましい。
【００３５】
【実施例】
次に、本発明の実施例のガスバリア性フィルムについて、表１〜４を参照して説明する。本実施例は、実施形態４，５の製造工程に従って、ガスバリア性フィルムの製造を行った。先ず、本実施例Ａの試料１は、ＰＶＡ（（株）クラレ製、ポバール１０５）を、ＩＰＡの有機溶剤と水との配合比が、ＩＰＡ／水＝２０／８０である溶媒に溶解して、ＰＶＡが６％溶液となるように調整した。続いて、このＰＶＡが６％の溶液に、室温（低温）で架橋する架橋剤である多官能アジリジン化合物（相互薬工（株）製のＴＡＺＭ）を、ＰＶＡと多官能アジリジン化合物との固形分の配合比が１００／５となるように、１００ｇの溶液に０．３ｇの多官能アジリジン化合物を添加して、ＰＶＡ塗布液を調整した。次に、このＰＶＡ塗布液を、ＰＥＴ（東洋紡績（株）製Ｅ５１００ 厚さ１２μｍ）の基材上にワイヤーバーにて塗布して乾燥させた。ＰＶＡ塗布膜は、乾燥状態で約１μｍの厚さとした。その後、この積層体を４０℃にてエージングした。
【００３６】
一方、本実施例Ｂの試料２〜５は、カルボン酸変性ＰＶＡ（（株）クラレ製ポバールＫＭ−１１８Ｍ）を、ＩＰＡの有機溶剤と水の配合比が、ＩＰＡ／水＝２０／８０である溶媒に溶解して、この溶媒にカルボン酸変性ＰＶＡが６％溶液となるように調整した。カルボン酸変性ＰＶＡが６％の溶液に、それぞれに室温（低温）で架橋する架橋剤である多官能アジリジン化合物（相互薬工（株）製のＴＡＺＭ）を、カルボン酸変性ＰＶＡと多官能アジリジン化合物との固形分の配合比がそれぞれ１００／１．５、１００／３、１００／５、１００／１０となるように、多官能アジリジン化合物を添加して、ＰＶＡ塗布液を調整した。例えば、配合比が１００／５の場合、１００ｇの溶液に０．３ｇの多官能アジリジン化合物を添加する。続いて、カルボン酸変性ＰＶＡと多官能アジリジン化合物との組成物であるＰＶＡ塗布液を、試料１と同様に、ＰＥＴ（東洋紡績（株）製Ｅ５１００、厚さ１２μｍ）の基材上にワイヤーバーにて塗布し、乾燥状態で約１μｍの厚さのＰＶＡ塗布膜を形成した。その後、この積層体を４０℃にてエージングした。
【００３７】
本実施例Ａ，Ｂ（試料１〜５）のガスバリア性フィルムについて、▲１▼ガスバリア性試験（酸素の透過度を測定）、▲２▼密着性試験、▲３▼高湿度保存性試験を行って、それぞれの特性を調べた。表１は、その試験結果を示している。
【００３８】
先ず、それぞれの試験方法について説明すると、▲１▼ガス（酸素）バリア性は、試料１〜５に対して、２３℃、０％Ｒｈ雰囲気下で酸素透過度測定装置（ＯＸ−ＴＲＡＮ ＴＷＩＮ ＭＯＣＯＮ社製）を用いて測定した。この試験では、ＰＥＴ上に、それぞれの塗布剤を塗布した後、塗布剤を乾燥させて、エージングが０日で酸素透過度の測定を行った。
【００３９】
（２）密着性試験は、本実施例の試料１〜５に対して、先ず、４０℃にて表記載の日数でエージングした後、セロテープ（登録商標）剥離試験を行った。次に、同試料のセロテープ剥離試験に用いていない部分を利用して、剥離試験を行った。剥離試験では、ガスバリア性フィルム塗剤面に、ポリウレタン系接着剤を用いて、厚さが２５μｍの未延伸ポリプロピレンフィルム（以下、ＣＰＰと称する）をドライラミネートにより貼り合わせ、さらに４０℃にて表記載の日数エージングした後、１５ｍｍ幅に切断し、ＣＰＰと本実施例のフィルムのＴ形剥離により、剥離強度を求めた。以下の表では、セロテープ剥離試験において、塗膜が剥離しなかったものを○とし、剥離したものを×とし、さらにＴ形剥離試験（剥離試験（１）〜（４））においては、剥離強度が、５０ｇｆ／１５ｍｍ（約０．４９Ｎ／１５ｍｍ）以下のものを×とし、基材破断または剥離強度が２００ｇｆ／１５ｍｍ（約１．９６Ｎ／１５ｍｍ）以上のものを○とし、中間の剥離強度のものは、△とした。（注釈：この段落の（２）．（１），（４）は丸付き数字に読み替える。）
【００４０】
▲３▼高湿度保存性は、ドライラミネートした本実施例の試料１〜５のガスバリア性フィルムを、４０℃にて３０日養成した後、室温２３℃、９０％Ｒｈ下、１週間保存し、１５ｍｍ幅に切断してＣＰＰと本フィルムの剥離強度を求めた。剥離強度の評価基準は、密着性評価と同様である。
【００４１】
【表１】

【００４２】
先ず、表１について、簡単に説明する。表１の試料１の最も右の欄（「エージング４０℃日」の「１４」とある欄）を例示して説明する。「エージング４０℃日」の「１４」とは、先ず、試料１を作製した後にガスバリア試験を行って、その後、試料１を４０℃にて１４日間エージングしたことを示している。１４日間エージングした後にセロテープ剥離試験が行われ、その結果が示されている。次に、剥離試験▲１▼〜▲４▼（Ｔ型剥離試験）に進んでいる。このＴ型剥離試験の欄は、セロテープ剥離試験で用いていない試料のガスバリア面にＣＰＰフィルムをドライラミネートして、さらに４０℃にて所定日数（剥離強度▲１▼の場合は３日）エージングを行って試料を作製し、Ｔ型剥離試験を行った結果を示している。Ｔ型剥離試験を行った試料のトータルのエージング日数は、セロテープ剥離試験前のエージング日数に剥離試験前のエージング日数を加えた日数である。すなわち、「エージング４０℃日」の欄の「１４」の行の剥離強度▲１▼では、剥離強度前のエージングに日数１４日に、３日間を加算した１７日間がエージングした日数となる。因みに、剥離試験▲４▼の「１４」欄では、エージング日数１４日に３０日間を加算した４４日間が合計のエージング日数となる。
【００４３】
表１から明らかなように、変性されていないＰＶＡとカルボン酸変性ＰＶＡとの比較をする。固形分の配合比（１００／５）が等しい試料１と試料４とで比較すると、カルボン酸変性ＰＶＡに多官能アジリジン化合物を添加した塗布液が剥離試験では、エージング時間が短いものであっても良好な特性を示した。一方、変性されていないＰＶＡの場合は、トータルの養成時間を１１日以上、好ましくは１７日以上とすることで、十分な特性を得ることができ、カルボン酸変性ＰＶＡの場合には、トータルの養成時間を３日以上とすることで十分な特性を得ることができた。すなわち、変性されていないＰＶＡに多官能アジリジン化合物を添加した塗布液の場合でも、エージング時間を長くすることによって、十分な特性を得ることができる。
【００４４】
また、塗布膜の固形分の配合比は、１００／１．５（試料２）が表１に示されているが、エージング時間を長くすることによって、１００／１でも良好な特性を示すことが明らかになった。また、配合比が１００／１０では、湿気を吸収して密着性が悪化して好ましくなく、従って、配合比が１００／１乃至１００／５の範囲が最も好ましいが、多官能アジリジン化合物の添加量を増やした場合、１００／８（図示なし、）が限界であることが明らかになった。従って、許容できる配合比の範囲は、１００／１乃至１００／８の範囲である。
【００４５】
さらに、ＰＶＡとカルボン酸変性ＰＶＡの架橋剤としての多官能アジリジン化合物の効果を検証するために、比較例１，２を作成して、上記▲１▼〜▲３▼の試験を行った。その試験結果は、表２に示した。
【００４６】
【表２】

【００４７】
表２から明らかのように、多官能アジリジン化合物を添加しなかったＰＶＡと変性ＰＶＡの塗布液で製造した場合、剥離試験において、５０ｇｆ／１５ｍｍ（約０．４９Ｎ／１５ｍｍ）以下であり、密着性が極めて悪いことを示している。ＰＶＡとカルボン酸変性ＰＶＡと差異による優位性がないことを示した。すなわち、試料１〜５に示したように、多官能アジリジン化合物がＰＶＡとカルボン酸変性ＰＶＡの架橋剤として有効であることを示している。
【００４８】
さらに、架橋剤としての多官能アジリジン化合物の有効性を検証するために、多官能アジリジン化合物以外の架橋剤であるポリエチレンイミン（以下、ｐｅｉと称する）を用いた比較試料１〜４の試験結果を表３，表４に示した。
【００４９】
【表３】

【００５０】
【表４】

【００５１】
表３，４の結果から明らかなように、剥離強度が不十分であることは明確である。また、ｐｅｉの分子量（７００００）と分子量（１００００）との差異は、明確ではないし、ＰＶＡと変性ＰＶＡとの塗布液の差異も明確でなく、ｐｅｉは、架橋剤として有効性はない。従来例２では、ポリオレフィンフィルムの基材に対してｐｅｉが水性アンカー層として効果的があると記載されているが、本比較試料１，２では、基材がＰＥＴフィルムであり、アンカー剤としての効果はないことが明らかになった。従って、表１に示した試料１〜４が効果的であることを示している。
【００５２】
なお、試料１のＰＶＡ塗布膜、及び試料２〜５のカルボン酸変性ＰＶＡ塗布膜の乾燥膜厚、及び比較例のＰＶＡ塗布膜及びカルボン酸変性ＰＶＡの乾燥膜厚が約１μｍとし、比較試料１〜４は、ＰＶＡ塗布膜及びカルボン酸変性ＰＶＡの乾燥膜厚が約３μｍとした。
【００５３】
一方、▲１▼ガスバリア性試験（酸素の透過度を測定）では、ガスバリア性の酸素透過度は、何れの試料も１ｃｃ／ｍ^２ ／ａｔｍ（乾燥雰囲気中、室温２３℃ ）未満であった。因みに、基材のＰＥＴの厚さが１２μｍの場合では、酸素透過度が約１００ｃｃ／ｍ^２ ／ａｔｍ（乾燥雰囲気中、室温２３℃ ）であった。従って、比較例、比較試料ともに、酸素バリア性は優れていた。なお、ＰＥＴ上に、それぞれのＰＶＡ塗布剤を塗布した後、塗布剤を乾燥させて、エージングが０日で酸素透過度の測定を行った。
【００５４】
なお、高湿度保存性▲３▼は、試料１〜試料５では、良好な結果が得られたのに対し、各比較例、各比較試料ともに劣っていた。
【００５５】
【発明の効果】
上述のように、本発明によれば、透明でＰＶＡのガスバリア性を維持したまま１液塗布で、基材（ＰＥＴ）との密着性を向上させることができる効果を有するとともに、高湿度下（９０％Ｒｈ）においても基材（ＰＥＴ）との密着性を維持することができるガスバリア性フィルム及びそのガスバリア性フィルムの製造方法を提供することができることが明らかになった。[0001]
BACKGROUND OF THE INVENTION
  The present invention is a gas barrier film suitable as a packaging film for foods, pharmaceuticals, agricultural chemicals, cosmetics, etc.And itsIt relates to a manufacturing method.
[0002]
[Prior art]
Conventionally, as a transparent gas barrier film, a film obtained by coating a plastic film with a solution of polyvinyl alcohol (hereinafter referred to as PVA) having excellent gas barrier properties is known. Since the PVA coating film is insufficiently adhered to the base material made of a plastic film, an anchor layer is usually provided between the PVA and the base material, and the PVA coating film is coated on the anchor layer. . Moreover, PVA has a high humidity dependency, and the PVA film is usually not affected by humidity as a laminate film having a two-layer or three-layer structure.
[0003]
For example, as a gas barrier molded article, there is Japanese Patent Publication No. 5-19580 (hereinafter referred to as Conventional Example 1). In Conventional Example 1, it is disclosed that an anchor coat layer is formed when a polyester molded product is coated with a PVA resin solution. As the anchor coat layer, for example, the acid component is terephthalic acid and / or isophthalic acid, aliphatic dicarboxylic acid, the diol component is a chain or cyclic diol, and a branched diol, and a polyester solvent solution of these compositions is used. It is formed by coating and drying. Examples of the polyester molded product include polyethylene terephthalate, polybutylene terephthalate, and polycarbonate.
[0004]
JP-A-8-245816 (hereinafter referred to as Conventional Example 2) relates to a barrier polyolefin film, and an aqueous coating in which polyvinyl alcohol and an aqueous anchor agent are mixed in a predetermined ratio on the surface-treated surface of the polyolefin film. It is a barrier polyolefin film formed by applying an agent. As the aqueous anchoring agent, aqueous isocyanate and polyethyleneimine are used.
[0005]
[Problems to be solved by the invention]
As described above, in Conventional Example 1, an anchor coat layer is formed on a polyester molded article, and a PVA resin solution is coated thereon to produce a polyester molded article having excellent gas barrier properties. However, in the conventional example 1, in consideration of the moisture resistance of the polyester molded product, an anchor coat layer and a PVA resin layer are laminated on the polyester molded product, and further, a multilayer structure in which one layer is added to improve the moisture resistance. There is a drawback that the number of manufacturing steps is increased.
[0006]
Further, in Conventional Example 2, it is pointed out that a film such as polyvinylidene chloride has a drawback that hydrogen chloride gas is generated when it is burned, and that a barrier film made of PVA does not have an oxygen gas barrier property in a high humidity atmosphere. Has been. Conventional example 2 is made in view of these problems, and the polyolefin film has sufficient gas barrier properties by applying a mixture of an aqueous PVA solution and an aqueous anchor agent without applying an anchor agent. That is, although the conventional example 2 discloses the gas barrier property of the polyolefin film, it is not clear whether it can be applied to other plastic films.
[0007]
  The present invention has been made in view of the above-described problems, and maintains the original transparency and high gas barrier properties of polyvinyl alcohol, and has good adhesion between the polyvinyl alcohol and the substrate without providing an anchor layer. And providing a gas barrier film that can maintain adhesion even under high humidity.ToAn object of the present invention is to provide a method for producing a subbarrier film.
[0008]
[Means for Solving the Problems]
  The present invention achieves the above-mentioned problems, and the invention according to claim 1 includes a solvent having a mixing ratio of water and alcohol of 10/90 to 30/70.,Carboxylic acid modified polyvinyl alcoholas well asMultifunctional aziridine compoundAnd are mixed,AndA coating solution in which the mixing ratio of the polyvinyl alcohol and the polyfunctional aziridine compound is 100/1 to 100/8Without the anchor layerDirect application to plastic filmAnd then aged to form a gas barrier film, and another substrate was laminated on one or both sides of the gas barrier film.It is characterized byFor packagingIt is a gas barrier film.
[0009]
  In the invention of claim 1,Polyvinyl alcohol (PVA)Use water as a solvent for gas barrier compositions mainly composed ofAlsoHowever, a mixed solvent in which alcohol is added to water is preferable in consideration of drying properties. In addition, since the solubility of PVA falls when there is too much alcohol content, as a mixing ratio of water and alcohol, water / alcohol = 10/90ThruA solvent mixed at a ratio of about 30/70, particularly water / alcohol = 20/80 is preferable. Examples of alcohols include methanol, ethanol, isopropanol, and butanol..
[0010]
  In addition, a polyfunctional aziridine compound, that is, a gas barrier film obtained by applying a PVA coating agent in which a polyfunctional aziridine compound having a plurality of aziridine functional groups is added as a crosslinking agent for a carboxylic acid-modified PVA and aging, There is an advantage that the adhesion to the film is goodThe
[0011]
  In addition, a polyfunctional aziridine compound having 3 or more functional groups is mixed with PVA rather than an aziridine functional group having 2 or less aziridine functional groups, and the adhesion to the substrate is better even if the aging time is shorter . As the polyfunctional aziridine compound, for example, TAZM manufactured by Mutual Pharmaceutical Co., Ltd. or Chemitite PZ-33 manufactured by Nippon Shokubai Co., Ltd. is preferable..
[0012]
  Also,As the plastic film, polyester such as polyethylene terephthalol (PET), stretched polypropylene (OPP), stretched nylon (ONy) and the like are preferable..
[0014]
  The invention of claim 2 is a first step of preparing a solution in which carboxylic acid-modified polyvinyl alcohol is dissolved in a solvent having a mixing ratio of water and alcohol of 10/90 to 30/70,
  The polyfunctional aziridine compound is added to the solution so that the solid content ratio of the carboxylic acid-modified polyvinyl alcohol and the polyfunctional aziridine compound is 100/1 to 100/8.With the coating liquidA second step of:
  The composition of the second stepDoes not have an anchor layerA third step of forming a dried laminate directly coated on a plastic film substrate;
  A fourth step of aging the laminate;,
  A fifth step of laminating another substrate on one or both sides of the laminate;
  HaveFor packaging characterized byIt is a manufacturing method of a gas barrier film.
[0015]
  Claim2In the invention of alcohol and waterMixing ratio is 10/90 to 30/70SolventCarboxylic acid modified polyvinyl alcohol (PVA)Adjust the dissolved solution,Carboxylic acid modificationWith PVAMultifunctionalThe solid content ratio (blending ratio) with the aziridine compound is 100/1 to 100/8.Multifunctional in this solutionAn aziridine compound is added to prepare a PVA coating solution, the PVA coating solution is applied to a plastic film, dried, and then aged to produce a sbarrier film.
[0016]
  Carboxylic acid-modified PVA is PVA modified with an organic acid.Is. Also,Of carboxylic acid-modified PVA and polyfunctional aziridine compoundMeltingThe medium is preferably a mixed solvent of water and alcohol in consideration of drying properties. If the alcohol content is too high, the solubility of PVA decreases, so the mixing ratio of water and alcohol is water / alcohol = 10/90.ThruA solvent mixed at a ratio of about 30/70, particularly about 20/80 is preferable. Examples of the alcohol include methanol, ethanol, isopropanol, butanol and the like as described above.
[0017]
PVA is dissolved in this solvent to prepare a 6% PVA solution. The solid content ratio (blending ratio) of PVA and aziridine compound is such that when the blending ratio of PVA and aziridine compound exceeds 100/8, the adhesion to the substrate deteriorates, and the mixing of the aziridine compound from 100/1 When the amount is small, the adhesiveness deteriorates after aging for a short time. Therefore, it is preferably 100/1 to 100/5. For example, 100/5 is most preferable. In that case, 0.3 g of a polyfunctional aziridine compound is added to 100 g of a PVA 6% solution. In addition, as for the aging temperature for apply | coating the coating agent which added the aziridine compound to PVA on a plastic film and accelerating a crosslinking reaction, 30-60 degreeC is preferable.
[0018]
After the fourth step, another base material may be laminated on one side or both sides of the gas barrier film according to the present invention, and as a laminating method, a method of melt extrusion laminating a thermoplastic resin, another film or Examples include a method of dry laminating a sheet using a known adhesive. The other side resin or film or sheet to be laminated is preferably one having heat sealability. For example, as the resin to be melt-extruded, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), ethylene polyethylene acetate ( EVA) and ionomers, and examples of the film or sheet to be dry-laminated include films or sheets of unstretched polypropylene (CPP), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), and the like. Such a gas barrier film of the present invention can be used for various packaging materials such as three-sided bags, pillow packaging, and PTP packaging.
[0019]
  Claim2In the invention ofAThe dilysine functional group is polyfunctionalMultifunctional aziridine compoundIs preferred. An aziridine compound having two functional groups has difficulty in adhesion when aging is short, but a polyfunctional aziridine compound having three or more aziridine functional groups is preferable even when aging is short.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, the gas barrier composition according to the present inventionbyAn embodiment of a gas barrier film and a method for producing the same will be described. The gas barrier film of the present invention shields foods, pharmaceuticals, agricultural chemicals, cosmetics and the like from water vapor and oxygen, and is used for packaging intended for long-term storage,Polyvinyl alcohol (PVA) A gas barrier film by a coating film is excellent in gas barrier properties, but has a problem in adhesion under high humidity, and is improved.
[0022]
(Embodiment 1)
The manufacturing method of the gas barrier film in this embodiment is demonstrated. In this embodiment, a plastic film is used as the base material of the gas barrier film. A coating agent for imparting gas barrier properties to a plastic film is obtained by dissolving PVA having gas barrier properties in water or a solvent of an organic solvent and water, and adding an aziridine compound as a cross-linking agent to the PVA solution. It is added and adjusted so that the solid content ratio (blending ratio) becomes a predetermined ratio. This PVA coating agent is applied on a plastic film and dried. The thickness of the layer in a state where the coating agent is dried is about 1 μm. Subsequently, after the coating agent is dried, for example, aging is performed at 40 ° C. for a predetermined time to form a gas barrier film. The aziridine compound is a compound having the following aziridine functional group.
[0023]
[Chemical 1]

[0024]
The gas barrier film of the present embodiment was found to maintain the gas barrier property and the adhesion under high humidity while maintaining the transparency of PVA, for example, by the following experiment.
[0025]
(Embodiment 2)
  The manufacturing method of the gas barrier film in this embodiment is demonstrated. In this embodiment, polyethylene terephthalate (hereinafter referred to as PET) whose plastic film is a saturated polyester is used as the base material of the gas barrier film. As a coating liquid for imparting gas barrier properties to PET, PVA having excellent gas barrier properties is dissolved in a solvent of an organic solvent such as isopropyl alcohol (hereinafter referred to as IPA) and water. In this solution, the above-mentioned aziridine compound having an aziridine functional group is mixed with a solid content ratio of PVA and aziridine compound of 100/1.ThruAdd to 100/8. The aziridine compound is a PVA crosslinking agent. Subsequently, a coating agent of a composition of PVA and an aziridine compound is applied to a PET film and dried. This laminate is aged at 40 ° C. for a predetermined time to form a gas barrier film made of a PET film.
[0026]
In Embodiments 1 and 2, PVA is preferably modified PVA modified with an organic acid rather than an unmodified molecular structure.
[0027]
(Embodiment 3)
The manufacturing method of the gas barrier film in this embodiment will be described in the following manufacturing process.
(1) a first step of preparing a 6% solution by dissolving PVA in a solvent in which the blending ratio of an organic solvent such as IPA and water is IPA / water = 20/80;
(2) Second step of adding the aziridine compound to the solution obtained in the first step so that the blending ratio of the solid content of PVA and the aziridine compound as the cross-linking agent is 100/1 to 100/8. When,
(3) a third step of forming a laminate obtained by applying the PVA coating liquid prepared in the second step (a composition of PVA and an aziridine compound) to a base material of a plastic film and drying it;
(4) a fourth step of aging the laminate;
It is a manufacturing method of the gas barrier film which has this.
[0028]
In the third embodiment, PVA is preferably modified PVA modified with an organic acid rather than an unmodified molecular structure.
[0029]
(Embodiment 4)
The manufacturing method of the gas barrier film in this embodiment will be described in the following manufacturing process.
(1) PVA (manufactured by Kuraray Co., Ltd., POVAL 105) is dissolved in a solvent having an organic solvent such as IPA and water in a ratio of IPA / water = 20/80 to prepare a 6% solution of PVA. A first step of:
(2) a second step of adjusting the PVA coating solution by adding the aziridine compound to the solution having a solid content ratio of PVA and the aziridine compound as the crosslinking agent of 100/1 to 100/8;
(3) A PVA coating solution (composition of PVA and an aziridine compound) prepared in the second step is a polyester film (hereinafter referred to as PET) (E5100, Toyobo Co., Ltd., thickness 12 μm) A third step of applying a wire bar on the base material of the substrate and forming a coating film having a thickness of about 1 μm in a dry state;
(4) a fourth step of aging the laminate obtained by drying the PVA coating liquid in the third step at 40 ° C .;
It is a manufacturing method of the gas barrier film which has this.
[0030]
(Embodiment 5)
About the manufacturing method of the gas barrier film in this embodiment, it can implement by the following manufacturing processes.
(1) Modified PVA (manufactured by Kuraray Co., Ltd., Poval, KM-118M) is dissolved in a solvent in which the compounding ratio of an organic solvent such as IPA and water is IPA / water = 20/80. A first step of preparing a 6% solution;
(2) a second step of adjusting the PVA coating solution by adding the aziridine compound to the solution in which the blending ratio of the solid content of the modified PVA and the aziridine compound as a crosslinking agent is 100/1 to 100/8; ,
(3) The PVA coating solution (composition of modified PVA and aziridine compound) in the second step is coated on a PET (Toyobo Co., Ltd., E5100, thickness 12 μm) substrate with a wire bar. A third step of forming a coating film having a thickness of about 1 μm in a dry state;
(4) a fourth step of aging the laminate obtained by drying the PVA coating liquid in the third step at 40 ° C .;
It is a manufacturing method of the gas barrier film which has this.
[0031]
In the above embodiment, the aziridine compound is preferably a polyfunctional aziridine compound shown below (TAZM manufactured by Mutual Yakuhin Co., Ltd. or Chemitite PZ-33 manufactured by Nippon Shokubai Co., Ltd.). Furthermore, PVA is preferably carboxylic acid-modified PVA (manufactured by Kuraray Co., Ltd., Poval KM-118).
[0032]
[Chemical formula 2]

[0033]
In the said embodiment, after forming the gas barrier film of Embodiments 1-5, you may laminate another base material on the one or both surfaces of this gas barrier film, for example. Examples of the laminating method include a method of melt extrusion laminating a thermoplastic resin, a method of dry laminating another film or sheet using a known adhesive, and the like. The resin or film or sheet on the other side to be laminated is preferably one having heat sealing properties. For example, as the resin to be melt-extruded, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), ethylene acetate polyethylene Examples of the film or sheet to be dry-laminated include films or sheets of unstretched polypropylene (CPP), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and the like. Moreover, the gas barrier film of this embodiment can be used for various packaging materials such as three-sided bags, pillow packaging, and PTP packaging.
[0034]
(Embodiment 6)
  An embodiment of the gas barrier composition (coating agent) of the present invention is apparent from the above embodiment, but is a gas barrier composition containing polyvinyl alcohol, an aziridine compound, and water or a mixed solvent of water and alcohol. . The gas barrier composition mainly composed of PVA can use water as the solvent. In order to improve the drying property of the solvent, a mixed solvent obtained by adding alcohol to water is preferable. In addition, since the solubility of PVA will fall when there is too much alcohol content, as a mixing ratio of water and alcohol, water / alcohol = 10/90ThruA solvent mixed at a ratio of about 30/70, particularly water / alcohol = 20/80 is preferable. Examples of the alcohol include methanol, ethanol, isopropanol, butanol and the like. As the aziridine compound, the polyfunctional aziridine compound shown above is preferable.
[0035]
【Example】
Next, the gas barrier film of the Example of this invention is demonstrated with reference to Tables 1-4. In this example, a gas barrier film was produced according to the production steps of Embodiments 4 and 5. First, sample 1 of Example A was prepared by dissolving PVA (manufactured by Kuraray Co., Ltd., Poval 105) in a solvent in which the blending ratio of IPA organic solvent and water was IPA / water = 20/80. , PVA was adjusted to be a 6% solution. Subsequently, a polyfunctional aziridine compound (TAZM manufactured by Mutual Yakuhin Co., Ltd.), which is a crosslinking agent that crosslinks to a 6% solution of PVA at room temperature (low temperature), is added to the solid content of PVA and the polyfunctional aziridine compound. The PVA coating solution was prepared by adding 0.3 g of a polyfunctional aziridine compound to 100 g of the solution so that the blending ratio of 100/5 was 100/5. Next, this PVA coating solution was coated on a base material of PET (E5100 thickness 12 μm, manufactured by Toyobo Co., Ltd.) with a wire bar and dried. The PVA coating film had a thickness of about 1 μm in a dry state. Thereafter, this laminate was aged at 40 ° C.
[0036]
On the other hand, Samples 2 to 5 of Example B are carboxylic acid-modified PVA (Poval KM-118M manufactured by Kuraray Co., Ltd.), and the blending ratio of IPA organic solvent and water is IPA / water = 20/80. It melt | dissolved in the solvent and it adjusted so that carboxylic acid modification PVA might become a 6% solution in this solvent. A polyfunctional aziridine compound (TAZM manufactured by Mutual Yakuhin Co., Ltd.) that is a crosslinking agent that crosslinks each of the carboxylic acid-modified PVA into a 6% solution at room temperature (low temperature), carboxylic acid-modified PVA and the polyfunctional aziridine compound The polyfunctional aziridine compound was added so that the blending ratio of the solid content was 100 / 1.5, 100/3, 100/5, and 100/10, respectively, to prepare a PVA coating solution. For example, when the blending ratio is 100/5, 0.3 g of a polyfunctional aziridine compound is added to 100 g of a solution. Subsequently, a PVA coating liquid, which is a composition of a carboxylic acid-modified PVA and a polyfunctional aziridine compound, was applied to a PET (E5100 manufactured by Toyobo Co., Ltd., thickness: 12 μm) as a wire bar on the substrate. The PVA coating film having a thickness of about 1 μm was formed in a dry state. Thereafter, this laminate was aged at 40 ° C.
[0037]
The gas barrier films of Examples A and B (Samples 1 to 5) were subjected to (1) gas barrier test (measurement of oxygen permeability), (2) adhesion test, and (3) high humidity storage stability test. Each characteristic was examined. Table 1 shows the test results.
[0038]
First, each test method will be described. (1) The gas (oxygen) barrier property is an oxygen permeability measuring device (OX-TRAN TWIN MOCON Co., Ltd.) at 23 ° C. and 0% Rh atmosphere with respect to samples 1 to 5. ). In this test, each coating agent was applied on PET, and then the coating agent was dried, and the oxygen permeability was measured at 0 days of aging.
[0039]
  (2)In the adhesion test, samples 1 to 5 of this example were first aged at 40 ° C. for the number of days shown in the table, and then subjected to a cello tape (registered trademark) peel test. Next, a peel test was performed using a portion of the sample that was not used for the cellophane peel test. In the peel test, an unstretched polypropylene film (hereinafter referred to as CPP) having a thickness of 25 μm is bonded to the gas barrier film coating surface by dry lamination using a polyurethane adhesive, and further described in a table at 40 ° C. After aging for several days, the film was cut to a width of 15 mm, and the peel strength was determined by T-shaped peeling between the CPP and the film of this example. In the following table, in the cellophane peeling test, the film that did not peel off was marked with ◯, the peeled film was marked with x, and the T-shaped peeling test (peeling test)(1)~(4)), The peel strength of 50 gf / 15 mm (about 0.49 N / 15 mm) or less was evaluated as x, and the substrate breakage or peel strength was 200 gf / 15 mm (about 1.96 N / 15 mm) or less.UpWas rated as ◯, and those with an intermediate peel strength as △.(Note: (2). (1) and (4) in this paragraph are read as circled numbers.)
[0040]
(3) The high humidity storage stability is that the dry-laminated gas barrier films of Samples 1 to 5 of this example were cultivated at 40 ° C. for 30 days and then stored at room temperature 23 ° C. and 90% Rh for 1 week. The film was cut to a width of 15 mm, and the peel strength between the CPP and this film was determined. The evaluation standard of peel strength is the same as the adhesion evaluation.
[0041]
[Table 1]

[0042]
First, Table 1 will be briefly described. The rightmost column of Sample 1 in Table 1 (the column with “14” in “Aging 40 ° C. Day”) will be described as an example. “14” in “Aging 40 ° C. Day” indicates that a gas barrier test was first performed after Sample 1 was manufactured, and then Sample 1 was aged at 40 ° C. for 14 days. A cellophane peel test was performed after aging for 14 days and the results are shown. Next, progress is made to peel tests (1) to (4) (T-type peel test). In this T-type peel test column, a CPP film is dry-laminated on the gas barrier surface of a sample not used in the cellophane peel test, and further aged for a predetermined number of days (3 days in the case of peel strength (1)) at 40 ° C. It shows the results of performing a T-type peel test. The total aging days of the samples subjected to the T-type peel test is the number of days obtained by adding the aging days before the peel test to the aging days before the cello tape peel test. That is, in the peel strength (1) in the row of “14” in the “Aging 40 ° C. Day” column, 17 days obtained by adding 3 days to 14 days to the aging before the peel strength is the number of days aged. Incidentally, in the “14” column of the peel test {circle around (4)}, the total number of aging days is 44 days obtained by adding 30 days to the aging days 14 days.
[0043]
  As is clear from Table 1, comparison is made between unmodified PVA and carboxylic acid-modified PVA..When Sample 1 and Sample 4 having the same solid content ratio (100/5) are compared, the coating solution in which the polyfunctional aziridine compound is added to the carboxylic acid-modified PVA has a short aging time in the peel test. It showed good characteristics. On the other hand, in the case of unmodified PVA, sufficient characteristics can be obtained by setting the total training time to 11 days or more, preferably 17 days or more. In the case of carboxylic acid-modified PVA, Sufficient characteristics could be obtained by setting the training time to 3 days or longer. That is, even in the case of a coating solution obtained by adding a polyfunctional aziridine compound to unmodified PVA, sufficient characteristics can be obtained by increasing the aging time.The
[0044]
  Moreover, as for the compounding ratio of the solid content of the coating film, 100 / 1.5 (sample 2) is shown in Table 1, but by increasing the aging time, good characteristics may be exhibited even at 100/1. It was revealed. Further, when the blending ratio is 100/10, moisture is absorbed and adhesion is deteriorated, which is not preferable. Therefore, the blending ratio is 100/1.ThruThe range of 100/5 is most preferable, but when the amount of polyfunctional aziridine compound added is increased, 100/8 (not shown) is the limit. Therefore, the range of acceptable compounding ratio is 100/1.ThruThe range is 100/8.
[0045]
Furthermore, in order to verify the effect of the polyfunctional aziridine compound as a crosslinking agent for PVA and carboxylic acid-modified PVA, Comparative Examples 1 and 2 were prepared and the tests (1) to (3) were performed. The test results are shown in Table 2.
[0046]
[Table 2]

[0047]
As apparent from Table 2, when manufactured with a coating solution of PVA and modified PVA to which no polyfunctional aziridine compound was added, it was 50 gf / 15 mm (about 0.49 N / 15 mm) or less in the peel test, and the adhesion Indicates that it is extremely bad. It was shown that there is no advantage due to the difference between PVA and carboxylic acid modified PVA. That is, as shown in Samples 1 to 5, the polyfunctional aziridine compound is effective as a crosslinking agent for PVA and carboxylic acid-modified PVA.
[0048]
Furthermore, in order to verify the effectiveness of the polyfunctional aziridine compound as a crosslinking agent, the test results of Comparative Samples 1 to 4 using polyethyleneimine (hereinafter referred to as pei) which is a crosslinking agent other than the polyfunctional aziridine compound were used. The results are shown in Tables 3 and 4.
[0049]
[Table 3]

[0050]
[Table 4]

[0051]
As is clear from the results of Tables 3 and 4, it is clear that the peel strength is insufficient. Further, the difference between the molecular weight (70000) and molecular weight (10000) of pei is not clear, and the difference between the coating solutions of PVA and modified PVA is not clear, and pei is not effective as a crosslinking agent. Conventional Example 2 describes that pei is effective as an aqueous anchor layer for a polyolefin film substrate, but in Comparative Samples 1 and 2, the substrate is a PET film, and the anchor agent is used as an anchor agent. It became clear that there was no effect. Therefore, it is shown that samples 1 to 4 shown in Table 1 are effective.
[0052]
The dry film thickness of the PVA coating film of Sample 1 and the carboxylic acid-modified PVA coating film of Samples 2 to 5 and the dry film thickness of the PVA coating film and the carboxylic acid-modified PVA of Comparative Example are about 1 μm, and Comparative Sample 1 In -4, the dry film thickness of the PVA coating film and the carboxylic acid-modified PVA was about 3 μm.
[0053]
On the other hand, in (1) gas barrier property test (measurement of oxygen permeability), the gas barrier oxygen permeability is 1 cc / m for any sample.²/ Atm (in a dry atmosphere, room temperature 23 ° C.). Incidentally, when the thickness of the PET substrate is 12 μm, the oxygen permeability is about 100 cc / m.²/ Atm (in a dry atmosphere, room temperature 23 ° C.). Therefore, both the comparative example and the comparative sample were excellent in oxygen barrier properties. In addition, after apply | coating each PVA coating agent on PET, the coating agent was dried and the oxygen permeability was measured by aging 0 days.
[0054]
The high-humidity storage stability (3) was good for Samples 1 to 5, but was inferior for each Comparative Example and each Comparative Sample.
[0055]
【The invention's effect】
  As described above, according to the present invention, it is possible to improve the adhesion with the base material (PET) by one-liquid coating while maintaining the gas barrier property of PVA, and at high humidity ( 90% Rh) gas barrier film capable of maintaining adhesion to the substrate (PET)And itsIt has been found that a method for producing a gas barrier film can be provided.

Claims (2)

A solvent mixture ratio of water to alcohol is 10/90 to 30/70, the mixing ratio of the carboxylic acid-modified polyvinyl alcohol and a polyfunctional aziridine compound and are mixed, and with the polyvinyl alcohol and the polyfunctional aziridine compound A coating solution of 100/1 to 100/8 was directly applied to a plastic film having no anchor layer , and then aged to form a gas barrier film, and another substrate was laminated on one or both sides of the gas barrier film. A gas barrier film for packaging , characterized by that. A first step of adjusting a solution in which carboxylic acid-modified polyvinyl alcohol is dissolved in a solvent having a mixing ratio of water and alcohol of 10/90 to 30/70;
A second step of adding a polyfunctional aziridine compound to the solution so that a solid content ratio of the carboxylic acid-modified polyvinyl alcohol and the polyfunctional aziridine compound is 100/1 to 100/8 to obtain a coating solution ;
A third step of directly applying the coating solution of the second step onto a plastic film substrate having no anchor layer to form a dried laminate;
A fourth step of aging the laminate,
And a fifth step of laminating another substrate on one or both sides of the laminate . A method for producing a packaging gas barrier film, comprising: