JP4089758B2

JP4089758B2 - Flexible container bag

Info

Publication number: JP4089758B2
Application number: JP00308995A
Authority: JP
Inventors: 史郎山本; 利之竹田; 規雄大石
Original assignee: Fujimori Kogyo Co Ltd
Current assignee: Fujimori Kogyo Co Ltd
Priority date: 1995-01-12
Filing date: 1995-01-12
Publication date: 2008-05-28
Anticipated expiration: 2023-05-28
Also published as: JPH08192891A

Description

【０００１】
【産業上の利用分野】
本発明は、熱可塑性樹脂よりなる延伸織布の両面に熱可塑性樹脂系フィルムを積層した積層シ−トで構成された立方体状又は直方体状のフレキシブルコンテナ袋に関し、特に、フレキシブルコンテナ袋の袋本体内部に設けた内張布と本体布との接合強度を向上させ、段積み強度を向上させたフレキシブルコンテナ袋に関する。
【０００２】
【従来の技術】
熱可塑性樹脂よりなる延伸織布の両面に熱可塑性樹脂系フィルムを積層した積層シ−トで構成されているフレキシブルコンテナ袋において、その内部に設けられた内張布と袋本体との接合は、そのフレキシブルコンテナ袋にとって極めて重要な問題である。
【０００３】
即ち、食品、穀物、肥料、化学薬品、或いは合成樹脂等の粉状もしくは粒状の輸送袋として利用されているフレキシブルコンテナ袋は、平織りのナイロン、ポリエステル或いは高密度ポリエチレン等の織布（クロスという）の両面にエチレン−酢酸ビニル共重合体（ＥＶＡタ−ポリン）、ポリ塩化ビニル（ＰＶＣタ−ポリン）或いは線状低密度ポリエチレン等の熱可塑性樹脂系フィルムを表層フィルムとして積層した積層シ−トで構成され、当該袋体の側壁の内側の偶角部には形状を保持するために同様の積層シ−トで構成されている内張布が設けられている。そして、袋本体と内張布との接合に際しては、表層フィルムがポリ塩化ビニルやエチレン−酢酸ビニル共重合体で構成されている積層シ−トの場合には高周波ウエルダ−で、また、ポリエチレンクロスにポリエチレンを表層フィルムとした積層した積層シ−トで構成されている場合には熱風溶着で、それぞれ溶着されている。
【０００４】
しかして、この高密度ポリエチレンクロスの両面に線状低密度ポリエチレンを表層フィルムとして積層した積層シ−トを形成するに際しては通常熱押出ラミネ−トによって行なっているが、線状低密度ポリエチレンとして炭素数４のアルキル基を側鎖に有するポリエチレン（以下、Ｃ４−ＬＬＤＰＥと称す。）が使用されている。このＣ４−ＬＬＤＰＥは、加工性がよく、熱押出温度においてポリエチレンクロスと容易に熱ラミネ−トすることが出来るが、この積層シ−トを使用してフレキシブルコンテナ袋とした場合、本体布と内張布との溶着部における接合強度に不十分な場合があった。
【０００５】
本体布と内張布との溶着強度が低い場合、高温充填や多段積みを行なうと剥離応力が溶着部の端部に作用し、その結果、表層フィルムが切断し積層シ−トのクロスと表層フィルムとの剥離や、表層フィルム同志の界面剥離等のトラブルが発生する。本体布と内張布とが剥離をすると袋本来の角型形状が失なわれ、段積み保管の場合には倒壊の恐れが生じる。このような剥離トラブルを防止するため、ラミネ−ト接着力の向上、ラミネ−トフィルム強度の向上、溶着強度の向上、特に剥離強度が作用する溶着端部の接合強度の向上等を図らなければならない。
【０００６】
【発明が解決しようとする課題】
そこで本発明者は種々検討した結果、本発明を完成したもので、本発明の目的は本体布と内張布との溶着部における接合強度が高く、段積み強度の高いフレキシブルコンテナ袋を提供することである。
【０００７】
【課題を解決するための手段】
本願の第１の発明の要旨は、袋体内部に形状を保持するため本体布に内張布を接合したフレキシブルコンテナ袋において、本体布と内張布との接合面が、ポリエチレンクロス面上に炭素数４のα−オレフィンを側鎖に有する線状低密度ポリエチレン層（以下、Ｃ４−ＬＬＤＰＥと称す。）を介して炭素数８のα−オレフィンを側鎖に有する線状低密度ポリエチレン層（以下、Ｃ８−ＬＬＤＰＥと称す。）同士を直接接合した接合面であるフレキシブルコンテナ袋であって、接合面を形成する本体布及び内張布の炭素数８のα−オレフィンを側鎖に有する線状低密度ポリエチレン層は、それぞれ、本体布及び内張布の少なくとも一方の面において炭素数４のα−オレフィンを側鎖に有する線状低密度ポリエチレン層に積層された炭素数８のα−オレフィンを側鎖に有する線状低密度ポリエチレン層であることを特徴とするフレキシブルコンテナ袋である。
本願の第２の発明の要旨は袋体内部に形状を保持するため本体布に中間布を介して内張布を接合したフレキシブルコンテナ袋において、本体布と内張布との接合面が、ポリエチレンクロス面上に炭素数４のα−オレフィンを側鎖に有する線状低密度ポリエチレン層を介して炭素数８のα−オレフィンを側鎖に有する線状低密度ポリエチレン層同士を接合した接合面であるフレキシブルコンテナ袋であって、接合面を形成する本体布の炭素数８のα−オレフィンを側鎖に有する線状低密度ポリエチレン層は、ポリエチレンクロスの両面に炭素数４のα−オレフィンを側鎖に有する線状低密度ポリエチレン層が積層された本体布の炭素数４のα−オレフィンを側鎖に有する線状低密度ポリエチレン層に、接合時に本体布と内張布との間に介在させて接合した、ポリエチレンクロスの両面に積層した炭素数４のα−オレフィンを側鎖に有する線状低密度ポリエチレン層を介して炭素数８のα−オレフィンを側鎖に有する線状低密度ポリエチレン層が積層された中間布の炭素数８のα−オレフィンを側鎖に有する線状低密度ポリエチレン層であり、接合面を形成する内張布の炭素数８のα−オレフィンを側鎖に有する線状低密度ポリエチレン層は、内張布の少なくとも一方の面において炭素数４のα−オレフィンを側鎖に有する線状低密度ポリエチレン層に積層された炭素数８のα−オレフィンを側鎖に有する線状低密度ポリエチレン層であることを特徴とするフレキシブルコンテナ袋である。
本願の第３の発明の要旨は、袋体内部に形状を保持するため本体布に中間布を介して内張布を接合したフレキシブルコンテナ袋において、本体布と内張布との接合面が、ポリエチレンクロス面上に炭素数４のα−オレフィンを側鎖に有する線状低密度ポリエチレン層を介して炭素数８のα−オレフィンを側鎖に有する線状低密度ポリエチレン層同士を接合した接合面であるフレキシブルコンテナ袋であって、接合面を形成する本体布の炭素数８のα−オレフィンを側鎖に有する線状低密度ポリエチレン層は、ポリエチレンクロスの両面に炭素数４のα−オレフィンを側鎖に有する線状低密度ポリエチレン層が積層された本体布の炭素数４のα−オレフィンを側鎖に有する線状低密度ポリエチレン層に、接合時に本体布と内張布との間に介在させて接合した、炭素数８のα−オレフィンを側鎖に有する線状低密度ポリエチレン単体シートからなる中間布の炭素数８のα−オレフィンを側鎖に有する線状低密度ポリエチレン層であり、接合面を形成する内張布の炭素数８のα−オレフィンを側鎖に有する線状低密度ポリエチレン層は、内張布の少なくとも一方の面において炭素数４のα−オレフィンを側鎖に有する線状低密度ポリエチレン層に積層された炭素数８のα−オレフィンを側鎖に有する線状低密度ポリエチレン層であることを特徴とするフレキシブルコンテナ袋である。
したがって、本発明においては、本体布と内張布との接合面が本体布と内張布とが直接接合されている場合は勿論、本体布と内張布との接合面が本体布と内張布との間に介在させた中間布によってなされていてもよい。
【０００８】
即ち、本発明においては本体布及び内張布の接合面がフィルム強度の高いＣ８−ＬＬＤＰＥを使用することによって表層フィルム強度を向上し、本体布と内張布との接合はＣ８−ＬＬＤＰＥ同志の溶着であるので接合強度も優れている。そしてポリエチレンクロスとＣ８−ＬＬＤＰＥとの間にはＣ４−ＬＬＤＰＥ樹脂が介在するのでＣ８−ＬＬＤＰＥフィルムの厚さが均質・均一であり、その結果、表層フィルム強度がアップするため本体布と内張布との溶着部における接合強度が向上し、段積み強度が向上する。
【０００９】
本発明で使用するポリエチレンクロスとしては特に限定させるものではないが、例えば１５００〜２０００デニ−ルの高密度ポリエチレン製偏平糸を経緯それぞれ１５本／インチとなるように平織りされたポリエチレンクロスが好適である。ポリエチレンクロスとＣ８−ＬＬＤＰＥとの間に介在するＣ４−ＬＬＤＰＥ樹脂とは密度０．９１〜０．９４を有する樹脂であり、これを厚さ５０〜１５０μ程度のフィルムとして積層する。Ｃ８−ＬＬＤＰＥ樹脂は密度０．９１〜０．９４であって、これを厚さ５０〜１５０μ程度のフィルムとして、Ｃ４−ＬＬＤＰＥ樹脂の層で熱押出ラミネ−ト積層する。本発明ではポリエチレンクロスの上に直ちにＣ８−ＬＬＤＰＥを積層するのではなくＣ４−ＬＬＤＰＥ樹脂を介在させるのでＣ８−ＬＬＤＰＥフィルムの厚さが均質・均一となり、その結果、表層フィルム強度がアップするため本体布と内張布との溶着部における接合強度が向上し、段積み強度が向上する。
そして、この層構成は本体布及び内張布の少なくとも一方の面にあればよく、他方の面は特に限定されるものではなく、ポリエチレンクロスが２層以上存在していても良い。また、本体布と内張布とは同一の積層シ−トであっても、また異なった積層シ−トであってもよい。本体布と内張布との間に中間布を使用する場合、その中間布はＣ８−ＬＬＤＥ単体シ−トあるいはポリエチレンクロスの両面にＣ４−ＬＬＤＰＥ樹脂層を、その層の上にＣ８−ＬＬＤＰＥフィルムを積層したものを使用する。なお、中間布はポリエチレンクロスが２層以上存在していても良いが、本体布と内張布とに接する面はＣ４−ＬＬＤＰＥ樹脂層に上にあるＣ８−ＬＬＤＰＥフィルムが存在するようにする。内張り布と中間布の溶着に際しては、中間布の剥離作用側端部に内張布の未溶着部分を残して溶着する。中間布と本体布とは全面溶着する。本体布と内張布との溶着手段としては、従来から利用されている、例えばバ−による熱接着、熱風による熱接着、或いは高周波ウエルダ−等の接着方法を利用することができる。
【００１０】
本発明を図面を持って説明する。図１はフレキシブルコンテナ袋の断面図であり図２はその袋の本体布と内張り布との接合部の拡大図である。図においてフレキシブルコンテナ袋１の内部は本体布２と内張り布３が接合部４で溶着されている。本体布２と内張り布３とはそれぞれポリエチレンクロス５の両面にＣ４−ＬＬＤＰＥ樹脂層６を介してＣ８−ＬＬＤＰＥ層７が形成されている。そして本体布と内張り布との接合部４では本体布２のＣ８−ＬＬＤＰＥ層７と内張り布３のＣ８−ＬＬＤＰＥ層７とが溶着されている。
【００１１】
【実施例】
次に実施例及び比較例をもって本発明を具体的に述べる。これらの例における試験方法は次の方法によって行った。
段積み強度
フレキシブルコンテナ袋として製袋したものを試験袋とし、ポリプロピレンペレットを１０００ｋｇ充填した後、３トン相当の鉄板を乗せて段積み荷重を加え５日間放置する。３トン５日間荷重後、荷重を開放し、試験袋の内部を目視確認して、内張剥離の有無を調べる。
【００１２】
実施例１
２０００デニ−ルの高密度ポリエチレン製偏平糸を経緯それぞれ１５本／インチとなるよう平織されたポリエチレンクロスの両面に厚さ８０μのＣ４−ＬＬＤＰＥフィルムを積層し、その一方に面に厚さ１００μのＣ８−ＬＬＤＰＥフィルムを積層したポリエチレンクロスシ−トをフレキシブルコンテナ袋の本体布として使用した。内張布としては２０００デニ−ルの高密度ポリエチレン製偏平糸を経緯それぞれ１５本／インチとなるよう平織されたポリエチレンクロスの両面に厚さ８０μのＣ４−ＬＬＤＰＥフィルムを積層し、このＣ４−ＬＬＤＰＥフィルムの上に高密度ポリエチレン製偏平糸を経緯それぞれ１５本／インチとなるよう平織されたポリエチレンクロス、厚さ８０μのＣ４−ＬＬＤＰＥフィルム及び厚さ１００μのＣ８−ＬＬＤＰＥフィルムを順次積層した積層シ−トを使用した。本体布と内張布との接合に際してはそれぞれのＣ８−ＬＬＤＰＥフィルム層が溶着面になるようにしてこの層同志を４０ｍｍ巾で熱風溶着した。得られた接合部の段積み強度の測定結果を表１に示す。
【００１３】
実施例２
２０００デニ−ルの高密度ポリエチレン製偏平糸を経緯それぞれ１５本／インチとなるよう平織されたポリエチレンクロスの両面に厚さ６０μのＣ４−ＬＬＤＰＥフィルムを積層した積層シ−トフレキシブルコンテナ袋の本体布としてを使用した。内張布としては厚さ８０μのＣ４−ＬＬＤＰＥフィルムを中心とし、その両面に２０００デニ−ルの高密度ポリエチレン製偏平糸を経緯それぞれ１５本／インチとなるよう平織されたポリエチレンクロスを、そして外側に厚さ８０μのＣ４−ＬＬＤＰＥフィルムをそれぞれ積層し、更にその最外側に厚さ１００μのＣ８−ＬＬＤＰＥフィルムを積層した。本体布と内張布との間に中間布を介在させて溶着した。中間布は１０００デニ−ルの高密度ポリエチレン製偏平糸を経緯それぞれ１０本／インチとなるように平織したポリエチレンクロスを厚さ８０μのＣ４−ＬＬＤＰＥフィルムで貼着し、更にその外側両面を１００μのＣ８−ＬＬＤＰＥフィルムで被覆した複合ポリエチレンクロスシ−トを使用した。この中間布は４０ｍｍ巾を有し、中間布と内張布との溶着は３０ｍｍ巾で行い、中間布の剥離作用側端部に内張布との間に未溶着部分を残して、本体布と中間布及び内張布の三者を４０ｍｍ巾で熱風溶着した。得られた接合部の段積み強度の測定結果を表１に示す。
【００１４】
比較例１
比較例として従来のＣ４−ＬＬＤＰＥのみを使用した積層シ−トを使用してフレキシブルコンテナ袋を構成した。即ち、本体布として２０００デニ−ルの高密度ポリエチレン製偏平糸を経緯それぞれ１５本／インチとなるよう平織されたポリエチレンクロスの両面に厚さ６０μのＣ４−ＬＬＤＰＥフィルムを積層した積層シ−トを使用し、内張布としては厚さ５０μのＣ４−ＬＬＤＰＥフィルムを中心とし、その両面に２０００デニ−ルの高密度ポリエチレン製偏平糸を経緯それぞれ１５本／インチとなるよう平織されたポリエチレンクロスを、そして外側に厚さ６０μのＣ４−ＬＬＤＰＥフィルムを積層した積層シ−トを使用した。本体布と内張布とは４０ｍ／ｍ巾で熱風溶着を行った。得られた接合部の段積み強度の測定結果を表１に示す。
【００１５】
【表１】

【００１６】
【発明の効果】
以上述べたように、本発明においては本体布及び内張布の少なくとも一方の面としてポリエチレンクロス面上に炭素数４の線状低密度ポリエチレン層を介して炭素数８の線状低密度ポリエチレン層を積層した積層フィルムを使用し、炭素数８の線状低密度ポリエチレン層同志を溶着することによって、表１に示されているように従来の方法に比して本体布と内張布との溶着部における接合強度の大なるフレキシブルコンテナ袋を得ることができ、その結果、フレキシブルコンテナ袋の角型形状を維持でき、従って、段積み強度を向上し、保管効率を向上させることができる等の効果を奏することができた。
【図面の簡単な説明】
【図１】本発明にかかるフレキシブルコンテナ袋の断面図である。
【図２】本発明にかかるフレキシブルコンテナ袋の本体布と内張布との接合部分の拡大図である。
【符号の説明】
１フレキシブルコンテナ袋２本体布３内張布４接合部
５ポリエチレンクロス６Ｃ４−ＬＬＤＰＥ樹脂層
７Ｃ８−ＬＬＤＰＥ層 [0001]
[Industrial application fields]
TECHNICAL FIELD The present invention relates to a cubic or rectangular parallelepiped flexible container bag composed of a laminated sheet in which thermoplastic resin films are laminated on both sides of a stretched woven fabric made of a thermoplastic resin, and in particular, the bag body of the flexible container bag. The present invention relates to a flexible container bag in which the bonding strength between a lining cloth and a main body cloth provided inside is improved and the stacking strength is improved.
[0002]
[Prior art]
In a flexible container bag composed of a laminated sheet in which thermoplastic resin films are laminated on both sides of a stretched woven fabric made of a thermoplastic resin, the bonding between the lining fabric provided in the bag and the bag body is as follows: This is an extremely important problem for the flexible container bag.
[0003]
In other words, flexible container bags used as powder or granular transport bags for food, grains, fertilizers, chemicals, or synthetic resins are woven fabrics (called cloth) made of plain weave nylon, polyester or high density polyethylene. A laminated sheet in which a thermoplastic film such as ethylene-vinyl acetate copolymer (EVA tarpaulin), polyvinyl chloride (PVC tarpaulin), or linear low density polyethylene is laminated as a surface film on both sides In order to maintain the shape, a lining cloth composed of a similar laminated sheet is provided at the even angle portion inside the side wall of the bag body. When the bag body and the lining fabric are joined, a high-frequency welder is used in the case where the surface film is a laminated sheet made of polyvinyl chloride or ethylene-vinyl acetate copolymer, and a polyethylene cloth is used. In the case of a laminated sheet in which polyethylene is used as a surface layer film, they are welded by hot air welding.
[0004]
Thus, when forming a laminated sheet in which linear low density polyethylene is laminated on both sides of this high density polyethylene cloth as a surface film, it is usually performed by hot extrusion lamination, but as linear low density polyethylene, carbon is used. Polyethylene having a number 4 alkyl group in its side chain (hereinafter referred to as C4-LLDPE) is used. This C4-LLDPE has good workability and can be easily heat-laminated with polyethylene cloth at the heat extrusion temperature. When this laminated sheet is used as a flexible container bag, In some cases, the bonding strength at the welded portion with the tension fabric is insufficient.
[0005]
When the welding strength between the main body fabric and the lining fabric is low, if high temperature filling or multi-stage stacking is performed, the peeling stress acts on the end of the welded portion, and as a result, the surface film is cut and the cloth and the surface layer of the laminated sheet are cut. Troubles such as peeling from the film and interfacial peeling between the surface layer films occur. When the main body cloth and the lining cloth are peeled off, the original square shape of the bag is lost, and in the case of stacking storage, there is a risk of collapse. In order to prevent such peeling troubles , it is necessary to improve the laminating adhesive strength, the laminating film strength, the welding strength, particularly the bonding strength of the welding end where the peeling strength acts. .
[0006]
[Problems to be solved by the invention]
Therefore, the present inventors have completed the present invention as a result of various studies, and an object of the present invention is to provide a flexible container bag having high joint strength at the welded portion between the main body cloth and the lining cloth and high stacking strength. That is.
[0007]
[Means for Solving the Problems]
Summary of the first invention of the present gun, in the flexible container bag joining the lining cloth main body fabric to retain its shape inside the bag, the junction surface of the main body fabric and the lining fabric, a polyethylene cross-plane A linear low density polyethylene layer having an α-olefin having 8 carbon atoms in the side chain via a linear low density polyethylene layer (hereinafter referred to as C4-LLDPE) having an α-olefin having 4 carbon atoms in the side chain. (Hereinafter referred to as C8-LLDPE.) A flexible container bag which is a joint surface obtained by directly joining each other, and has α-olefin having 8 carbon atoms of the main body cloth and the lining cloth forming the joint surface in the side chain. Each of the linear low density polyethylene layers is an α-carbon having 8 carbon atoms laminated on a linear low-density polyethylene layer having an α-olefin having 4 carbon atoms in the side chain on at least one surface of the main body fabric and the lining fabric. me The flexible container bag is a linear low-density polyethylene layer having fins in side chains .
The gist of the second invention of the present application is a flexible container bag in which a lining cloth is joined to a main body cloth via an intermediate cloth in order to maintain the shape inside the bag body, and the joining surface of the main body cloth and the lining cloth is made of polyethylene. In the joining surface which joined the linear low density polyethylene layer which has a C8 alpha olefin in a side chain via the linear low density polyethylene layer which has a C4 alpha olefin in a side chain on a cross surface A linear low-density polyethylene layer in a flexible container bag having a side chain of an α-olefin having 8 carbon atoms in a main body cloth forming a bonding surface is a side of the α-olefin having 4 carbon atoms on both sides of a polyethylene cloth. The linear low density polyethylene layer having a chain of linear low density polyethylene layer laminated with a linear low density polyethylene layer having 4 carbon atoms in the side chain is interposed between the main body cloth and the lining fabric at the time of joining. The A linear low-density polyethylene layer having an α-olefin having 8 carbon atoms in the side chain through a linear low-density polyethylene layer having a 4-carbon α-olefin laminated in both sides of the polyethylene cloth. A linear low-density polyethylene layer having an α-olefin having 8 carbon atoms in the side chain of the laminated intermediate cloth, and a linear having an α-olefin having 8 carbon atoms in the lining cloth forming the bonding surface in the side chain. The low density polyethylene layer is a line having an α-olefin having 8 carbon atoms in the side chain laminated on a linear low density polyethylene layer having an α-olefin having 4 carbon atoms in the side chain on at least one surface of the lining fabric. It is a flexible container bag characterized by being a low-density polyethylene layer.
The gist of the third invention of the present application is the flexible container bag in which the lining cloth is joined to the main body cloth via the intermediate cloth in order to maintain the shape inside the bag body, and the joint surface between the main body cloth and the lining cloth is: Bonding surface obtained by bonding linear low density polyethylene layers having an α-olefin having 8 carbon atoms in a side chain via a linear low density polyethylene layer having an α-olefin having 4 carbon atoms in a side chain on a polyethylene cloth surface. A linear low density polyethylene layer having a side chain with an α-olefin having 8 carbon atoms in a main body cloth forming a joining surface is a flexible container bag having an α-olefin having 4 carbon atoms on both sides of a polyethylene cloth. Interposed between the main body cloth and the lining cloth at the time of joining in the linear low density polyethylene layer having the α-olefin having 4 carbon atoms in the side chain of the main body cloth in which the linear low density polyethylene layer having the side chain is laminated. Let me It is a linear low density polyethylene layer having a side chain with an α-olefin having 8 carbon atoms in an intermediate cloth made of a linear low density polyethylene single sheet having a side chain with an α-olefin having 8 carbon atoms, which is joined, The linear low density polyethylene layer having an α-olefin having 8 carbon atoms in the side chain of the lining fabric forming the linear fabric having an α-olefin having 4 carbon atoms in the side chain on at least one surface of the lining fabric. The flexible container bag is a linear low-density polyethylene layer having an α-olefin having 8 carbon atoms laminated on a low-density polyethylene layer in a side chain .
Therefore, in the present invention, not only when the main body cloth and the lining cloth are directly bonded to the bonding surface between the main body cloth and the lining cloth, but also the bonding surface between the main body cloth and the lining cloth is the inner cloth and the inner cloth. It may be made by an intermediate cloth interposed between the tension cloth.
[0008]
That is, in the present invention, the surface layer film strength is improved by using C8-LLDPE having a high film strength for the bonding surface of the main body cloth and the lining cloth, and the bonding between the main body cloth and the lining cloth is similar to that of C8-LLDPE. Bonding strength is also excellent because of welding. Since C4-LLDPE resin is interposed between the polyethylene cloth and C8-LLDPE, the thickness of the C8-LLDPE film is uniform and uniform. The joint strength at the welded portion is improved, and the stacking strength is improved.
[0009]
The polyethylene cloth used in the present invention is not particularly limited, but, for example, a polyethylene cloth woven flat with a high density polyethylene flat yarn of 1500 to 2000 denier so as to be 15 / inch each is suitable. is there. The C4-LLDPE resin interposed between the polyethylene cloth and the C8-LLDPE is a resin having a density of 0.91 to 0.94, and is laminated as a film having a thickness of about 50 to 150 μm. The C8-LLDPE resin has a density of 0.91 to 0.94, and is formed into a film having a thickness of about 50 to 150 μm by heat extrusion lamination with a layer of the C4-LLDPE resin. In the present invention, the C8-LLDPE resin is not laminated immediately on the polyethylene cloth but the C4-LLDPE resin is interposed, so that the thickness of the C8-LLDPE film becomes uniform and uniform, and as a result, the strength of the surface film is increased. The joint strength at the welded portion between the cloth and the lining cloth is improved, and the stacking strength is improved.
And this layer structure should just exist in at least one surface of a main body cloth and a lining cloth, and the other surface is not specifically limited, Two or more layers of polyethylene cloth may exist. Further, the main body cloth and the lining cloth may be the same laminated sheet or different laminated sheets. When using an intermediate cloth between the main body cloth and the lining cloth, the intermediate cloth is a C8-LLDE single sheet or a polyethylene cloth on both sides of a C4-LLDPE resin layer, and a C8-LLDPE film on the layer. Use a laminate of The intermediate cloth may have two or more layers of polyethylene cloth, but the C8-LLDPE film on the C4-LLDPE resin layer is present on the surface in contact with the main body cloth and the lining cloth. When the lining cloth and the intermediate cloth are welded, the lining cloth is welded while leaving the unwelded portion of the lining cloth at the end of the peeling action side of the intermediate cloth. The intermediate cloth and the main body cloth are welded together. As a means for welding the main body cloth and the lining cloth, a conventionally used bonding method such as thermal bonding with a bar, thermal bonding with hot air, or a high-frequency welder can be used.
[0010]
The present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of a flexible container bag, and FIG. 2 is an enlarged view of a joint portion between the main body cloth and the lining cloth of the bag. In the drawing, a main body cloth 2 and a lining cloth 3 are welded to each other at a joint portion 4 inside the flexible container bag 1. In the main body cloth 2 and the lining cloth 3, C8-LLDPE layers 7 are formed on both surfaces of a polyethylene cloth 5 via C4-LLDPE resin layers 6. The C8-LLDPE layer 7 of the main body cloth 2 and the C8-LLDPE layer 7 of the inner cloth 3 are welded at the joint 4 between the main body cloth and the inner cloth.
[0011]
【Example】
Next, the present invention will be specifically described with reference to examples and comparative examples. The test method in these examples was performed by the following method .
Stacking strength A bag made as a flexible container bag is used as a test bag, filled with 1000 kg of polypropylene pellets, loaded with an iron plate equivalent to 3 tons, left to stand for 5 days. After loading for 3 tons and 5 days, the load is released, and the inside of the test bag is visually confirmed to check for the presence of lining peeling.
[0012]
Example 1
A C4-LLDPE film having a thickness of 80 μm is laminated on both sides of a polyethylene cloth flattened to a density of 15 denier / inch of 2000 denier high density polyethylene flat yarn, and 100 μm in thickness on one side. A polyethylene cloth sheet laminated with a C8-LLDPE film was used as the main body cloth of the flexible container bag. As the lining fabric, a C4-LLDPE film having a thickness of 80 μm is laminated on both sides of a polyethylene cloth flattened to a density of 15 / inch each of 2000 denier high density polyethylene flat yarn. A laminated sheet in which a high-density polyethylene flat yarn is laminated on a film, and a polyethylene cloth woven in a plain weaving to 15 pieces / inch each, a C4-LLDPE film having a thickness of 80 μm, and a C8-LLDPE film having a thickness of 100 μm are sequentially laminated. Used. When joining the main body cloth and the lining cloth, the respective C8-LLDPE film layers were welded with hot air in a width of 40 mm so that the respective C8-LLDPE film layers became welding faces. Table 1 shows the results of measuring the stacking strength of the obtained joints.
[0013]
Example 2
A main body cloth of a laminated sheet flexible container bag in which a C4-LLDPE film having a thickness of 60 μm is laminated on both sides of a polyethylene cloth flat-woven with 2000 denier high-density polyethylene flat yarns each 15 inches / inch As used. As the lining fabric, a C4-LLDPE film with a thickness of 80 μm is used as the center, and a polyethylene cloth flat-woven so that the density is 15 deniers / inch of 2000 denier high density polyethylene flat yarn on both sides, and the outside A C4-LLDPE film having a thickness of 80 μm was laminated on each of the films, and a C8-LLDPE film having a thickness of 100 μm was further laminated on the outermost side thereof. An intermediate cloth was interposed between the main body cloth and the lining cloth for welding. The intermediate cloth is made of a 1000 denier high density polyethylene flat yarn, and a polyethylene cloth, which is plain woven so as to be 10 pieces / inch each, is attached with a C4-LLDPE film having a thickness of 80 μm, and both outer sides are 100 μm thick. A composite polyethylene cloth sheet coated with C8-LLDPE film was used. This intermediate cloth has a width of 40 mm, and the intermediate cloth and the lining cloth are welded with a width of 30 mm, leaving the unwelded portion between the intermediate cloth and the lining cloth at the end of the peeling action side of the intermediate cloth. The intermediate cloth and the lining cloth were hot-air welded with a width of 40 mm. Table 1 shows the results of measuring the stacking strength of the obtained joints.
[0014]
Comparative Example 1
As a comparative example, a flexible container bag was constructed using a laminated sheet using only conventional C4-LLDPE. That is, a laminated sheet in which a C4-LLDPE film having a thickness of 60 μm is laminated on both sides of a polyethylene cloth, which is plain woven so as to have a density of 15 / inch each, is a high density polyethylene flat yarn of 2000 denier. Used as the lining fabric is a 50-μm thick C4-LLDPE film with a 2000-denier high-density polyethylene flat yarn on both sides of a plain cloth woven into a plain weave so that there are 15 threads / inch each. A laminated sheet in which a C4-LLDPE film having a thickness of 60 μm was laminated on the outside was used. The main body cloth and the lining cloth were subjected to hot air welding at a width of 40 m / m. Table 1 shows the results of measuring the stacking strength of the obtained joints.
[0015]
[Table 1]

[0016]
【The invention's effect】
As described above, in the present invention, a linear low density polyethylene layer having 8 carbon atoms via a linear low density polyethylene layer having 4 carbon atoms on a polyethylene cloth surface as at least one surface of the main body cloth and the lining fabric. As shown in Table 1, the main body cloth and the lining cloth are bonded to each other by welding linear low density polyethylene layers having 8 carbon atoms. A flexible container bag having a large bonding strength at the welded portion can be obtained, and as a result, the square shape of the flexible container bag can be maintained, and accordingly, the stacking strength can be improved and the storage efficiency can be improved. I was able to play an effect.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a flexible container bag according to the present invention.
FIG. 2 is an enlarged view of a joint portion between the main body cloth and the lining cloth of the flexible container bag according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Flexible container bag 2 Main body cloth 3 Lining cloth 4 Joint part
5 Polyethylene cloth 6 C4-LLDPE resin layer
7 C8-LLDPE layer

Claims

In a flexible container bag in which a lining cloth is bonded to a main body cloth in order to maintain the shape inside the bag body, the bonding surface between the main body cloth and the lining cloth is a side chain of α-olefin having 4 carbon atoms on the polyethylene cloth surface. A flexible container bag which is a joining surface obtained by directly joining linear low density polyethylene layers having an α-olefin having 8 carbon atoms in a side chain through a linear low density polyethylene layer having
The linear low-density polyethylene layer having α-olefin having 8 carbon atoms in the side chain of the main body cloth and the lining cloth forming the bonding surface has a carbon number of 4 on at least one surface of the main body cloth and the lining cloth, respectively. A flexible container bag, which is a linear low density polyethylene layer having an α-olefin having 8 carbon atoms in a side chain laminated on a linear low density polyethylene layer having an α-olefin in a side chain .

In a flexible container bag in which a lining cloth is bonded to a main body cloth via an intermediate cloth in order to maintain the shape inside the bag body, the bonding surface between the main body cloth and the lining cloth is an α having 4 carbon atoms on the polyethylene cloth surface. A flexible container bag that is a joint surface obtained by joining linear low density polyethylene layers having an α-olefin having 8 carbon atoms in a side chain via a linear low density polyethylene layer having an olefin in a side chain ,
The linear low density polyethylene layer having α-olefin having 8 carbon atoms in the side chain of the main body cloth forming the joining surface is a linear low density polyethylene having α-olefin having 4 carbon atoms in the side chain on both sides of the polyethylene cloth. Double-sided polyethylene cloth joined to a linear low-density polyethylene layer having a side chain of an α-olefin having 4 carbon atoms in the main body layer on which the layers are laminated, interposed between the main body cloth and the lining cloth at the time of bonding. Carbon of an intermediate cloth in which a linear low density polyethylene layer having an α-olefin having 8 carbon atoms in a side chain is laminated via a linear low density polyethylene layer having an α-olefin having 4 carbon atoms in a side chain laminated on A linear low density polyethylene layer having an α-olefin of several 8 in the side chain, and a linear low density polyethylene layer having an α-olefin of 8 carbon atoms in the side chain of the lining fabric forming the bonding surface, Less tension It is a linear low-density polyethylene layer having an α-olefin having 8 carbon atoms in a side chain laminated on a linear low-density polyethylene layer having an α-olefin having 4 carbon atoms in a side chain on at least one surface. Characteristic flexible container bag.

In the flexible container bag bonding the lining cloth through an intermediate cloth main body fabric to retain the shape inside the bag, the junction surface of the main body fabric and the lining fabric, having 4 carbons in port triethylene cross plane A flexible container bag which is a joint surface obtained by joining linear low density polyethylene layers having an α-olefin having 8 carbon atoms in a side chain via a linear low density polyethylene layer having an α-olefin in a side chain ,
The linear low density polyethylene layer having α-olefin having 8 carbon atoms in the side chain of the main body cloth forming the joining surface is a linear low density polyethylene having α-olefin having 4 carbon atoms in the side chain on both sides of the polyethylene cloth. The carbon cloth having 8 carbon atoms bonded to the linear low-density polyethylene layer having the α-olefin of 4 carbon atoms in the side chain of the main body cloth laminated with the layers interposed between the main body cloth and the lining cloth at the time of joining. A linear low density polyethylene layer having an α-olefin having 8 carbon atoms in the side chain as an intermediate cloth made of a single sheet of linear low density polyethylene having an α-olefin in the side chain. The linear low density polyethylene layer having an α-olefin having 8 carbon atoms in the side chain is laminated on the linear low density polyethylene layer having an α-olefin having 4 carbon atoms in the side chain on at least one surface of the lining fabric. Charcoal Flexible container bag, characterized in that the number 8 of the α- olefin is a linear low density polyethylene layer having a side chain.