JP2004284135A - Laminated polypropylene film and sealed trimmed package comprising the same - Google Patents
Laminated polypropylene film and sealed trimmed package comprising the same Download PDFInfo
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- JP2004284135A JP2004284135A JP2003077502A JP2003077502A JP2004284135A JP 2004284135 A JP2004284135 A JP 2004284135A JP 2003077502 A JP2003077502 A JP 2003077502A JP 2003077502 A JP2003077502 A JP 2003077502A JP 2004284135 A JP2004284135 A JP 2004284135A
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- -1 polypropylene Polymers 0.000 title claims abstract description 50
- 239000004743 Polypropylene Substances 0.000 title claims abstract description 47
- 229920001155 polypropylene Polymers 0.000 title claims abstract description 46
- 229920005989 resin Polymers 0.000 claims abstract description 54
- 239000011347 resin Substances 0.000 claims abstract description 54
- 238000002844 melting Methods 0.000 claims abstract description 13
- 230000008018 melting Effects 0.000 claims abstract description 13
- 229920006378 biaxially oriented polypropylene Polymers 0.000 claims abstract description 11
- 239000011127 biaxially oriented polypropylene Substances 0.000 claims abstract description 11
- 239000005026 oriented polypropylene Substances 0.000 claims abstract description 10
- CTQNGGLPUBDAKN-UHFFFAOYSA-N O-Xylene Chemical compound CC1=CC=CC=C1C CTQNGGLPUBDAKN-UHFFFAOYSA-N 0.000 claims abstract description 5
- 229920001577 copolymer Polymers 0.000 claims abstract description 5
- 239000008096 xylene Substances 0.000 claims abstract description 5
- 229920005674 ethylene-propylene random copolymer Polymers 0.000 claims description 7
- 229920005676 ethylene-propylene block copolymer Polymers 0.000 claims description 3
- 238000009736 wetting Methods 0.000 claims description 3
- IYYGCUZHHGZXGJ-UHFFFAOYSA-N but-1-ene;ethene;prop-1-ene Chemical compound C=C.CC=C.CCC=C IYYGCUZHHGZXGJ-UHFFFAOYSA-N 0.000 claims 1
- 238000007789 sealing Methods 0.000 abstract description 5
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 abstract description 2
- 239000005977 Ethylene Substances 0.000 abstract description 2
- HQQADJVZYDDRJT-UHFFFAOYSA-N ethene;prop-1-ene Chemical group C=C.CC=C HQQADJVZYDDRJT-UHFFFAOYSA-N 0.000 abstract 2
- 229920001400 block copolymer Polymers 0.000 abstract 1
- 229920005604 random copolymer Polymers 0.000 abstract 1
- 229920001897 terpolymer Polymers 0.000 abstract 1
- 238000009966 trimming Methods 0.000 abstract 1
- 239000010410 layer Substances 0.000 description 103
- 238000000034 method Methods 0.000 description 18
- 239000002245 particle Substances 0.000 description 11
- IMNFDUFMRHMDMM-UHFFFAOYSA-N N-Heptane Chemical compound CCCCCCC IMNFDUFMRHMDMM-UHFFFAOYSA-N 0.000 description 6
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 6
- 238000000605 extraction Methods 0.000 description 6
- 150000003973 alkyl amines Chemical class 0.000 description 5
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 4
- 239000002216 antistatic agent Substances 0.000 description 4
- 238000001816 cooling Methods 0.000 description 4
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- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 3
- 239000000460 chlorine Substances 0.000 description 3
- 229910052801 chlorine Inorganic materials 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
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- 229920003229 poly(methyl methacrylate) Polymers 0.000 description 3
- 239000004926 polymethyl methacrylate Substances 0.000 description 3
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- 238000012545 processing Methods 0.000 description 3
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 3
- 235000012239 silicon dioxide Nutrition 0.000 description 3
- 239000000377 silicon dioxide Substances 0.000 description 3
- 239000003381 stabilizer Substances 0.000 description 3
- CXWXQJXEFPUFDZ-UHFFFAOYSA-N tetralin Chemical compound C1=CC=C2CCCCC2=C1 CXWXQJXEFPUFDZ-UHFFFAOYSA-N 0.000 description 3
- 101000582396 Escherichia phage D108 Repressor c protein Proteins 0.000 description 2
- 101000582397 Escherichia phage Mu Repressor protein c Proteins 0.000 description 2
- ZHNUHDYFZUAESO-UHFFFAOYSA-N Formamide Chemical compound NC=O ZHNUHDYFZUAESO-UHFFFAOYSA-N 0.000 description 2
- 239000004793 Polystyrene Substances 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- 125000001931 aliphatic group Chemical group 0.000 description 2
- 239000012298 atmosphere Substances 0.000 description 2
- 238000009835 boiling Methods 0.000 description 2
- 229910000019 calcium carbonate Inorganic materials 0.000 description 2
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- 230000007423 decrease Effects 0.000 description 2
- GDVKFRBCXAPAQJ-UHFFFAOYSA-A dialuminum;hexamagnesium;carbonate;hexadecahydroxide Chemical compound [OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Al+3].[Al+3].[O-]C([O-])=O GDVKFRBCXAPAQJ-UHFFFAOYSA-A 0.000 description 2
- ZBCBWPMODOFKDW-UHFFFAOYSA-N diethanolamine Chemical compound OCCNCCO ZBCBWPMODOFKDW-UHFFFAOYSA-N 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 229960001545 hydrotalcite Drugs 0.000 description 2
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- 238000009413 insulation Methods 0.000 description 2
- 238000010030 laminating Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000011146 organic particle Substances 0.000 description 2
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 2
- 229920002223 polystyrene Polymers 0.000 description 2
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 2
- 239000002516 radical scavenger Substances 0.000 description 2
- 235000011888 snacks Nutrition 0.000 description 2
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 2
- LDVVTQMJQSCDMK-UHFFFAOYSA-N 1,3-dihydroxypropan-2-yl formate Chemical compound OCC(CO)OC=O LDVVTQMJQSCDMK-UHFFFAOYSA-N 0.000 description 1
- VXNZUUAINFGPBY-UHFFFAOYSA-N 1-Butene Chemical compound CCC=C VXNZUUAINFGPBY-UHFFFAOYSA-N 0.000 description 1
- ZNQVEEAIQZEUHB-UHFFFAOYSA-N 2-ethoxyethanol Chemical compound CCOCCO ZNQVEEAIQZEUHB-UHFFFAOYSA-N 0.000 description 1
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N EtOH Substances CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- AOMUHOFOVNGZAN-UHFFFAOYSA-N N,N-bis(2-hydroxyethyl)dodecanamide Chemical compound CCCCCCCCCCCC(=O)N(CCO)CCO AOMUHOFOVNGZAN-UHFFFAOYSA-N 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 150000008431 aliphatic amides Chemical class 0.000 description 1
- 239000003963 antioxidant agent Substances 0.000 description 1
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- 235000008429 bread Nutrition 0.000 description 1
- IAQRGUVFOMOMEM-UHFFFAOYSA-N butene Natural products CC=CC IAQRGUVFOMOMEM-UHFFFAOYSA-N 0.000 description 1
- CJZGTCYPCWQAJB-UHFFFAOYSA-L calcium stearate Chemical compound [Ca+2].CCCCCCCCCCCCCCCCCC([O-])=O.CCCCCCCCCCCCCCCCCC([O-])=O CJZGTCYPCWQAJB-UHFFFAOYSA-L 0.000 description 1
- 235000013539 calcium stearate Nutrition 0.000 description 1
- 239000008116 calcium stearate Substances 0.000 description 1
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- 229920006026 co-polymeric resin Polymers 0.000 description 1
- 235000009508 confectionery Nutrition 0.000 description 1
- 239000002537 cosmetic Substances 0.000 description 1
- 150000005690 diesters Chemical class 0.000 description 1
- 238000004043 dyeing Methods 0.000 description 1
- BXKDSDJJOVIHMX-UHFFFAOYSA-N edrophonium chloride Chemical compound [Cl-].CC[N+](C)(C)C1=CC=CC(O)=C1 BXKDSDJJOVIHMX-UHFFFAOYSA-N 0.000 description 1
- UAUDZVJPLUQNMU-KTKRTIGZSA-N erucamide Chemical compound CCCCCCCC\C=C/CCCCCCCCCCCC(N)=O UAUDZVJPLUQNMU-KTKRTIGZSA-N 0.000 description 1
- 239000000706 filtrate Substances 0.000 description 1
- 235000013305 food Nutrition 0.000 description 1
- 230000004927 fusion Effects 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
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- 150000002596 lactones Chemical class 0.000 description 1
- 229940031957 lauric acid diethanolamide Drugs 0.000 description 1
- 238000004811 liquid chromatography Methods 0.000 description 1
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- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- LYRFLYHAGKPMFH-UHFFFAOYSA-N octadecanamide Chemical compound CCCCCCCCCCCCCCCCCC(N)=O LYRFLYHAGKPMFH-UHFFFAOYSA-N 0.000 description 1
- 239000005022 packaging material Substances 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 150000002989 phenols Chemical class 0.000 description 1
- OJMIONKXNSYLSR-UHFFFAOYSA-N phosphorous acid Chemical class OP(O)O OJMIONKXNSYLSR-UHFFFAOYSA-N 0.000 description 1
- 238000009832 plasma treatment Methods 0.000 description 1
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- 229930003799 tocopherol Natural products 0.000 description 1
- 239000011732 tocopherol Substances 0.000 description 1
- 235000019149 tocopherols Nutrition 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 239000004711 α-olefin Substances 0.000 description 1
- QUEDXNHFTDJVIY-UHFFFAOYSA-N γ-tocopherol Chemical class OC1=C(C)C(C)=C2OC(CCCC(C)CCCC(C)CCCC(C)C)(C)CCC2=C1 QUEDXNHFTDJVIY-UHFFFAOYSA-N 0.000 description 1
Images
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- Laminated Bodies (AREA)
Abstract
Description
【０００１】
【発明の属する技術分野】
本発明は、包装材料に好適な直線カット性に優れる積層ポリプロピレンフイルムに関するものであり、更に詳しくは、サンドイッチ等、スナック類、一般菓子類の包装体に好適な溶断シール包装体に関するものである。
【０００２】
【従来の技術】
ポリプロピレンフイルムの直線カット性を付与する技術としては、一軸延伸フイルム層と二軸延伸フイルム層とを積層することで優れたカット性を付与できることが提案されている（例えば特許文献１〜３参照）。これらの中でも一軸配向ポリプロピレン樹脂層と二軸配向ポリプロピレン樹脂層との間に結晶融解熱量の小さいＰＰを積層する事が提案されている。（例えば特許文献４参照）。しかしながら、該構成によると一軸延伸層と二軸延伸層との接着性は良好となるものの、その加工適性の中でも特に溶断シール特性については、該フイルムの強い異方性から使用方法が制限されるという問題があった。すなわち、溶断シール構造部は樹脂が一旦溶融することで無配向化されるが近接する未溶融部分は熱を受けることによりむしろ結晶化による脆化現象を生じる。特に、該一軸延伸層の分子鎖の配向と平行な方向をシール面となるように溶断シールを行うと、近接する一軸延伸フイルム構造部は脆化し、分子配向方向に避け易くなり、溶断シール部分から容易に切断する可能性があった。
【０００３】
【特許文献１】実開昭４９−５７５６７号公報
【０００４】
【特許文献２】特開昭５１−１９０８０号公報
【０００５】
【特許文献３】特開５７−２５９５３号公報
【０００６】
【特許文献４】特開２０００−２５１７３号公報
【０００７】
【発明が解決しようとする課題】
本発明は直線カット性に優れ、かつ溶断シール強度が高い溶断シール体を提供せんとするものである。
【０００８】
【課題を解決するための手段】
上記課題は、少なくとも二軸配向ポリプロピレン層（Ａ層）、一軸配向ポリプロピレン層（Ｂ層）、共重合ポリプロピレン樹脂層（Ｃ層）の３層からなるフィルムであって、Ａ層とＢ層の厚み比率がＡ：Ｂ＝１１：１００〜１００：１００であり、Ｂ層の冷キシレン可溶分ＣＸＳ値が１．０〜６．０％であり、かつＣ層がエチレンプロピレンランダム共重合体、エチレンプロピレンブテン３元共重合体、エチレンプロピレンブロック共重合体からなる群より選ばれた少なくとも一種からなり、Ｃ層の融点が１２５〜１５０℃、Ｃ層の厚みが０．５〜５μｍであることを特徴とする積層ポリプロピレンフイルム、によって解決される。
【０００９】
【発明の実施の形態】
本発明において二軸配向ポリプロピレン層（Ａ層）とは、ポリプロピレン樹脂を溶融押出し、シート状に成型した未延伸シートを、長手方向に４〜７倍延伸後、引き続いてその直角方向に５〜１５倍延伸する逐次二軸延伸法によって得られるものもの、あるいは未延伸シートを縦横同時に延伸することで長手方向に５〜１０倍、その直角方向に５〜１０に延伸されたものを指すが、本発明においては特に逐次二軸延伸法によって得られるものが直線カット性に優れるので好ましい。
【００１０】
また、一軸配向ポリプロピレンフイルム（Ｂ層）とは、ポリプロピレン樹脂を溶融押出して得られた未延伸シートを一軸に５〜１５倍に延伸することにより得られるフイルムである。
【００１１】
本発明は、このような二軸配向ポリプロピレン樹脂層（Ａ層）と一軸配向ポリプロピレン樹脂層（Ｂ層）とが積層されてなるものであるが、その積層方法としては、Ａ層の最大屈折率方向とＢ層の最大屈折率方向とが平行になるようにすることが直線カット性を良好とする上で好ましい。
【００１２】
また、Ａ層とＢ層の厚み比率はＡ：Ｂ＝１１：１００〜１００：１００であることが必要であり、好ましくは２５：１００〜６７：１００である。Ａ層の厚みがＢ層に比して小さすぎるとフイルムの破断が容易に起こるため包装体としての強度が低下したり、加工時にフイルムが破断する等の問題を生じる。一方、Ａ層の厚みがＢ層に比して大きすぎると直線カット性の劣ったものとなる。
【００１３】
また、Ａ層を形成するポリプロピレン樹脂としては、機械特性と直線カット性を良好とする上で、極限粘度［η］が１．６〜２．３ｄｌ／ｇであることが好ましく、更に１．８〜２．１ｄｌ／ｇであることが好ましい。更に該ポリプロピレン樹脂の規則性の指標であるアイソタクチックインデックス（ＩＩ）は８０〜９８％であることが好ましく、更に好ましくは９３〜９６％である。ＩＩがこの範囲であると、直線カット性が良好となる他、印刷等の加工適性、フイルムの層間強度、帯電防止性能、ヘイズが良好となるので好ましい。また、同様の理由で該ポリプロピレン樹脂の融点は、１５５〜１６４℃であることが好ましく、更に好ましくは１５７〜１５２℃である。このためには、該ポリプロピレン樹脂はエチレンプロピレンランダム共重合体等のプロピレン系共重合体を添加するあるいは予め少量のエチレン、ブテン等のαオレフインモノマーを共重合することで制御することができる。
【００１４】
次いで、Ｂ層を形成するポリプロピレン樹脂としては、溶断シール強度を良好とし、かつ直線カット性を良好とする上で、該ポリプロピレン樹脂のＣＸＳ値は１．０〜６．０％であり、更に好ましくは１．５〜５．５％、特に好ましくは２．０〜５．０％である。ＣＸＳ値は冷キシレンへの可溶分であるが、近似的には該樹脂の非晶性成分の含有量を表す。ＣＸＳ値が増加していくと結晶性が低下して溶断シール等の高温加工に際して受けた熱で結晶化することを防止できるが、一方で、分子配向が弱くなり、直線カット性が不十分になる。本発明者らは一軸配向層のＣＸＳ値を上述の範囲とすることで直線カット性を維持としながら、溶断シール強度を付与することに達成したものである。このようなＣＸＳ値を制御する方法としては、例えば（ＩＩ）が９６％以上である立体規則性の高いポリプロピレン樹脂にエチレンプロピレンランダムコポリマー、エチレンプロピレンブテンターポリマー等のプロピレン系の共重合体を添加する方法、あるいは、低結晶性乃至は非晶性のポリプロピレン樹脂を添加する方法、あるいはポリプロピレン樹脂を製造する際にマルチサイト触媒等を用いることで低結晶性成分を生成させＣＸＳ値を制御する方法等が例示される。本発明においては、例示した前者の方法、すなわち、立体規則性の高いポリプロピレン樹脂にプロピレン系共重合体及び／又は低結晶性性乃至非晶性ポリプロピレン樹脂を添加する方法がコスト面でも有利であり、特性制御も容易であり好ましい。
【００１５】
このようにＢ層のＣＸＳ値を上述の範囲に制御しておくことの効果としては、溶断シール部の強度を好適に保つ以外に、帯電防止性能を安定して発現することが可能になるので好ましい。通常、二軸配向ポリプロピレンフイルムであれば、該フイルムを構成するポリプロピレン樹脂に アルキルメチルジベタイン、アルキルアミンジエタノール及び／又はアルキルアミンエタノールエステル及び／又はアルキルアミンジエタノールジエステル等を添加しておけば、帯電防止性能の指標である表面比抵抗（ｌｏｇΩ）が８〜１４、好ましくは９〜１３の製品を比較的安定して製造することができる。一方、一軸配向ポリプロピレンフイルムの場合、同様に帯電防止剤のみを添加しても、配向によりポリプロピレン鎖の分子運動が制限されているためか、安定した性能が出せず、１０乗レベルから１８乗レベルに表面比抵抗がばらつく可能性があった。このような観点からのＣＸＳ値の制限は下限については、上述の範囲と同様であるが、上限については特に制約は無く、実質的には直線カット性の観点からの制約条件となる。
また該Ｂ層を構成する樹脂として具備すべき特性としては、直線カット性を良好とし、強度を維持する観点から該樹脂の極限粘度［η］は１．３〜２．１ｄｌ／ｇであることが好ましく、更に好ましくは１．５〜１．９ｄｌ／ｇである。
【００１６】
また、該Ｂ層を構成する樹脂の融点としては、１５２〜１６１℃であるとカット性・強度共に良好になるので好ましく、更に好ましくは１５５〜１５９℃である。
【００１７】
更に、Ａ層およびＢ層のいずれにもにも酸化防止剤等の安定剤、塩素捕獲剤、帯電防止剤、スリップ剤等を含有することができる。安定剤としては、ヒンダードフエノール系、ヒンダードアミン系、フォスファイト系化合物、あるいはトコフェロール類、ラクトン類が例示される。更に塩素捕獲剤としては、ステアリン酸カルシウム、ハイドロタルサイト等が例示されるが、特にハイドロタルサイトが異物の発生が少なく好ましい。また、耐電防止剤としては、アルキルメチルジベタイン、アルキルアミンジエタノール及び／又はアルキルアミンエタノールエステル及び／又はアルキルアミンジエタノールジエステル、スリップ剤としては有機系としてはステアリン酸アミド、エルカ酸アミド等脂肪族アミド、ラウリル酸ジエタノールアミド、アルキルジエタノールアミン、脂肪族モノグリセライド、脂肪族ジグリセライド等、無機系としては炭酸カルシウム、酸化チタン、二酸化珪素粒子、酸化アルミニウム粒子等、更にシリコーン粒子、架橋ポリメチルメタアクリレート粒子、架橋ポリスチレン等粒子の有機粒子等も使用可能である。
【００１８】
本発明においては、Ａ層、Ｂ層に加えて、共重合ポリプロピレン樹脂層（Ｃ層）からなることが必要である。Ｃ層を形成する樹脂は、溶断シール特性、光沢感を良好とする上で、エチレンプロピレンランダム共重合体、エチレンプロピレンブテン３元共重合体、エチレンプロピレンブロック共重合体からなる群より選ばれた少なくとも一種からなることが必要である。また、Ｃ層融点は１２５〜１５０℃であることが必要であり、好ましくは１３０〜１４８℃である。融点が低すぎると結晶化が遅くなるため溶断シール速度が低下する。一方融点が高すぎると溶断シール強度が低下するという問題を生じる。また、Ｃ層の厚みが０．５〜５μｍであることが必要であり、好ましくは１〜４μｍである。該厚みが薄すぎると溶断シール強度が低下する。一方厚すぎると溶断シールの仕上がり概観が悪化する。
【００１９】
Ｃ層には公知の安定剤、塩素捕獲剤、滑り剤を添加することができる。特に、Ｃ層には炭酸カルシウム、二酸化珪素、酸化チタン、酸化アルミニウム粒子等の無機粒子あるいはシリコーン粒子、架橋ポリメチルメタアクリレート、架橋ポリスチレン等の有機粒子から選ばれた少なくとも一種の粒子を添加しておくことが好ましく、特に二酸化珪素粒子、シリコーン粒子粒子、架橋ポリメチルメタアクリレート粒子であることが好ましい。その平均粒子径として、１〜５μｍであることが好ましく、更に好ましくは２〜４μｍである。また、添加量としては５００〜５０００ｐｐｍ、更に好ましくは１０００〜４０００ｐｐｍである。
【００２０】
本発明の積層ポリプロピレンフィルムにおいて、Ｃ層は、Ａ層とＢ層との関係において何れの位置に配置されても良い。特に、Ａ層とＢ層の間に配置すると両樹脂層の接着力が良好となると共に溶断シール特性が良好になるので好ましい。また、Ｃ層が更にＡ層の両面に配置され、すなわち、Ｃ層／Ａ層／Ｃ層／Ｂ層の構成としても良い。尚、かかる構成においては、Ｃ層に用いられる共重合ポリプロピレン樹脂層は同種のものであっても異種のものであっても構わない。かかる構成においては、溶断シール特性が更に安定すると共にヒートシール特性を付与できるので好ましい。この場合、溶断シール特性の観点から、両共重合樹脂層の合計が０．５〜５μｍであることが好ましく、より好ましくは１〜４μｍである。
【００２１】
特に本発明の積層ポリプロピレンフイルムはその性質上、二軸配向ポリプロピレン樹脂層（Ａ層）が積層されている側にカールする特性を有し、印刷等を施す場合には、一軸配向ポリプロピレン樹脂層（Ｂ層）が積層されている側の表面に印刷する方が工程適性に優れている。そのため、少なくともＢ層が積層されている側のフィルム表面の濡れ張力を３６〜５０ｍＮ／ｍ、より好ましくは３８〜４８ｍＮ／ｍとしておくと好ましい。このような表面張力を付与するための技術としては公知のコロナ放電処理、常温プラズマ処理、火炎処理等が例示される。また、印刷後の加工適性を良好とするために、該Ｂ層の表面比抵抗（ｌｏｇΩ）は８〜１４、更に好ましくは９〜１３であることが好ましい。
【００２２】
また、本発明の積層ポリプロピレンフイルムのシャルピー衝撃強さは１．０〜２．５ＭＪ／ｍ２であると、フイルムをカット性と加工適性を両立できるので好ましく、更に好ましくは１．３〜２．３ＭＪ／ｍ２である。
【００２３】
尚、本発明の積層ポリプロピレンフイルムのトータル厚みは限定されるものではないが、通常１０〜１００μｍの範囲である。
【００２４】
次に本発明溶断シール包装体は、上述の特徴を有する積層ポリプロピレンフイルムからなり、他のフイルムを積層する事も可能であるが、通常は単独で使用することが本発明フイルムの有する直線カット性が良好となるので好ましい。
【００２５】
また、該包装体の開口方法として、直線的に開口できるような加工を施すことが好ましいが、本発明フイルムの最大屈折率方向に２〜２０ｍｍの切り込みを１カ所以上入れることで可能となるので好ましく、更に、該切り込みは３ｍｍ〜２０ｍｍの間隔を開けて２カ所に設置すると好ましい。このようにした場合は、本発明溶断シール体はテイアテープ等の直線的にカットする補助的手段が不要となるので好ましい。
【００２６】
尚、本発明溶断シール包装体は上述の様に積層フイルムのカール特性から、Ｂ層が積層された側を包装体の外面にすることが好ましい。
【００２７】
本発明溶断シール包装体は、サンドイッチ、食パン、スナック等の食品類、書籍、コンパクトデイスク、化粧品類等を包装する包装体として好ましく使用される。
【００２８】
次に本発明積層ポリプロピレンフイルムの製造方法について説明するが、本記述に限定されるものでは無い。
【００２９】
二軸配向ポリプロピレン樹脂層（Ａ層）を形成するポリプロピレン樹脂Ａを押出機Ｉにて２３０〜２８０℃で溶融混練する、と共に、別な押出機ＩＩにて共重合ポリプロピレン樹脂層（Ｃ層）を形成する樹脂Ｃを２３０〜２８０℃で溶融混練する。次いでそれぞれの樹脂をポリマー管を通じてＴ型口金に導いて、口金内で積層してＣ／Ａ／ＣまたはＡ／Ｃからなるシート状に押出し、冷却ドラム上で冷却固化する。このようにして得られた未延伸シートを１２０〜１５５℃で予熱して、低速ロールと高速ロールの間で長手方向に３．５〜７．０倍に延伸し直ちに冷却し一軸延伸フイルムを得る。
【００３０】
次いで、一軸ポリプロピレン樹脂層（Ｂ層）形成する樹脂Ｂを押出機ＩＩＩにて２３０〜２８０℃で溶融混練し、Ｔ型口金よりシート状に押出し、冷却ドラム上で先の一軸延伸フイルムとラミネートし該一軸延伸フイルムと樹脂Ｂとが一体化した積層フイルムを得る。
【００３１】
こうして得られた積層フイルムの両端部をクリップで把持して１４０〜１７０℃に予熱後、幅方向に５〜１２倍延伸する。次いで１４０〜１６０℃で熱固定し、更に幅方向に０〜１０％のリラックスを取りながら１３０〜１５５℃でアニールし、両エッジ部をトリミングし、必要に応じて少なくとも片面にコロナ放電処理、火炎処理等の表面処理等を施した後に巻き取る。
【００３２】
また、本発明溶断シール体は本発明フイルムに必要に印刷加工等を施し、公知の溶断シール方法で加工されるものであり、特に製造方法を限定されるものでは無い。
【００３３】
【実施例】
本発明の実施例で用いた、測定方法、評価方法を以下に述べる。
（１）樹脂層の厚み及び厚み比率
ミクロトームでフイルム断面を切り出し、該フイルム断面を走査型電子顕微鏡で観測して厚みを求める。樹脂層が区分しにくい場合は必要に応じて染色法により層区分することができる。尚、Ａ層とＢ層との厚み比率はＢ層厚みを基準（１００）として表す。
（２）アイソタクチックインデックス（ＩＩ）
沸騰ｎ−ヘプタン抽出残分であり、次の様に測定される。すなわち、円筒濾紙を１１０±５℃で２時間乾燥し、恒温恒湿の室内で２時間以上放置してから、円筒濾紙中に試料（粉体またはフレーク状）８〜１０ｇを入れ、秤量カップ、ピンセットを用いて精秤する。これをｎ−ヘプタン約８０ｃｃの入ったソックスレー抽出器にセットして１２時間抽出する。抽出条件としては、冷却器からの滴下数が１分間１３０滴以上とする。抽出後抽出残査の入った円筒濾紙を取り出し、真空乾燥機にて８０℃、１００ｍｍＨｇ以下の真空で５時間乾燥する。ついで恒温恒湿中に２時間放置した後に精秤し、以下の式で求める。
【００３４】
ＩＩ（％）＝Ｐ／Ｐ０×１００
但し、Ｐ０は抽出前の試料重量（ｇ）、Ｐは抽出後の試料重量（ｇ）である。
（３）融点
示差走査型熱量計（ＤＳＣ）を用いて求める。サンプル５ｍｇを窒素雰囲気中で室温より速度は２０℃／１０分で昇温して、結晶の融解に基づく吸熱ピークを融点とする。尚、ピークが複数検出される場合は複数のピークの面積平均値をその融点とする。
（４）極限粘度［η］
ＡＳＴＭ Ｄ １６０１に従って、テトラリン中で測定する（ｄｌ／ｇ）。
（５）ＣＸＳ値
試料０．５ｇを沸騰キシレン１００ｍｌに溶解して放冷後、２０℃の恒温水槽で１時間再結晶化させた後のろ過液に溶解しているポリプロピレン系成分を液体クロマトグラフ法にて定量する（Ｘ（ｇ））。試料０．５ｇの精量値（Ｘ０（ｇ）を用いて以下の式で求める。
【００３５】
ＣＸＳ値（％）＝Ｘ／Ｘ０×１００
（６）濡れ張力
ホルムアミドとエチレングリコールモノエチルエーテルとの混合液によるＪＩＳ Ｋ ６７６に規定された測定方法に基づいて測定する。
（７）加熱収縮率
ＪＩＳ Ｋ１７１２に準じて測定する。
（８）表面比抵抗（ｌｏｇΩ）
サンプルを１００ｍｍ×１００ｍｍに切り出し、２３±２℃、６５±５％ＲＨの雰囲気に１時間放置した後に、超絶縁計（東亜ディーケーケー（株）：絶縁計（ＤＳＭー８１０３），平板資料測定用電極（ＳＭＥ−８３１０））により測定した。
（９）シャルピー衝撃強さ
一軸配向フイルムの配向方向に平行な方向をＤ１、直角方向をＤ２としたときに、１０ｍｍ（Ｄ１）×１００ｍｍ（Ｄ２）の形状にサンプルを切り出し、シャルピー衝撃強度試験機（東洋精機製）を用いてＪＩＳ−Ｋ７１１１に準じて、サンプル１０ｍｍ幅当たりの衝撃強さを測定する。衝撃強さはフイルムの単位厚み当たりの値として、シャルピー衝撃強さ（ＭＪ／ｍ２）＝測定衝撃強さ（Ｊ／１０ｍｍ幅）／測定厚み（ｍｍ）で算出する。
（１０）ヘイズ
ＪＩＳ−Ｋ７１０５に従い、フイルム１枚当たりのヘイズを求めた。単位は％。
（１１）溶断シール加工適性
幅４００ｍｍのロール状フイルムサンプルを、溶断シールテスト装置にてフイルム幅方向の中央部で折り曲げ、溶断シールして、２００ｍｍ×１５０ｍｍの袋体とした。尚、溶断シール条件としては、シールバーの温度が３５０℃になるようにコントロールした。
Ａ．作業適性
この際に成形された袋体２０枚の端面を突き揃えてセットにする際の作業適性を以下のように判定した。
【００３６】
突き揃えができない ：×
突き揃えはなんとかできるができたセットの最表層から
袋体１体を剥離しようとすると抵抗感を感じる ：△
突き揃えが容易にでき、袋体の剥離も抵抗感無くできる ：○
Ｂ．溶断シール強度
溶断シール部を含むを１５ｍｍ幅×１００ｍｍ長の短冊状のサンプルをテンシロンにて引張り試験を行い測定する。引張り速度は２００ｍｍ／分とする。尚、サンプリングは、該シールラインが短冊の長軸に直角で、かつ、中央に位置するように行う。
（１２）直線カット性
フイルムサンプルの最大屈折率の方向と並行な方向が長辺となる長方形のサンプル（Ａ４版サイズ）を切り出し、長辺の上端部を水平な平板に両面テープで固定する。次に一方の短辺の中央部に幅が１０ｍｍ深さが１０ｍｍの切り出し口を設け、手でゆっくりと切り出し口を引っ張りながら切り開いていく際の角度を該長辺と並行な角度と３０度をなす角度とした際に、切り出されたフイルムの長さと角度を評価して、直線カット性とする。
【００３７】
［実施例１〜３］
二軸配向ポリプロピレン樹脂（Ａ）層、共重合ポリプロピレン樹脂（Ｃ）層、一軸配向ポリプロピレン樹脂（Ｂ）層として表１の樹脂を選定した。また、このために準備した各樹脂の構成は表２に示す通りであり、それぞれ帯電防止性能、滑り性を付与するために帯電防止剤、有機・無機の滑り剤を所定量添加した。
【００３８】
次いで、樹脂Ａを押出機Ｉに、樹脂Ｃを押出機ＩＩにてそれぞれ溶融混練し、口金内で積層した後、冷却ドラムで冷却して未延伸シートを得た。
【００３９】
次いで該シートを予熱ロールにて１４０℃に予熱後長手方向に４．５倍延伸し、直ちに２５℃に保たれた金属ロールで急冷し一軸延伸フイルムを得た。次いで、押出機ＩＩＩで溶融混練した樹脂ＢをＴ型口金よりシート状に押出しこの一軸延伸フイルムに積層すると同時にニップロールと２０℃の冷却ドラム間で圧着・冷却固化して、一軸延伸フイルム／樹脂層Ｂからなる積層フイルムとした。
【００４０】
引き続き該積層フイルムの両端部をクリップにて把持して、１６０℃に保たれたオーブン中に導き幅方向に８倍の延伸を行い、次いで１５０℃の雰囲気で幅方向に５％のリラックスを許しながら熱処理を施した上で、エッジトリミング後樹脂層（Ｂ）の表層にコロナ放電処理を行い巻き取った。 。
【００４１】
こうして得られたフイルムの主要特性は表１に示す如く結果となり、フイルムの実用特性の評価の結果、表３に示すように直線カット性・溶断シール強度ともに優れた特性を示した。
［比較例１］
実施例１において、Ａ層の厚みを１３μｍ、Ｂ層の厚みを１０μｍとした以外は同様にして積層ポリプロピレンフイルムを得た。こうして得られたフイルムは直線カット性に劣ったものとなった（表３）。
［比較例２］
実施例１において、Ｂ層にエチレンプロピレンランダム共重合体（ｒＥＰＣ）を添加しなかった以外は同様にして積層ポリプロピレンフイルムを得た。こうして得られたフイルムは溶断シール強度の劣るものとなった（表３）。
［比較例３］
実施例１において、Ｂ層にエチレンプロピレンランダム共重合体（ｒＥＰＣ）を添加せず、また、Ｃ層として表２に示す低結晶性ポリプロピレン樹脂（ＬＰＰ）（ＩＩ＝８０％）を用いた以外は同様にして積層ポリプロピレンフイルムを得た。こうして得られたフイルムは溶断シール強度の劣るものとなった（表３）。
【００４２】
【表１】
【表２】
【表３】
【発明の効果】
【図面の簡単な説明】
【図１】本発明の積層ポリプロピレンフイルムを示す実施例１の説明図
【符号の説明】
１：一軸配向ポリプロピレン層（Ｂ層）
２：共重合ポリプロピレン層（Ｃ層）
３：二軸配向ポリプロピレン層（Ａ層）
４：共重合ポリプロピレン層（Ｃ層）[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a laminated polypropylene film having excellent linear cutability suitable for a packaging material, and more particularly to a fusing seal package suitable for a package of snacks such as sandwiches and general confectionery.
[0002]
[Prior art]
As a technique for imparting a linear cut property to a polypropylene film, it has been proposed that an excellent cut property can be imparted by laminating a uniaxially stretched film layer and a biaxially stretched film layer (for example, see
[0003]
[Patent Document 1] Japanese Utility Model Publication No. 49-57567
[Patent Document 2] Japanese Patent Application Laid-Open No. 51-19080
[Patent Document 3] Japanese Patent Application Laid-Open No. 57-25953
[Patent Document 4] Japanese Patent Application Laid-Open No. 2000-25173
[Problems to be solved by the invention]
An object of the present invention is to provide a fusing seal body which is excellent in linear cutability and has high fusing seal strength.
[0008]
[Means for Solving the Problems]
An object of the present invention is to provide a film comprising at least three layers of a biaxially oriented polypropylene layer (layer A), a uniaxially oriented polypropylene layer (layer B), and a copolymerized polypropylene resin layer (layer C). The ratio is A: B = 11: 100 to 100: 100, the layer B has a cold xylene solubles CXS value of 1.0 to 6.0%, and the layer C is an ethylene propylene random copolymer, ethylene Propylene butene terpolymer, at least one selected from the group consisting of ethylene propylene block copolymer, the melting point of the C layer is 125 to 150 ° C., and the thickness of the C layer is 0.5 to 5 μm. It is solved by a laminated polypropylene film, which is characterized by the following.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
In the present invention, the biaxially oriented polypropylene layer (layer A) refers to a non-stretched sheet obtained by melt-extruding a polypropylene resin and forming it into a sheet shape, stretching it 4 to 7 times in the longitudinal direction, and then 5 to 15 times in the perpendicular direction. What is obtained by a sequential biaxial stretching method in which the sheet is double-stretched, or an unstretched sheet which is stretched 5 to 10 times in the longitudinal direction by stretching simultaneously and vertically and 5 to 10 in the perpendicular direction thereof, In the invention, those obtained by the successive biaxial stretching method are particularly preferred because they have excellent linear cut properties.
[0010]
The uniaxially oriented polypropylene film (layer B) is a film obtained by uniaxially stretching an unstretched sheet obtained by melt-extruding a polypropylene resin by a factor of 5 to 15 times.
[0011]
In the present invention, such a biaxially oriented polypropylene resin layer (layer A) and a uniaxially oriented polypropylene resin layer (layer B) are laminated. The laminating method is as follows. It is preferable to make the direction parallel to the direction of the maximum refractive index of the layer B in order to improve the linear cut property.
[0012]
Further, the thickness ratio of the A layer and the B layer needs to be A: B = 11: 100 to 100: 100, and preferably 25: 100 to 67: 100. If the thickness of the layer A is too small as compared with the layer B, the film is easily broken, which causes problems such as a decrease in strength as a package and a break of the film during processing. On the other hand, if the thickness of the layer A is too large as compared with the layer B, the straight-line cut property is inferior.
[0013]
The polypropylene resin forming the layer A preferably has an intrinsic viscosity [η] of 1.6 to 2.3 dl / g, and more preferably 1.8, in order to improve the mechanical properties and the linear cut property. Preferably it is ~ 2.1 dl / g. Further, the isotactic index (II), which is an index of the regularity of the polypropylene resin, is preferably from 80 to 98%, more preferably from 93 to 96%. When the value of II is in this range, the linear cutability is improved, and the workability of printing and the like, the interlayer strength of the film, the antistatic performance, and the haze are improved, which is preferable. For the same reason, the melting point of the polypropylene resin is preferably from 155 to 164 ° C, more preferably from 157 to 152 ° C. For this purpose, the polypropylene resin can be controlled by adding a propylene-based copolymer such as an ethylene-propylene random copolymer or by previously copolymerizing a small amount of an α-olefin monomer such as ethylene or butene.
[0014]
Next, as the polypropylene resin forming the layer B, the CXS value of the polypropylene resin is preferably 1.0 to 6.0%, and more preferably, in order to improve the fusing seal strength and the linear cut property. Is 1.5 to 5.5%, particularly preferably 2.0 to 5.0%. The CXS value is a soluble component in cold xylene, and approximately indicates the content of an amorphous component of the resin. As the CXS value increases, the crystallinity decreases and it is possible to prevent crystallization by the heat received during high-temperature processing such as fusing seals, but on the other hand, the molecular orientation is weakened and the linear cutability is insufficient. Become. The present inventors have achieved achieving the fusing seal strength while maintaining the linear cut property by setting the CXS value of the uniaxially oriented layer in the above range. As a method of controlling the CXS value, for example, a propylene copolymer such as an ethylene propylene random copolymer or an ethylene propylene butene terpolymer is added to a highly stereoregular polypropylene resin having (II) of 96% or more. Or a method of adding a low-crystalline or non-crystalline polypropylene resin, or a method of controlling the CXS value by generating a low-crystalline component by using a multi-site catalyst or the like when producing a polypropylene resin. Etc. are exemplified. In the present invention, the former method exemplified above, that is, a method of adding a propylene-based copolymer and / or a low-crystalline to amorphous polypropylene resin to a polypropylene resin having high stereoregularity is advantageous in terms of cost. In addition, it is easy and preferable to control characteristics.
[0015]
The effect of controlling the CXS value of the B layer in the above range as described above is that, besides maintaining the strength of the fusing seal portion suitably, it is also possible to stably exhibit antistatic performance. preferable. Normally, in the case of a biaxially oriented polypropylene film, charging is achieved by adding alkylmethyldibetaine, alkylamine diethanol and / or alkylamine ethanolester and / or alkylamine diethanoldiester to the polypropylene resin constituting the film. A product having a surface resistivity (logΩ) of 8 to 14, preferably 9 to 13, which is an index of the prevention performance, can be produced relatively stably. On the other hand, in the case of a uniaxially oriented polypropylene film, even if only an antistatic agent is similarly added, it is likely that the molecular motion of the polypropylene chain is restricted by the orientation, and stable performance cannot be obtained. The surface resistivity may vary. The lower limit of the CXS value from this viewpoint is the same as the above-mentioned range, but the upper limit is not particularly limited, and is substantially a constraint from the viewpoint of straight-line cutability.
In addition, as a characteristic to be provided as the resin constituting the layer B, the intrinsic viscosity [η] of the resin is 1.3 to 2.1 dl / g from the viewpoint of improving the linear cut property and maintaining the strength. And more preferably 1.5 to 1.9 dl / g.
[0016]
Further, the melting point of the resin constituting the layer B is preferably from 152 to 161 ° C., since both the cut properties and the strength are improved, and more preferably from 155 to 159 ° C.
[0017]
Further, both the layer A and the layer B may contain a stabilizer such as an antioxidant, a chlorine scavenger, an antistatic agent, a slip agent and the like. Examples of the stabilizer include hindered phenol compounds, hindered amine compounds, phosphite compounds, or tocopherols and lactones. Examples of the chlorine scavenger include calcium stearate and hydrotalcite. Hydrotalcite is particularly preferable since it does not generate foreign substances. Examples of the antistatic agent include alkylmethyldibetaine, alkylamine diethanol and / or alkylamine ethanol ester and / or alkylamine diethanol diester, and slip agents such as organic stearic acid amide and erucic acid amide such as aliphatic amide. , Lauric acid diethanolamide, alkyl diethanolamine, aliphatic monoglyceride, aliphatic diglyceride, etc., inorganic materials such as calcium carbonate, titanium oxide, silicon dioxide particles, aluminum oxide particles, etc., and further silicone particles, cross-linked polymethyl methacrylate particles, cross-linked polystyrene Organic particles having the same size can also be used.
[0018]
In the present invention, it is necessary to include a copolymerized polypropylene resin layer (C layer) in addition to the A layer and the B layer. The resin forming the C layer is selected from the group consisting of ethylene propylene random copolymer, ethylene propylene butene terpolymer, and ethylene propylene block copolymer in order to improve the fusing seal characteristics and glossiness. It must be at least one kind. Further, the melting point of the C layer needs to be 125 to 150 ° C, preferably 130 to 148 ° C. If the melting point is too low, the crystallization will be slow, and the fusing seal speed will be reduced. On the other hand, if the melting point is too high, there is a problem that the fusing seal strength is reduced. Further, the thickness of the C layer needs to be 0.5 to 5 μm, and preferably 1 to 4 μm. If the thickness is too small, the fusing seal strength is reduced. On the other hand, if it is too thick, the finished appearance of the fusing seal deteriorates.
[0019]
Known stabilizers, chlorine scavengers, and slip agents can be added to the C layer. In particular, to the C layer, at least one kind of particles selected from inorganic particles such as calcium carbonate, silicon dioxide, titanium oxide and aluminum oxide particles or organic particles such as silicone particles, cross-linked polymethyl methacrylate and cross-linked polystyrene is added. It is particularly preferable to use silicon dioxide particles, silicone particles, and crosslinked polymethyl methacrylate particles. The average particle size is preferably from 1 to 5 μm, more preferably from 2 to 4 μm. Further, the addition amount is 500 to 5000 ppm, more preferably 1000 to 4000 ppm.
[0020]
In the laminated polypropylene film of the present invention, the C layer may be arranged at any position in the relationship between the A layer and the B layer. In particular, it is preferable to dispose the resin layer between the layer A and the layer B because the adhesive strength between the two resin layers becomes good and the fusing seal characteristics become good. Further, the C layer may be further arranged on both sides of the A layer, that is, a configuration of C layer / A layer / C layer / B layer. In such a configuration, the copolymerized polypropylene resin layers used for the C layer may be of the same type or different types. Such a configuration is preferable because the fusing seal characteristics can be further stabilized and the heat seal characteristics can be imparted. In this case, the total of both copolymer resin layers is preferably 0.5 to 5 μm, and more preferably 1 to 4 μm, from the viewpoint of fusing seal characteristics.
[0021]
In particular, the laminated polypropylene film of the present invention has a property of curling on the side on which the biaxially oriented polypropylene resin layer (layer A) is laminated, and when printing is performed, the uniaxially oriented polypropylene resin layer ( Printing on the surface on the side where the layer (B) is laminated is more excellent in process suitability. Therefore, it is preferable to set the wetting tension of the film surface at least on the side where the layer B is laminated to 36 to 50 mN / m, more preferably 38 to 48 mN / m. Examples of techniques for imparting such surface tension include known corona discharge treatment, room temperature plasma treatment, flame treatment, and the like. Further, in order to improve the processing suitability after printing, the surface specific resistance (logΩ) of the B layer is preferably 8 to 14, more preferably 9 to 13.
[0022]
Further, the Charpy impact strength of the laminated polypropylene film of the present invention is preferably from 1.0 to 2.5 MJ / m 2 , because both the cutability and the workability of the film can be achieved, and more preferably from 1.3 to 2.2. 3 MJ / m 2 .
[0023]
Although the total thickness of the laminated polypropylene film of the present invention is not limited, it is usually in the range of 10 to 100 μm.
[0024]
Next, the fusion-sealed package of the present invention is made of a laminated polypropylene film having the above-described characteristics, and it is possible to laminate another film. Is preferred because
[0025]
In addition, as a method of opening the package, it is preferable to perform a process that allows opening in a straight line. However, since it becomes possible by making one or more cuts of 2 to 20 mm in the maximum refractive index direction of the film of the present invention. More preferably, the cuts are preferably installed at two places with an interval of 3 mm to 20 mm. In such a case, the fusing seal body of the present invention is preferable because auxiliary means for cutting linearly, such as tear tape, becomes unnecessary.
[0026]
In addition, in the fusing seal package of the present invention, it is preferable that the side on which the layer B is laminated is set as the outer surface of the package, from the curl characteristic of the laminated film as described above.
[0027]
The fusing seal package of the present invention is preferably used as a package for packaging foods such as sandwiches, breads, snacks, etc., books, compact discs, cosmetics, and the like.
[0028]
Next, a method for producing the laminated polypropylene film of the present invention will be described, but the present invention is not limited to this description.
[0029]
The polypropylene resin A for forming the biaxially oriented polypropylene resin layer (layer A) is melt-kneaded at 230 to 280 ° C. in an extruder I, and the copolymerized polypropylene resin layer (C layer) is formed in another extruder II. The resin C to be formed is melt-kneaded at 230 to 280 ° C. Next, each resin is guided to a T-type die through a polymer tube, laminated in the die, extruded into a sheet of C / A / C or A / C, and cooled and solidified on a cooling drum. The unstretched sheet thus obtained is preheated at 120 to 155 ° C., stretched 3.5 to 7.0 times in the longitudinal direction between a low-speed roll and a high-speed roll, and immediately cooled to obtain a uniaxially stretched film. .
[0030]
Next, the resin B for forming the uniaxial polypropylene resin layer (B layer) is melt-kneaded at 230 to 280 ° C. by an extruder III, extruded into a sheet shape from a T-type die, and laminated with a uniaxially stretched film on a cooling drum. A laminated film in which the uniaxially stretched film and the resin B are integrated is obtained.
[0031]
The laminated film thus obtained is gripped at both ends by clips and preheated to 140 to 170 ° C., and then stretched 5 to 12 times in the width direction. Then heat-set at 140-160 ° C., further annealed at 130-155 ° C. while relaxing 0-10% in the width direction, trim both edges, and if necessary, at least one side has corona discharge treatment, flame After being subjected to a surface treatment such as a treatment, it is wound up.
[0032]
Further, the fusing seal body of the present invention is obtained by subjecting the film of the present invention to printing or the like as necessary, and is processed by a known fusing sealing method, and the manufacturing method is not particularly limited.
[0033]
【Example】
The measurement method and the evaluation method used in the examples of the present invention will be described below.
(1) Thickness and thickness ratio of the resin layer A film section is cut out with a microtome, and the film section is observed with a scanning electron microscope to determine the thickness. If the resin layer is difficult to separate, the layer can be separated by a dyeing method as necessary. The thickness ratio between the layer A and the layer B is expressed with the thickness of the layer B as a reference (100).
(2) Isotactic index (II)
Boiling n-heptane extraction residue, measured as follows. That is, the cylindrical filter paper is dried at 110 ± 5 ° C. for 2 hours, left in a room of constant temperature and humidity for 2 hours or more, and then 8 to 10 g of a sample (powder or flake form) is placed in the cylindrical filter paper. Weigh precisely using tweezers. This is set in a Soxhlet extractor containing about 80 cc of n-heptane and extracted for 12 hours. The extraction condition is that the number of drops from the cooler is 130 drops or more per minute. After the extraction, the cylindrical filter paper containing the extraction residue is taken out and dried in a vacuum drier at 80 ° C. under a vacuum of 100 mmHg or less for 5 hours. Then, after being left in a constant temperature and constant humidity for 2 hours, it is precisely weighed and determined by the following formula.
[0034]
II (%) = P / P0 × 100
Here, P0 is the sample weight (g) before extraction, and P is the sample weight (g) after extraction.
(3) Determined using a melting point differential scanning calorimeter (DSC). 5 mg of the sample is heated at a rate of 20 ° C./10 minutes from room temperature in a nitrogen atmosphere, and an endothermic peak based on melting of the crystal is defined as a melting point. When a plurality of peaks are detected, the average value of the area of the plurality of peaks is used as the melting point.
(4) Intrinsic viscosity [η]
Determined in tetralin according to ASTM D 1601 (dl / g).
(5) CXS value 0.5 g of a sample was dissolved in 100 ml of boiling xylene, allowed to cool, recrystallized in a constant temperature water bath at 20 ° C. for 1 hour, and the polypropylene component dissolved in the filtrate was subjected to liquid chromatography. (X (g)). It is determined by the following equation using the precise value (X0 (g)) of 0.5 g of the sample.
[0035]
CXS value (%) = X / X0 × 100
(6) Wetting tension Measured according to a measuring method prescribed in JIS K 676 using a mixed solution of formamide and ethylene glycol monoethyl ether.
(7) Heat shrinkage rate Measured according to JIS K1712.
(8) Surface resistivity (logΩ)
A sample was cut out to 100 mm × 100 mm and left in an atmosphere of 23 ± 2 ° C. and 65 ± 5% RH for 1 hour. Then, a super-insulation meter (Toa DKK Co., Ltd .: insulation meter (DSM-8103), electrode for flat plate measurement) (SME-8310)).
(9) Charpy impact strength When a direction parallel to the orientation direction of the uniaxially oriented film is D1 and a perpendicular direction is D2, a sample is cut out into a shape of 10 mm (D1) × 100 mm (D2), and a Charpy impact strength tester is used. The impact strength per 10 mm width of the sample is measured using (manufactured by Toyo Seiki) in accordance with JIS-K7111. The impact strength is calculated as a value per unit thickness of the film, that is, Charpy impact strength (MJ / m2) = measured impact strength (J / 10 mm width) / measured thickness (mm).
(10) Haze Haze per film was determined according to JIS-K7105. Units%.
(11) Fusing Sealing Process A roll-shaped film sample having a width of 400 mm was bent at the center of the film in the film width direction by a fusing seal test device and fused and sealed to obtain a 200 mm × 150 mm bag. The fusing sealing conditions were controlled so that the temperature of the seal bar was 350 ° C.
A. Work suitability Work suitability in setting the end faces of the 20 molded bags at the same time was determined as follows.
[0036]
Unable to align: ×
You can manage the butt, but you feel resistance when you try to remove one bag from the outermost layer of the set: 抵抗
Butting can be easily done, and the bag can be peeled off without any resistance.
B. Fusing seal strength A rectangular sample having a width of 15 mm and a length of 100 mm including a fusing seal portion is measured by performing a tensile test with Tensilon. The pulling speed is 200 mm / min. Sampling is performed so that the seal line is at right angles to the long axis of the strip and at the center.
(12) Straight cut film A rectangular sample (A4 size) having a long side in a direction parallel to the direction of the maximum refractive index of the film sample is cut out, and the upper end of the long side is fixed to a horizontal flat plate with a double-sided tape. Next, a cutout having a width of 10 mm and a depth of 10 mm is provided at the center of one of the short sides, and the angle at which the cutout is opened while slowly pulling the cutout by hand is set to an angle parallel to the long side and 30 degrees. When the angle is formed, the length and the angle of the cut out film are evaluated to determine the straight-line cutability.
[0037]
[Examples 1 to 3]
The resins shown in Table 1 were selected as the biaxially oriented polypropylene resin (A) layer, the copolymerized polypropylene resin (C) layer, and the uniaxially oriented polypropylene resin (B) layer. The composition of each resin prepared for this purpose is as shown in Table 2, and a predetermined amount of an antistatic agent and an organic / inorganic slip agent were added to impart antistatic performance and lubricity, respectively.
[0038]
Next, the resin A was melt-kneaded in the extruder I and the resin C was melt-kneaded in the extruder II, laminated in a die, and cooled with a cooling drum to obtain an unstretched sheet.
[0039]
Next, the sheet was preheated to 140 ° C. by a preheating roll and then stretched 4.5 times in the longitudinal direction, and immediately quenched by a metal roll kept at 25 ° C. to obtain a uniaxially stretched film. Next, the resin B melt-kneaded by an extruder III is extruded into a sheet shape from a T-type die, laminated on this uniaxially stretched film, and simultaneously pressed and cooled and solidified between a nip roll and a cooling drum at 20 ° C. to obtain a uniaxially stretched film / resin layer. B was a laminated film.
[0040]
Subsequently, both ends of the laminated film are gripped with clips, guided into an oven maintained at 160 ° C., stretched eight times in the width direction, and then allowed to relax 5% in the width direction in an atmosphere at 150 ° C. After performing edge treatment, the surface layer of the resin layer (B) was subjected to corona discharge treatment and wound up. .
[0041]
The main characteristics of the film thus obtained were as shown in Table 1, and as a result of evaluation of the practical characteristics of the film, as shown in Table 3, excellent characteristics were exhibited in both the linear cut property and the fusing seal strength.
[Comparative Example 1]
A laminated polypropylene film was obtained in the same manner as in Example 1, except that the thickness of the layer A was 13 μm and the thickness of the layer B was 10 μm. The film thus obtained was inferior in straight-line cutting properties (Table 3).
[Comparative Example 2]
A laminated polypropylene film was obtained in the same manner as in Example 1, except that the ethylene propylene random copolymer (rEPC) was not added to the B layer. The film thus obtained was inferior in fusing seal strength (Table 3).
[Comparative Example 3]
In Example 1, except that the ethylene propylene random copolymer (rEPC) was not added to the layer B and the low crystalline polypropylene resin (LPP) (II = 80%) shown in Table 2 was used as the layer C, Similarly, a laminated polypropylene film was obtained. The film thus obtained was inferior in fusing seal strength (Table 3).
[0042]
[Table 1]
[Table 2]
[Table 3]
【The invention's effect】
[Brief description of the drawings]
FIG. 1 is an explanatory view of Example 1 showing a laminated polypropylene film of the present invention.
1: Uniaxially oriented polypropylene layer (B layer)
2: Copolypropylene layer (C layer)
3: Biaxially oriented polypropylene layer (layer A)
4: Copolypropylene layer (C layer)
Claims (7)
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| JP2003077502A JP4254289B2 (en) | 2003-03-20 | 2003-03-20 | Laminated polypropylene film and fusing sealed package comprising the same |
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| JP2003077502A JP4254289B2 (en) | 2003-03-20 | 2003-03-20 | Laminated polypropylene film and fusing sealed package comprising the same |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006248066A (en) * | 2005-03-11 | 2006-09-21 | Toray Ind Inc | Laminated polypropylene film |
| JP2007083580A (en) * | 2005-09-22 | 2007-04-05 | Toray Ind Inc | Laminated polypropylene film |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007331603A (en) | 2006-06-15 | 2007-12-27 | Kanzaki Kokyukoki Mfg Co Ltd | Shift device for inboard and outboard engine |
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