JP5159003B2 - Thermal fusion film and package comprising the same - Google Patents
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- JP5159003B2 JP5159003B2 JP2000281108A JP2000281108A JP5159003B2 JP 5159003 B2 JP5159003 B2 JP 5159003B2 JP 2000281108 A JP2000281108 A JP 2000281108A JP 2000281108 A JP2000281108 A JP 2000281108A JP 5159003 B2 JP5159003 B2 JP 5159003B2
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Description
【０００１】
【発明の技術分野】
本発明は、低密度ポリエチレン組成物からなる易剥離性、開封時のソフト感、耐ブロッキング性、衛生性、製膜加工性、ラミネート加工性に優れたプロピレン重合体用熱融着フィルム及びそれを用いた包装体に関する。
【０００２】
【発明の技術的背景】
せんべい、ポテトチップス等のスナック菓子包装、あるいはゼリー、ミルク、ヨーグルト、プリン、とうふ、乳酸飲料等の食品包装や、ブリスター包装、その他日用品や雑貨等の包装として、ボトル、カップ、ないしトレー状のプラスチック容器をプラスチックラミネートフィルムないしアルミ箔ラミネートフィルムからなる蓋材でシールした包装が広く採用されている。このような包装に要求されることは、流通経路に耐える機械的な強度、衛生性の保持ができるシール強度および使用時における開封性の良さである。
【０００３】
又、近年包装材のポリオレフィン化という流れから、剛性に優れたポリプロピレンが包装材料の一つとして多く使用されるようになっている。しかしながら、一般に用いられている熱融着材であるＥＶＡ系樹脂が提案されている（例えば、特開昭５８−４７０３８号公報）はブロッキング性に劣り、ポリプロピレン系からなる熱融着層と融着後剥離する際に剥離し難いという欠点を有している。
【０００４】
かかるポリプロピレン包装材に適したヒートシーラントとしてシングルサイト触媒を用いて重合されたエチレンとα−オレフィンとの共重合体のフィルムが提案されている（特開平９−９５３５６号公報）。しかしながら、かかる共重合体を単一で用いた場合は、熱融着（ヒートシール）温度を高くするとともに熱融着強度が強くなり過ぎ易剥離性が損なわれる虞がある。
【０００５】
【発明が解決しようとする課題】
そこで本発明者等は、耐ブロッキング性、ソフトな開封性、衛生性、加工性に優れ、ポリプロピレン系熱融着層と熱融着した際の熱融着強度の温度依存性が小さく、被包装物の充填後にボイル殺菌した際の熱融着強度の低下が少なく、輸送時等には被包装物が漏れ出る虞がない熱融着強度を有しながら被包装物を取出す際には、容易に剥離し、剥離時にソフトでスタッキングがないポリプロピレン用の熱融着フィルム及び包装体を得るべく、種々検討した。
【０００６】
【課題を解決するための手段】
【発明の概要】
本発明は、高圧法低密度ポリエチレン（A）と直鎖状低密度ポリエチレン（B）との密度０．９１０〜０．９３５ｇ／ｃｍ３の組成物（C）からなることを特徴とするポリプロピレン用熱融着フィルムに関する。
又、本発明は相対する面が、高圧法低密度ポリエチレン（A）と直鎖状低密度ポリエチレン（B）とからなる密度０．９１０〜０．９３５ｇ／ｃｍ３の組成物（C）からなる熱融着フィルムとポリプロピレン（Ｄ）層からなる熱融着層を備えたことを特徴とする包装体に関する。
【０００７】
【発明の具体的説明】
高圧法低密度ポリエチレン（Ａ）
本発明に係わる高圧法低密度ポリエチレン（A）は、通常、密度が０．９１０〜０．９３５ｇ／ｃｍ３、好ましくは０．９２０〜０．９３５ｇ／ｃｍ３、ＭＦＲ（ＡＳＴＭ Ｄ１２３８ 荷重２１６０ｇ、温度１９０℃）が通常、０．５〜１００ｇ／１０分、好ましくは１〜３０ｇ／１０分、より好ましくは１〜１０ｇ／１０分の高圧下で重合されるエチレンの単独重合体若しくは５重量％以下の他のα−オレフィンあるいは酢酸ビニル等のビニル化合物との共重合体である。
【０００８】
直鎖状低密度ポリエチレン（ B ）
本発明に係わる直鎖状低密度ポリエチレン（B）は、通常、密度が０．９０５〜０．９４０ｇ／ｃｍ３、好ましくは０．９１０〜０．９３５ｇ／ｃｍ３、ＭＦＲ（ＡＳＴＭ Ｄ１２３８ 荷重２１６０ｇ、温度１９０℃）が通常、０．５〜５０ｇ／１０分、好ましくは０．５〜２０ｇ／１０分、より好ましくは１〜１０ｇ／１０分のエチレンと炭素数が３〜１０のα−オレフィン、例えばプロピレン、ブテン−１、ヘプテン−１、ヘキセン−１、オクテン−１、４−メチル−ペンテン−１とのランダム共重合体である。又、かかる直鎖状低密度ポリエチレン（Ｂ）は、分子量分布（重量平均分子量：Ｍｗ、と数平均分子量：Ｍｎ、との比：Ｍｗ／Ｍｎで表示）が通常１．５〜４．０、好ましくは１．８〜３．５の範囲にある。このＭｗ／Ｍｎはゲル透過クロマトグラフィー（ＧＰＣ）によって測定できる。
【０００９】
又、直鎖状低密度ポリエチレン（Ｂ）は、示差走査熱量計（ＤＳＣ）の昇温速度１０℃／分で測定した吸熱曲線から求めた鋭いピークが１個ないし複数個あり、該ピークの最高温度、すなわち融点が通常７０〜１３０℃、好ましくは８０〜１２０℃の範囲にある。
【００１０】
上記のような直鎖状低密度ポリエチレン（B）は、シングルサイト触媒を用いた従来公知の製造法により調整することができる。たとえば直鎖状低密度ポリエチレン（B）は、遷移金属のメタロセン化合物を含む触媒を用いて調整することができる。このメタロセン化合物を含む触媒は、（ａ）遷移金属のメタロセン化合物と、（ｂ）有機アルミニウムオキシ化合物と、（ｃ）担体とから形成されることが好ましく、さらに必要に応じて、これらの成分と（ｄ）有機アルミニウム化合物および／または有機ホウ素化合物とから形成さていてもよい。
【００１１】
なお、このようなメタロセン化合物を含むオレフィン重合用触媒、および触媒を用いた直鎖状低密度ポリエチレン（B）の調整方法は、たとえば特開平８−２６９２７０号公報に記載されている。
【００１２】
プロピレン重合体（ D ）
本発明に係わるプロピレン重合体（D）は、一般にポリプロピレンの名称で製造・販売されている樹脂で、通常、密度が０．９００〜０．９２０、ＭＦＲ（ＡＳＴＭ Ｄ１２３８ 荷重２１６０ｇ、温度２３０℃）が０．５〜２０ｇ／１０分、好ましくは０．５〜５ｇ／１０分のプロピレンの単独重合体若しくはプロピレンと他の少量のα−オレフィン、例えばエチレン、ブテン、ヘキセン−１等とのランダムあるいはブロック共重合体である。プロピレン重合体（D）には５０重量％未満であれば、上記低密度ポリエチレンを始め、中密度ポリエチレン、高密度ポリエチレン、ポリブテン、エチレン・酢酸ビニル共重合体等のオレフィン系重合体がブレンドされていてもよい。
【００１３】
組成物（ C ）
本発明に係わる組成物（C）は、前記、高圧法低密度ポリエチレン（A）と直鎖状低密度ポリエチレン（B）とからなり、組成物の密度が通常、０．９１０〜０．９３５ｇ／ｃｍ３、好ましくは０．９１５〜０．９３０ｇ／ｃｍ２で、通常、ＭＦＲ（ＡＳＴＭ Ｄ１２３８ 荷重２１６０ｇ、温度１９０℃）が０．５〜５０ｇ／１０分、好ましくは１〜３０ｇ／１０分、より好ましくは１〜１０ｇ／１０分の範囲にある。
【００１４】
本発明に係わる組成物（Ｃ）における高圧法低密度ポリエチレン（A）と直鎖状低密度ポリエチレン（B）との重量比は特に限定はされないが、通常、高圧法低密度ポリエチレン（A）が１０〜８０重量％、好ましくは３０〜５０重量％と直鎖状低密度ポリエチレン（B）が９０〜２０重量％、好ましくは７０〜５０重量％の範囲にある。
【００１５】
又、本発明に係わる高圧法低密度ポリエチレン（A）、直鎖状低密度ポリエチレン（B）あるいはその組成物（Ｃ）およびプロピレン重合体（D）には、本発明の目的を損なわない範囲で、通常用いられる酸化防止剤、耐候安定剤、帯電防止剤、防曇剤等の添加剤を必要に応じて配合することができる。特に、アンチブロッキング剤、スリップ剤を配合することによって、フィルム成形時、ラミネート加工時、包装作業時等における加工性や作業性を向上させることができる。
【００１６】
熱融着フィルム
本発明に係わる熱融着フィルムは種々公知の方法で製造できる。例えば、高圧法低密度ポリエチレン（A）と直鎖状低密度ポリエチレン（B）とを所定の量で混合した後、直接フィルム成形機に投入してＴ−ダイ、環状ダイ等を用いてフィルムにする方法、予め高圧法低密度ポリエチレン（A）、直鎖状低密度ポリエチレン（B）とを所定の量で混合して押出機等で溶融混練して組成物（C）を得た後、Ｔ−ダイ、環状ダイ等を用いてフィルム成形する方法が例示できる。熱融着フィルムは単層でも用いられるが、補強層として上記低密度ポリエチレンを始め、中密度ポリエチレン、高密度ポリエチレン、ポリブテン、エチレン・酢酸ビニル共重合体等のオレフィン系重合体あるいは後述の熱可塑性樹脂からなる補強材との積層フィルムを得る場合には、シール層となる熱融着フィルムの原料である熱可塑性樹脂（C）と補強層に用いる樹脂とを多層ダイを用いて共押出しフィルムとしても良い。又、予め得られた補強材に熱可塑性樹脂組成物（C）を押出しラミネートして積層フィルムとしても良いし、あるいは夫々別個に得たフィルムを貼り合せて積層フィルムとしても良い。又、蓋材として用いる場合は、前記製法で得た熱融着層を備えた単層あるいは積層フィルム若しくはシートをそのまま蓋材として用いても良いし、印刷して用いても良い。更に印刷されたあるいはされていない紙、アルミ箔等と貼り合せて蓋材にしても良い。又、用途によっては予め容器形状に合わせてカットして蓋材にしても良い。
【００１７】
補強材
本発明に係わる熱融着フィルムに積層される補強材としては、たとえば、ポリエチレンテレフタレートに代表されるポリエステルフィルム、ポリアミドフィルム、ポリプロピレンフィルム等の熱可塑性樹脂製フィルム、アルミニューム箔、紙等が挙げられる。かかる熱可塑性樹脂製フィルムからなる補強材は無延伸であっても一軸あるいは二軸延伸フィルムであっても良い。勿論、補強材は１層でも２層以上としても良い。
【００１８】
熱融着層
本発明に係わる熱融着層は、被包装材料に合わせてプロピレン重合体（Ｄ）を公知の方法でフィルム、シート、トレー、カップ、ボトル等の種々の形状とすることができる。フィルム若しくはシートの場合は、上記熱融着フィルムと同様な方法で製造し得る。トレー若しくはカップの場合は、一旦上記方法でシートを製造した後、真空成形、圧空成形等の熱成形によりトレー、カップ等の容器とすることにより製造し得る。又、カップあるいはボトルの場合は射出成形、射出中空成形（インジェクションブロー）、中空成形等により容器として成形し得る。更に用途によっては上記補強材と積層してもよい。又、熱融着層に静電防止性を付与するために非帯電性アイオノマー等の静電防止剤を混合しておいてもよい。
【００１９】
【実施例】
次に実施例を挙げて本発明を更に具体的に説明するが、本発明はその要旨を越えない限りこれらの実施例に制約されるものではない。
【００２０】
実施例及び比較例で使用した原料は次の通りである。
（１）エチレン重合体−１（高圧法低密度ポリエチレン）：
三井化学社製（商品名；ミラソン、銘柄名；Ｍ１２Ｐ）
密度０．９２７（ｇ／ｃｍ３）、ＭＦＲ３．０（ｇ／１０分）
融点１１４℃
（２）エチレン重合体−２（シングルサイト触媒重合直鎖状低密度ポリエチレン）：
三井化学社製（商品名；エボリュー、銘柄名；ＳＰ１５４０）
密度０．９１５（ｇ／ｃｍ３）、ＭＦＲ４（ｇ／１０分）、融点１１３℃
（３）エチレン重合体−３（シングルサイト触媒重合直鎖状低密度ポリエチレン）：
三井化学社製（商品名；エボリュー、銘柄名；ＳＰ２５４０）
密度０．９２５（ｇ／ｃｍ３）、ＭＦＲ４（ｇ／１０分）、融点１２０℃
（４）エチレン重合体−４（直鎖状低密度ポリエチレン）
三井化学社製（商品名；ウルトゼックス、銘柄名；ＵＺ３５２３Ｌ）
密度０．９３５（ｇ／ｃｍ３）、ＭＦＲ２．１（ｇ／１０分）、融点１２３℃
（５）エチレン・酢酸ビニル共重合体（ＥＶＡ）：
酢酸ビニル含量１０重量％
（６）エチレン・１−ブテン共重合体（ＥＢＲ）：
三井化学社製（商品名；タフマ−Ａ、銘柄：Ａ４０８５）
１−ブテン含量１０重量％、密度０．８８（ｇ／ｃｍ３）
ＭＦＲ４．０（ｇ／１０分）
（７）脂肪族系炭化水素樹脂：
荒川化学（株）製品（商品名；アルコン）
環球法軟化点１１５℃
【００２１】
実施例１
シール層となる熱融着フィルムの原料であるエチレン重合体−１：４０重量％とエチレン重合体−２：６０重量％をドライブレンドした組成物（Ｃ）と、補強層−１の原料であるエチレン重合体−３：３０重量％とエチレン重合体−４：７０重量％をドライブレンドした組成物と、補強層−２の原料であるエチレン共重合体−４：１００重量％を夫々別々の押出機に供給し、Ｔダイ法によってシール層／補強層−１／補強層−２なる構成の３層共押出フイルムを得た。フィルムの総厚は３０μｍで、各槽の厚みはシール層：補強層：補強層＝５：１９：６μｍであった。
【００２２】
実施例２（参考例２とする）
シール層となる熱融着フィルムの原料であるエチレン重合体−１：２０重量％とエチレン重合体−２：８０重量％をドライブレンドした組成物（Ｃ）と、補強層−１の原料であるエチレン重合体−３：３０重量％とエチレン重合体−４：７０重量％をドライブレンドした組成物と、補強層−２の原料でエチレン重合体−４：１００重量％を夫々別々の押出機に供給し、Ｔダイ法によってシール層／補強層−１／補強層−２なる構成の３層共押出フィルムを得た。フィルムの総厚は３０μｍで、各槽の厚みはシール層：補強層：補強層＝５：１９：６μｍであった。
【００２３】
実施例３
シール層となる熱融着フィルムの原料であるエチレン重合体−１：４０重量％とエチレン重合体−３：６０重量％をドライブレンドした組成物（Ｃ）と、補強層−１の原料であるエチレン重合体−３：３０重量％とエチレン重合体−４：７０重量％をドライブレンドした組成物と、補強層−２の原料でエチレン重合体−４：１００重量％を夫々別々の押出機に供給し、Ｔダイ法によってシール層／補強層−１／補強層−２なる構成の３層共押出フイルムを得た。フィルムの総厚は３０μｍで、各槽の厚みはシール層：補強層：補強層＝５：１９：６μｍであった。
【００２４】
実施例４（参考例４とする）
シール層となる熱融着フィルムの原料であるエチレン重合体−１：２０重量％とエチレン重合体−３：８０重量％をドライブレンドした組成物（Ｃ）と、補強層−１の原料であるエチレン重合体−３：３０重量％とエチレン重合体−４：７０重量％をドライブレンドした組成物と、補強層−２の原料でエチレン重合体−４：１００重量％を夫々別々の押出機に供給し、Ｔダイ法によってシール層／補強層−１／補強層−２なる構成の３層共押出フィルムを得た。フィルムの総厚は３０μｍで、各槽の厚みはシール層：補強層：補強層＝５：１９：６μｍであった。
【００２５】
比較例１
シール層となる熱融着フィルムの原料であるエチレン重合体−２：１００重量％と、補強層−１の原料であるエチレン重合体−３：３０重量％とエチレン重合体−４：７０重量％をドライブレンドした組成物と、補強層−２の原料でエチレン重合体−４：１００重量％を夫々別々の押出機に供給し、Ｔダイ法によってシール層／補強層−１／補強層−２なる構成の３層共押出フイルムを得た。フィルムの総厚は３０μｍで、各槽の厚みはシール層：補強層：補強層＝５：１９：６μｍであった。
【００２６】
比較例２
シール層となる熱融着フィルムの原料であるエチレン重合体−３：１００重量％と、補強層−１の原料であるエチレン重合体−３：３０重量％とエチレン重合体−４：７０重量％をドライブレンドした組成物と、補強層−２の原料でエチレン重合体−４：１００重量％を夫々別々の押出機に供給し、Ｔダイ法によってシール層／補強層−１／補強層−２なる構成の３層共押出フイルムを得た。フィルムの総厚は３０μｍで、各槽の厚みはシール層：補強層：補強層＝５：１９：６μｍであった。
【００２７】
参考例
シール層となる熱融着フィルムの原料であるエチレン・酢酸ビニル共重合体（ＥＶＡ）：４０重量％とエチレン・１−ブテン共重合体（ＥＢＲ）：４０重量％と脂肪族系炭化水素樹脂２０重量％をドライブレンドした組成物と、補強層−１の原料であるエチレン重合体−３：３０重量％とエチレン重合体−４：７０重量％をドライブレンドした組成物と、補強層−２の原料でエチレン重合体−４：１００重量％の組成物を夫々別々の押出機に供給し、Ｔダイ法によってシール層／補強層−１／補強層−２なる構成の３層共押出フイルムを得た。フィルムの総厚は３０μｍで、各槽の厚みはシール層：補強層：補強層＝５：１９：６μｍであった。
【００２８】
各実施例、比較例及び参考例で得られたフィルムの特性値は以下の方法で測定した。
（１）ヒ−トシ−ル性：
延伸された厚さ１２μｍのポリエチレンテレフタレ−トフィルム（ＰＥＴ）と、各実施例および比較例等で得られたフィルムの補強層−２面をウレタン系接着剤を用いてドライラミネ−ションにより積層して、易開封性包装体の材料を製造した。熱融着層として用いたプロピレン重合体の基材は、東セロ社製のポリプロピレンシ−ト（商品名：Ｔ−Ｔ＃３００）を用いた。
（２）ヒートシール性 ：
１）シール層面と熱融着層のシ−ル面を重ね合せ、表記載の温度、幅５ｍｍのシールバーにより、０．２ＭＰａの圧力で１秒間シールした後放冷した。これから１５ｍｍ幅の試験片を切り取りクロスヘッド速度５００ｍｍ／ｍｉｎでヒートシール部を剥離し、その強度をヒートシール強度とした。耐熱水処理後の適正は上記方法でヒートシールした試験片を９０℃の熱水中で３０分間放置した冷却したのち自然乾燥し、上記方法でヒートシール強度を測定した。
２）剥離強度が５〜１５Ｎ／１５ｍｍ程度の範囲に有る物を◎、剥離強度が２０Ｎ／１５ｍｍ以上の強い強度の物を△で表した。
３）開封時のピ−ル感を観察し、ソフトなピ−ル性のものを◎、ピリピリ感の有る（スタッキング性の有る）ピ−ル性のものを△、より完全シールに近い強いピ−ル性のものを×で表した。
（３）熱融着面のブロッキングが（ラミ加工時のラミロ−ルのブロッキング性）しないものを◎、１．５Ｎ／１５ｃｍ２とバリバリと音がするレベルにあるものを×で表した。
（４） イ−ジ−ピ−ル性フィルムとしての機能性として総合適性は、対被着体との剥離強度が５〜１５Ｎ／１５ｍｍ程度、綺麗な界面剥離でソフトな感触で剥離可能な物で、尚かつフィルム・ラミネ−ト加工時或いは実包作業時においてブロッキングのしないフィルムが好適である。従って、総合適性の判定は◎：最適、○：適、△：不十分、×：不適とした。
【００２９】
【表１】
【発明の効果】
本発明に係わる易開封性包装体は、高圧法低密度ポリエチレンと直鎖状低密度ポリエチレンとの組成物とが特定の割合で混合された熱可塑性樹脂組成物となっているので、低温ヒ−トシ−ル性があり、ヒ−トシ−ル温度幅も広く、ボイル処理等によるヒ−ト−シル強度の変化も少なく、適度なヒートシール強度を有しており、又開封時にはソフトに容易に開封できてるという特性を有している。また、フィルムのブロキング性にも優れているので加工時の粉振り加工が不要で、ラミネート品のエ−ジング温度を一般のフィルム並以下に低くすることも必要なく、或いはユ−ザ−等で使用する場合も問題が無く使える。このようなことにより、広く各種のヨ−グルト、プリン、ゼリ−、スナック、麺などの紙ポリ容器の食品包装やブリスタ−包装、その他日用品や雑貨等の袋物包装、ボトル、カップ、ないしトレ−のプラスチックス容器などのシ−ル材等の包装体として好適に利用することができる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides a heat-sealing film for a propylene polymer, which is excellent in easy peelability, soft feeling at the time of opening, blocking resistance, hygiene, film-forming processability, laminate processability, and a low-density polyethylene composition. It relates to the package used.
[0002]
TECHNICAL BACKGROUND OF THE INVENTION
Packaging for snacks such as rice crackers, potato chips, etc., food packaging such as jelly, milk, yogurt, pudding, tofu, lactic acid beverages, blister packaging, and other daily necessities and miscellaneous goods packaging, bottles, cups or tray-like plastic containers Wrapped in a lid made of a plastic laminate film or aluminum foil laminate film is widely used. What is required for such packaging is mechanical strength that can withstand distribution channels, sealing strength that can maintain hygiene, and good openability during use.
[0003]
In recent years, polypropylene having excellent rigidity has been widely used as one of packaging materials due to the trend of making packaging materials into polyolefins. However, an EVA-based resin that is a commonly used heat-sealing material (for example, Japanese Patent Application Laid-Open No. 58-47038) is inferior in blocking property, and a heat-sealing layer composed of a polypropylene-based material is fused with a heat-sealing layer. It has a drawback that it is difficult to peel off after peeling.
[0004]
As a heat sealant suitable for such a polypropylene packaging material, a copolymer film of ethylene and α-olefin polymerized using a single site catalyst has been proposed (Japanese Patent Laid-Open No. 9-95356). However, when such a copolymer is used singly, there is a possibility that the heat-sealing (heat-sealing) temperature is raised and the heat-sealing strength becomes too strong and the easy peelability is impaired.
[0005]
[Problems to be solved by the invention]
Therefore, the present inventors are excellent in blocking resistance, soft openability, hygiene, and processability, and the temperature dependency of the thermal fusion strength when thermally fused with the polypropylene-based thermal fusion layer is small. There is little decrease in the heat-sealing strength when boil sterilization after filling the product, and it is easy to take out the package while having the heat-sealing strength that prevents the package from leaking during transportation. In order to obtain a heat-sealing film for polypropylene and a packaging body that is soft and free of stacking at the time of peeling, various studies were made.
[0006]
[Means for Solving the Problems]
Summary of the Invention
The present invention is for a polypropylene characterized by comprising a composition (C) having a density of 0.910 to 0.935 g / cm 3 of a high pressure method low density polyethylene (A) and a linear low density polyethylene (B). The present invention relates to a heat fusion film.
In the present invention, the opposite surface is composed of a composition (C) having a density of 0.910 to 0.935 g / cm 3 composed of a high-pressure method low-density polyethylene (A) and a linear low-density polyethylene (B). The present invention relates to a package comprising a heat fusion layer comprising a heat fusion film and a polypropylene (D) layer.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
High pressure low density polyethylene (A)
The high-pressure low-density polyethylene (A) according to the present invention usually has a density of 0.910 to 0.935 g / cm 3 , preferably 0.920 to 0.935 g / cm 3 , MFR (ASTM D1238 load 2160 g, temperature) 190 ° C) is usually 0.5 to 100 g / 10 min, preferably 1 to 30 g / 10 min, more preferably 1 to 10 g / 10 min. It is a copolymer with other α-olefins or vinyl compounds such as vinyl acetate.
[0008]
Linear low density polyethylene ( B )
The linear low density polyethylene (B) according to the present invention usually has a density of 0.905 to 0.940 g / cm 3 , preferably 0.910 to 0.935 g / cm 3 , MFR (ASTM D1238 load 2160 g, A temperature of 190 ° C.) is usually 0.5 to 50 g / 10 minutes, preferably 0.5 to 20 g / 10 minutes, more preferably 1 to 10 g / 10 minutes, and an α-olefin having 3 to 10 carbon atoms, For example, it is a random copolymer with propylene, butene-1, heptene-1, hexene-1, octene-1, 4-methyl-pentene-1. In addition, the linear low density polyethylene (B) has a molecular weight distribution (weight average molecular weight: Mw, number average molecular weight: Mn, ratio: Mw / Mn) is usually 1.5 to 4.0, Preferably it exists in the range of 1.8-3.5. This Mw / Mn can be measured by gel permeation chromatography (GPC).
[0009]
The linear low-density polyethylene (B) has one or more sharp peaks obtained from an endothermic curve measured at a heating rate of 10 ° C./min with a differential scanning calorimeter (DSC). The temperature, that is, the melting point is usually in the range of 70 to 130 ° C, preferably 80 to 120 ° C.
[0010]
The linear low density polyethylene (B) as described above can be prepared by a conventionally known production method using a single site catalyst. For example, the linear low density polyethylene (B) can be prepared using a catalyst containing a metallocene compound of a transition metal. The catalyst containing the metallocene compound is preferably formed from (a) a transition metal metallocene compound, (b) an organoaluminum oxy compound, and (c) a carrier, and if necessary, these components and (D) It may be formed from an organoaluminum compound and / or an organoboron compound.
[0011]
An olefin polymerization catalyst containing such a metallocene compound and a method for adjusting linear low density polyethylene (B) using the catalyst are described, for example, in JP-A-8-269270.
[0012]
Propylene polymer ( D )
The propylene polymer (D) according to the present invention is a resin that is generally produced and sold under the name of polypropylene, and usually has a density of 0.900 to 0.920, MFR (ASTM D1238 load 2160 g, temperature 230 ° C.). Random or block of propylene homopolymer of 0.5 to 20 g / 10 min, preferably 0.5 to 5 g / 10 min, or propylene and a small amount of other α-olefin such as ethylene, butene, hexene-1, etc. It is a copolymer. If it is less than 50% by weight, the propylene polymer (D) is blended with the above-mentioned low density polyethylene, olefin polymers such as medium density polyethylene, high density polyethylene, polybutene, and ethylene / vinyl acetate copolymer. May be.
[0013]
Composition ( C )
The composition (C) according to the present invention comprises the above-mentioned high-pressure method low-density polyethylene (A) and linear low-density polyethylene (B), and the density of the composition is usually 0.910 to 0.935 g / cm 3 , preferably 0.915 to 0.930 g / cm 2, and usually MFR (ASTM D1238 load 2160 g, temperature 190 ° C.) is 0.5 to 50 g / 10 minutes, preferably 1 to 30 g / 10 minutes, more preferably Is in the range of 1-10 g / 10 min.
[0014]
The weight ratio of the high pressure method low density polyethylene (A) and the linear low density polyethylene (B) in the composition (C) according to the present invention is not particularly limited, but usually the high pressure method low density polyethylene (A) is 10 to 80% by weight, preferably 30 to 50% by weight, and the linear low density polyethylene (B) is in the range of 90 to 20% by weight, preferably 70 to 50% by weight.
[0015]
Further, the high pressure method low density polyethylene (A), the linear low density polyethylene (B) or the composition thereof (C) and the propylene polymer (D) according to the present invention are within a range that does not impair the object of the present invention. Ordinarily used additives such as antioxidants, weathering stabilizers, antistatic agents and antifogging agents can be blended as necessary. In particular, by blending an anti-blocking agent and a slip agent, workability and workability during film forming, laminating, packaging, etc. can be improved.
[0016]
Heat-sealing film The heat-sealing film according to the present invention can be produced by various known methods. For example, after mixing a predetermined amount of high-pressure low-density polyethylene (A) and linear low-density polyethylene (B), the mixture is directly put into a film forming machine, and a film is formed using a T-die, an annular die, etc. A high pressure method low density polyethylene (A) and linear low density polyethylene (B) are mixed in a predetermined amount and melt-kneaded with an extruder or the like to obtain a composition (C); -The method of film-forming using a die, an annular die, etc. can be illustrated. The heat-sealing film can be used as a single layer, but the olefinic polymer such as the above-mentioned low-density polyethylene, medium-density polyethylene, high-density polyethylene, polybutene, ethylene / vinyl acetate copolymer, etc. When a laminated film with a reinforcing material made of resin is obtained, a thermoplastic resin (C), which is a raw material of the heat-sealing film that becomes the sealing layer, and a resin used for the reinforcing layer are coextruded using a multilayer die. Also good. Alternatively, the thermoplastic resin composition (C) may be extruded and laminated to a reinforcing material obtained in advance to form a laminated film, or films obtained separately may be bonded to form a laminated film. Moreover, when using as a lid | cover material, the single layer or laminated | multilayer film or sheet | seat provided with the heat sealing | fusion layer obtained by the said manufacturing method may be used as a lid | cover material as it is, and may be printed and used. Further, it may be bonded to paper that is printed or not, aluminum foil, or the like to form a lid. Further, depending on the application, it may be cut in advance according to the shape of the container to form a lid.
[0017]
Reinforcing material Examples of the reinforcing material laminated on the heat-sealing film according to the present invention include, for example, a film made of a thermoplastic resin such as a polyester film represented by polyethylene terephthalate, a polyamide film, and a polypropylene film, and an aluminum foil. And paper. The reinforcing material made of such a thermoplastic resin film may be unstretched or may be a uniaxial or biaxially stretched film. Of course, the reinforcing material may be one layer or two or more layers.
[0018]
Heat-seal layer The heat-seal layer according to the present invention has various shapes such as films, sheets, trays, cups, bottles, and the like by using a known method for the propylene polymer (D) according to the material to be packaged. can do. In the case of a film or sheet, it can be produced by the same method as that for the heat-sealing film. In the case of a tray or a cup, it can be produced by once producing a sheet by the above method and then forming a container such as a tray or a cup by thermoforming such as vacuum forming or pressure forming. In the case of a cup or bottle, it can be molded as a container by injection molding, injection hollow molding (injection blow), hollow molding or the like. Furthermore, you may laminate | stack with the said reinforcing material depending on a use. Further, an antistatic agent such as an unchargeable ionomer may be mixed in order to impart antistatic properties to the heat-sealing layer.
[0019]
【Example】
EXAMPLES Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples unless it exceeds the gist.
[0020]
The raw materials used in Examples and Comparative Examples are as follows.
(1) Ethylene polymer-1 (high pressure method low density polyethylene):
Made by Mitsui Chemicals (trade name; Mirason, brand name; M12P)
Density 0.927 (g / cm 3 ), MFR 3.0 (g / 10 min)
Melting point 114 ° C
(2) Ethylene polymer-2 (single site catalyst polymerization linear low density polyethylene):
Made by Mitsui Chemicals (trade name: Evolue, brand name: SP1540)
Density 0.915 (g / cm 3 ), MFR4 (g / 10 min), melting point 113 ° C.
(3) Ethylene polymer-3 (single site catalyst polymerized linear low density polyethylene):
Made by Mitsui Chemicals (trade name: Evolue, brand name: SP2540)
Density 0.925 (g / cm 3 ), MFR4 (g / 10 min), melting point 120 ° C.
(4) Ethylene polymer-4 (linear low density polyethylene)
Made by Mitsui Chemicals, Inc. (trade name; Ultzex, brand name; UZ3523L)
Density 0.935 (g / cm 3 ), MFR2.1 (g / 10 min), melting point 123 ° C.
(5) Ethylene / vinyl acetate copolymer (EVA):
10% vinyl acetate content
(6) Ethylene / 1-butene copolymer (EBR):
Made by Mitsui Chemicals (trade name; Toughma-A, Brand: A4085)
1-butene content 10% by weight, density 0.88 (g / cm 3 )
MFR 4.0 (g / 10 min)
(7) Aliphatic hydrocarbon resin:
Arakawa Chemical Co., Ltd. product (trade name: Archon)
Ring and ball method softening point 115 ° C
[0021]
Example 1
A composition (C) obtained by dry blending ethylene polymer-1: 40% by weight and ethylene polymer-2: 60% by weight, which are raw materials for a heat-sealing film to be a sealing layer, and a raw material for reinforcing layer-1. A composition obtained by dry blending ethylene polymer-3: 30% by weight and ethylene polymer-4: 70% by weight, and ethylene copolymer-4: 100% by weight, which is a raw material of the reinforcing layer-2, are separately extruded. A three-layer coextruded film having a structure of seal layer / reinforcing layer-1 / reinforcing layer-2 was obtained by a T-die method. The total thickness of the film was 30 μm, and the thickness of each tank was seal layer: reinforcing layer: reinforcing layer = 5: 19: 6 μm.
[0022]
Example 2 (referred to as Reference Example 2)
A composition (C) obtained by dry blending ethylene polymer-1: 20% by weight and ethylene polymer-2: 80% by weight, which are raw materials for a heat-sealing film to be a sealing layer, and a raw material for reinforcing layer-1. A composition obtained by dry blending ethylene polymer-3: 30% by weight and ethylene polymer-4: 70% by weight, and ethylene polymer-4: 100% by weight with the raw material of the reinforcing layer-2 in separate extruders, respectively. Then, a three-layer coextruded film having a structure of sealing layer / reinforcing layer-1 / reinforcing layer-2 was obtained by a T-die method. The total thickness of the film was 30 μm, and the thickness of each tank was seal layer: reinforcing layer: reinforcing layer = 5: 19: 6 μm.
[0023]
Example 3
A composition (C) obtained by dry blending ethylene polymer-1: 40% by weight and ethylene polymer-3: 60% by weight, which are raw materials for a heat-sealing film to be a sealing layer, and a raw material for the reinforcing layer-1. A composition obtained by dry blending ethylene polymer-3: 30% by weight and ethylene polymer-4: 70% by weight, and ethylene polymer-4: 100% by weight with the raw material of the reinforcing layer-2 in separate extruders, respectively. Then, a three-layer coextruded film having a structure of seal layer / reinforcing layer-1 / reinforcing layer-2 was obtained by the T-die method. The total thickness of the film was 30 μm, and the thickness of each tank was seal layer: reinforcing layer: reinforcing layer = 5: 19: 6 μm.
[0024]
Example 4 (referred to as Reference Example 4)
A composition (C) obtained by dry blending ethylene polymer-1: 20% by weight and ethylene polymer-3: 80% by weight, which are raw materials for a heat-sealing film to be a sealing layer, and a raw material for the reinforcing layer-1. A composition obtained by dry blending ethylene polymer-3: 30% by weight and ethylene polymer-4: 70% by weight, and ethylene polymer-4: 100% by weight with the raw material of the reinforcing layer-2 in separate extruders, respectively. Then, a three-layer coextruded film having a structure of sealing layer / reinforcing layer-1 / reinforcing layer-2 was obtained by a T-die method. The total thickness of the film was 30 μm, and the thickness of each tank was seal layer: reinforcing layer: reinforcing layer = 5: 19: 6 μm.
[0025]
Comparative Example 1
Ethylene polymer-2 which is a raw material of a heat-sealing film to be a sealing layer: 100% by weight, ethylene polymer-3 which is a raw material of a reinforcing layer-1, 3: 30% by weight and ethylene polymer-4: 70% by weight The composition obtained by dry blending and the ethylene polymer-4: 100% by weight as the raw material of the reinforcing layer-2 are supplied to separate extruders, respectively, and the sealing layer / reinforcing layer-1 / reinforcing layer-2 is applied by the T-die method. A three-layer coextrusion film having the structure as described above was obtained. The total thickness of the film was 30 μm, and the thickness of each tank was seal layer: reinforcing layer: reinforcing layer = 5: 19: 6 μm.
[0026]
Comparative Example 2
Ethylene polymer-3, which is a raw material for the heat-sealing film to be a sealing layer, 100% by weight, ethylene polymer-3, which is a raw material for the reinforcing layer-1, 30% by weight, and ethylene polymer-4, 70% by weight The composition obtained by dry blending and the ethylene polymer-4: 100% by weight as the raw material of the reinforcing layer-2 are supplied to separate extruders, respectively, and the sealing layer / reinforcing layer-1 / reinforcing layer-2 is applied by the T-die method. A three-layer coextrusion film having the structure as described above was obtained. The total thickness of the film was 30 μm, and the thickness of each tank was seal layer: reinforcing layer: reinforcing layer = 5: 19: 6 μm.
[0027]
Reference example : Ethylene / vinyl acetate copolymer (EVA): 40% by weight and ethylene / 1-butene copolymer (EBR): 40% by weight, which are raw materials for a heat-sealing film serving as a sealing layer, and fat A composition obtained by dry blending 20% by weight of an aromatic hydrocarbon resin, and a composition obtained by dry blending ethylene polymer-3: 30% by weight and ethylene polymer-4: 70% by weight which are the raw materials of the reinforcing layer-1 The composition of ethylene polymer-4: 100% by weight as the raw material of the reinforcing layer-2 is supplied to separate extruders, and the sealing layer / the reinforcing layer-1 / the reinforcing layer-2 is formed by the T-die method. A layer coextruded film was obtained. The total thickness of the film was 30 μm, and the thickness of each tank was seal layer: reinforcing layer: reinforcing layer = 5: 19: 6 μm.
[0028]
The characteristic value of the film obtained by each Example, the comparative example, and the reference example was measured with the following method.
(1) Heat seal properties:
The stretched polyethylene terephthalate film (PET) having a thickness of 12 μm and the reinforcing layer-2 side of the film obtained in each of Examples and Comparative Examples were laminated by dry lamination using a urethane-based adhesive. An easy-open packaging material was produced. A polypropylene sheet (trade name: TT # 300) manufactured by Tosero Co., Ltd. was used as the base material for the propylene polymer used as the heat-sealing layer.
(2) Heat sealability:
1) The seal layer surface and the seal surface of the heat-sealing layer were overlapped, sealed at a pressure of 0.2 MPa for 1 second with a seal bar having a temperature and a width of 5 mm, and then allowed to cool. From this, a test piece having a width of 15 mm was cut, and the heat seal part was peeled off at a crosshead speed of 500 mm / min, and the strength was defined as the heat seal strength. Appropriate after the hot water treatment, the test piece heat-sealed by the above method was left to stand in hot water at 90 ° C. for 30 minutes, and then naturally dried, and the heat seal strength was measured by the above method.
2) A product having a peel strength in the range of about 5 to 15 N / 15 mm is represented by ◎, and a product having a peel strength of 20 N / 15 mm or more is represented by Δ.
3) Observe the peel feeling at the time of opening, ◎ for soft peel, △ for peel (stacking), △ for strong peel closer to perfect seal -The thing of a ru property is represented by x.
(3) “A” indicates that the heat-sealing surface does not block (blocking property of the lamellar at the time of the laminating process), and “×” indicates that the sound level is 1.5 N / 15 cm 2 .
(4) Comprehensive suitability as an easy-peeling film is that the peel strength from the adherend is about 5 to 15 N / 15 mm, and it can be peeled with a soft touch with clean interface peeling. In addition, a film that does not block during film laminating or actual packaging is preferred. Therefore, the overall suitability was judged as ◎: optimal, ○: appropriate, Δ: insufficient, and x: inappropriate.
[0029]
[Table 1]
【Effect of the invention】
Since the easy-open packaging body according to the present invention is a thermoplastic resin composition in which a composition of high-pressure method low-density polyethylene and linear low-density polyethylene is mixed at a specific ratio, Has tossile properties, wide heatseal temperature range, little change in heatsill strength due to boil treatment, etc., moderate heat seal strength, and soft and easy when opened It has the property that it can be opened. In addition, since the film is excellent in blocking property, it is not necessary to shake the powder at the time of processing, and it is not necessary to lower the aging temperature of the laminated product below that of a general film, or by a user or the like. It can be used without problems when used. As a result, food packaging and blister packaging of paper plastic containers such as various yogurts, puddings, jellies, snacks, noodles, and other bag packaging such as daily necessities and sundries, bottles, cups, and trays It can be suitably used as a package for sealing materials such as plastic containers.
Claims (2)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000281108A JP5159003B2 (en) | 2000-09-18 | 2000-09-18 | Thermal fusion film and package comprising the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000281108A JP5159003B2 (en) | 2000-09-18 | 2000-09-18 | Thermal fusion film and package comprising the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2002088168A JP2002088168A (en) | 2002-03-27 |
| JP5159003B2 true JP5159003B2 (en) | 2013-03-06 |
Family
ID=18765816
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2000281108A Expired - Lifetime JP5159003B2 (en) | 2000-09-18 | 2000-09-18 | Thermal fusion film and package comprising the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP5159003B2 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4184684B2 (en) * | 2002-03-20 | 2008-11-19 | 日本ポリプロ株式会社 | Coextrusion laminate and coextrusion laminate molding using the same |
| JP4906381B2 (en) * | 2006-03-23 | 2012-03-28 | 日本ポリプロ株式会社 | Easily peelable heat seal article and method for producing the same |
| JP4898631B2 (en) * | 2007-11-06 | 2012-03-21 | 日本ポリエチレン株式会社 | Polyethylene resin composition, film for print lamination using the same, and print laminate product |
| JP6704878B2 (en) * | 2017-07-24 | 2020-06-03 | 大日本印刷株式会社 | Laminated film |
| CN115122740B (en) * | 2022-07-28 | 2024-03-26 | 上海佰鑫新材料科技有限公司 | Barrier hot melt adhesive film and preparation method thereof |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2980876B2 (en) * | 1992-12-03 | 1999-11-22 | 三菱化学株式会社 | the film |
| JPH0995356A (en) * | 1995-09-28 | 1997-04-08 | Dainippon Printing Co Ltd | Easily unsealable packaged body |
| JPH09124856A (en) * | 1995-11-02 | 1997-05-13 | Nippon Poriorefuin Kk | Resin composition for extrusion lamination |
| JP3720904B2 (en) * | 1996-03-15 | 2005-11-30 | 大日本印刷株式会社 | Multilayer film |
| JPH1036581A (en) * | 1996-04-30 | 1998-02-10 | Ube Ind Ltd | Polyethylene composition for heavy duty packaging bag |
| JPH10166520A (en) * | 1996-12-12 | 1998-06-23 | Sumitomo Bakelite Co Ltd | Multilayered sheet |
| JPH11140240A (en) * | 1997-11-04 | 1999-05-25 | Asahi Chem Ind Co Ltd | Polyethylene-based resin composition for heavy duty packaging and polyethylene-based film for heavy duty packaging |
| JP2000026669A (en) * | 1998-07-10 | 2000-01-25 | Nippon Polyolefin Kk | Resin composition and preparation of film therefrom |
| JP2000198171A (en) * | 1998-10-28 | 2000-07-18 | Mitsui Chemicals Inc | Laminate |
-
2000
- 2000-09-18 JP JP2000281108A patent/JP5159003B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JP2002088168A (en) | 2002-03-27 |
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