JP4571328B2 - Multilayer film and container using the same - Google Patents

Description

【００４８】
（式(1) 中、Ｒ¹ およびＲ² は同一または異なって、水素、炭化水素残基、またはハロゲン、エステル、ニトリル、ピリジル等の極性基を示す。また、Ｒ¹ およびＲ² は互いに結合して環を形成してもよい。ｍは１以上の整数、ｎは０または１以上の整数である。）
および／または一般式(2) ：
【００４９】
【化２】

【００５０】
（式(2) 中、Ｒ³ およびＲ⁴ は同一または異なって、水素、炭化水素残基、またはハロゲン、エステル、ニトリル、ピリジル等の極性基を示す。また、Ｒ³ およびＲ⁴ は互いに結合して環を形成してもよい。ｘおよびｚは１以上の整数、ｐは０または１以上の整数である。）
で表される構成単位を有するポリマーを挙げることができる。
一般式(1) で表される構成単位を有するポリマーは、１種または２種以上の単量体を公知の開環重合方法によって重合させ、こうして得られる開環重合体を常法に従って水素添加したものである。
【００５１】
当該ポリマーの具体例としては、日本ゼオン（株）製の水添重合体〔商品名「ゼオノア」、比重１．０１、ＭＦＲ７０ｇ／１０分（１９０℃）、ガラス転移温度（Ｔｇ）１００℃〕、日本合成ゴム（株）製の商品名「ＡＲＴＯＮ」等が挙げられる。
一般式(2) で表される構造単位を有するポリマーは、単量体としての、１種または２種以上のノルボルネン系モノマーと、エチレンとを公知の方法によって付加共重合させたもの、および／またはこれを常法に従って水素添加したものである。
【００５２】
当該ポリマーの具体例としては、三井化学（株）製の〔商品名「アペル６５０９」、比重１．０２、ＭＦＲ４０ｇ／１０分（１９０℃）、ガラス転移温度（Ｔｇ）８０℃〕、ＴＩＣＯＮＡ社製の商品名「ＴＯＰＡＳ」等が挙げられる。
上記一般式(1) および(2) で表される構成単位を有するポリマーを含む、前記共重合体の水素添加物は、いずれも飽和ポリマーであるので、ガス遮蔽性や水分遮蔽性に加えて、耐熱性や透明性、さらには安定性の点で優れている。
【００５３】
第３層に使用する環状オレフィン共重合体は、そのガラス転移温度（Ｔ_g ）が７０℃以上であるのが好ましく、８０〜１５０℃であるのがより好ましい。また、その分子量の範囲が、シクロヘキサンを溶媒とするゲル浸透クロマトグラフィ（ＧＰＣ）分析により測定した数平均分子量＜Ｍｎ＞において１万〜１０万であるのが好ましく、２万〜５万であるのがより好ましい。当該共重合体の分子鎖中に残留する不飽和結合を水素添加により飽和させる場合において、その水添率は、９０％以上、好ましくは９５％以上、特に好ましくは９９％以上となるように設定される。
【００５４】
第３層には、前述の環状オレフィン共重合体を単独で用いてもよく、２種以上を混合して用いてもよい。また、同種のものであっても分子量が異なるものをブレンドして用いることも可能である。
第３層の厚みの割合は、多層フィルム全体の厚みに対して３〜１５％とするのが好ましい。第３層の厚みの割合が上記範囲を下回ると、多層フィルムおよびそれを用いた容器のガスおよび水分遮蔽性が不十分になる。逆に、上記範囲を超えると、多層フィルムおよびそれを用いた容器の柔軟性が損なわれる。
【００５５】
〔第４層〕
本発明の多層フィルムにおける第４層には、前述の第３層と、後述する第５層との接着を良好にすることに加え、多層フィルムのガスおよび水分遮蔽性を損なうことなく、柔軟性、耐衝撃性、シール強度を向上させることが求められる。
そこで、本発明の多層フィルムにおける第４層を構成する樹脂には、
(1) メタロセン触媒を用いて製造された密度０．８６０〜０．９２０ｇ／ｃｍ³ の直鎖状超低密度エチレン・α−オレフィン共重合体（Ｍｅｔａｌｌｏｃｅｎｅ−ＶＬＤＰＥ）、または、
(2) メタロセン触媒を用いて製造された密度０．８６０〜０．９２０ｇ／ｃｍ³ の直鎖状超低密度エチレン・α−オレフィン共重合体（Ｍｅｔａｌｌｏｃｅｎｅ−ＶＬＤＰＥ）と、密度０．９５５〜０．９７０ｇ／ｃｍ³ の高密度ポリエチレン（ＨＤＰＥ）とを、当該ＨＤＰＥの含有割合が全体の１０重量％以下となるように混合してなる樹脂
が用いられる。
【００５６】
かかる樹脂は、本発明の第１の多層フィルムにおける第２層と同様のものである。本発明の多層フィルムにおける第４層は、本発明の多層フィルムを薬液容器等の容器に適用した場合に最内層から２番目の層となるものであって、ガスおよび水分遮蔽性に優れた第３層の内側に位置するものであるが、第３層の機能を補強するという観点から、十分なガスおよび水分遮蔽性が求められる。従って、第４層に使用するＶＬＤＰＥは、Ｚｉｅｇｌｅｒ−ＶＬＤＰＥではなく、Ｍｅｔａｌｌｏｃｅｎ−ＶＬＤＰＥを用いることが求められる。
【００５７】
Ｍｅｔａｌｌｏｃｅｎ−ＶＬＤＰＥの密度が上記範囲を外れた場合の問題点、密度のより好ましい範囲、具体例、α−オレフィンの種類、メルトフローレート（ＭＦＲ）の好適範囲、Ｍｅｔａｌｌｏｃｅｎ−ＶＬＤＰＥ（およびｄｅ−ＰＥ）とＨＤＰＥとからなる混合樹脂中でのＨＤＰＥの混合割合については、第１の多層フィルムにおける第２層の説明において示したものと同様である。
一方、本発明の多層フィルムにおける第４層の厚みの割合は、前記第１の多層フィルムにおける第２層とは異なり、多層フィルム全体の厚みに対して３５〜６５％とすることが求められる。すなわち、一般に、第２層に比べてその割合を大きくすることが求められる。これにより、多層フィルムに十分な柔軟性と耐衝撃性とを付与することができる。
【００５８】
第４層の厚みの割合が上記範囲を下回ると、多層フィルムの柔軟性が低下する。逆に、上記範囲を超えると、多層フィルムの耐熱性が低下したり、熱シール部でのピンホールの発生率がかえって上昇したりする問題が生じる。
〔第５層〕
本発明の多層フィルムにおける第５層は本発明の容器の最内層になるものであって、シール性と耐ブロッキング性とに優れていることが求められる。
【００５９】
そこで、本発明の多層フィルムにおける第５層を構成する樹脂には、密度０．９３０〜０．９５０ｇ／ｃｍ³ の直鎖状エチレン・α−オレフィン共重合体（Ｌ−ＰＥ）が用いられる。
かかる樹脂は、本発明の第１の多層フィルムにおける第１層と同様のものである。また、直鎖状エチレン・α−オレフィン共重合体（Ｌ−ＰＥ）の密度が上記範囲を外れた場合の問題点、密度のより好ましい範囲、具体例、α−オレフィンの種類、メルトフローレート（ＭＦＲ）の好適範囲等については、第１層の説明において示したものと同様である。
【００６０】
第５層の厚みの割合は、多層フィルム全体の厚みに対して３〜１５％とするのが好ましい。第５層の厚みの割合が上記範囲を下回ると、多層フィルムのシール性が低下して、容器の外観が劣化するおそれがある。逆に、上記範囲を超えて厚くしてもシール性や耐ブロッキング性に大きな変化はなく、かえって多層フィルムの柔軟性が低下するおそれがある。
第５層の厚みの割合は、上記範囲の中でも、特に５〜１０％であるのが好ましい。
【００６１】
〔多層フィルムの製造方法〕
次に、本発明の多層フィルムの製造方法について説明する。
本発明の多層フィルムを製造するには、水冷式または空冷式共押出しインフレーション法、共押出しＴダイ法、ドライラミネーション法、押出しラミネーション法等が使用可能であるが、性能、特に透明性、経済性および衛生性等の点から水冷共押出しインフレーション法および共押出しＴダイ法を使用するのが好ましい。
【００６２】
いずれの方法においても、各層の樹脂が溶融する温度で実施する必要があるが、温度を上げ過ぎると樹脂の一部が熱劣化を起こし、劣化物による性能低下のおそれが生じる。従って、本発明の多層フィルムを製造する際の温度条件は、通常１５０〜２５０℃、好ましくは１７０〜２００℃とするのが望ましい。
上記により製造される本発明フィルムの厚みは、一般に１００〜３００μｍ、好ましくは２００〜３００μｍであるが、使用目的等に応じて適宜増減することができ、８０μｍ程度の厚みでも充分な強度を保持している。
【００６３】
〔容器の実施形態〕
次に、本発明の容器について、その一実施形態を示す図１を参照しつつ説明する。
図１は、医療用容器（輸液バッグ）の一例を示す正面図である。
医療用容器１０は、上記本発明の多層フィルム２枚を通常の方法により裁断し、それぞれの第５層を内層として重ね合わせてその周縁２２をヒートシールし、さらに口部材２０をヒートシール等の手段により取付けることによって製造される。
【００６４】
また、多層フィルムの第５層を内側にしてチューブ状に成形した上で、周縁２２をヒートシールすることにより容器１０を成形してもよい。
ここで、多層フィルムのヒートシールの条件としては、１３０〜２００℃の温度範囲を採用することができ、例えば２５０μｍ程度の厚さを有するフィルムの場合、前記の温度範囲では約０．５〜６秒という短い時間でシールできる。
口部材２０には、本発明の多層フィルムにおける第５層との溶着性に優れた樹脂、例えばポリエチレンで成形したものを用いるのが好ましい。口部材２０を融点約１２０〜１３０℃のポリエチレン製とした場合のヒートシールの条件としては、口部材を数秒間予備加熱した上で、約１４０〜１７０℃で約０．５〜５秒間の範囲で加熱すればよい。
【００６５】
【実施例】
以下、実施例および比較例を挙げて本発明を説明する。
〔多層フィルムの製造〕
実施例１〜５および比較例１〜３
下記の樹脂Ａ〜Ｇを使用し、水冷共押出しインフレーション法によって５層構造の多層フィルムを成形した。各実施例、比較例での多層フィルムの層構成および各層の厚みについては、下記の表１に示すとおりである。
【００６６】
（使用した樹脂）
樹脂Ａ：チーグラー触媒直鎖状エチレン・１−ブテン共重合体（Ｌ−ＰＥ）〔三井化学（株）製、密度０.９４０ｇ／ｃｍ³ 、ＭＦＲ２．１ｇ／１０分（１９０℃）、商品名「ウルトゼックス４０２０Ｂ」〕…本発明に係る第１の多層フィルムにおける第１層または第５層用、第２の多層フィルムにおける第５層用
樹脂Ｂ１：メタロセン触媒直鎖状超低密度エチレン・１−ヘキセン共重合体（Ｍｅｔａｌｌｏｃｅｎｅ−ＶＬＤＰＥ）〔三井化学（株）製、密度０．９０１ｇ／ｃｍ³ 、ＭＦＲ１．５ｇ／１０分（１９０℃）、商品名「エボリュー」〕…第１の多層フィルムにおける第２層(1) または第４層(1) 用、第２の多層フィルムにおける第４層(1) 用
樹脂Ｂ２：上記樹脂Ｂ１（Ｍｅｔａｌｌｏｃｅｎｅ−ＶＬＤＰＥ）９５重量％と、高密度ポリエチレン（ＨＤＰＥ）〔三井化学（株）製、密度０．９６５ｇ／ｃｍ³ 、ＭＦＲ１５ｇ／１０分（１９０℃）、商品名「ハイゼックス」〕５重量％との混合樹脂…第１の多層フィルムにおける第２層(2) または第４層(2) 用、第２の多層フィルムにおける第４層(2) 用
樹脂Ｃ：エチレン・テトラシクロドデセン共重合体〔三井化学（株）製、比重１．０２、ＭＦＲ４０ｇ／１０分（１９０℃）、ガラス転移温度（Ｔｇ）８０℃、商品名「アペル６５０９」〕…第１および第２の多層フィルムにおける第３層用
樹脂Ｄ：ナイロン６（Ｎｙ）〔東レ（株）製、商品名「アミラン」〕…第２の多層フィルムにおける第１層用
樹脂Ｅ：チーグラー触媒直鎖状超低密度エチレン・１−ブテン共重合体（Ｚｉｅｇｌｅｒ−ＶＬＤＰＥ）〔三井化学（株）製、密度０．８８５ｇ／ｃｍ³ 、ＭＦＲ１５ｇ／１０分（１９０℃）、商品名「タフマー」〕
樹脂Ｅ１：上記樹脂Ｅ（Ｚｉｅｇｌｅｒ−ＶＬＤＰＥ）５０重量％と、無水マレイン酸グラフト変性ポリエチレン〔三井化学（株）製、商品名「アドマー」〕４５重量％と、ＨＤＰＥ〔前出の商品名「ハイゼックス」〕５重量％との混合樹脂…第２の多層フィルムにおける第２層(2) 用
樹脂Ｅ２：上記樹脂Ｂ１（Ｍｅｔａｌｌｏｃｅｎｅ−ＶＬＤＰＥ）５０重量％と、無水マレイン酸グラフト変性ポリエチレン〔前出の商品名「アドマー」〕４５重量％と、ＨＤＰＥ〔前出の商品名「ハイゼックス」〕５重量％との混合樹脂…第２の多層フィルムにおける第２層(2) 用
樹脂Ｆ：直鎖状エチレン・１−ブテン共重合体（Ｌ−ＰＥ）〔三井化学（株）製、密度０.９３０ｇ／ｃｍ³ 、ＭＦＲ２．１ｇ／１０分（１９０℃）、商品名「ウルトゼックス２０３０Ｂ」〕
樹脂Ｇ：上記樹脂Ｅ（Ｚｉｅｇｌｅｒ−ＶＬＤＰＥ）２０重量％と、上記樹脂Ｆ（Ｌ−ＰＥ）７５重量％と、ＨＤＰＥ〔前出の商品名「ハイゼックス」〕５重量％との混合樹脂
なお、下記の表１中、“ＣＯＣ”とは環状オレフィン共重合体（実施例・比較例ではエチレン・テトラシクロドデセン共重合体）を、“ｄｅ−ＰＥ”とは不飽和カルボン酸変性ポリオレフィン（実施例・比較例では無水マレイン酸グラフト変性ポリエチレン）を、それぞれ示す。
【００６７】
【表１】

【００６８】
表１より明らかなように、実施例１，２および３は本発明の第１の多層フィルムに該当する。また、実施例４および５は本発明の第２の多層フィルムに該当する。
一方、比較例１は、第２層および第４層を構成する樹脂（樹脂Ｇ）中でのＭｅｔａｌｌｏｃｅｎｅ−ＶＬＤＰＥの含有割合が少ないこと、当該Ｍｅｔａｌｌｏｃｅｎｅ−ＶＬＤＰＥと混合して用いられている樹脂が不飽和カルボン酸変性ポリオレフィン（ｄｅ−ＰＥ）ではないこと、および第３層を構成する樹脂（樹脂Ｆ）が環状オレフィン共重合体（ＣＯＣ）でないことから、本発明の多層フィルムに該当しない。比較例２は、第３層を構成する樹脂（樹脂Ｆ）が環状オレフィン共重合体でなく、脂肪族ポリアミド樹脂であることから、本発明の多層フィルムに該当しない。また、比較例３は、第２層および第４層を構成する樹脂（樹脂Ｅ）が直鎖状超低密度エチレン・α−オレフィン共重合体（ＶＬＤＰＥ）ではあるものの、Ｍｅｔａｌｌｏｃｅｎｅ−ＰＥではなくＺｉｅｇｌｅｒ−ＶＬＤＰＥであることから、本発明の多層フィルムに該当しない。
【００６９】
〔容器の製造〕
次に、実施例１〜５および比較例１〜３で得られた多層フィルムを用いて、図１に示すような幅１３６ｍｍ、高さ２７０ｍｍ輸液バッグ１０を製造した。この輸液バッグ１０を成形する際の周縁部のヒートシールは１５５℃で４．５秒間行い、口部材２０のシールは１４０〜１５０℃で３秒間行った。なお、輸液バッグ１０には５００ｃｃの蒸留水を充填密封し、ヘッドスペースの容積は５０ｃｃとなるように調整した。
【００７０】
〔容器の性能試験〕
実施例１〜５および比較例１〜３の多層フィルムを用いて得られた輸液バッグ１０について、各種特性の評価試験を以下の方法に従って行った。
(a) 耐熱性：５００ｃｃの蒸留水が密封充填され、ヘッドスペースが５０ｃｃに調整された輸液バッグ１０に対して、１１０℃で４０分間の高圧蒸気滅菌処理を施して、滅菌処理後の輸液バッグの変形、破袋、シール漏れの有無を目視で観察した。
【００７１】
(b) 透明性：輸液バッグ１０の滅菌処理後における波長４５０ｎｍでの光透過率（％）を測定した。
(c) 耐衝撃性：輸液バッグ１０を４℃で冷蔵保存した後、容器を３方向から各５回、１．２ｍの高さから落下させて、輸液バッグの破袋、シール漏れの有無を目視で観察した。
(d) ヘッドスペース増加量：輸液バッグ１０を６０℃，１０％ＲＨで１０日間放置（室温で２年間放置に相当）した後、ヘッドスペースの増加量を測定した。
【００７２】
(e) 水分減少量：輸液バッグ１０を６０℃，１０％ＲＨで１０日間放置した後、容器中の水分の減少量を質量の変化を測定することにより求めた。
以上の試験結果を表１に示す。
なお、耐熱性および耐衝撃性の評価において、Ａ＋は非常に良好、Ａは良好（実用に適している）、Ｂはやや不良（実用上不適当）、Ｃは不良を示す。
【００７３】
【表２】

【００７４】
表２の結果より明らかなように、実施例１〜５の容器（輸液バッグ）は、耐熱性、耐衝撃性および透明性の各特性が優れている上に、空気の侵入によるバッグの膨れや、水分透過による内容液の減少の問題が十分に抑制されていることがわかった。
一方、比較例１の輸液バッグは、バッグ自体の特性は優れているものの、空気の侵入によるバッグの膨れが著しい。比較例２の輸液バッグは、中間層がナイロンであるため、内容液の減少傾向が大きい。また、比較例３の輸液バッグは、接着樹脂としてチーグラー触媒の超低密度ポリエチレンを用いているので耐衝撃性が低下しており、滅菌後に口部材のシール部分においてピンホールが発生しているものが見られ、落下試験ではシール部における破損品が数多く生じた。
【図面の簡単な説明】
【図１】本発明の容器の一実施形態を示す正面図である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a multilayer film and a container formed using the multilayer film, and more particularly to a multilayer film and a container that are particularly suitable as a storage material for medical solutions and blood in the medical field.
[0002]
[Prior art]
Conventionally, polyethylene that is excellent in transparency, flexibility, safety, and the like has been widely used for medical flexible plastic containers such as infusion bags and drug solution containers.
In recent years, for the purpose of improving the performance of plastic containers, attempts have been made to use them in flexible plastic containers using multilayer films made of various polyethylene resins (Japanese Patent Application Laid-Open No. Sho 62-64363, special feature). JP-A 63-248633, JP-A-3-277365, JP-A-4-266759, etc.). All of the multilayer films disclosed in these publications are obtained by laminating polyethylene resins or copolymers having different densities, molecular chain shapes, polymer compositions, and the like.
[0003]
However, all of the above flexible plastic containers have problems such as low heat resistance, film tensile strength, seal strength, blocking resistance, etc., and the transparency and flexibility of the film decrease after heating such as sterilization treatment. There was also a problem that it was easy to do.
Moreover, since the polyethylene-based resin is a gas-permeable resin, if a container sealed with infusion or the like is stored for a long period of time, air will enter the container and swell up. As a result, problems such as poor appearance, reduced handling due to an increase in storage space, and a shift in the scale for displaying the liquid amount have been caused.
[0004]
[Problems to be solved by the invention]
On the other hand, Japanese Patent Application Laid-Open No. 60-55958 proposes that a layer made of nylon is provided in an intermediate layer of a multilayer film made of polyethylene resin for the purpose of suppressing gas permeability of a flexible plastic container. Yes.
However, the infusion bag disclosed in the above publication has problems such as poor flexibility, low heat seal temperature and low infusion bag manufacturing efficiency, and low film transparency.
[0005]
Furthermore, since nylon has a high moisture permeability, there is a problem that the concentration of the internal solution is increased by storing the infusion bag for a long period of time, and the concentration of the internal solution is increased. There was a risk of crystal precipitation or deterioration.
On the other hand, a multilayer structure using a cyclic polyolefin has been proposed for the purpose of improving both gas shielding properties (gas barrier properties) and moisture shielding properties (moisture barrier properties) of flexible plastic containers. In particular, the following prior art documents (a) to (d) can be exemplified as those showing a multilayer structure with polyolefin.
[0006]
(a) A multilayer container provided with a layer comprising a saturated norbornene polymer as a cyclic polyolefin (Japanese Patent Laid-Open No. 4-276253)
(b) A multilayer sheet provided with a layer made of amorphous polyolefin (cyclic polyolefin) such as norbornene resin (Japanese Patent Laid-Open No. 6-255053)
(c) A multilayer sheet in which a polyolefin resin layer containing a cyclic polyolefin component is sandwiched between polyolefin layers (JP-A-7-266517)
(d) A multilayer container in which inner and outer layers made of a linear olefin-based resin and an intermediate layer made of a cyclic polyolefin-based copolymer are laminated via an adhesive resin layer made of a linear ultra-low density polyethylene (Japanese Patent Laid-Open No. Hei 10). -59345)
However, when the multilayer structure described in the above-mentioned publications (a) to (d) is applied to a relatively thin film such as an infusion bag, the gas and moisture shielding properties according to the application are used. In order to obtain the above, it is necessary to increase the thickness of the cyclic polyolefin layer. As a result, there arises a problem that the film becomes hard and brittle. In particular, the multilayer container disclosed in the above publication (d) uses linear ultra-low density polyethylene having low impact resistance and moisture shielding properties as the adhesive resin layer, so that flexibility, impact resistance, It is difficult to obtain an infusion bag satisfying both gas shielding properties and moisture shielding properties.
[0007]
Therefore, the object of the present invention is excellent in heat resistance, blocking resistance, strength, sealability, transparency, impact resistance and flexibility characteristics, and the occurrence of pinholes during heat sealing and the decrease in transparency due to heating. It is possible to obtain a multilayer film with low gas permeability and low water permeability, and it is safe for medical use. It is to provide a container in which reduction and the like are sufficiently suppressed.
[0008]
[Means for Solving the Problems and Effects of the Invention]
  The first multilayer film according to the present invention for solving the above problems is
  A multilayer film consisting of five layers,
  The first layer and the fifth layer have a density of 0.930 to 0.950 g / cm.^ThreeA linear ethylene / α-olefin copolymer of
  The second and fourth layers, MeDensity 0.860-0.920 g / cm produced using tarocene catalyst^ThreeLinear ultra low density ethylene / α-olefin copolymer, and a density of 0.955 to 0.970 g / cm^ThreeConsisting of a resin obtained by mixing the high-density polyethylene with a high-density polyethylene content of 10% by weight or less, and
  The third layer is made of a cyclic olefin copolymer
It is characterized by that.
[0009]
Moreover, the second multilayer film according to the present invention for solving the above problems is
A multilayer film consisting of five layers,
The first layer is made of an aliphatic polyamide resin,
The second layer is (1) density 0.860-0.920 g / cm^ThreeOr a mixed resin of 70 to 30% by weight of a linear ultra-low density ethylene / α-olefin copolymer and 30 to 70% by weight of an unsaturated carboxylic acid-modified polyolefin, or (2) a density of 0.860 to 0. 920 g / cm^ThreeLinear ultra low density ethylene / α-olefin copolymer, unsaturated carboxylic acid-modified polyolefin, and a density of 0.955 to 0.970 g / cm.^ThreeAnd the content ratio of the linear ultra-low density ethylene / α-olefin copolymer and the unsaturated carboxylic acid-modified polyolefin is 70:30 to 30:70 by weight ratio. It consists of a resin that is mixed so that the content ratio of the high-density polyethylene is 10% by weight or less of the whole,
The third layer is made of a cyclic olefin copolymer,
The fourth layer has a density of 0.860 to 0.920 g / cm produced using (1) a metallocene catalyst.^ThreeA linear ultra-low-density ethylene / α-olefin copolymer alone or (2) a density produced from a metallocene catalyst of 0.860 to 0.920 g / cm^ThreeLinear ultra low density ethylene / α-olefin copolymer, and a density of 0.955 to 0.970 g / cm^ThreeConsisting of a resin obtained by mixing the high-density polyethylene with a high-density polyethylene content of 10% by weight or less, and
The fifth layer has a density of 0.930-0.950 g / cm.^ThreeMade of a linear ethylene / α-olefin copolymer
It is characterized by that.
[0010]
By the way, the applicant of the present invention has previously described that the first layer (outermost layer) and the fifth layer (innermost layer) have medium density (density 0.925 to 0.950 g / cm).^ThreeThe second and fourth layers are low density (0.920 g / cm).^ThreeThe following is an ethylene / α-olefin copolymer, and the third layer has a medium density (0.925 to 0.950 g / cm).^Three) And a container using the multilayer film (JP-A-7-96589). Such containers are extremely excellent in heat resistance, blocking resistance, tensile strength, flexibility, transparency, sealing properties, etc., and can sufficiently suppress the decrease in transparency and flexibility after heating such as sterilization treatment. In recent years, it has been widely used.
[0011]
However, since the multilayer film disclosed in the above publication has gas permeability as a whole, the problem that the container swells when stored for a long time in a state where the infusion solution or the like is sealed has not been solved.
In contrast, the first and second multilayer films according to the present invention are common in that the main component is a polyolefin resin, but the cyclic olefin copolymer is disposed in the third layer, and The linear ultra-low density ethylene / α-olefin copolymer produced using a metallocene catalyst in the four layers is different from the multilayer film in the above publication and has the features of the present invention. is doing.
[0012]
Here, the layer made of the specific resin is arranged on the fourth layer, and the thickness thereof is 35 to 65% of the whole, thereby maintaining the adhesion between the third layer and the fifth layer, The flexibility, strength, impact resistance, gas shielding property and moisture shielding property of the entire film can be improved.
Further, by arranging a layer made of a high-density ethylene / α-olefin copolymer or aliphatic polyamide resin in the first layer which is the outermost layer of the container, the strength of the outer surface of the container is made sufficient. it can.
[0013]
In addition, by disposing a layer made of a cyclic olefin copolymer having excellent gas shielding properties on the third layer which is an intermediate layer, a long period of time in a state where the infusion solution or the like is sealed in the container made of the multilayer film of the present invention. Even when stored, it is possible to sufficiently prevent the container from being swollen due to the intrusion of air.
Therefore, according to the first and second multilayer films according to the present invention, the multilayer film disclosed in JP-A-7-96589 has excellent heat resistance, blocking resistance, tensile strength, sealability, and transparency. Excellent gas and moisture shielding properties and good interlaminar properties, while maintaining the properties of heat resistance and flexibility, as well as preventing the generation of pinholes during heat sealing and the loss of transparency due to heating Adhesiveness can be realized.
[0014]
The first and second multilayer films according to the present invention are suitably used in the above-described characteristics, particularly in the use of medical materials such as infusion bags and blood bags.
In the first and second multilayer films according to the present invention, the cyclic olefin copolymer constituting the third layer is preferably a hydrogenated product of a copolymer of ethylene and cyclic olefin. In this case, the effect of improving the heat resistance, transparency, deterioration resistance, moisture shielding property and gas shielding property of the multilayer film is further enhanced.
[0015]
  Above1'sIn the multilayer film, the ratio of the thickness of each layer is 5 to 20% for the first layer, 10 to 40% for the second layer, 3 to 15% for the third layer, and 4 to 4% for the thickness of the entire film. 35 to 65%, the fifth layer is 3 to 15%. On the other hand, in the second multilayer film, the ratio of the thickness of each layer is 5 to 20% for the first layer, 10 to 40% for the second layer, and 3 to 15 for the third layer with respect to the thickness of the entire film. %, The fourth layer is 35 to 65%, and the fifth layer is 3 to 15%.Is preferred. By setting the thickness of each layer as described above, heat resistance, blocking resistance, strength, sealability, pinhole resistance during heat sealing, transparency, turbidity resistance during heating, flexibility, gas shielding In addition, each characteristic of moisture shielding properties can be exhibited in a well-balanced manner.
[0016]
  In addition, the thickness of the entire film is used for a flexible plastic container for medical use such as an infusion bag and a chemical solution container.In the first multilayer film100-300 μm.
  The container according to the present invention uses the multilayer film of the present invention, and the first layer of the multilayer film is an outer layer and the fifth layer is an inner layer.
  According to the container of the present invention, air can be prevented from entering the container without impairing basic properties such as transparency, flexibility, heat resistance, etc. It is possible to solve problems such as lowering, deterioration of liquid contents, and lowering of handleability due to an increase in storage space.
[0017]
The container of the present invention is suitably used in the field of medical containers such as infusion bags and blood bags.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the multilayer film of the present invention and a container using the same will be described in detail. The physical property values defined in the present invention are all based on the American Society for Testing and Materials (ASTM), the density is ASTM D1505, the melt flow rate (MFR) is ASTM D1238, and the melting point is ASTM. It is measured according to D2117.
[0019]
First, the resin, copolymer and elastomer used for each layer of the multilayer film of the present invention will be described.
[First layer]
Since the first layer in the multilayer film of the present invention is the outermost layer of the container of the present invention, it is required to be excellent in mechanical strength (particularly tensile strength) and heat resistance.
[0020]
Therefore, in the resin constituting the first layer in the multilayer film of the present invention,
(I) Density 0.930-0.950 g / cm^ThreeLinear ethylene / α-olefin copolymer (L-PE), or
(II) Aliphatic polyamide resin
Is used.
When the copolymer (L) of the above (I) is used for the first layer, the first multilayer film according to the present invention is obtained, and when the aliphatic polyamide resin of the above (II) is used, A second multilayer film according to the invention is obtained.
[0021]
When the heat seal temperature cannot be lowered as a characteristic of the first layer, it is preferable to use the copolymer (I). When the gas shielding property and strength are important, the fat (II) is used. It is preferable to use a group polyamide resin. Even in the case of the above (I), it is possible to further improve the gas shielding property by using a specific resin for the second layer resin as described later.
The density of the above (I) is 0.930-0.950 g / cm^ThreeThe linear ethylene / α-olefin copolymer (L-PE) (in the middle / high density region) is not limited to this, but is widely used as a resin material for medical containers. And a linear ethylene / α-olefin copolymer produced by a low pressure polymerization method using a Ziegler catalyst.
[0022]
If the density of the linear ethylene / α-olefin copolymer (L-PE) used in the first layer is below the above range, blocking or heat resistance may be deteriorated. On the other hand, when the density exceeds the above range, transparency may be lowered. The density of the copolymer is particularly 0.935 to 0.945 g / cm in the above range.^ThreePreferably, 0.940 g / cm^ThreeMore preferred is the degree.
The linear ethylene / α-olefin copolymer (L-PE) used in the first layer has a melt flow rate (MFR) of 1.5 to 2.5 g / 10 minutes (190 ° C.). The melting point is preferably 120 to 130 ° C. When the MFR and melting point satisfy the above ranges, the mechanical strength and heat resistance of the first layer can be further improved.
[0023]
Examples of the α-olefin in the copolymer include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene, 1-decene, Examples thereof include α-olefins having 3 to 12 carbon atoms such as 1-undecene and 1-dodecene.
Specific examples of the copolymer (I) include a Ziegler linear ethylene / 1-butene copolymer [trade name “Ultzex 4020B”, density 0.940 g / cm, manufactured by Mitsui Chemicals, Inc.^Three, MFR 2.1 g / 10 min (190 ° C.)], trade name “Sumikasen” manufactured by Sumitomo Chemical Co., Ltd., trade name “Moretech” manufactured by Idemitsu Petrochemical Co., Ltd., and the like.
[0024]
On the other hand, examples of the aliphatic polyamide resin (II) include nylon resins (Ny) such as nylon 6, nylon 6,6, nylon 12, and nylon 6,12. Among these, nylon 6 or nylon 12 is used which is less likely to deteriorate due to light decomposition during high temperature sterilization such as high pressure steam sterilization or hot water sterilization. The first layer may be a two-layer structure of nylon 6 and nylon 12.
Specific examples of the aliphatic polyamide resin (II) include nylon 6 (trade name “Amilan”) manufactured by Toray Industries, Inc. and nylon 6 (trade name “NOVAMID”) manufactured by Mitsubishi Chemical Corporation. It is done.
[0025]
The thickness ratio of the first layer is preferably 5 to 20% with respect to the thickness of the entire multilayer film. If the ratio of the thickness of the first layer is below the above range, the mechanical strength and heat resistance of the multilayer film or container may be insufficient. On the other hand, even if the thickness exceeds the above range, there is no significant change in mechanical strength and heat resistance, and conversely, the flexibility of the multilayer film may be reduced. The ratio of the thickness of the first layer is preferably 5 to 15% in the above range.
[0026]
[Second layer]
The second layer in the multilayer film of the present invention is provided with excellent flexibility in the multilayer film without impairing impact resistance, gas and moisture shielding properties and heat resistance, and the first layer (outermost layer of the container) And a third layer (an intermediate layer of a container) made of a cyclic olefin copolymer, which will be described later, are required to have good adhesion.
Therefore, the resin constituting the second layer in the multilayer film of the present invention is set according to the resin constituting the first layer.
[0027]
When using the ethylene / α-olefin copolymer of the above (I) for the first layer, that is, when producing the first multilayer film according to the present invention,
(1) Density 0.860-0.920 g / cm produced using a metallocene catalyst^ThreeLinear ultra low density ethylene / α-olefin copolymer (Metalcenene-VLDPE), or
(2) Density 0.860-0.920 g / cm produced using metallocene catalyst^ThreeLinear ultra low density ethylene / α-olefin copolymer (Metalcenene-VLDPE) and a density of 0.955 to 0.970 g / cm^ThreeA high-density polyethylene (HDPE) mixed with the HDPE so that the HDPE content is 10% by weight or less.
Is used.
[0028]
On the other hand, when the aliphatic polyamide resin (II) is used for the first layer, that is, when the second multilayer film according to the present invention is produced,
(1) Density 0.860-0.920g / cm^ThreeA mixed resin of 30 to 70% by weight of a linear very low density ethylene / α-olefin copolymer (VLDPE) and 70 to 30% by weight of an unsaturated carboxylic acid-modified polyolefin (de-PE), or
(2) Density 0.860-0.920g / cm^ThreeLinear ultra-low density ethylene / α-olefin copolymer (VLDPE), unsaturated carboxylic acid-modified polyolefin (de-PE), and a density of 0.955 to 0.970 g / cm.^ThreeHigh-density polyethylene (HDPE), the content ratio of the VLDPE and the de-PE is 30:70 to 70:30 in a weight ratio, and the content ratio of the HDPE is 10% by weight or less of the whole Mixed resin
Is used.
[0029]
(In the case of the first multilayer film)
First, the second layer in the first multilayer film of the present invention will be described.
In the multilayer container disclosed in JP-A-10-59345 (the above-mentioned publication (d)), an ethylene / α-olefin copolymer layer constituting the inner and outer layers, and a cyclic olefin resin layer constituting the intermediate layer, For the purpose of bonding, linear ultra-low density polyethylene (VLDPE) is used.
[0030]
However, general-purpose VLDPE is produced by a low-pressure polymerization method using a Ziegler catalyst (Ziegler-VLDPE), and has a problem that moisture shielding is not sufficient. In order to maintain the shielding property, it is necessary to increase the thickness of the third layer (intermediate layer) for the purpose of improving the moisture and gas shielding properties. As a result, as will be described later, the cyclic olefin copolymer constituting the third layer is hard and brittle, resulting in a problem that the flexibility of the entire multilayer film is lowered.
[0031]
On the other hand, in the first multilayer film of the present invention, a layer composed of a cyclic olefin copolymer constituting the third layer and a layer composed of a linear ethylene / α-olefin copolymer constituting the first layer. Density of 0.860 to 0.920 g / cm produced using a metallocene catalyst^ThreeLinear ultra-low density ethylene / α-olefin copolymer (Metalcenene-VLDPE) or a mixed resin mainly composed of Metallocene-VLDPE is used.
[0032]
Here, the ethylene / α-olefin copolymer produced using a metallocene catalyst is a complex (metallocene) of a transition metal such as zirconium, hafnium, or titanium and cyclopentadienyl, indenyl, fluorenyl, or the like. It refers to a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms, which is produced as a catalyst. In the present invention, those which are linear and have an extremely low density are used.
The metallocene-VLDPE is different from the above-described Ziegler-VLDPE in that it has a certain amount of moisture shielding property, so that it is not necessary to make the third layer so thick, and the entire multilayer film has excellent flexibility. And impact resistance can be maintained.
[0033]
Regarding the difference in characteristics of the multilayer film and the container using the multilayer film when using Metallocene-VLDPE for the second layer and using Ziegler-VLDPE, Examples 1 and 2 described later and Comparative Examples It is clear by comparison with 3.
In the first multilayer film of the present invention, the metallocene-VLDPE used as the main component of the resin constituting the second layer has a density of 0.860 to 0.920 g / cm.^ThreeIt is required to be. When the density of Metallocene-VLDPE is less than the above range, there is a risk that the film-sealability is lowered. On the other hand, when the density exceeds the above range, flexibility may be reduced. The density of the copolymer is 0.890 to 0.915 g / cm, particularly in the above range.^ThreeIs preferred.
[0034]
The metallocene-VLDPE has a melt flow rate (MFR) of preferably 0.5 to 20 g / 10 minutes (190 ° C.), and more preferably 1 to 10 g / 10 minutes (190 ° C.).
Density is 0.860-0.920g / cm^ThreeAs a specific example of Metallocene-VLDPE, a metallocene linear ultra-low density ethylene / 1-hexene copolymer [trade name “Evolue”, density 0.901 g / cm, manufactured by Mitsui Chemicals, Inc.^Three, MFR 1.5 g / 10 min (190 ° C.)] and the like.
[0035]
For the resin constituting the second layer in the first multilayer film, the above-mentioned Metallocene-VLDPE is used alone, and for the purpose of increasing heat resistance and strength, a density of 0.955 to 0.970 g / cm as necessary.^ThreeHigh density polyethylene (HDPE) can be mixed.
In this case, the mixing ratio of the HDPE is set to be 10% by weight or less of the entire mixed resin constituting the second layer in the first multilayer film. Even if the mixing ratio of HDPE is larger than the above range, the improvement in the performance of the film cannot be expected, and the flexibility is lowered.
[0036]
Here, examples of the high-density polyethylene include copolymers with α-olefins having 3 to 12 carbon atoms in addition to ethylene homopolymers. In this case, the content ratio of the α-olefin is not particularly limited, but is usually set in the range of 0.1 to 5 mol%. The high density polyethylene preferably has an MFR of 1 to 30 g / 10 min (190 ° C.).
Density 0.955 to 0.970 g / cm^ThreeSpecific examples of high-density polyethylene include high-density polyethylene manufactured by Mitsui Chemicals (trade name “Hi-X”, density 0.965 g / cm^Three, MFR15g / 10min (190 ° C)), Idemitsu Petrochemical Co., Ltd. trade name "Idemitsu Polyethylene", Asahi Kasei Co., Ltd. trade name "Suntech", Showa Denko Co., Ltd. trade name "Shorex ", Trade name" STAFREN "manufactured by Nippon Petrochemical Co., Ltd., and the like.
[0037]
(In the case of the second multilayer film)
Next, the second layer in the second multilayer film of the present invention will be described.
In the second multilayer film of the present invention, an aliphatic polyamide resin excellent in impact resistance and gas shielding properties is adopted as the resin constituting the first layer. On the other hand, this aliphatic polyamide resin does not have sufficient moisture shielding properties. Therefore, for the second layer in the second multilayer film of the present invention, a resin having excellent gas shielding properties, moisture shielding properties, and impact resistance, such as Metallocene-VLDPE, is used. From the viewpoint of maintenance, this is a more preferable embodiment.
[0038]
However, the second layer in the multilayer film of the present invention is the second layer from the outermost layer when applied to a container such as a chemical solution container, and is a third layer excellent in gas and moisture shielding (described later). ) And a layer made of a resin excellent in moisture shielding property is provided on the fourth layer, which is inside the third layer, as will be described later. In addition, the outermost first layer aliphatic polyamide (particularly nylon) is a resin having relatively good impact resistance. Therefore, the second layer is not required to have a strict moisture shielding property or impact resistance, and a commonly used Ziegler-VLDPE or the like can be used.
[0039]
The aliphatic polyamide resin constituting the first layer in the second multilayer film has a feature that its weldability is not sufficient. Therefore, an unsaturated carboxylic acid-modified polyolefin (de-PE) may be mixed with the resin of the second layer intended for adhesion with the third layer in the above-described ratio for the purpose of improving the adhesiveness.
That is, as described above, the density of the second layer in the second multilayer film is 0.860 to 0.920 g / cm.^ThreeA mixed resin of 70 to 30% by weight of a linear ultra-low density ethylene / α-olefin copolymer (VLDPE) and 30 to 70% by weight of an unsaturated carboxylic acid-modified polyolefin (de-PE) is used.
[0040]
Here, as the linear ultra-low density ethylene / α-olefin copolymer (VLDPE), various conventionally known VLDPEs such as the above-mentioned Ziegler-VLDPE and Metallocene-VLDPE can be used. Examples of the α-olefin in the VLDPE include the same as those exemplified for the first multilayer film. The preferred range of melt flow rate (MFR) required for VLDPE is the same as previously shown for Metallocene-VLDPE.
[0041]
Examples of the unsaturated carboxylic acid-modified polyolefin (de-PE) include those obtained by grafting an unsaturated carboxylic acid such as maleic acid, acrylic acid or itaconic acid to a polyolefin such as polyethylene or polypropylene. Here, the mixing ratio of the unsaturated carboxylic acid is not particularly limited, but can be appropriately selected from the range of 35 to 55% by weight.
In the mixed resin constituting the second layer, when the mixing ratio of de-PE is less than the above range, a desired adhesive force cannot be exhibited. On the other hand, even if the mixing ratio of de-PE is larger than the above range, there is no significant change in the adhesive force, which causes a problem that the manufacturing cost is increased. The mixing ratio of VLDPE and de-PE in the mixed resin is preferably 60:40 to 40: 0 (weight ratio), particularly in the above range (70:30 to 30:70 by weight ratio).
[0042]
Density is 0.860-0.920g / cm^ThreeAs specific examples of VLDPE, a Ziegler catalyst linear ultra-low density ethylene / 1-butene copolymer manufactured by Mitsui Chemicals, Inc. [trade name “ Toughmer A0585X ", density 0.885 g / cm^Three, MFR 15 g / 10 min (190 ° C.)] and the like.
The mixed resin constituting the second layer in the second multilayer film further has a density of 0.955 to 0.970 g / cm as necessary for the purpose of increasing heat resistance and strength.^ThreeHigh density polyethylene (HDPE) can be mixed. In this case, the content ratio of VLDPE and de-PE is adjusted to be 70:30 to 30:70 by weight ratio.
[0043]
In this case, the mixing ratio of the HDPE is set to be 10% by weight or less of the entire mixed resin constituting the second layer in the second multilayer film. Even if the mixing ratio of HDPE is larger than the above range, the improvement in the performance of the film cannot be expected, and the flexibility is rather lowered.
Here, the high density polyethylene (HDPE) is the same as that exemplified for the first multilayer film. The preferred range of melt flow rate (MFR) required for HDPE is the same range as previously indicated.
[0044]
(Ratio of thickness of second layer)
The thickness ratio of the second layer is preferably 10 to 40% with respect to the thickness of the entire multilayer film. When the ratio of the thickness of the second layer is out of the above range, the flexibility of the multilayer film and the container using the multilayer film may be insufficient, or heat resistance and pinhole resistance may be deteriorated. The ratio of the thickness of the second layer is preferably 15 to 30% in the above range.
[0045]
[Third layer]
The third layer in the multilayer film of the present invention is required to maintain the strength of the multilayer film and to impart excellent gas shielding properties and moisture shielding properties to the multilayer film.
Therefore, a cyclic olefin copolymer (COC) is used as the resin constituting the third layer in the multilayer film of the present invention.
[0046]
Examples of the cyclic olefin copolymer include a copolymer of ethylene and dicyclopentadiene or norbornene compound, and a hydrogenated product thereof. Among these, it is preferable to use a hydrogenated product of a copolymer of ethylene and a norbornene compound.
As the hydrogenated product, for example, the general formula (1):
[0047]
[Chemical 1]

[0048]
(In formula (1), R¹And R²Are the same or different and each represents hydrogen, a hydrocarbon residue, or a polar group such as halogen, ester, nitrile, or pyridyl. R¹And R²May combine with each other to form a ring. m is an integer of 1 or more, and n is 0 or an integer of 1 or more. )
And / or general formula (2):
[0049]
[Chemical 2]

[0050]
(In formula (2), R^ThreeAnd R^FourAre the same or different and each represents hydrogen, a hydrocarbon residue, or a polar group such as halogen, ester, nitrile, or pyridyl. R^ThreeAnd R^FourMay combine with each other to form a ring. x and z are integers of 1 or more, and p is 0 or an integer of 1 or more. )
The polymer which has the structural unit represented by these can be mentioned.
The polymer having the structural unit represented by the general formula (1) is obtained by polymerizing one or more monomers by a known ring-opening polymerization method, and hydrogenating the ring-opened polymer thus obtained according to a conventional method. It is a thing.
[0051]
Specific examples of the polymer include a hydrogenated polymer manufactured by Nippon Zeon Co., Ltd. [trade name “ZEONOR”, specific gravity 1.01, MFR 70 g / 10 min (190 ° C.), glass transition temperature (Tg) 100 ° C.], A trade name “ARTON” manufactured by Nippon Synthetic Rubber Co., Ltd. can be mentioned.
The polymer having the structural unit represented by the general formula (2) is obtained by addition copolymerization of one or more norbornene monomers as a monomer and ethylene by a known method, and / or Or this is hydrogenated according to a conventional method.
[0052]
Specific examples of the polymer include [trade name “Apel 6509”, specific gravity 1.02, MFR 40 g / 10 min (190 ° C.), glass transition temperature (Tg) 80 ° C.], manufactured by Mitsui Chemicals, Inc., manufactured by TICONA For example, “TOPAS”.
Since the hydrogenated product of the copolymer including the polymer having the structural units represented by the general formulas (1) and (2) is a saturated polymer, in addition to gas shielding properties and moisture shielding properties, Excellent in heat resistance, transparency, and stability.
[0053]
The cyclic olefin copolymer used in the third layer has a glass transition temperature (T_g) Is preferably 70 ° C or higher, more preferably 80 to 150 ° C. The molecular weight range is preferably 10,000 to 100,000, preferably 20,000 to 50,000 in the number average molecular weight <Mn> measured by gel permeation chromatography (GPC) analysis using cyclohexane as a solvent. More preferred. When the unsaturated bond remaining in the molecular chain of the copolymer is saturated by hydrogenation, the hydrogenation rate is set to 90% or more, preferably 95% or more, particularly preferably 99% or more. Is done.
[0054]
In the third layer, the above-mentioned cyclic olefin copolymer may be used alone, or two or more kinds may be mixed and used. Moreover, even if it is the same kind, it is also possible to blend and use those having different molecular weights.
The thickness ratio of the third layer is preferably 3 to 15% with respect to the thickness of the entire multilayer film. When the ratio of the thickness of the third layer is less than the above range, the gas and moisture shielding properties of the multilayer film and the container using the multilayer film become insufficient. On the contrary, when the above range is exceeded, the flexibility of the multilayer film and the container using the multilayer film is impaired.
[0055]
[Fourth layer]
The fourth layer in the multilayer film of the present invention is flexible without sacrificing the gas and moisture shielding properties of the multilayer film, in addition to improving the adhesion between the aforementioned third layer and the fifth layer described later. Further, it is required to improve impact resistance and seal strength.
Therefore, in the resin constituting the fourth layer in the multilayer film of the present invention,
(1) Density 0.860-0.920 g / cm produced using a metallocene catalyst^ThreeLinear ultra low density ethylene / α-olefin copolymer (Metalcenene-VLDPE), or
(2) Density 0.860-0.920 g / cm produced using metallocene catalyst^ThreeLinear ultra low density ethylene / α-olefin copolymer (Metalcenene-VLDPE) and a density of 0.955 to 0.970 g / cm^ThreeA high-density polyethylene (HDPE) mixed with the HDPE so that the HDPE content is 10% by weight or less.
Is used.
[0056]
Such a resin is the same as the second layer in the first multilayer film of the present invention. The fourth layer in the multilayer film of the present invention is the second layer from the innermost layer when the multilayer film of the present invention is applied to a container such as a chemical solution container, and is the second layer excellent in gas and moisture shielding properties. Although located inside the three layers, sufficient gas and moisture shielding properties are required from the viewpoint of reinforcing the function of the third layer. Therefore, it is required to use Metallocene-VLDPE instead of Ziegler-VLDPE as the VLDPE used for the fourth layer.
[0057]
Problems when the density of Metallocene-VLDPE is outside the above range, more preferable range of density, specific examples, types of α-olefin, preferred range of melt flow rate (MFR), Metallocen-VLDPE (and de-PE) The mixing ratio of HDPE in the mixed resin comprising HDPE and HDPE is the same as that shown in the description of the second layer in the first multilayer film.
On the other hand, unlike the second layer in the first multilayer film, the ratio of the thickness of the fourth layer in the multilayer film of the present invention is required to be 35 to 65% with respect to the thickness of the entire multilayer film. That is, it is generally required to increase the ratio as compared with the second layer. Thereby, sufficient softness | flexibility and impact resistance can be provided to a multilayer film.
[0058]
When the ratio of the thickness of the fourth layer is less than the above range, the flexibility of the multilayer film is lowered. On the other hand, when the above range is exceeded, there arises a problem that the heat resistance of the multilayer film is lowered or the occurrence rate of pinholes at the heat seal portion is raised.
[Fifth layer]
The fifth layer in the multilayer film of the present invention is the innermost layer of the container of the present invention, and is required to be excellent in sealing properties and blocking resistance.
[0059]
Therefore, the resin constituting the fifth layer in the multilayer film of the present invention has a density of 0.930 to 0.950 g / cm.^ThreeThe linear ethylene / α-olefin copolymer (L-PE) is used.
Such a resin is the same as the first layer in the first multilayer film of the present invention. In addition, when the density of the linear ethylene / α-olefin copolymer (L-PE) is out of the above range, a more preferable range of density, a specific example, the type of α-olefin, a melt flow rate ( The preferred range of MFR) is the same as that shown in the description of the first layer.
[0060]
The ratio of the thickness of the fifth layer is preferably 3 to 15% with respect to the thickness of the entire multilayer film. When the ratio of the thickness of the fifth layer is less than the above range, the sealing property of the multilayer film is lowered, and the appearance of the container may be deteriorated. On the contrary, even if the thickness exceeds the above range, there is no significant change in the sealing property and blocking resistance, and the flexibility of the multilayer film may be lowered.
The ratio of the thickness of the fifth layer is particularly preferably 5 to 10% in the above range.
[0061]
[Method for producing multilayer film]
Next, the manufacturing method of the multilayer film of this invention is demonstrated.
In order to produce the multilayer film of the present invention, water-cooled or air-cooled coextrusion inflation method, coextrusion T-die method, dry lamination method, extrusion lamination method, etc. can be used. From the viewpoints of hygiene and the like, it is preferable to use the water-cooled coextrusion inflation method and the coextrusion T-die method.
[0062]
In either method, it is necessary to carry out at a temperature at which the resin of each layer melts. However, if the temperature is raised too much, a part of the resin undergoes thermal degradation, and there is a risk of performance degradation due to degraded products. Therefore, the temperature condition for producing the multilayer film of the present invention is usually 150 to 250 ° C., preferably 170 to 200 ° C.
The thickness of the film of the present invention produced as described above is generally 100 to 300 μm, preferably 200 to 300 μm, but can be appropriately increased or decreased depending on the purpose of use and the like, and a sufficient strength is maintained even at a thickness of about 80 μm. ing.
[0063]
(Embodiment of container)
Next, the container of this invention is demonstrated, referring FIG. 1 which shows the one embodiment.
FIG. 1 is a front view showing an example of a medical container (infusion bag).
The medical container 10 is obtained by cutting the two multilayer films of the present invention by an ordinary method, superimposing the respective fifth layers as inner layers, heat-sealing the peripheral edge 22, and further sealing the mouth member 20 by heat sealing or the like. Manufactured by mounting by means.
[0064]
Alternatively, the container 10 may be formed by heat-sealing the peripheral edge 22 after forming the tube with the fifth layer of the multilayer film inside.
Here, as a heat seal condition of the multilayer film, a temperature range of 130 to 200 ° C. can be adopted. For example, in the case of a film having a thickness of about 250 μm, the temperature range is about 0.5 to 6 Can be sealed in a short time of seconds.
For the mouth member 20, it is preferable to use a resin molded with a resin excellent in weldability with the fifth layer in the multilayer film of the present invention, for example, polyethylene. The heat sealing conditions when the mouth member 20 is made of polyethylene having a melting point of about 120 to 130 ° C. include preheating the mouth member for several seconds and then about 140 to 170 ° C. for about 0.5 to 5 seconds. You can heat with.
[0065]
【Example】
Hereinafter, the present invention will be described with reference to examples and comparative examples.
[Manufacture of multilayer films]
Examples 1-5 and Comparative Examples 1-3
Using the following resins A to G, a multilayer film having a five-layer structure was formed by a water-cooled coextrusion inflation method. The layer configuration of the multilayer film and the thickness of each layer in each example and comparative example are as shown in Table 1 below.
[0066]
(Resin used)
Resin A: Ziegler catalyst linear ethylene / 1-butene copolymer (L-PE) [Mitsui Chemicals, density 0.940 g / cm^Three, MFR 2.1 g / 10 min (190 ° C.), trade name “Ultzex 4020B”]] for the first layer or the fifth layer in the first multilayer film according to the present invention, for the fifth layer in the second multilayer film
Resin B1: Metallocene-catalyzed linear ultra low density ethylene / 1-hexene copolymer (Metalcenene-VLDPE) [Mitsui Chemicals, Density 0.901 g / cm^ThreeMFR 1.5 g / 10 min (190 ° C., trade name “Evolue”) ... for the second layer (1) or the fourth layer (1) in the first multilayer film, the fourth layer in the second multilayer film ( 1) For
Resin B2: 95% by weight of the above-mentioned resin B1 (Metalcene-VLDPE) and high-density polyethylene (HDPE) [Mitsui Chemicals, Inc., density: 0.965 g / cm^Three, MFR 15 g / 10 min (190 ° C., trade name “Hi-Zex”) mixed resin with 5% by weight. Second multilayer film for second layer (2) or fourth layer (2) in first multilayer film For the 4th layer (2)
Resin C: Ethylene / tetracyclododecene copolymer [Mitsui Chemicals, Inc., specific gravity 1.02, MFR 40 g / 10 min (190 ° C.), glass transition temperature (Tg) 80 ° C., trade name “Apel 6509”] ... For third layer in first and second multilayer films
Resin D: Nylon 6 (Ny) [manufactured by Toray Industries, Inc., trade name “Amilan”]... For first layer in second multilayer film
Resin E: Ziegler catalyst linear ultra-low density ethylene / 1-butene copolymer (Ziegler-VLDPE) [Mitsui Chemicals, Inc., density 0.885 g / cm^Three, MFR15g / 10min (190 ° C), trade name "Toughmer")
Resin E1: 50% by weight of the above-mentioned resin E (Ziegler-VLDPE), 45% by weight of maleic anhydride graft-modified polyethylene (trade name “Admer” manufactured by Mitsui Chemicals, Inc.), HDPE [the above-mentioned trade name “Hi-X” ]] 5% by weight of mixed resin ... for the second layer (2) in the second multilayer film
Resin E2: 50% by weight of the above-mentioned resin B1 (Metalcenene-VLDPE), 45% by weight of maleic anhydride graft-modified polyethylene [the above-mentioned trade name “Admer”], and HDPE [the above-mentioned trade name “Hi-X”] 5% % Mixed resin for second layer (2) in second multilayer film
Resin F: Linear ethylene / 1-butene copolymer (L-PE) [Mitsui Chemicals, Inc., density 0.930 g / cm^Three, MFR 2.1 g / 10 min (190 ° C), trade name "Ultzex 2030B"]
Resin G: Mixed resin of 20% by weight of the resin E (Ziegler-VLDPE), 75% by weight of the resin F (L-PE), and 5% by weight of HDPE (the above-mentioned trade name “Hi-X”).
In Table 1 below, “COC” is a cyclic olefin copolymer (ethylene tetracyclododecene copolymer in Examples and Comparative Examples), and “de-PE” is an unsaturated carboxylic acid-modified polyolefin. (In the Examples and Comparative Examples, maleic anhydride graft-modified polyethylene) is shown respectively.
[0067]
[Table 1]

[0068]
As is clear from Table 1, Examples 1, 2 and 3 correspond to the first multilayer film of the present invention. Examples 4 and 5 correspond to the second multilayer film of the present invention.
On the other hand, in Comparative Example 1, the content ratio of Metallocene-VLDPE in the resin (resin G) constituting the second layer and the fourth layer is small, and the resin used mixed with the Metallocene-VLDPE is not used. Since it is not a saturated carboxylic acid-modified polyolefin (de-PE) and the resin (resin F) constituting the third layer is not a cyclic olefin copolymer (COC), it does not fall under the multilayer film of the present invention. Comparative Example 2 does not correspond to the multilayer film of the present invention because the resin (resin F) constituting the third layer is not a cyclic olefin copolymer but an aliphatic polyamide resin. Moreover, although the resin (resin E) which comprises the 2nd layer and the 4th layer is a linear very low density ethylene * alpha-olefin copolymer (VLDPE), the comparative example 3 is not Metallocene-PE but Ziegler. -Since it is VLDPE, it does not correspond to the multilayer film of this invention.
[0069]
[Manufacture of containers]
Next, using the multilayer film obtained in Examples 1 to 5 and Comparative Examples 1 to 3, an infusion bag 10 having a width of 136 mm and a height of 270 mm as shown in FIG. 1 was produced. When the infusion bag 10 was molded, the peripheral portion was heat sealed at 155 ° C. for 4.5 seconds, and the mouth member 20 was sealed at 140 to 150 ° C. for 3 seconds. The infusion bag 10 was filled and sealed with 500 cc of distilled water, and the volume of the head space was adjusted to 50 cc.
[0070]
[Container performance test]
About the infusion bag 10 obtained using the multilayer film of Examples 1-5 and Comparative Examples 1-3, the evaluation test of various characteristics was done according to the following method.
(a) Heat resistance: An infusion bag 10 that has been subjected to high-pressure steam sterilization at 110 ° C. for 40 minutes is applied to the infusion bag 10 that is sealed and filled with 500 cc of distilled water and the head space is adjusted to 50 cc. The presence or absence of deformation, bag breakage, and seal leakage were visually observed.
[0071]
(b) Transparency: The light transmittance (%) at a wavelength of 450 nm after sterilization of the infusion bag 10 was measured.
(c) Impact resistance: After the infusion bag 10 is refrigerated at 4 ° C, the container is dropped 5 times from 3 directions from a height of 1.2m to check whether the infusion bag is broken or there is a seal leak. It was observed visually.
(d) Increase in head space: After the infusion bag 10 was left at 60 ° C. and 10% RH for 10 days (equivalent to being left at room temperature for 2 years), the increase in head space was measured.
[0072]
(e) Water loss amount: The infusion bag 10 was allowed to stand at 60 ° C. and 10% RH for 10 days, and then the water decrease amount in the container was determined by measuring the change in mass.
The test results are shown in Table 1.
In the evaluation of heat resistance and impact resistance, A + is very good, A is good (suitable for practical use), B is slightly defective (unsuitable for practical use), and C is defective.
[0073]
[Table 2]

[0074]
As is apparent from the results in Table 2, the containers (infusion bags) of Examples 1 to 5 have excellent heat resistance, impact resistance, and transparency characteristics, and the bag swells due to air intrusion. It was found that the problem of decrease in the content liquid due to moisture permeation was sufficiently suppressed.
On the other hand, although the infusion bag of Comparative Example 1 is excellent in the characteristics of the bag itself, the bag is significantly swollen due to the intrusion of air. In the infusion bag of Comparative Example 2, since the intermediate layer is nylon, the content liquid tends to decrease. In addition, the infusion bag of Comparative Example 3 uses Ziegler-catalyzed ultra-low density polyethylene as the adhesive resin, so the impact resistance is low, and pinholes are generated in the seal part of the mouth member after sterilization. In the drop test, many damaged parts occurred in the seal portion.
[Brief description of the drawings]
FIG. 1 is a front view showing an embodiment of a container of the present invention.

Claims (4)

A multilayer film consisting of five layers,
The first layer and the fifth layer are composed of a linear ethylene / α-olefin copolymer having a density of 0.930 to 0.950 g / cm ³ ,
The second layer and the fourth layer, and linear very low density ethylene · alpha-olefin copolymer having a density 0.860~0.920g / cm ³ produced by using the main Tarosen catalyst, density 0.955 a high density polyethylene ~0.970g / cm ^3, consist mixture comprising a resin as the content of the high-density polyethylene is the total 10% by weight or less, and,
Ri third layer Do from cyclic olefin copolymer,
The thickness of the entire multilayer film is 100 to 300 μm,
The ratio of the thickness of each layer is relative to the thickness of the entire film.
1st layer: 5-20%,
Second layer: 10-40%,
3rd layer: 3-15%,
4th layer: 35-65%,
5th layer: 3-15%
Is a multilayer film. A multilayer film consisting of five layers,
The first layer is made of an aliphatic polyamide resin,
The second layer comprises (1) 70-30% by weight of a linear ultra-low density ethylene / α-olefin copolymer having a density of 0.860-0.920 g / cm ³ and an unsaturated carboxylic acid-modified polyolefin 30-70. (2) a linear ultra-low density ethylene / α-olefin copolymer having a density of 0.860 to 0.920 g / cm ³ , an unsaturated carboxylic acid-modified polyolefin, and a density of 0 .955 to 0.970 g / cm ³ of high-density polyethylene, and the content ratio of the linear ultra-low density ethylene / α-olefin copolymer and the unsaturated carboxylic acid-modified polyolefin is 70:30 by weight. It is made of a resin obtained by mixing so that the content ratio of the high-density polyethylene is 10% by weight or less based on the total density of about 30:70
The third layer is made of a cyclic olefin copolymer,
The fourth layer is either (1) a linear ultra-low density ethylene / α-olefin copolymer having a density of 0.860 to 0.920 g / cm ³ produced using a metallocene catalyst, or (2) a metallocene. Linear ultra-low density ethylene / α-olefin copolymer having a density of 0.860 to 0.920 g / cm ³ and high density polyethylene having a density of 0.955 to 0.970 g / cm ³ produced using a catalyst And a resin that is mixed so that the content of the high-density polyethylene is 10% by weight or less of the whole, and
A multilayer film comprising a linear ethylene / α-olefin copolymer having a density of 0.930 to 0.950 g / cm ^{3 in} the fifth layer.   The multilayer film according to claim 1 or 2, wherein the cyclic olefin copolymer is a hydrogenated product of a copolymer of ethylene and cyclic olefin. A container using the multilayer film according to any one of claims 1 to 3 , wherein a first layer of the multilayer film is an outer layer and a fifth layer is an inner layer.

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