JP2004136907A

JP2004136907A - Gas barrier container, method and apparatus for manufacturing the same

Info

Publication number: JP2004136907A
Application number: JP2002301479A
Authority: JP
Inventors: Takahiro Harada; 原田　隆宏; Hidemi Nakajima; 中島　英実; Tsutomu Shirai; 白井　励; Naoto Kusaka; 日下　直人
Original assignee: Toppan Printing Co Ltd
Current assignee: Toppan Inc
Priority date: 2002-10-16
Filing date: 2002-10-16
Publication date: 2004-05-13
Anticipated expiration: 2022-10-16
Also published as: JP4007149B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a container with a three-dimensional shape such as a bottle which is colorless and has high transparency and high gas barrier properties without using a plasma CVD method having such a problem as adhesion of a film, and to provide a method and an apparatus for manufacturing it. <P>SOLUTION: Plasma is generated on the inner face of the container by the method for manufacturing the container, ions fed from the plasma are accelerated by a high voltage pulse applied from the external face of the container, and implanted on the inner face of the container. The method for manufacturing the gas barrier container is characterized by that the electric voltage of the high voltage pulse is a negative voltage, and its absolute value is at least 2 kV, and starting-up of the voltage of the high voltage pulse is ≥1 kV/1 μs in its absolute value in the negative direction. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明はガスバリア性を有する、ボトルなどの３次元形状の容器とその製造方法並びにその製造装置に関する。
【０００２】
【従来の技術】
従来、軽量且つ耐衝撃性に強いため、ＰＥＴボトルに代表される高分子樹脂製の３次元容器が広範に使われている。最近、酸素、水蒸気の気体遮断性（以下バリア性と称す）に優れた飲料容器として、容器内面或いは外面にダイヤモンドライクカーボン（以下ＤＬＣとする）に代表される硬質炭素膜や酸化珪素（ＳｉＯｘ）膜のコーティングを施したＰＥＴボトルが提案された（特許文献１、２参照）。これらのコーティングＰＥＴボトルは、二酸化炭素のバリア性にも優れているため炭酸飲料、ビール等にも採用されつつある。
【０００３】
これらのコーティング処理は、真空装置内にＰＥＴボトルを挿入し真空排気した後に、反応ガスをボトル内面に導入して外部から電圧やマイクロ波による電磁界エネルギーを加えてボトル内空間にプラズマを発生、反応ガスの化学反応により薄膜成長させる、いわゆるプラズマＣＶＤ法により、ボトル内面にバリア層を形成する。これらの方法は、極めて高い光透過性とバリア性を有する。
【０００４】
一方、プラズマＣＶＤ法以外のバリア性付与の方法として、高分子樹脂容器の内部にプラズマを発生させると同時に内部に施設した電極により高電圧のパルスを印加し、高分子樹脂容器内面にイオン照射して樹脂表面をＤＬＣ等の硬質炭素膜に改質しバリア性を付与することが提案された（特許文献３参照）。
この技術では、前述のプラズマＣＶＤ法による硬質炭素膜の膜剥がれを防止し、密着性の非常に良好な信頼性の高いバリア性を有する容器を提供できるとされている。
【０００５】
しかし、上記の技術では以下の様な問題がある。前者は、反応容器内で反応ガスを化学反応させて薄膜を成長させるため、反応ガス自体を導入する機構を必要とする。また薄膜成長させるため反応容器内で膜付着が起こり、長時間運転すると大気解放する際に付着した膜が剥離し高分子樹脂容器に付着する。硬質炭素膜では茶色に着色し無色透明とはならない。
【０００６】
後者は、膜付着が起こらないが高分子樹脂容器の内面の表面改質により硬質炭素化させるため、茶色に着色し、無色透明とはならない。
【０００７】
【特許文献１】
特許第２７８８４１２号公報
【特許文献２】
特開２００１−３１０９６０号公報
【特許文献３】
特開２００２−４６７２６号公報
【０００８】
【発明が解決しようとする課題】
本発明では、前述した膜の付着などが問題となるプラズマＣＶＤ法を用いることなく、着色がなく、高透明性、高いガスバリア性のある、ボトルなどの３次元形状の容器及びその製造方法並びにその製造装置を提供することにある。
【０００９】
【課題を解決するための手段】
請求項１の発明は、イオン注入することにより、容器の内面の最表面より１μｍ以下に高密度層を形成されてなることを特徴とする請求項１記載のガスバリア性容器である。
【００１０】
請求項２の発明は、前記注入されるイオンが、窒素、酸素、水素、及び希ガスの少なくとも１種類を含むことを特徴とする請求項１記載のガスバリア性容器である。
【００１１】
請求項３の発明は、容器の内面にプラズマを発生させ、該容器内面にプラズマから供給されるイオンを容器外面から印加した高電圧パルスにより加速しイオン注入する容器の製造方法であって、該高電圧パルスの電圧が、負の電圧であり絶対値が２ｋＶより大きい電圧で、かつ該高電圧パルス電圧の立ち上がりが、負の方向で１μｓ当たり絶対値が１ｋＶ以上であることを特徴とするガスバリア性容器の製造方法である。
【００１２】
請求項４の発明は、前記高電圧パルス電圧の立ち下がりが、１μｓ当たり絶対値が１ｋＶ以上であることを特徴とする請求項３記載のガスバリア性容器の製造方法である。
【００１３】
請求項５の発明は、前記容器内面に発生させるプラズマが、空気、窒素、酸素、二酸化炭素、水素、及び希ガスの少なくとも１種類を含む気体で構成されることを特徴とする請求項３または４記載のガスバリア性容器の製造方法である。
【００１４】
請求項６の発明は、少なくとも、チャンバーと該チャンバー内に容器を具備し、かつ該チャンバーが外部電極を兼ねており、該チャンバー内及び該容器内を真空排気する手段を有し、該容器内にガス導入可能な内部電極を備え、該容器内にプラズマを発生させるプラズマ発生用交流電源と、負の電圧であり絶対値が２ｋＶより大きい電圧を印加可能であり、かつ該高電圧パルス電圧の立ち上がりが、負の方向で１μｓ当たり絶対値が１ｋＶ以上、立ち下がりが１μｓ当たり絶対値が１ｋＶ以上の動作が可能な高電圧パルス電源を有することを特徴とするガスバリア性容器の製造装置である。
【００１５】
請求項７の発明は、少なくとも、チャンバーと該チャンバー内に容器を具備し、該チャンバー内及び該容器内を真空排気する手段を有し、該チャンバーの内側または外側に外部電極を有し、該容器内にガス導入可能な内部電極を備え、該容器内にプラズマを発生させるプラズマ発生用交流電源と、負の電圧であり絶対値が２ｋＶより大きい電圧を印加可能であり、かつ該高電圧パルス電圧の立ち上がりが、負の方向で１μｓ当たり絶対値が１ｋＶ以上、立ち下がりが１μｓ当たり絶対値が１ｋＶ以上の動作が可能な高電圧パルス電源を有することを特徴とするガスバリア性容器の製造装置である。
【００１６】
請求項８の発明は、前記プラズマ発生用交流電源の出力部と高電圧パルス電源の出力部が、前記外部電極と、高周波の相互干渉を防止するフィルタ回路を介して接続されていることを特徴とする請求項６または７記載のガスバリア性容器の製造装置である。
【００１７】
【発明の実施の形態】
以下、本発明の一実施例について図面を用いて詳細に説明する。
図１に本発明に関する装置の一実施例として、本発明に関わるガスバリア性容器の製造装置を示す。
【００１８】
チャンバー１内に容器２を具備し、真空容器内を排気するため、補助真空容器３を挟んだ反対側にある真空排気系４を備える。図１の形態においては、チャンバーは導電材料からなり、非導電性碍子６により、電気的に非接地（浮遊状態）にある。所望の圧力に到達した後、プラズマ発生用電源７により高周波相互干渉防止用フィルタ兼マッチングボックス９を介して高周波電力が供給されて、容器２内にプラズマを発生させる。
また、チャンバーは絶縁性の材料からなり、チャンバーの内または外側に外部電極を設けても良い。
【００１９】
本発明では、プラズマ発生用電源７により高周波電圧を容器内に印加し、プラズマを発生させ、高電圧パルス電源８により発生したプラズマ中のイオンを加速させ、容器内表面に注入する。
高周波相互干渉防止用フィルタ兼マッチングボックス９は、プラズマ発生用電源７と高電圧パルス電源８が共に交流成分を持つため相互干渉することから、電源を保護し安定した出力を可能とするため必要である。特に高周波になる程この傾向は強く出るため必須となる。この時、チャンバー１、及び容器２内の圧力は０．１Ｐａ〜１０Ｐａ程度の圧力が好ましい。
【００２０】
本発明に用いられる容器としては、例えば高分子樹脂製等の容器が挙げられる。中でもポリエチレンテレフタレート（ＰＥＴ）等のポリエステルからなる容器を好適に用いることができる。また容器の形状は特に限定するものではないが、ボトル形状のものなどを用いることができる。
【００２１】
本発明では、前記容器のバリア性付与のための手段として、排気時における残留空気でもイオン注入は可能であるが、一度上記圧力以下に排気した後、ガス導入系５を介して、イオン注入の原料となる気体を導入することができる。導入する気体としては特に限定するものではなく、目的に応じて様々なものを用いることができるが、例えば、乾燥空気、窒素、酸素、二酸化炭素、水素、及び希ガスの少なくとも１種類を含む気体で構成されるガスを導入し、上記圧力域でプラズマを発生させたることができる。
【００２２】
次に、イオン注入について説明する。
容器２内にプラズマを発生させた後、高電圧パルス電源８により高周波相互干渉防止用フィルタ兼マッチングボックス９を介して高電圧パルスが金属製の真空容器１に印加されると、容器２内のプラズマ中にあるイオンが、この高電圧によって加速され、高エネルギーのイオンが容器２の内表面に注入される。
この時イオンを容器に注入させるため、負の電圧をかけ、加速させる必要がある。この高電圧パルスは、電圧が負の電圧で絶対値が２ｋＶ、より好ましくは５ｋＶより大きい電圧であり、且つパルス電圧の立ち上がりが、負の方向で１μｓ当たり絶対値で１ｋＶ以上、より好ましくは１０ｋＶ以上の高速の立ち上がりであり、また立ち下がりが１μｓ当たり絶対値で１ｋＶ以上、より好ましくは１０ｋＶ以上の高速の立ち下がりであることが本発明では重要である。
【００２３】
図２に示すように、イオン加速用の電圧が負の電圧で絶対値が２ｋＶより小さいとイオンによる容器２の内表面をスパッタリングすることになり、表面を削ると同時にイオン注入は行われない。
更に、容器２として高分子樹脂を用いる場合、内表面の樹脂を分解するため硬質炭素の層に改質するため、バリア性の発現が可能であっても着色し、無色透明とすることは出来ない。
【００２４】
このスパッタリングが起こる電圧よりも高電圧を印加する場合、立ち上がり・立ち下がりの過程で必ずこの領域の電圧を通過することとなるため、パルスの立ち上がり・立ち下がり動作が緩慢では、スパッタリングが起こり、また着色することとなる。よって、パルスの立ち上がり・立ち下がり動作を極めて短くする必要がある。本発明においては、パルス電圧の立ち上がりを負の方向で１μｓ当たり絶対値で１ｋＶ以上、より好ましくは１０ｋＶ以上の高速の立ち上がりであり、また立ち下がりが１μｓ当たり絶対値で１ｋＶ以上、より好ましくは１０ｋＶ以上の高速の立ち下がりとすることにより、イオン注入によるバリアー性付与と無色透明を可能とする。なお、この範囲で行えば、フィルムのＤＬＣ化している部分が１０％以下、好ましくは５％以下にすることができる。
【００２５】
また、本発明では、加速電圧によりイオンの注入深さを制御できる。最も効果が現れるのが表面から１μｍ以内であり、これ以上深く注入するには、大掛かりな加速器などが必要であり困難である。また、イオンの注入深さは、イオンの質量、半径、運動エネルギーと容器に用いる高分子樹脂の種類などの材質によるが、容器２に高分子樹脂を用いるとすると、高分子樹脂は概ね炭素、水素、酸素、窒素から構成されており、どの材質を用いてもほぼ同じ深さに注入できる。
また、加速電圧が大きいほど深い位置に注入可能であるが、高分子樹脂内での散乱もあり注入域は広がる。この点からも、パルス電圧の立ち上がり・立ち下がり動作を極めて短くすることにより、注入域を狭められ高密度層を形成しやすいのでバリア性が発現しやすい。
また、高密度層は、注入されたイオンが、高分子樹脂などの容器２を構成する材料と、何らかの相互作用を持ちながら存在することによりできると考えられる。
【００２６】
プラズマ発生用の電力と高電圧パルスは、同時に印加しても、交互に印加しても良く、任意の条件で可能である。典型的な例として交互に印加した場合を図３に示す。プラズマ発生用電源、高電圧パルス電源は共に上記の条件を満たせば市販のものが使用できる。プラズマ発生用電源は、周波数１３．５６ＭＨｚの高周波電源が価格、プラズマ発生の安定性からも好適である。高電圧パルス電源は、例えばハイデン研究所のＰＨＦ−２Ｋ型やＳＢＰ−５Ｋ−ＨＦ型、栗田製作所３Ｄ・ＰＢＩＩ型などが好適である。
【００２７】
【実施例】
以下に製造したガスバリア性容器の実施例を示す。
【００２８】
＜実施例１＞
容器２として、５００ｍｌのＰＥＴボトルを使用し、図１の装置で１×１０^−２Ｐａまで排気した後、窒素ガスを導入し真空容器内を圧力５Ｐａにした。１３．５６ＭＨｚの高周波電源で間欠的に電力を５００Ｗ印加し、交互に高電圧パルス−２０ｋＶで、パルス電圧の立ち上がり、立ち下がりを−２０Ｋｖ／μｓ、２０Ｋｖ／μｓで印加し、約６０秒間イオン注入した。ボトルを大気に取り出し、目視により着色の有無を評価し、バリア性を酸素透過率測定装置（ＭＯＣＯＮ社製、ＯＸ−ＴＲＡＮ１０／５０）で評価した。目視の結果、着色は認められず高い透明性を有し、酸素透過率は０．００７ｃｃ／ｐｋｇ／ｄａｙであり、処理前のＰＥＴボトルの酸素透過率０．０７ｃｃ／ｐｋｇ／ｄａｙの約１０倍に向上した。また、イオンの注入深さは、ＳＩＭＳ（Ｓｅｃｏｎｄａｒｙ　Ｉｏｎ　Ｍａｓｓ　Ｓｐｅｃｔｒｏｓｃｏｐｙ）により測定したところ、１〜３０ｎｍに相当すると思われた。
【００２９】
＜実施例２＞
容器２として、５００ｍｌのＰＥＴボトルを使用し、図１の装置で１×１０^−２Ｐａまで排気した後、二酸化炭素ガスを導入し真空容器内を圧力５Ｐａにした。１３．５６ＭＨｚの高周波電源で間欠的に電力を５００Ｗ印加し、交互に高電圧パルス−２０ｋＶで、パルス電圧の立ち上がり、立ち下がりを−２０Ｋｖ／μｓ、２０Ｋｖ／μｓで印加し、約６０秒間イオン注入した。ボトルを大気に取り出し、目視の結果、着色は認められず高い透明性を有し、酸素透過率は０．００９ｃｃ／ｐｋｇ／ｄａｙであり、処理前のＰＥＴボトルの酸素透過率０．０７ｃｃ／ｐｋｇ／ｄａｙの約１０倍に向上した。また、イオンの注入深さは、ＳＩＭＳ（Ｓｅｃｏｎｄａｒｙ　Ｉｏｎ　Ｍａｓｓ　Ｓｐｅｃｔｒｏｓｃｏｐｙ）により測定したところ、１〜３０ｎｍに相当すると思われた。
【００３０】
＜実施例３＞
容器２として、５００ｍｌのＰＥＴボトルを使用し、図１の装置で１×１０^−２Ｐａまで排気した後、乾燥空気を導入し真空容器内を圧力７Ｐａにした。１３．５６ＭＨｚの高周波電源で間欠的に電力を５００Ｗ印加し、交互に高電圧パルス−２０ｋＶで、パルス電圧の立ち上がり、立ち下がりを−２０Ｋｖ／μｓ、２０Ｋｖ／μｓで印加し、約６０秒間イオン注入した。ボトルを大気に取り出し、目視の結果、着色は認められず高い透明性を有し、酸素透過率は０．０１０ｃｃ／ｐｋｇ／ｄａｙであり、処理前のＰＥＴボトルの酸素透過率０．０７ｃｃ／ｐｋｇ／ｄａｙの約１０倍に向上した。また、イオンの注入深さは、ＳＩＭＳ（Ｓｅｃｏｎｄａｒｙ　Ｉｏｎ　Ｍａｓｓ　Ｓｐｅｃｔｒｏｓｃｏｐｙ）により測定したところ、１〜３０ｎｍに相当すると思われた。
【００３１】
＜比較例１＞
容器２として、５００ｍｌのＰＥＴボトルを使用し、図１の装置で１×１０^−２Ｐａまで排気した後、乾燥空気を導入し真空容器内を圧力７Ｐａにした。１３．５６ＭＨｚの高周波電源で間欠的に電力を５００Ｗ印加し、交互に高電圧パルス−１ｋＶで、パルス電圧の立ち上がり、立ち下がりを−１Ｋｖ／μｓ、１Ｋｖ／μｓで印加し、約６０秒間イオン注入した。大気に取り出し、目視の結果、薄茶色の着色があり、酸素透過率は０．０７ｃｃ／ｐｋｇ／ｄａｙであり、処理前のＰＥＴボトルの酸素透過率０．０７ｃｃ／ｐｋｇ／ｄａｙと同等の値を示した。また、イオンの注入深さは、ＳＩＭＳ（Ｓｅｃｏｎｄａｒｙ　Ｉｏｎ　ＭａｓｓＳｐｅｃｔｒｏｓｃｏｐｙ）により測定したところ、見られなかった。
【００３２】
＜比較例２＞
容器２として、５００ｍｌのＰＥＴボトルを使用し、図１の装置で１×１０^−２Ｐａまで排気した後、乾燥空気を導入し真空容器内を圧力７Ｐａにした。１３．５６ＭＨｚの高周波電源で間欠的に電力を５００Ｗ印加し、交互に高電圧パルス−２０ｋＶを印加させ、約６０秒間イオン注入した。この際、パルス電圧の立ち上がりを−０．５ｋＶ／１μｓ、立ち下がりを０．５ｋＶ／１μｓとした。大気に取り出し、目視の結果、薄茶色の着色があり、酸素透過率は０．０７ｃｃ／ｐｋｇ／ｄａｙであり、処理前のＰＥＴボトルの酸素透過率０．００７ｃｃ／ｐｋｇ／ｄａｙと処理前のＰＥＴボトルの酸素透過率０．０７ｃｃ／ｐｋｇ／ｄａｙの約１０倍に向上した。
【００３３】
【発明の効果】
以上詳述したように、本発明の方法によれば、ボトルなどの容器の内面に高速の高電圧パルスを印加してイオン注入することにより、プラズマＣＶＤ法、従来のイオン注入法と比較して無色透明で高いガス遮断性を有するガスバリア性容器の製造方法と製造装置、及び製造されたガスバリア性容器を提供できる。
【００３４】
【図面の簡単な説明】
【図１】本発明に関するバリア性容器の一例を示す装置の説明図である
【図２】本発明に関する説明図で、イオン加速電圧と固体表面の効果を説明する説明図である。
【図３】本発明に関する説明図で、プラズマ発生用の電力と高電圧パルスの出力の時間変化を説明する説明図である。
【符号の説明】
１　　　チャンバー
２　　　容器
３　　　補助真空容器
４　　　真空排気系
５　　　ガス導入系
６　　　非伝導性碍子
７　　　プラズマ発生用電源
８　　　高電圧パルス電源
９　　　高周波相互干渉防止用フィルタ兼マッチングボックス[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a three-dimensionally shaped container such as a bottle having gas barrier properties, a method for manufacturing the same, and an apparatus for manufacturing the same.
[0002]
[Prior art]
BACKGROUND ART Conventionally, polymer resin three-dimensional containers represented by PET bottles have been widely used because of their light weight and high impact resistance. Recently, as a beverage container having an excellent barrier property against oxygen and water vapor (hereinafter referred to as a barrier property), a hard carbon film represented by diamond-like carbon (hereinafter referred to as DLC) or silicon oxide (SiOx) is provided on the inner surface or outer surface of the container. A PET bottle coated with a film has been proposed (see Patent Documents 1 and 2). These coated PET bottles are also being used in carbonated beverages, beer, etc. because of their excellent carbon dioxide barrier properties.
[0003]
In these coating processes, after inserting a PET bottle into a vacuum device and evacuating, a reaction gas is introduced into the inner surface of the bottle, and a voltage or microwave electromagnetic field energy is applied from outside to generate plasma in the bottle space. A barrier layer is formed on the inner surface of the bottle by a so-called plasma CVD method in which a thin film is grown by a chemical reaction of a reaction gas. These methods have extremely high light transmission and barrier properties.
[0004]
On the other hand, as a method of imparting a barrier property other than the plasma CVD method, a plasma is generated inside the polymer resin container, and at the same time, a high voltage pulse is applied by an electrode provided inside, and ions are irradiated to the polymer resin container inner surface. It has been proposed to modify the resin surface to a hard carbon film such as DLC to impart a barrier property (see Patent Document 3).
According to this technique, the hard carbon film is prevented from peeling off by the above-mentioned plasma CVD method, and it is possible to provide a container having very good adhesion and a highly reliable barrier property.
[0005]
However, the above technique has the following problems. The former requires a mechanism for introducing the reaction gas itself in order to grow the thin film by chemically reacting the reaction gas in the reaction vessel. In addition, film deposition occurs in the reaction container for growing a thin film, and when the device is operated for a long time, the film adheres when released to the atmosphere, and adheres to the polymer resin container. The hard carbon film is colored brown and does not become colorless and transparent.
[0006]
Although the latter does not cause film adhesion, it is hard carbonized by surface modification of the inner surface of the polymer resin container, so that it is colored brown and is not colorless and transparent.
[0007]
[Patent Document 1]
Japanese Patent No. 2788412 [Patent Document 2]
JP 2001-310960 A [Patent Document 3]
JP-A-2002-46726
[Problems to be solved by the invention]
In the present invention, a three-dimensional container such as a bottle, a method for producing the same, and a method for producing the three-dimensional container without coloring, having high transparency and high gas barrier properties, without using the plasma CVD method in which the above-described film adhesion and the like are problematic. It is to provide a manufacturing apparatus.
[0009]
[Means for Solving the Problems]
The invention according to claim 1 is the gas barrier container according to claim 1, wherein a high-density layer is formed at 1 μm or less from the outermost surface of the inner surface of the container by ion implantation.
[0010]
The invention according to claim 2 is the gas barrier container according to claim 1, wherein the implanted ions include at least one of nitrogen, oxygen, hydrogen, and a rare gas.
[0011]
The invention according to claim 3 is a method for manufacturing a container which generates plasma on the inner surface of the container, accelerates ions supplied from the plasma on the inner surface of the container by a high voltage pulse applied from the outer surface of the container, and implants the ions. A gas barrier characterized in that the voltage of the high-voltage pulse is a negative voltage and a voltage whose absolute value is larger than 2 kV, and the rising of the high-voltage pulse voltage is 1 kV or more per 1 μs in the negative direction. This is a method for producing a conductive container.
[0012]
The invention according to claim 4 is the method for manufacturing a gas barrier container according to claim 3, wherein the fall of the high voltage pulse voltage has an absolute value of 1 kV or more per 1 μs.
[0013]
The invention according to claim 5 is characterized in that the plasma generated on the inner surface of the container is composed of a gas containing at least one of air, nitrogen, oxygen, carbon dioxide, hydrogen, and a rare gas. 5. A method for producing a gas barrier container according to item 4.
[0014]
The invention according to claim 6 comprises at least a chamber and a container in the chamber, and the chamber also serves as an external electrode, and has means for evacuating the inside of the chamber and the inside of the container. A plasma generating AC power supply for generating a plasma in the vessel, a negative voltage having an absolute value greater than 2 kV, and a high voltage pulse voltage. An apparatus for manufacturing a gas barrier container, comprising: a high voltage pulse power supply capable of operating with an absolute value of 1 kV or more per 1 μs in a negative rising direction and an absolute value of 1 kV or more per 1 μs in a falling direction.
[0015]
The invention according to claim 7 includes at least a chamber and a container in the chamber, has means for evacuating the inside of the chamber and the inside of the container, and has an external electrode inside or outside the chamber, An internal electrode capable of introducing a gas into the container, an AC power supply for generating plasma in the container, and a high voltage pulse capable of applying a negative voltage and an absolute value greater than 2 kV; An apparatus for manufacturing a gas barrier container, comprising: a high-voltage pulse power supply capable of operating such that an absolute value of a voltage is 1 kV or more per 1 μs in a negative direction and an absolute value is 1 kV or more per 1 μs in a negative direction. is there.
[0016]
The invention according to claim 8 is characterized in that the output section of the AC power supply for plasma generation and the output section of the high-voltage pulse power supply are connected to the external electrode via a filter circuit for preventing high-frequency interference. An apparatus for manufacturing a gas barrier container according to claim 6 or 7.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows an apparatus for manufacturing a gas barrier container according to the present invention as an embodiment of the apparatus according to the present invention.
[0018]
A chamber 2 is provided in the chamber 1, and a vacuum exhaust system 4 is provided on the opposite side of the auxiliary vacuum vessel 3 to exhaust the inside of the vacuum vessel. In the embodiment of FIG. 1, the chamber is made of a conductive material and is electrically non-grounded (floating state) by the non-conductive insulator 6. After reaching the desired pressure, high-frequency power is supplied from the plasma generation power supply 7 via the high-frequency mutual interference prevention filter and matching box 9 to generate plasma in the container 2.
Further, the chamber may be made of an insulating material, and an external electrode may be provided inside or outside the chamber.
[0019]
In the present invention, a high frequency voltage is applied to the inside of the container by the plasma generating power source 7 to generate plasma, and ions in the plasma generated by the high voltage pulse power source 8 are accelerated and injected into the inner surface of the container.
The high-frequency mutual interference prevention filter / matching box 9 is necessary for protecting the power supply and enabling stable output since the plasma generation power supply 7 and the high-voltage pulse power supply 8 both have an AC component and thus interfere with each other. is there. In particular, this tendency becomes stronger as the frequency becomes higher, so it is essential. At this time, the pressure in the chamber 1 and the container 2 is preferably about 0.1 Pa to 10 Pa.
[0020]
Examples of the container used in the present invention include a container made of a polymer resin or the like. Above all, a container made of polyester such as polyethylene terephthalate (PET) can be preferably used. The shape of the container is not particularly limited, but a bottle shape or the like can be used.
[0021]
In the present invention, as a means for imparting the barrier property of the container, ion implantation can be performed even with residual air at the time of evacuation. However, once the pressure is reduced to the pressure or lower, the ion implantation is performed via the gas introduction system 5. A gas serving as a raw material can be introduced. The gas to be introduced is not particularly limited, and various gases can be used depending on the purpose. For example, a gas containing at least one of dry air, nitrogen, oxygen, carbon dioxide, hydrogen, and a rare gas Can be introduced to generate plasma in the above pressure range.
[0022]
Next, ion implantation will be described.
After the plasma is generated in the container 2, when a high-voltage pulse is applied to the metal vacuum container 1 by the high-voltage pulse power supply 8 through the high-frequency mutual interference prevention filter and matching box 9, The ions in the plasma are accelerated by the high voltage, and high-energy ions are injected into the inner surface of the container 2.
At this time, in order to inject ions into the container, it is necessary to apply a negative voltage and accelerate the ions. The high-voltage pulse is a voltage having a negative voltage and an absolute value of 2 kV, more preferably a voltage of more than 5 kV, and a rising of the pulse voltage in a negative direction of 1 kV or more in absolute value per 1 μs, more preferably 10 kV. It is important in the present invention that the above-mentioned high-speed rising and the falling are high-speed falling of 1 kV or more, more preferably 10 kV or more, in absolute value per 1 μs.
[0023]
As shown in FIG. 2, when the voltage for ion acceleration is a negative voltage and the absolute value is smaller than 2 kV, the inner surface of the container 2 is sputtered by the ions, and the ion is not implanted at the same time as the surface is shaved.
Further, when a polymer resin is used for the container 2, the resin on the inner surface is reformed into a hard carbon layer to decompose the resin, so that even if the barrier property can be developed, it can be colored and made colorless and transparent. Absent.
[0024]
When a voltage higher than the voltage at which this sputtering occurs is applied, the voltage in this region must be passed during the rising / falling process, so if the rising / falling operation of the pulse is slow, sputtering occurs, and It will be colored. Therefore, it is necessary to make the rising and falling operations of the pulse extremely short. In the present invention, the rising of the pulse voltage is a high-speed rising of 1 kV or more in absolute value per 1 μs in the negative direction, more preferably 10 kV or more, and the falling is 1 kV or more in absolute value per 1 μs, more preferably 10 kV. With the above-mentioned high-speed falling, it is possible to impart a barrier property by ion implantation and to achieve colorless and transparent. If performed in this range, the DLC portion of the film can be reduced to 10% or less, preferably 5% or less.
[0025]
Further, in the present invention, the ion implantation depth can be controlled by the acceleration voltage. The effect is most effective within 1 μm from the surface, and it is difficult to implant deeper than this because a large-scale accelerator is required. The ion implantation depth depends on materials such as the mass, radius, kinetic energy of the ions, and the type of the polymer resin used for the container. However, when the polymer resin is used for the container 2, the polymer resin is substantially carbon, It is composed of hydrogen, oxygen and nitrogen, and can be implanted at almost the same depth using any material.
The higher the acceleration voltage, the deeper the injection can be. However, the injection area is widened due to scattering in the polymer resin. From this point as well, by extremely shortening the rising and falling operations of the pulse voltage, the injection region is narrowed and a high-density layer is easily formed, so that the barrier property is easily developed.
Further, it is considered that the high-density layer is formed by the presence of the implanted ions while having some kind of interaction with the material constituting the container 2 such as a polymer resin.
[0026]
The power for generating plasma and the high voltage pulse may be applied simultaneously or alternately, and can be applied under any conditions. FIG. 3 shows a typical example in which the voltage is applied alternately. As the power source for plasma generation and the high-voltage pulse power source, commercial products can be used as long as the above conditions are satisfied. As the power supply for plasma generation, a high-frequency power supply with a frequency of 13.56 MHz is suitable in terms of cost and stability of plasma generation. As the high-voltage pulse power supply, for example, PHF-2K type, SBP-5K-HF type, and 3D / PBII type of Kurita Manufacturing Co., Ltd. of Heiden Laboratory are suitable.
[0027]
【Example】
Examples of the manufactured gas barrier container will be described below.
[0028]
<Example 1>
As a container 2, a 500 ml PET bottle was used. After evacuation was performed to 1 × 10 ⁻² Pa using the apparatus shown in FIG. 1, nitrogen gas was introduced to make the pressure in the vacuum container 5 Pa. An electric power of 500 W is applied intermittently with a 13.56 MHz high frequency power supply, and a high voltage pulse of −20 kV is alternately applied, and the rising and falling of the pulse voltage are applied at −20 Kv / μs and 20 Kv / μs, and ion implantation is performed for about 60 seconds. did. The bottle was taken out to the atmosphere, the presence or absence of coloring was visually evaluated, and the barrier property was evaluated with an oxygen permeability measuring device (OX-TRAN 10/50, manufactured by MOCON). As a result of visual inspection, no coloring was observed and the transparency was high. The oxygen permeability was 0.007 cc / pkg / day, which was about 10 times the oxygen permeability of the PET bottle before treatment, 0.07 cc / pkg / day. Improved. The ion implantation depth was measured by SIMS (Secondary Ion Mass Spectroscopy), and was considered to correspond to 1 to 30 nm.
[0029]
<Example 2>
As a container 2, a 500 ml PET bottle was used. After evacuation was performed to 1 × 10 ⁻² Pa with the apparatus shown in FIG. 1, carbon dioxide gas was introduced to make the pressure in the vacuum container 5 Pa. An electric power of 500 W is intermittently applied by a 13.56 MHz high frequency power supply, and a high voltage pulse of −20 kV is alternately applied, and the rising and falling of the pulse voltage are applied at −20 Kv / μs and 20 Kv / μs, and ion implantation is performed for about 60 seconds. did. The bottle was taken out to the atmosphere, and as a result of visual observation, no coloring was observed, the bottle had high transparency, the oxygen permeability was 0.009 cc / pkg / day, and the oxygen permeability of the PET bottle before treatment was 0.07 cc / pkg. / Day was improved about 10 times. The ion implantation depth was measured by SIMS (Secondary Ion Mass Spectroscopy) and found to correspond to 1 to 30 nm.
[0030]
<Example 3>
As a container 2, a 500 ml PET bottle was used. After evacuation was performed to 1 × 10 ⁻² Pa by the apparatus shown in FIG. 1, dry air was introduced to make the pressure in the vacuum container 7 Pa. An electric power of 500 W is applied intermittently with a 13.56 MHz high frequency power supply, and a high voltage pulse of −20 kV is alternately applied, and the rising and falling of the pulse voltage are applied at −20 Kv / μs and 20 Kv / μs, and ion implantation is performed for about 60 seconds. did. The bottle was taken out to the atmosphere, and as a result of visual observation, no coloring was observed, the bottle had high transparency, the oxygen permeability was 0.010 cc / pkg / day, and the oxygen permeability of the PET bottle before treatment was 0.07 cc / pkg. / Day was improved about 10 times. The ion implantation depth was measured by SIMS (Secondary Ion Mass Spectroscopy) and found to correspond to 1 to 30 nm.
[0031]
<Comparative Example 1>
As a container 2, a 500 ml PET bottle was used. After evacuation was performed to 1 × 10 ⁻² Pa using the apparatus shown in FIG. 1, dry air was introduced to make the pressure in the vacuum container 7 Pa. A power of 500 W is applied intermittently with a 13.56 MHz high frequency power supply, and a high voltage pulse of -1 kV is applied alternately, and the rising and falling of the pulse voltage are applied at -1 Kv / μs and 1 Kv / μs, and ion implantation is performed for about 60 seconds. did. It was taken out to the atmosphere, and as a result of visual inspection, it had a light brown coloration, and the oxygen permeability was 0.07 cc / pkg / day, which was equivalent to the oxygen permeability of the PET bottle before treatment, 0.07 cc / pkg / day. Indicated. Further, the ion implantation depth was not found when measured by SIMS (Secondary Ion Mass Spectroscopy).
[0032]
<Comparative Example 2>
As a container 2, a 500 ml PET bottle was used. After evacuation was performed to 1 × 10 ⁻² Pa by the apparatus shown in FIG. 1, dry air was introduced to make the pressure in the vacuum container 7 Pa. An electric power of 500 W was intermittently applied by a 13.56 MHz high frequency power supply, and a high voltage pulse of −20 kV was alternately applied, and ions were implanted for about 60 seconds. At this time, the rise of the pulse voltage was -0.5 kV / 1 [mu] s, and the fall was 0.5 kV / 1 [mu] s. It was taken out to the atmosphere, and as a result of visual inspection, it had a light brown coloration, and the oxygen permeability was 0.07 cc / pkg / day. The oxygen permeability of the bottle was improved to about 10 times of 0.07 cc / pkg / day.
[0033]
【The invention's effect】
As described above in detail, according to the method of the present invention, a high-speed high-voltage pulse is applied to the inner surface of a container such as a bottle to perform ion implantation. It is possible to provide a method and an apparatus for producing a gas barrier container which is colorless and transparent and has a high gas barrier property, and a produced gas barrier container.
[0034]
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of an apparatus showing an example of a barrier container according to the present invention. FIG. 2 is an explanatory diagram illustrating an ion accelerating voltage and an effect of a solid surface in the present invention.
FIG. 3 is an explanatory diagram related to the present invention, and is an explanatory diagram illustrating a time change of the power for plasma generation and the output of a high-voltage pulse.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Chamber 2 Container 3 Auxiliary vacuum container 4 Vacuum exhaust system 5 Gas introduction system 6 Non-conductive insulator 7 Plasma generation power supply 8 High voltage pulse power supply 9 High frequency mutual interference prevention filter and matching box

Claims

2. The gas barrier container according to claim 1, wherein a high-density layer is formed 1 μm or less from the outermost surface of the inner surface of the container by ion implantation.

The gas barrier container according to claim 1, wherein the implanted ions include at least one of nitrogen, oxygen, hydrogen, and a rare gas.

A method for producing a container in which plasma is generated on the inner surface of a container, ions supplied from the plasma on the inner surface of the container are accelerated by a high-voltage pulse applied from the outer surface of the container, and ions are implanted, and the voltage of the high-voltage pulse is A method for producing a gas barrier container, wherein the voltage is a negative voltage, the absolute value of which is greater than 2 kV, and the rising of the high voltage pulse voltage is 1 kV or more per 1 μs in the negative direction.

4. The method for manufacturing a gas barrier container according to claim 3, wherein the fall of the high voltage pulse voltage has an absolute value of 1 kV or more per 1 [mu] s.

The gas barrier container according to claim 3, wherein the plasma generated on the inner surface of the container is formed of a gas containing at least one of air, nitrogen, oxygen, carbon dioxide, hydrogen, and a rare gas. Production method.

At least a chamber and a container in the chamber, and the chamber also serves as an external electrode, and means for evacuating the chamber and the container, and an internal electrode capable of introducing a gas into the container. A plasma generating AC power supply for generating plasma in the vessel, a negative voltage having an absolute value greater than 2 kV can be applied, and the rising of the high voltage pulse voltage is performed in a negative direction. An apparatus for manufacturing a gas barrier container, comprising: a high-voltage pulse power supply capable of operating with an absolute value of 1 kV or more per 1 μs and an absolute value of 1 kV or more per 1 μs in fall.

At least comprising a chamber and a container in the chamber, a means for evacuating the chamber and the container, an external electrode inside or outside the chamber, and gas can be introduced into the container. An AC power supply for generating plasma in the vessel, which is provided with an internal electrode, and a negative voltage whose absolute value is larger than 2 kV can be applied, and the rising of the high-voltage pulse voltage is negative; An apparatus for manufacturing a gas barrier container, comprising: a high-voltage pulse power supply capable of operating with an absolute value of 1 kV or more per 1 μs in the direction and an absolute value of 1 kV or more per 1 μs in fall.

8. An output section of the plasma generating AC power supply and an output section of the high-voltage pulse power supply are connected to the external electrode via a filter circuit for preventing high-frequency mutual interference. An apparatus for producing a gas barrier container according to the above.