JP2004059088A - Packaging method, coexttrusion laminated film, and square-bottomed bag - Google Patents
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【０００１】
【発明の属する技術分野】
本発明は、食パン、菓子パン等の食品やその他の物品の角底包装袋による包装に好適で、角底包装袋の開口部側に角底袋としての形態を維持したままでの開封が可能な易開封シールを設け、異物の混入を防止しうる包装方法、この包装方法に使用する角底袋の製造に好適な共押出積層フィルムおよび角底袋に関する。
【０００２】
【従来の技術】
従来の食パン包装、菓子パン包装等の食品包装袋は開口部を、ひねって固定する結束具、即ちスリットを有する約２ｃｍ四方のプラスチック板、テープ、ひも等により結束した状態で販売されている。内容物が複数個であったり、単数個であっても大きなものは、再封が可能な結束具により何度も開閉できるため利便性が高く、多く使用されている。
【０００３】
しかしながら、このような結束具による包装は簡易であるため、包装袋の結束部に隙間があり、異物の侵入を防止できないという欠点がある。そのため異物の侵入が防止できる包装方法、フィルムおよび包装用袋が強く望まれている。
【０００４】
【発明が解決しようとする課題】
本発明の課題は、異物の侵入が防止でき、しかも、角底袋の形態を維持したままでの開封が可能な易開封性があり、結束具等により何度も角底袋の開閉できるという利便性を損なうことがない物品の包装方法、この包装方法に使用する角底袋の製造に好適な共押出積層フィルムおよび角底袋を提供することである。
【０００５】
【課題を解決するための手段】
発明者等は、上記実状に鑑みて鋭意検討した結果、
１−ブテンとその他のα−オレフィンとからなる１−ブテン系共重合体を含有してなるヒートシール樹脂層（Ａ）と、該１−ブテン系共重合体よりもヒートシール開始温度が高いプロピレン系樹脂を含有してなる中間樹脂層（Ｂ）と、エチレン系樹脂を含有してなる厚さ０．５〜５μｍの表面樹脂層（Ｃ）とが（Ａ）／（Ｂ）／（Ｃ）の順で積層している共押出積層フィルム（Ｉ）は、角底袋の製造に好適であり、しかも、異物の侵入が防止でき、角底袋の形態を維持したままでの開封が可能な易開封性があり、結束具等により何度も角底袋の開閉できるという利便性を損なうことがない物品の包装が容易であることを見出した。
【０００６】
その理由としては、次の▲１▼〜▲５▼が挙げられる。
▲１▼ヒートシール樹脂層（Ａ）が６０℃以上の温度領域で溶融接着が可能で、しかもこの温度領域では溶融接着温度におおよそ比例して接着強度が上昇し、高温領域での溶融接着では接着強度が高く強固に接着するが、低温領域での溶融接着では接着強度が弱く、容易に易開封性シールとなる。
▲２▼ヒートシール樹脂層（Ａ）を内側として溶融切断接着を行うと、強固に接着するが、表面樹脂層（Ｃ）を内側として溶融切断接着を行うと、中間樹脂層（Ｂ）と表面樹脂層（Ｃ）の層間接着強度が低く、かつ表面樹脂層（Ｃ）の厚さが薄いために溶融切断接着部の接着強度が低くなり破断して、容易に角底袋が得られる。
▲３▼得られた角底袋に食品等の物品を充填し、低い温度で開口部、例えば該包装用袋の開口部上端と充填された食品の間の部分をヒートシールすることにより安定した易開封シールとなり、容易に易開封角底包装袋とすることができる。
▲４▼角底袋上部を結束具で結束することにより従来のパン角底包装と同様の結束包装とすることができる。
▲５▼得られた易開封角底包装袋は、易開封シールがなされているため異物の侵入を防止でき、しかも、易開封シール部分で容易に開封でき、開封しても袋が破損しないため、プラスチック板、テープ、ひも等の結束具による再封が可能である。
【０００７】
即ち、本発明は、ヒートシール樹脂層（Ａ）と中間樹脂層（Ｂ）と表面樹脂層（Ｃ）とが（Ａ）／（Ｂ）／（Ｃ）の順で積層している共押出積層フィルムのヒートシール樹脂層（Ａ）を袋の内側として溶融切断接着して角底袋に製袋され、かつ、物品が充填された角底袋の開口部を、角底袋の形態を維持したままで開封可能となる加熱条件でヒートシールして易開封角底包装とする包装方法であって、しかも、該共押出積層フィルムが１−ブテンとその他のα−オレフィンとからなる１−ブテン系共重合体を含有してなるヒートシール樹脂層（Ａ）と、該１−ブテン系共重合体よりもヒートシール開始温度が高いプロピレン系樹脂を含有してなる中間樹脂層（Ｂ）と、エチレン系樹脂を含有してなる厚さ０．５〜５μｍの表面樹脂層（Ｃ）とを有する共押出積層フィルム（Ｉ）であることを特徴とする包装方法を提供するものである。
【０００８】
また、本発明は、１−ブテンとその他のα−オレフィンとからなる１−ブテン系共重合体を含有してなるヒートシール樹脂層（Ａ）と、該１−ブテン系共重合体よりもヒートシール開始温度が高いプロピレン系樹脂を含有してなる中間樹脂層（Ｂ）と、エチレン系樹脂を含有してなる厚さ０．５〜５μｍの表面樹脂層（Ｃ）とが（Ａ）／（Ｂ）／（Ｃ）の順で積層していることを特徴とする共押出積層フィルムを提供するものである
【０００９】
さらに、本発明は、前記共押出積層フィルムをヒートシール樹脂層（Ａ）を袋の内側として溶融切断接着して角底製袋されていることを特徴とする角底袋を提供するものである。
【００１０】
【発明の実施の形態】
本発明で用いる積層フィルム（Ｉ）は、１−ブテンとその他のα−オレフィンとからなる１−ブテン系共重合体を含有してなるヒートシール樹脂層（Ａ）と、該１−ブテン系共重合体よりもヒートシール開始温度が高いプロピレン系樹脂を含有してなる中間樹脂層（Ｂ）と、エチレン系樹脂を含有してなる厚さ０．５〜５μｍの表面樹脂層（Ｃ）とを有しておればよい。
【００１１】
ヒートシール樹脂層（Ａ）としては、１−ブテンとその他のα−オレフィンとからなる１−ブテン系共重合体を含有してなる樹脂層であれば良いが、１−ブテン系共重合体として１−ブテンとプロピレンとを必須成分として共重合してなる１−ブテン−プロピレン系共重合体（ａ）を用いることが好ましく、１−ブテン由来成分含有率が５０〜９９モル％（重合に使用した全単量体成分中における１−ブテンの割合が５０〜９９モル％を意味する。）の１−ブテン系−プロピレン共重合体（ａ１）を用いることがより好ましい。なかでも、ヒートシール樹脂層（Ａ）としては、低温での易開封シール時のヒートシール温度や強度の調整が容易で、ヒートシール温度幅が広く、易開封シールとして適度なヒートシール強度が容易に得られることから、該１−ブテン−プロピレン共重合体（ａ１）と、プロピレン−エチレン共重合体（ｐｅ）とを併用してなる樹脂層であることが特に好ましい。その重量比（ａ１）／（ｐｅ）としては２０／８０〜８０／２０となる割合であることが好ましく、なかでも２５／７５〜６０／４０となる割合であることが特に好ましい。なお、１−ブテン系−プロピレン共重合体（ａ１）としては、なかでも、１−ブテン由来成分含有率が５５〜９０モル％の１−ブテン系−プロピレン共重合体であることが好ましい。
【００１２】
前記エチレン−プロピレン共重合体（ｅｐ）は、プロピレンとプロピレンの共重合体であればよく、特に限定されないが、なかでも低温シール性、耐衝撃性、滑り性に優れるものが得られることから、エチレン由来成分含有量が２〜１０重量％（重合に使用した全単量体成分中におけるエチレンの割合が２〜１０重量％を意味する。）のプロピレン−エチレン共重合体が特に好ましい。
【００１３】
前記ヒートシール層（Ａ）は、ＪＩＳ Ｋ−１７１３に定めるヒートシール開始温度試験に準拠して測定したヒートシール開始温度が、表面樹脂層（Ｃ）のヒートシール開始温度よりも低いことが、角底袋の作成と易開封性シールが容易なことから好ましい。このため、本発明に係る共押出積層フィルム（Ｉ）としては、ヒートシール層（Ａ）と表面樹脂層（Ｃ）の間のヒートシール開始温度差を１０℃以上とすることが好ましい。
【００１４】
中間樹脂層（Ｂ）としては、ヒートシール樹脂層（Ａ）中に含有される前記１−ブテン系共重合体よりもＪＩＳ Ｋ−１７１３に定めるヒートシール開始温度が高いプロピレン系樹脂を含有してなる樹脂層であればよい。該中間樹脂層（Ｂ）としては、例えば、プロピレンの単独重合体；プロピレン−エチレン共重合体、プロピレンとエチレン以外のα−オレフィンとの共重合体等のプロピレン系共重合体；などのようなプロピレン系樹脂の１種以上を主成分として、好ましくは７５重量％以上含有してなり、必要に応じて、エチレン−１−ブテン共重合体、直鎖状低密度ポリエチレン等のような他の熱可塑性樹脂や各種の添加剤を混合してなる樹脂層が挙げられるが、なかでも、プロピレンの単独重合体および／またはプロピレン−エチレン系共重合体（ｂ）を含有してなる樹脂層であることが好ましい。該プロピレン−エチレン系共重合体（ｂ）としては、エチレン由来成分含有率３〜７重量％のプロピレン−エチレン共重合体が挙げられる。
【００１５】
また、前記中間樹脂層（Ｂ）は、ヒートシール樹脂層（Ａ）側の中間樹脂層（Ｂ１）と、表面樹脂層（Ｃ）側の中間樹脂層（Ｂ２）の２層からなる樹脂層であっても良い。この場合、表面樹脂層（Ｃ）側の中間樹脂層（Ｂ２）としては、前記中間樹脂層（Ｂ）として記載した組成と同様の組成であることが好ましい。また、ヒートシール樹脂層（Ａ）側の中間樹脂層（Ｂ１）としては、例えば、プロピレンの単独重合体；プロピレン−エチレン共重合体、プロピレンとエチレン以外のα−オレフィンとの共重合体等のプロピレン系共重合体；などのようなプロピレン系樹脂の１種以上を主成分として、好ましくは７０重量％以上含有してなり、必要に応じて、エチレン−１−ブテン系共重合体、直鎖状低密度ポリエチレン等のような他の熱可塑性樹脂や、本積層フィルム製造に際して発生した回収物等を混合してなる樹脂層が挙げられる。また、中間樹脂層（Ｂ１）は、中間樹脂層（Ｂ２）と同一組成の樹脂層であっても良い。具体例としては、エチレン由来成分含有率３〜７重量％のプロピレン−エチレン共重合体を含有してなる樹脂層（Ｂ１）とプロピレン由来成分含有率９５重量％以上のプロピレン系樹脂、好ましくはプロピレン単独重合体からなる樹脂層（Ｂ２）とを、樹脂層（Ｂ１）をヒートシール樹脂層（Ｃ）側として積層してなる樹脂層が挙げられる。なお、耐寒性に優れる積層フィルムが望ましい場合には、中間樹脂層（Ｂ１）を低温耐衝撃性の優れる組成、例えば直鎖状低密度ポリエチレンを含有させた組成からなる樹脂層とすることが好ましい。
【００１６】
更に、前記中間樹脂層（Ｂ１）は２層以上に分割することも可能で、中間樹脂層（Ｂ）全体の層構成が３層以上となっても何ら問題ない。
【００１７】
表面樹脂層（Ｃ）としては、エチレン系樹脂を含有してなる厚さ０．５〜５μｍの樹脂層（Ｃ）であればよく、例えば、低密度ポリエチレン、中密度ポリエチレン、高密度ポリエチレン、直鎖状低密度ポリエチレン等エチレン系樹脂の１種以上を主成分として８０重量％以上含有する厚さ０．５〜５μｍ、好ましくは厚さ１〜３．５μｍの樹脂層が挙げられる。これらのなかでも、中間樹脂層（Ｂ）との接着性が低く、表面樹脂層（Ｃ）を内側として溶融切断接着して製袋した角底袋の溶融切断接着部の接着強度が２．５Ｎ／１５ｍｍ以下となるエチレン系樹脂であって、ヒートシール樹脂層（Ａ）に含有されている１−ブテン系共重合体よりもヒートシール開始温度が高いエチレン系樹脂からなる樹脂層であることが、物品が充填された角底袋の開口部に外観良好な易開封シールを容易に形成できることから好ましい。このような好ましい表面樹脂層としては、密度０．９１０〜０．９３０ｇ／ｃｍ３の低密度ポリエチレンからなる樹脂層が挙げられる。
【００１８】
なお、表面樹脂層（Ｃ）は、エンボス加工を施すことによりマット調の表面を有する樹脂層とすることが可能であり、これにより表面がマット調の共押出積層フィルムと角底袋を得ることができる。
【００１９】
本発明に係る共押出積層フィルム（Ｉ）の厚みは、通常２０〜５０μｍであるが、なかでも２５〜４０μｍが好ましい。また、ヒートシール層（Ａ）の厚みは、通常０．１〜１０μｍであるが、なかでも１〜８μｍが好ましく、１〜５μｍが特に好ましい。
【００２０】
本発明に係る共押出積層フィルム（Ｉ）が、（Ａ）／（Ｂ１）／（Ｂ２）／（Ｃ）の順に積層された４層フィルムである場合、中間樹脂層（Ｂ１）と中間樹脂層（Ｂ２）の全厚に対する厚み比率は、各層の樹脂組成により異なり特に限定されないが、中間樹脂層（Ｂ１）が通常３０〜８０％、好ましくは４０〜７０％であり、中間樹脂層（Ｂ２）が通常１０〜５０％、好ましくは１５〜４５％であり。
【００２１】
本発明に係る積層フィルム（Ｉ）の具体例としては、例えば、
▲１▼１−オクテン−プロピレン共重合体（ａ１）とエチレン−プロピレンーエチレン共重合体（ｐｅ）を、その重量比（ａ１）／（ｐｅ）が２０／８０〜８０／２０となる割合で含有してなるヒートシール樹脂層（Ａ−１）と、プロピレン単独重合体および／またはエチレン−プロピレン系共重合体（ｂ）を７５重量％以上含有してなる中間樹脂層（Ｂ−１）と、密度０．９１０〜０．９３０ｇ／ｃｍ３の低密度ポリエチレンからなる表面樹脂層（Ｃ−１）を、（Ａ−１）／（Ｂ−１）／（Ｃ−１）の順に積層してなるフィルムで、例えば、その平均厚さの比が１．２／８．３／０．５となるように積層してなる、厚さが２５μｍもしくは３０μｍの角底袋用として好適な３層フィルム（Ｉ−１）、
▲２▼前記ヒートシール樹脂層（Ａ−１）と、直鎖状低密度ポリエチレンとプロピレン−エチレン共重合体とを含有し、該プロピレン−エチレン共重合体の含有率が７０重量％以上である中間樹脂層（Ｂ１−２）と、プロピレン単独重合体および／またはエチレン−プロピレン共重合体（ｂ）を７５重量％以上含有してなる中間樹脂層（Ｂ２−２）と、前記表面樹脂層（Ｃ−１）とを、（Ａ−１）／（Ｂ１−２）／（Ｂ２−２）／（Ｃ−１）の順に積層してなるフィルムで、例えば、その平均厚さの比が１／５．５／３／０．５となるように積層してなる、厚さが２５μｍもしくは３０μｍの角底袋用として好適な４層フィルム（Ｉ−２）、
などが挙げられる。
【００２２】
本発明に係る積層フィルム（Ｉ）は、そのまま用いてもよいが、印刷による商品訴求力向上のために表面樹脂層（Ｃ）にコロナ放電処理をしてもよい。また、共押出積層フィルム（Ｉ）各層の中には、必要に応じて酸化防止剤、スリップ剤、アンチブロッキング剤、防曇剤、着色剤、シリカなどの添加剤等を、本発明の範囲内で適宜添加しうる。
【００２３】
本発明に係る共押出積層フィルム（Ｉ）の製造方法は、共押出成形法であればよく、特に限定されないが、例えば、３台以上の押出機を用いて溶融押出する、共押出多層ダイス法、フィードブロック法等の公知の共押出法により溶融状態で積層した後、インフレーション、Ｔダイ・チルロール法等の方法で長尺巻フィルムに加工する方法が好ましい。
【００２４】
上記のような共押出積層フィルム（Ｉ）を用いた本発明の包装方法としては、該共押出積層フィルム（Ｉ）のヒートシール樹脂層（Ａ）を袋の内側として溶融切断接着して角底袋として製袋され、かつ、物品が充填された角底袋の開口部を、角底袋の形態を維持したままで開封可能となる加熱条件でヒートシールして易開封包装とする包装方法であればよいが、前記ヒートシール樹脂層（Ａ）を袋の内側として溶融切断接着して製袋した角底袋の溶融切断接着部の接着強度が７．５〜３０Ｎ／１５ｍｍで、かつ、表面樹脂層（Ｃ）を内側として溶融切断接着して製袋した角底袋の溶融切断接着部の接着強度が２．５Ｎ／１５ｍｍ以下であり、しかも、物品が充填された角底袋の開口部をヒートシールして得られた易開封シール部分のヒートシール強度が０．１〜５Ｎ／１５ｍｍであるものが好ましく、なかでも、角底袋の溶融切断接着部の接着強度が９〜２０Ｎ／１５ｍｍで、かつ、易開封シール部分のヒートシール強度が０．２〜３．５Ｎ／１５ｍｍであるものが特に好ましい。次いで、角底袋の開口部をヒートシールした後、物品の上部を結束具により結束してもよく、これにより、結束具を用いた開封後の袋の再封が可能となる。
【００２５】
前記３層フィルム（Ｉ−１）または前記４層フィルム（Ｉ−２）を用いた食パン包装方法を以下に例示することにより、本発明の包装方法を説明する。
【００２６】
食パン包装方法
食パン包装方法用には、前記３層フィルム（Ｉ−１）または前記４層フィルム（Ｉ−２）を使用することが好ましい。前記３層フィルム（Ｉ−１）または前記４層フィルム（Ｉ−２）を用いる場合、これらの共押出積層フィルムは印刷された後、ヒートシール樹脂層（Ａ）が袋の内側になるようにして製袋機、例えばトタニ技研工業（株）製ＨＫ−４０Ｖ等により角底袋に加工する。この際、ヒートシール樹脂層（Ａ）を内側として溶融切断接着して製袋した角底袋の溶融接着部の接着強度が７．５〜３０Ｎ／１５ｍｍになる条件で溶融切断接着温度、製袋速度等を調整することが好ましい。次いで、得られた角底袋は、食パン自動充填機に供給され、食パン充填後、好ましくはヒートシール強度が０．１〜５Ｎ／１５ｍｍになる条件でヒートシールして、易開封性食パン包装角底袋とし、更に必要に応じて、角底袋の上部、好ましくは食パンの上部で易開封性シール部分またはその上もしくは下付近をプラスチック板、テープ、ひも等の結束具を用い結束する。
【００２７】
尚、本発明で言う易開封性シールとは、袋のヒートシール部分から切り出した幅１５ｍｍの試験片のヒートシール強度を、引張試験機〔（株）エー・アンド・デー製テンシロン〕を用いて、温度２３℃、引張速度３００ｍｍ／分の条件で測定した場合のヒートシール強度が０．１〜５Ｎ／１５ｍｍで、かつ、試験片の８割以上がフィルムの破断なしにシール面より剥離するヒートシールをいう。
【００２８】
前記食パン包装方法で、食パン充填後のヒートシールを、ヒートシール強度が０．１〜５Ｎ／１５ｍｍで易開封となるようにするシール温度やシール時間としては、シールパターンやシール圧力によりことなり特に限定されないが、好ましくは６５〜９５℃で０．１〜２秒間、特に好ましくは７０〜９０℃で０．３〜１．５秒間である。
【実施例】
以下に、実施例および比較例を挙げて、本発明を更に具体的に説明する。尚、例中の部および％は、特に断りのない限りすべて重量基準である。
【００２９】
実施例１
ヒートシール樹脂層（Ａ）用として１−ブテン−プロピレン共重合体〔１−ブテン由来成分含有率：６５モル％、密度：０．９０ｇ／ｃｍ３、ＭＩ（測定温度１９０℃）：４ｇ／１０分間〕５０部とプロピレン−エチレン共重合体〔エチレン由来成分含率：７．０％、密度：０．９０ｇ／ｃｍ３、ＭＩ（測定温度２３０℃）：７ｇ／１０分間〕５０部とからなる混合物を用い、中間樹脂層（Ｂ）用としてプロピレン単独重合体〔密度：０．９０ｇ／ｃｍ３、ＭＩ（測定温度２３０℃）：９ｇ／１０分間〕を用い、表面樹脂層（Ｃ）用として低密度ポリエチレン〔密度：０．９１ｇ／ｃｍ３、ＭＩ（測定温度１９０℃）：８ｇ／１０分間〕を用い、これらをそれぞれ３台の押出機に供給し、ヒートシール樹脂層（Ａ）と中間樹脂層（Ｂ）と表面樹脂層（Ｃ）の平均厚さの比（Ａ）：（Ｂ）：（Ｃ）が１．２：８．３：０．５となるように共押出して、厚さ３０μｍの３層フィルムを成形した。
【００３０】
次いで、表面樹脂層（Ｃ）の表面エネルギーが３６ｍＮ／ｍになるようにコロナ放電処理を施し、角底袋用共押出積層フィルムを製造した。得られた共押出積層フィルムを３５℃で４８時間エージングした後、ヒートシール樹脂層（Ａ）を内側にしてフィルムを半折後、折り込みの内側に折り返しをつけて二重折り底部を形成させ、この二重折り底部の内部折り目を頂点とし外部折り目を底辺とする直角二等辺三角形の両二等辺部を、第１表に示す温度で溶融切断接着（以下、Ｖシールという。）し、次いで、前記直角二等辺三角形の頂点を通り流れ方向と直角に第１表に示す温度で溶融切断接着（以下、サイドシールという。）することにより製袋〔製袋機：トタニ技研工業（株）製ＨＫ−４０Ｖ、製袋速度：１３０枚／分〕して、角底袋（縦：３４５ｍｍ、横：２３５ｍｍ）を得た。
【００３１】
得られた角底袋に食パンを充填した後、開口部上端と食パンの間（開口部上端から下に５０ｍｍの部分）を開口部と平行にヒートシーラー〔テスター産業（株）製、圧力：０．２ＭＰａ、時間：１秒間、シール温度：上部シールバーの温度を第１表に示す温度で、下部シールバーは５０℃に固定、シールバー形状：３００ｍｍ×１０ｍｍの平面〕で易開封ヒートシールして、易開封性食パン包装角底袋を得た。この易開封性食パン包装角底袋用い、以下のように、Ｖシール強度とサイドシール強度と易開封ヒートシール強度を測定すると共に、易開封ヒートシール強度測定時のフィルム破断の有無を観察した。この結果を第１表（１）〜（２）に示す。
【００３２】
＊Ｖシール強度とサイドシール強度：得られた角底袋５枚の両側のＶシール部の中央と、このＶシール部上部の両側のサイドシール部の中央とから、それぞれ１５ｍｍ幅の試験片を１枚づつ（１つの袋でそれぞれ２枚）合計でそれぞれ１０枚を切り出し、２３℃、引張速度３００ｍｍ／分の条件でテンシロン引張試験機〔（株）エー・アンド・デー製〕で引き剥がす時の最大荷重を測定し、それぞれＶシール強度とサイドシール強度とした。
【００３３】
＊易開封ヒートシール強度：得られた角底袋５枚の易開封ヒートシール部分から、それぞれ１５ｍｍ幅の試験片を２枚づつ（易開封ヒートシール部分を２等分し、その中央部分からそれぞれ１枚）、合計で１０枚を切り出し、２３℃、引張速度３００ｍｍ／分の条件でテンシロン引張試験機〔（株）エー・アンド・デー製〕で引き剥がす時の最大荷重を測定し、易開封ヒートシール強度とした。また、易開封ヒートシール強度測定時の試験片の破断の有無を観察し、フィルム破断がなしで引き剥がされたものを「破断なし」、フィルムが破断したものを「破断あり」と評価した。
【００３４】
比較例１
ヒートシール樹脂層（Ａ）としてプロピレン−エチレン共重合体〔エチレン由来成分含有率：３．７％、密度：０．９０ｇ／ｃｍ３、ＭＩ（測定温度２３０℃）：８ｇ／１０分〕を用い、ヒートシール樹脂層（Ａ）、中間樹脂層（Ｂ）、表面樹脂層（Ｃ）の平均厚さの比（Ａ）：（Ｂ）：（Ｃ）が３：６．５：０．５となるように共押出するように変更した以外は実施例１と全く同様にして、驚異紙だし積層フィルムを製造し、同様にシール強度を測定し、フィルム破断の有無を評価した。この結果を第１表（１）〜（２）に示す。
【００３５】
【表１】
【表２】
第１表（１）〜（２）の結果からわかる様に、本発明の共押出積層フィルム（Ｉ）を用いて得た角底袋は従来の積層フィルムで得られた角底袋と同様な充分なＶシール強度とサイドシール強度が得られ、しかも、袋の開口部を８０℃でヒートシールするとフィルムの破断無くして、シール面より剥離できる易開封性が得られる。
【００３８】
【発明の効果】
本発明の包装方法は、共押出積層フィルム（Ｉ）のヒートシール樹脂層（Ａ）が袋の内側となるように角底袋用に二重折り底部を形成し、角底袋用の溶融切断接着すると、ヒートシール樹脂層（Ａ）を内側とした溶融切断接着部は強固に接着するが、表面樹脂層（Ｃ）を内側とした溶融切断接着部は接着が弱いために、容易に角底袋が得られるうえに、得られた角底袋に食品等の物品を充填し、より低い温度で開口部をヒートシールすると安定して易開封ヒートシールすることができ、容易に食品が密封された易開封包装袋とすることができる。得られた易開封角底包装袋は、易開封ヒートシールがなされているため異物の侵入を防止でき、しかも、易開封ヒートシール部分で容易に開封でき、開封しても角底袋が破損しないため、プラスチック板、テープ、ひも等の結束具による再封が可能であり、更に袋上部を結束具で結束することにより従来の食パン包装と同様の結束包装とすることができる。
【００３９】
本発明の包装方法および共押出積層フィルムは、なかでも、パン、スナック、青果物等のツイストバッグ包装の角底袋としてその実用的価値は多大である。[0001]
TECHNICAL FIELD OF THE INVENTION
INDUSTRIAL APPLICABILITY The present invention is suitable for packaging foods such as bread, confectionery bread, and other articles by a square bottom packaging bag, and can be opened while maintaining the form as a square bottom bag on the opening side of the square bottom packaging bag. The present invention relates to a packaging method provided with an easy-open seal and capable of preventing the intrusion of foreign matter, a coextruded laminated film and a square-bottom bag suitable for producing a square-bottom bag used in this packaging method.
[0002]
[Prior art]
Conventional food packaging bags such as bread packaging and confectionery bread packaging are sold in a state of being bound by a binding device for twisting and fixing the opening, that is, a plastic plate of about 2 cm square having slits, tape, string, or the like. A large number of contents, even if a plurality of contents or a single content, can be opened and closed many times by a resealable tying member, so that the contents are high in convenience and are often used.
[0003]
However, since packaging with such a binding device is simple, there is a gap in the binding portion of the packaging bag, and there is a disadvantage that intrusion of foreign matter cannot be prevented. Therefore, there is a strong demand for a packaging method, a film and a packaging bag that can prevent foreign substances from entering.
[0004]
[Problems to be solved by the invention]
An object of the present invention is to prevent the invasion of foreign matter, and furthermore, there is an easy-opening property that can be opened while maintaining the shape of the square-bottom bag, and the square-bottom bag can be opened and closed many times with a tying tool or the like. An object of the present invention is to provide a method of packaging articles that does not impair convenience, and a coextruded laminated film and a square bottom bag suitable for producing a square bottom bag used in this packaging method.
[0005]
[Means for Solving the Problems]
The inventors have conducted intensive studies in view of the above situation,
A heat-sealing resin layer (A) containing a 1-butene copolymer comprising 1-butene and another α-olefin, and propylene having a heat-sealing start temperature higher than that of the 1-butene copolymer. (A) / (B) / (C) comprising an intermediate resin layer (B) containing a resin and a surface resin layer (C) having a thickness of 0.5 to 5 μm containing an ethylene resin. The co-extruded laminated film (I) laminated in this order is suitable for the manufacture of a square bottom bag, furthermore, can prevent foreign substances from entering and can be opened while maintaining the shape of the square bottom bag. It has been found that it is easy to open, and it is easy to package articles without impairing the convenience of opening and closing the square bottom bag many times with a tying tool or the like.
[0006]
The reasons are the following (1) to (5).
{Circle around (1)} The heat-sealing resin layer (A) can be melt-bonded in a temperature range of 60 ° C. or more, and in this temperature range, the bonding strength increases approximately in proportion to the melt-bonding temperature. Although the bonding strength is high and the bonding is strong, the bonding strength is low in the melt bonding in a low temperature range, and the seal can be easily opened.
{Circle around (2)} When the melt-cut bonding is performed with the heat-sealing resin layer (A) inside, the bonding is strong. However, when the melt-cut bonding is performed with the surface resin layer (C) inside, the intermediate resin layer (B) and the surface are bonded. Since the interlayer adhesive strength of the resin layer (C) is low and the thickness of the surface resin layer (C) is thin, the adhesive strength of the melt-cut adhesive portion is low and the resin layer (C) is broken, so that a square bottom bag can be easily obtained.
{Circle around (3)} The obtained square-bottom bag is filled with an article such as food, and the opening is stabilized at a low temperature, for example, by heat-sealing a portion between the upper end of the opening of the packaging bag and the filled food. It becomes an easy-open seal and can be easily made into an easy-open square bottom packaging bag.
{Circle around (4)} By tying the upper part of the square bottom bag with a tying tool, it is possible to make the same wrapping package as the conventional bread square bottom packaging.
(5) The obtained easy-opening square-bottomed packaging bag has an easy-opening seal, so that invasion of foreign substances can be prevented. Further, the bag can be easily opened at the easy-opening seal portion, and the bag is not damaged even when opened. It can be resealed with a binding device such as a plastic plate, tape, string, or the like.
[0007]
That is, the present invention provides a co-extrusion lamination in which a heat seal resin layer (A), an intermediate resin layer (B), and a surface resin layer (C) are laminated in the order of (A) / (B) / (C). The heat-sealing resin layer (A) of the film was melt-cut and adhered to the inside of the bag to form a square-bottom bag, and the opening of the square-bottom bag filled with articles was maintained in the shape of the square-bottom bag. This is a packaging method in which heat-sealing is carried out under heating conditions that can be opened as it is to make it easy to open square bottom packaging, and the co-extruded laminated film is composed of 1-butene and other α-olefin. A heat seal resin layer (A) containing a copolymer, an intermediate resin layer (B) containing a propylene resin having a heat seal initiation temperature higher than that of the 1-butene copolymer, and ethylene. And a surface resin layer (C) having a thickness of 0.5 to 5 μm containing a base resin. The present invention provides a packaging method characterized by being a co-extruded laminated film (I).
[0008]
Further, the present invention provides a heat-sealing resin layer (A) containing a 1-butene-based copolymer composed of 1-butene and another α-olefin, and a heat-sealing resin layer (A) that is more heat-resistant than the 1-butene-based copolymer. An intermediate resin layer (B) containing a propylene-based resin having a high sealing start temperature and a surface resin layer (C) having a thickness of 0.5 to 5 μm containing an ethylene-based resin are (A) / ( The present invention provides a co-extruded laminated film characterized by being laminated in the order of B) / (C).
Further, the present invention provides a square-bottomed bag, wherein the co-extruded laminated film is melt-cut and bonded with the heat-sealing resin layer (A) inside the bag to form a square-bottomed bag. .
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
The laminated film (I) used in the present invention comprises a heat seal resin layer (A) containing a 1-butene copolymer comprising 1-butene and another α-olefin, and the 1-butene copolymer. An intermediate resin layer (B) containing a propylene-based resin having a higher heat-sealing start temperature than a polymer, and a surface resin layer (C) having a thickness of 0.5 to 5 μm containing an ethylene-based resin. You only need to have it.
[0011]
The heat-sealing resin layer (A) may be a resin layer containing a 1-butene-based copolymer composed of 1-butene and another α-olefin. It is preferable to use a 1-butene-propylene copolymer (a) obtained by copolymerizing 1-butene and propylene as essential components, and the 1-butene-derived component content is 50 to 99 mol% (used for polymerization). It is more preferable to use the 1-butene-propylene copolymer (a1) in which the proportion of 1-butene in the total monomer components is 50 to 99 mol%. Above all, as the heat-sealing resin layer (A), it is easy to adjust the heat-sealing temperature and strength at the time of easy-opening sealing at a low temperature, the heat-sealing temperature range is wide, and an appropriate heat-sealing strength is easy as the easy-opening seal. It is particularly preferable that the resin layer is a resin layer obtained by using the 1-butene-propylene copolymer (a1) and the propylene-ethylene copolymer (pe) in combination. The weight ratio (a1) / (pe) is preferably a ratio of 20/80 to 80/20, and particularly preferably a ratio of 25/75 to 60/40. The 1-butene-propylene copolymer (a1) is particularly preferably a 1-butene-propylene copolymer having a content of 1-butene-derived component of 55 to 90 mol%.
[0012]
The ethylene-propylene copolymer (ep) is not particularly limited as long as it is a copolymer of propylene and propylene, but among them, a material having excellent low-temperature sealability, impact resistance, and slipperiness is obtained. A propylene-ethylene copolymer having an ethylene-derived component content of 2 to 10% by weight (meaning that the proportion of ethylene in all monomer components used for the polymerization is 2 to 10% by weight) is particularly preferable.
[0013]
In the heat seal layer (A), the heat seal start temperature measured according to the heat seal start temperature test defined in JIS K-1713 is lower than the heat seal start temperature of the surface resin layer (C). It is preferable because the preparation of the bottom bag and the easy-open seal are easy. For this reason, as the co-extruded laminated film (I) according to the present invention, it is preferable that the difference in the heat sealing start temperature between the heat seal layer (A) and the surface resin layer (C) is 10 ° C. or more.
[0014]
The intermediate resin layer (B) contains a propylene-based resin having a higher heat-sealing start temperature defined by JIS K-1713 than the 1-butene-based copolymer contained in the heat-sealed resin layer (A). Any resin layer may be used. Examples of the intermediate resin layer (B) include propylene homopolymers; propylene-based copolymers such as propylene-ethylene copolymers and copolymers of propylene and α-olefins other than ethylene; One or more propylene-based resins are contained as a main component, preferably at least 75% by weight, and if necessary, other heats such as ethylene-1-butene copolymer, linear low-density polyethylene and the like. Examples of the resin layer include a mixture of a plastic resin and various additives. Among them, a resin layer containing a propylene homopolymer and / or a propylene-ethylene-based copolymer (b) is preferable. Is preferred. As the propylene-ethylene copolymer (b), a propylene-ethylene copolymer having an ethylene-derived component content of 3 to 7% by weight is exemplified.
[0015]
The intermediate resin layer (B) is a resin layer composed of an intermediate resin layer (B1) on the heat sealing resin layer (A) side and an intermediate resin layer (B2) on the surface resin layer (C) side. There may be. In this case, it is preferable that the intermediate resin layer (B2) on the side of the surface resin layer (C) has the same composition as the composition described as the intermediate resin layer (B). Examples of the intermediate resin layer (B1) on the heat seal resin layer (A) side include, for example, a propylene homopolymer; a propylene-ethylene copolymer, and a copolymer of propylene and an α-olefin other than ethylene. Propylene-based copolymer; one or more propylene-based resins such as propylene-based resin as a main component, preferably 70% by weight or more. If necessary, ethylene-1-butene-based copolymer, linear Thermoplastic resin such as a low-density polyethylene, or a resin layer formed by mixing a collected product generated during the production of the present laminated film. Further, the intermediate resin layer (B1) may be a resin layer having the same composition as the intermediate resin layer (B2). Specific examples include a resin layer (B1) containing a propylene-ethylene copolymer having an ethylene-derived component content of 3 to 7% by weight and a propylene-based resin having a propylene-derived component content of 95% by weight or more, preferably propylene. A resin layer obtained by laminating a resin layer (B2) made of a homopolymer and the resin layer (B1) on the heat sealing resin layer (C) side is exemplified. When a laminated film having excellent cold resistance is desirable, the intermediate resin layer (B1) is preferably a resin layer having a composition having excellent low-temperature impact resistance, for example, a composition containing linear low-density polyethylene. .
[0016]
Further, the intermediate resin layer (B1) can be divided into two or more layers, and there is no problem even if the entire intermediate resin layer (B) has three or more layers.
[0017]
The surface resin layer (C) may be a resin layer (C) containing an ethylene resin and having a thickness of 0.5 to 5 μm. For example, low-density polyethylene, medium-density polyethylene, high-density polyethylene, A resin layer having a thickness of 0.5 to 5 μm, preferably 1 to 3.5 μm, containing at least 80% by weight of at least one ethylene-based resin such as a chain low-density polyethylene as a main component is exemplified. Among these, the adhesive strength to the intermediate resin layer (B) is low, and the adhesive strength of the melt-cut adhesive portion of the square-bottom bag formed by melt-cut adhesive with the surface resin layer (C) inside is 2.5N. / 15 mm or less, wherein the resin layer is made of an ethylene resin having a heat sealing start temperature higher than that of the 1-butene copolymer contained in the heat sealing resin layer (A). It is preferable because an easy-open seal with good appearance can be easily formed at the opening of the square bottom bag filled with the article. Examples of such a preferable surface resin layer include a resin layer made of low-density polyethylene having a density of 0.910 to 0.930 g / cm 3 .
[0018]
The surface resin layer (C) can be a resin layer having a mat-like surface by embossing, thereby obtaining a mat-like co-extruded laminated film and a square bottom bag. Can be.
[0019]
The thickness of the co-extruded laminated film (I) according to the present invention is usually from 20 to 50 μm, but preferably from 25 to 40 μm. The thickness of the heat seal layer (A) is usually 0.1 to 10 μm, preferably 1 to 8 μm, and particularly preferably 1 to 5 μm.
[0020]
When the co-extruded laminated film (I) according to the present invention is a four-layer film laminated in the order of (A) / (B1) / (B2) / (C), the intermediate resin layer (B1) and the intermediate resin layer The thickness ratio of (B2) to the total thickness depends on the resin composition of each layer and is not particularly limited, but the intermediate resin layer (B1) is usually 30 to 80%, preferably 40 to 70%, and the intermediate resin layer (B2) Is usually 10 to 50%, preferably 15 to 45%.
[0021]
Specific examples of the laminated film (I) according to the present invention include, for example,
{Circle around (1)} 1-octene-propylene copolymer (a1) and ethylene-propylene-ethylene copolymer (pe) at a weight ratio (a1) / (pe) of 20/80 to 80/20. A heat-sealing resin layer (A-1), and an intermediate resin layer (B-1) containing 75% by weight or more of a propylene homopolymer and / or an ethylene-propylene copolymer (b). And a surface resin layer (C-1) made of low-density polyethylene having a density of 0.910 to 0.930 g / cm 3 , laminated in the order of (A-1) / (B-1) / (C-1). Three-layer film having a thickness of 25 μm or 30 μm and suitable for use in a bag with a thickness of 25 μm or 30 μm, for example, laminated so that the average thickness ratio is 1.2 / 8.3 / 0.5. (I-1),
{Circle around (2)} The heat-sealing resin layer (A-1) contains a linear low-density polyethylene and a propylene-ethylene copolymer, and the content of the propylene-ethylene copolymer is 70% by weight or more. An intermediate resin layer (B1-2), an intermediate resin layer (B2-2) containing 75% by weight or more of a propylene homopolymer and / or an ethylene-propylene copolymer (b), and the surface resin layer (B1-2). C-1) and (A-1) / (B1-2) / (B2-2) / (C-1) in this order. For example, the ratio of the average thickness is 1 /. A four-layer film (I-2) having a thickness of 25 μm or 30 μm suitable for a square-bottom bag, which is laminated so as to have a thickness of 5.5 / 3 / 0.5;
And the like.
[0022]
The laminated film (I) according to the present invention may be used as it is, or the surface resin layer (C) may be subjected to a corona discharge treatment in order to improve product appeal by printing. In each layer of the co-extruded laminated film (I), if necessary, additives such as an antioxidant, a slip agent, an antiblocking agent, an antifogging agent, a colorant, and silica are included within the scope of the present invention. Can be added as appropriate.
[0023]
The method for producing the coextruded laminated film (I) according to the present invention is not particularly limited as long as it is a coextrusion molding method. For example, a coextrusion multilayer die method in which melt extrusion is performed using three or more extruders. After laminating in a molten state by a known co-extrusion method such as a feed block method, it is preferable to process the film into a long rolled film by a method such as inflation or a T-die chill roll method.
[0024]
As a packaging method of the present invention using the co-extruded laminated film (I) as described above, the heat-sealing resin layer (A) of the co-extruded laminated film (I) is melt-cut and adhered to the inside of a bag to form a square base. The bag is made as a bag, and the opening of the square-bottom bag filled with articles is heat-sealed under a heating condition that allows opening while maintaining the shape of the square-bottom bag, and is a packaging method of easy-open packaging. It is sufficient if the heat-sealing resin layer (A) is melt-cut and bonded with the inside of the bag as the inside of the bag. The adhesive strength of the melt-cut bonding portion of the square-bottom bag formed by melt-cut bonding with the resin layer (C) inside is 2.5 N / 15 mm or less, and the opening of the square-bottom bag filled with the article. Of the easy-open seal obtained by heat sealing the Preferably, the adhesive strength of the melt-cut adhesive portion of the square bottom bag is 9-20 N / 15 mm, and the heat seal strength of the easy-open seal portion is 0. Those having a thickness of 0.2 to 3.5 N / 15 mm are particularly preferred. Next, after the opening of the square bottom bag is heat-sealed, the upper part of the article may be tied with a tying tool, so that the bag after opening with the tying tool can be resealed.
[0025]
The packaging method of the present invention will be described by exemplifying a bread packaging method using the three-layer film (I-1) or the four-layer film (I-2).
[0026]
Bread packaging method For the bread packaging method, it is preferable to use the three-layer film (I-1) or the four-layer film (I-2). When the three-layer film (I-1) or the four-layer film (I-2) is used, these co-extruded laminated films are printed so that the heat-sealing resin layer (A) is located inside the bag. It is processed into a square bottom bag by a bag making machine such as HK-40V manufactured by Totani Giken Kogyo Co., Ltd. At this time, under the condition that the adhesive strength of the melt-bonded portion of the square bottom bag formed by melt-cutting and bonding with the heat seal resin layer (A) as the inner side is 7.5 to 30 N / 15 mm, the melting temperature and the bonding temperature are set. It is preferable to adjust the speed and the like. Next, the obtained square bottom bag is supplied to an automatic bread filling machine, and after filling the bread, the bag is preferably heat-sealed under the condition that the heat seal strength becomes 0.1 to 5 N / 15 mm, and the easily openable bread packaging angle. A bottom bag, and, if necessary, the upper portion of the square bottom bag, preferably the upper portion of the bread, or the upper or lower portion of the easily-openable seal portion is bound by using a binding device such as a plastic plate, tape, or a string.
[0027]
The easily-openable seal referred to in the present invention means that the heat-sealing strength of a 15 mm-wide test piece cut out from the heat-sealed portion of the bag is measured by using a tensile tester [Tensilon manufactured by A & D Corporation]. Heat at a temperature of 23 ° C. and a tensile speed of 300 mm / min, a heat seal strength of 0.1 to 5 N / 15 mm, and 80% or more of the test pieces peel off from the seal surface without breaking the film. Refers to a seal.
[0028]
In the bread packaging method, the sealing temperature and the sealing time at which the heat sealing after the filling of the bread is easy to open with a heat sealing strength of 0.1 to 5 N / 15 mm vary depending on the sealing pattern and the sealing pressure. Although not limited, it is preferably at 65 to 95 ° C for 0.1 to 2 seconds, particularly preferably at 70 to 90 ° C for 0.3 to 1.5 seconds.
【Example】
Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. All parts and percentages in the examples are by weight unless otherwise specified.
[0029]
Example 1
1-butene-propylene copolymer [1-butene-derived component content: 65 mol%, density: 0.90 g / cm 3 , MI (measurement temperature 190 ° C): 4 g / 10 for the heat seal resin layer (A) Minutes) and 50 parts of a propylene-ethylene copolymer [content of ethylene-derived component: 7.0%, density: 0.90 g / cm 3 , MI (measuring temperature 230 ° C): 7 g / 10 minutes]. Using a mixture, a propylene homopolymer [density: 0.90 g / cm 3 , MI (measuring temperature 230 ° C): 9 g / 10 minutes] for the intermediate resin layer (B), and for the surface resin layer (C) Using low-density polyethylene [density: 0.91 g / cm 3 , MI (measuring temperature 190 ° C.): 8 g / 10 minutes], these are supplied to three extruders, respectively, and are interposed between the heat seal resin layer (A) and the intermediate. Resin layer (B) A three-layer film having a thickness of 30 μm is coextruded so that the ratio (A) :( B) :( C) of the average thickness of the surface resin layer (C) becomes 1.2: 8.3: 0.5. Was molded.
[0030]
Next, a corona discharge treatment was performed so that the surface energy of the surface resin layer (C) became 36 mN / m, thereby producing a co-extruded laminated film for a square bottom bag. After the obtained co-extruded laminated film was aged at 35 ° C. for 48 hours, the film was half-folded with the heat-sealing resin layer (A) inside, and then the inside of the fold was folded to form a double folded bottom. The two isosceles portions of a right-angled isosceles triangle having the inner fold at the top and the outer fold at the bottom at the top of the double fold are melt cut and adhered (hereinafter referred to as V-seal) at the temperatures shown in Table 1, and then. A bag is formed by melting and bonding (hereinafter, referred to as a side seal) at a temperature shown in Table 1 through a vertex of the right-angled isosceles triangle at right angles to the flow direction (bag making machine: HK manufactured by Totani Giken Kogyo Co., Ltd.). −40 V, bag making speed: 130 sheets / min] to obtain a square bottom bag (length: 345 mm, width: 235 mm).
[0031]
After filling the bread into the obtained square bottom bag, a heat sealer (manufactured by Tester Sangyo Co., Ltd., pressure: 0) is provided between the upper end of the opening and the bread (a portion 50 mm below the upper end of the opening) in parallel with the opening. .2 MPa, time: 1 second, sealing temperature: the temperature of the upper seal bar is the temperature shown in Table 1, the lower seal bar is fixed at 50 ° C., and the shape of the seal bar is a flat surface of 300 mm × 10 mm]. Thus, an easily-openable bread packaging square bottom bag was obtained. Using this easy-opening bread loaf square bottom bag, V seal strength, side seal strength, and easy-open heat seal strength were measured as described below, and the presence or absence of film breakage during easy-open heat seal strength measurement was observed. The results are shown in Tables (1) and (2).
[0032]
* V-seal strength and side-seal strength: A test specimen having a width of 15 mm was obtained from the center of the V-seal part on both sides of the five obtained square bottom bags and the center of the side seal parts on both sides above the V-seal part. When 10 pieces are cut out one by one (two pieces in one bag) in total, and peeled off with a Tensilon tensile tester (manufactured by A & D Co., Ltd.) at 23 ° C. and a tensile speed of 300 mm / min. Was measured, and the results were defined as V seal strength and side seal strength, respectively.
[0033]
* Easy-opening heat seal strength: From the obtained five easy-opening heat-sealed parts, two test specimens each having a width of 15 mm were used. 1 piece), a total of 10 pieces were cut out, the maximum load when peeling off was measured with a Tensilon tensile tester (manufactured by A & D Corporation) at 23 ° C. and a tensile speed of 300 mm / min, and the package was easily opened. The heat seal strength was used. In addition, the presence or absence of breakage of the test piece during the measurement of the easy-open heat seal strength was observed, and the test piece that was peeled off without breaking the film was evaluated as “no break”, and the one where the film was broken was evaluated as “broken”.
[0034]
Comparative Example 1
A propylene-ethylene copolymer [ethylene-derived component content: 3.7%, density: 0.90 g / cm 3 , MI (measuring temperature 230 ° C): 8 g / 10 minutes] was used as the heat seal resin layer (A). The ratio (A) :( B) :( C) of the average thickness of the heat seal resin layer (A), the intermediate resin layer (B), and the surface resin layer (C) is 3: 6.5: 0.5. A marvelous paper-laminated film was produced in the same manner as in Example 1 except that coextrusion was changed so as to obtain a film, and the seal strength was measured in the same manner to evaluate the presence or absence of film breakage. The results are shown in Tables (1) and (2).
[0035]
[Table 1]
[Table 2]
As can be seen from the results of Tables 1 (1) and (2), the square bottom bag obtained by using the co-extruded laminated film (I) of the present invention is similar to the square bottom bag obtained by the conventional laminated film. Sufficient V-seal strength and side-seal strength can be obtained, and when the bag opening is heat-sealed at 80 ° C., the film can be peeled off from the sealing surface without breaking the film without breakage.
[0038]
【The invention's effect】
In the packaging method of the present invention, a double-folded bottom portion is formed for a square-bottom bag so that the heat-sealing resin layer (A) of the co-extruded laminated film (I) is inside the bag, and is melt-cut for the square-bottom bag. When bonded, the melt-cut adhesive portion with the heat-sealing resin layer (A) inside adheres firmly, but the melt-cut adhesive portion with the surface resin layer (C) inside weakly adheres, so that the square bottom easily fits. In addition to obtaining a bag, filling the resulting square bottom bag with an article such as food, and heat-sealing the opening at a lower temperature can be easily opened and heat-sealed, and the food is easily sealed. It can be an easy-open packaging bag. The obtained easy-opening square-bottom packaging bag can be prevented from invading foreign matters because of the easy-opening heat seal, and can be easily opened at the easy-opening heat seal portion, and the square bottom bag is not damaged even when opened. Therefore, it is possible to reseal with a binding device such as a plastic plate, a tape, a string, or the like, and further, by binding the upper portion of the bag with the binding device, a binding package similar to the conventional bread packaging can be obtained.
[0039]
The packaging method and the co-extruded laminated film of the present invention have a great practical value as a square bottom bag for twist bag packaging of bread, snacks, fruits and vegetables, and the like.
Claims (16)
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| JP2002221155A JP4140307B2 (en) | 2002-07-30 | 2002-07-30 | Packaging method, coextrusion laminated film and square bottom bag |
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| JP2002221155A JP4140307B2 (en) | 2002-07-30 | 2002-07-30 | Packaging method, coextrusion laminated film and square bottom bag |
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| JP2004059088A true JP2004059088A (en) | 2004-02-26 |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007125722A (en) * | 2005-11-01 | 2007-05-24 | Dainippon Ink & Chem Inc | Coextrusion multilayered film and paper laminated film using it |
| JP2015047842A (en) * | 2013-09-04 | 2015-03-16 | サン・トックス株式会社 | Laminate sealant film |
| JP2019209477A (en) * | 2018-05-31 | 2019-12-12 | Dic株式会社 | Laminate film and square bottom bag |
| CN114801239A (en) * | 2022-04-13 | 2022-07-29 | 上海新旺科技有限公司 | Special-shaped two-dimensional high-temperature release flexible air bag and forming process |
-
2002
- 2002-07-30 JP JP2002221155A patent/JP4140307B2/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007125722A (en) * | 2005-11-01 | 2007-05-24 | Dainippon Ink & Chem Inc | Coextrusion multilayered film and paper laminated film using it |
| JP2015047842A (en) * | 2013-09-04 | 2015-03-16 | サン・トックス株式会社 | Laminate sealant film |
| JP2019209477A (en) * | 2018-05-31 | 2019-12-12 | Dic株式会社 | Laminate film and square bottom bag |
| JP7196427B2 (en) | 2018-05-31 | 2022-12-27 | Dic株式会社 | Laminated film and square bottom bag |
| CN114801239A (en) * | 2022-04-13 | 2022-07-29 | 上海新旺科技有限公司 | Special-shaped two-dimensional high-temperature release flexible air bag and forming process |
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| JP4140307B2 (en) | 2008-08-27 |
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