JP3737415B2 - Paper bag with inlet valve - Google Patents

Description

【０００１】
【発明の属する技術分野】
この発明は吹込口弁付紙袋に関し、更に詳細には両側にまち部を有し、且つ口部端側の幅方向一側部に、内側に折込んでなる吹込口弁を備える吹込口弁付紙袋に関する。
【０００２】
【従来の技術】
従来、この種の吹込口弁付袋は、例えば特公平１−５０６６２号公報やその他多くの特許公報などに開示されており、周知である。そこで、特公平１−５０６６２号公報に開示されている従来の吹込口弁付袋の構成について図９〜図１２を参照して簡単に説明する。
【０００３】
前述の特許公報に開示された吹込口弁付袋１は以下のように構成されていた。すなわち、図９に示される吹込口弁付袋１は、袋本体４を基本構成要素としている。この袋本体４は、図１０に示されるように横断面Ｖ字形に中折り可能なまち部２を両側部に形成した筒状体であって、その一側端口部上にまち部２を含む幅の突起部３を設けて形成されている。そして、吹込口弁付袋１は、この袋本体４の突起部３をその基部Ｐから側縁にに対してほぼ４５度の折曲線５を形成しつつまち部２の谷折り線２ａを中心として図１１に示されるようにほぼ台形状に開披する。
【０００４】
その後、ほぼ台形状に開披した部分を図１２に示されるように内側に折り込んで吹込口弁６を当該袋本体４に形成し、この袋本体４の口部端縁（図には示されていないが底部端縁も）を折り返し、図９に示されるようにその折返し部を跨いで補強シートである当て紙７を配置し、この当て紙７を袋本体４の両壁面８に接着して封緘部９を形成することによって、吹込口弁付袋１は構成されていた。
【０００５】
【発明が解決しようとする課題】
前述の特許公報に開示された吹込口弁付袋１は、非常に優れた構造のものであったことから小麦粉等の粉体や穀物等の粒状体などの輸送や保管に長年に亘って使用され続けてきた。ところが、この吹込口弁付袋を長年に亘って使用している間に、粉体等の輸送や保管に使用する時に「漏れ」が発生するという問題のあることが分かった。
【０００６】
この点について具体的に説明すると、この吹込口弁付袋１に小麦粉などの粉体を自動充填する場合には空気輸送の手法が用いられる。すなわち、内側に折り込んだ吹込口弁６と当て紙７との間に形成されている吹込口から内容物充填用ノズルを吹込口弁付袋１内に差込み、粉体を圧送空気に乗せて吹き込んでいる。
【０００７】
この充填作業において、同時に吹き込まれた輸送用空気は、吹込口に差し込んだ内容物充填用ノズルの周囲隙間や通気性のある袋胴部（まち部２とこれに連接する両壁面８）を通して外部に逃げ、これにより粉体だけが吹込口弁付袋内に貯留されることで充填される。
【０００８】
このような空気輸送による吹込口弁付袋内への粉体の充填は、標準的な大きさの吹込口弁付袋の場合、約１３〜１４秒程度で終了するが、最初の数秒間の充填圧力で、袋上端の吹込口とは反対側の側部から粉体の漏れが発生することがあった。勿論、粉体充填時には吹込口における内容物充填用ノズルの周囲隙間から粉体が袋外部に吹き出すが、このような粉体については粉体充填側即ち吹込口近傍に設置された粉体回収装置で回収されるため問題とはならない。
【０００９】
問題は、袋上端の吹込口とは反対側の側部からの粉体の漏れである。この点について更に具体的に説明すると、吹込口弁付袋１の上端には封緘部９が形成されているが、この封緘部９は扁平状態にした口部端縁を１回折り返し、その折返し部を跨いで当て紙７で覆って構成されている。
【００１０】
この時、袋本体４の口部端における吹込口とは反対側の側部は、まち部２を幅方向中央の谷折り線２ａで内側に横断面Ｖ字状に折り込んで扁平にされており、まち部２に連接する両側の壁面８を含めた状態で上部方向から見た形状又は横断面形状はほぼ横Ｍ字形を呈している。
【００１１】
この横断面ほぼ横Ｍ字形の幅方向最も側方に位置する上端開口即ち壁面と折り込まれたまち部２の片側半分との山折り部上端は、当て紙７の最も端部に位置しているため閉鎖機能が発揮され難い箇所である。しかも、扁平状態にした口部端は、１回折り返されているだけである。
【００１２】
そのため、扁平状態にある吹込口弁付袋１に空気圧送で粉体が吹き込まれた時、最初の数秒間の充填圧力で当該吹込口弁付袋が一気に膨らみ、その勢いで前述した横断面ほぼ横Ｍ字形の幅方向最も側方に位置する上端開口が微少に開き、この部分に対する当て紙７の閉鎖機能が有効に発揮されていないことも手伝って、ここから圧送空気に乗って粉体が外に漏れることが分かった。
【００１３】
この部分からの粉体の漏れは、粉体充填時だけではなく、粉体が充填されて吹込口弁６がホットメルトによって当て紙７に接着された状態の吹込口弁付袋１を倉庫内の所定位置に積載する作業をしている時にも取り扱い方によっては発生することがあった。すなわち、作業者は、粉体充填済みの吹込口弁付袋１を抱えて、搬送パレットの上に載せたり、或いは搬送パレットに既に積載されている他の吹込口弁付袋に重ねて乗せる時、吹込口弁付袋の一方の壁面を下にしてかなり勢いよく落とすように乗せることがある。
【００１４】
すると、吹込口弁付袋を衝撃的に落とした時に壁面８に加わる圧迫力で、当該吹込口弁付袋１内の内圧が急激に上昇して前述した粉体充填時とほとんど同じ現象が発生し、その結果前述した横断面ほぼ横Ｍ字形の幅方向最も側方に位置する上端開口が微少に開き、ここから瞬間的に加圧された内部空気に乗って粉体が外に漏れ出るのである。
【００１５】
そのため、数多くの吹込口弁付袋に継続的に粉体の充填作業をした時や、粉体が充填された数多くの吹込口弁付袋を倉庫などに積載保管する作業をした時など、作業員は漏れた粉体を被って白くなってしまうことがあった。粉体が小麦粉である場合には、それ自体が人体に害のあるものではないので、単に作業員の衣服などが汚れるという程度のことで、取り立てて問題となることはない。
【００１６】
しかし、粉体がセメントなどの場合には作業環境が極度に悪化することが想定されるため、吹込口弁付袋への空気圧送力を低くする必要がある。空気圧送力を低くすると充填時間が長くなるため、充填の作業効率が低下することになる。また、粉体がセメントなどの場合、充填後の吹込口弁付袋については乱暴に取り扱わないようにする等の注意を払わなければならなかった。
【００１７】
このような粉体の漏れの発生をなくすため、端部を２回折りして当て紙で包囲固定している底部閉鎖部と同じように口部端を２回折りすることも提案されたが構造上できず、そこで吹込口弁付袋の上端に形成される封緘部９を、２枚重ねの当て紙を用いた構造に改良し、充填時に封緘部７に掛かる圧力を厚手にした当て紙で吸収するように工夫されたが、前述した漏れは防止できなかった。
【００１８】
この発明の目的は、かかる従来の問題点を解決するためになされたもので、充填時や荷扱い時に吹込口とは反対側の側部から内容物の漏れを起こさない改良された吹込口弁付紙袋を提供することにある。
【００１９】
【課題を解決するための手段】
この発明は、両側部に断面Ｖ字状に中折り可能なまち部を備える筒状体の一端を加工して閉鎖することにより底部閉鎖部とし、他端である口部端側の幅方向一側部における一方のまち部上縁とこのまち部に連接する両壁面の一部の上縁に突起部を備える袋本体と、この突起部をまち部中央の谷折り線を中心としてほぼ台形状に開披すると共に内側に折り込んで形成された吹込口弁と、袋本体の口部端を一方の壁面側に折り返し、その折返し部を跨いで当て紙を配置し、その当て紙を両壁面に接着して形成された封緘部とを備える吹込口弁付紙袋において、封緘部が、当て紙の一部を口部端の端縁から飛び出させて糊代部を形成するように当該当て紙を他方の壁面に最初に接着する時に吹込口弁とは反対側の当て紙の端部を袋本体から突出させ、この突出片を袋本体の扁平なまち部の全部又は片側半分を包み込むように横方向に折り返し、口部端を一方の壁面側に当て紙と共に折り返して当て紙の糊代部を一方の壁面に接着して構成されていることを特徴とする。
【００２０】
また、この発明の吹込口弁付紙袋では、吹込口弁とは反対側の当て紙の端部を袋本体から突出させた突出片を折り返して扁平なまち部の全部又は片側半分を包み込むように横方向に折り返す時、折り返された突出片が、対面する当て紙の糊代部と袋本体の一方の壁面又はまち部に接着されていることを特徴とする。
【００２１】
更に、この発明の吹込口弁付紙袋では、袋本体の一端を加工して形成された底部閉鎖部が、袋本体の一端を少なくとも２回折り返して、その折返し部を跨いで開封テープ付当て紙を配置し、その開封テープ付当て紙を両壁面に接着して形成されていることを特徴とする。
【００２２】
更にまた、この発明の吹込口弁付紙袋では、袋本体の内側に重ねて配置された樹脂フィルム製の内袋を備えた防湿性能付きであることを特徴とする。なお、袋本体はクラフト紙から形成された筒状体から構成されていてもよい。
【００２３】
【発明の実施の形態】
次に、この発明の吹込口弁付袋を図に示される好適な実施形態について更に詳細に説明する。図１はこの発明の一実施形態に係る吹込口弁付紙袋１０を示しており、図２は図１の２−２線に沿って吹込口弁付紙袋１０を切断してその縦断面構造を模式的に示す構成説明図であり、更に図３〜図７は本実施形態の吹込口弁付紙袋１０の形成手順を示す部分的な構成説明図である。
【００２４】
ところで、この実施形態に係る吹込口弁付紙袋１０の基本的な構成は従来の吹込口弁付袋１と実質的に同じであるので、この吹込口弁付紙袋１０の基本構成については従来の吹込口弁付袋１の基本部分を示す図１０〜図１２を参照して説明する。
【００２５】
この発明の一実施形態に係る吹込口弁付紙袋１０は、図１に示されるように両側部にまち部２を備える筒状体４の一端を加工して閉鎖することにより底部閉鎖部（底部閉鎖部については後述する）とし、他端である口部端側の幅方向一側部における一方のまち部２上縁とこのまち部２に連接する両壁面８の一部の上縁に突起部３を備える袋本体４を備えている。
【００２６】
そして、この袋本体４の突起部３は、その基部Ｐから側縁に対してほぼ４５度の折曲線５を形成しつつまち部２の谷折り線２ａを中心として図１１に示されるようにほぼ台形状に開披される。その後、ほぼ台形状に開披した部分を図１２に示されるように内側に折り込んで吹込口弁６が当該袋本体４に形成される。
【００２７】
この実施形態の吹込口弁付紙袋１０は、前述したように構成された袋本体４の口部端４ａを１回折り返し、図２に示されるようにその折返し部１１を跨いで補強シートである当て紙１２が配置され、この当て紙１２を袋本体４の両壁面８ａ、８ｂに接着して封緘部１３を形成することによって構成されている。
【００２８】
この実施形態の吹込口弁付紙袋１０は、この封緘部１３の構造に特徴がある。この封緘部１３の構造については、その形成手順に従って説明する。この吹込口弁付紙袋１０の封緘部１３は、図３に示されるように当て紙１２を、その一部が袋本体４の口部端４ａにおける端縁４ｂから飛び出して糊代部１２ａを形成するように他方の壁面８ｂに最初に接着する。
【００２９】
その時に吹込口弁６とは反対側の当て紙１２の端部を袋本体４から突出させ、糊代部１２ａとこの突出片１２ｂに接着剤を塗布すると共に当該突出片１２ｂを図４及び図５に示されるように袋本体４の一方の壁面８ａ側に扁平な口部端４ａの幅方向他側部即ちまち部２の全部（厚み方向の全部）を包み込むように折り返えし、口部端４ａと当て紙１２の糊代部１２ａとに重ねて接着する。
【００３０】
この結果、袋本体４の口部端４ａにおける吹込口とは反対側の側部において、図４に示されているように扁平状態で上方向から見た時にほぼ横Ｍ字形をした幅方向最も側方に位置する上端開口１５即ち壁面８ａ、８ｂと折り込まれたまち部２のそれぞれ片側半分との山折り部上端口は、当て紙１２の突出片１２ｂでまち部全部を側方から巻き込んだことによってサンドイッチ状に挟み込まれると共に上端開口１５の直上を当て紙１２の糊代部１２ａとこれに重なる突出片１２ｂとの相互接着によって完全に閉じられることになる。
【００３１】
その後、口部端４ａと当て紙１２の糊代部１２ａとに重合接着された突出片１２ｂにおいて、当て紙１２の糊代部１２ａに重なった領域がそのまま新たな糊代部１２ａとなるため、図５に示されるようにこの領域にも接着剤が塗布される。その際、当て紙１２の糊代部１２ａにおいて吹込口弁６に対応する領域即ち吹込口弁６に被さる領域には例えばホットメルト系接着剤のような熱可塑性接着剤１４ａが塗布され（図３において影線で示す部分）、この熱可塑性接着剤塗布部分を除く他の領域全面には水溶性或いは耐熱性接着剤１４ｂが塗布される。
【００３２】
このように当て紙１２の糊代部１２ａにおいて吹込口弁６に被さる領域に熱可塑性接着剤１４ａを塗布し、それ以外の領域に水溶性接着剤１４ｂを塗布する理由は、吹込口から内容物を紙袋内に充填した後にこの吹込口を閉鎖すべく熱を掛けて接着剤１４ａを再活性させる時、当該熱付与時に既に接着に供している糊代部１２ａの接着剤が溶けて当て紙１２の剥離を起こさないようにするためである。
【００３３】
そして、最後に、この袋本体４の口部端４ａを当て紙１２と共に折り返し線１６で壁面８ａ側に折り返され、当て紙１２の糊代部１２ａを壁面８ａに貼着し、これにより袋本体４の口部に封緘部１３が形成される。他方、袋本体４の底部側は、常法に従って底部端を巻き込むように２回折り曲げ、その後この折曲げ部１７を跨ぐように開封テープ付当て紙１８で包囲固定して底部閉鎖部１９とされている。
【００３４】
開封テープ付当て紙１８は、具体的には、折曲げ部１７を跨ぐように配置した時に袋本体４の長手方向に位置する両端部をそれぞれ接着剤２０により袋本体４の壁面８ａ、８ｂに接着して固定されている。なお、折曲げ部１７を跨ぐように開封テープ付当て紙１８を配置する時、この当て紙１８の内側に貼り付けられている開封テープ２１が折曲げ部１７のほぼ上面側に位置するようにすることがよい。
【００３５】
このようにして形成された吹込口弁付紙袋１０に吹込口から粉体を空気圧送で充填すると、当該吹込口弁付紙袋１０は、図６に矢印２２で示されるように次第に膨張し、横断面横Ｖ字状であったまち部２が開いて図７に示されるように角形となり、これにより図６に示されるようにまち部２を扁平状態に押さえている当て紙１２の下側から強い引裂き力が働く。
【００３６】
この引裂き力によって当て紙１２の突出片１２ｂが折り返された山折り部は破れ（引裂き開始部を符号２３で示す）、吹込口弁付紙袋１０の最終的な角形への成形が何の問題もなく行われる。当て紙１２の突出片１２ｂが折り返された山折り部が破れる範囲（長さ）は、図５の状態で示すと当て紙１２の下縁１２ｃから口端部折り返し線１６迄の間の範囲２４である。そのため、折り返された口部端４ａにおけるほぼ横Ｍ字形をした幅方向最も側方に位置する上端開口１５を塞いでいる当て紙１２の折り返し部には何の影響も起こらない。
【００３７】
前述した実施形態の吹込口弁付紙袋１０では、口部端４ａを封緘する際に、当て紙１２の突出片１２ｂを図４及び図５に示されるように扁平な口部端４ａの幅方向他側部即ちまち部２の全部（厚み方向の全部）を包み込むように折り返えし、口部端４ａと当て紙１２の糊代部１２ａとに重ねて接着したが、本発明はこのような形態に限定されるものではない。
【００３８】
例えば、図８に示されるように、口部端４ａを封緘する際に、当て紙１２の突出片１２ｂをまち部２の片側半分、即ち壁面８ｂと中折りされたまち部２の片側半分との山折り部上端口のみを包み込むように側方に折り返してもよい。要するには、当て紙１２の突出片１２ｂを側方に折り返す時、袋本体４の壁面８ａに重ねるように折り返すのではなく、断面Ｖ字状に中折りされたまち部２のその中折り部に入り込ませるように側方に折り返すのである。
【００３９】
このように当て紙１２の突出片１２ｂでまち部２の片側半分の山折り部上端口のみを側方から包み込むだけでもよい理由は、このような紙袋の場合、その構造上、壁面８ｂと中折りされたまち部２の片側半分との山折り部上端口へ内容物が最も回り込み易いからである。すなわち、壁面８ａとこれに連接する中折りされたまち部２の片側半分とは折曲げ線１６で壁面８ａ側にほぼ１８０度折り曲げられるため内容物の上端口への回り込みが起きにくく、逆に壁面８ｂとこれに連接する中折りされたまち部２の片側半分とは内容物が充填されて紙袋が角形に膨張成型された時にほとんど折れ曲がっていない状態となるからである。
【００４０】
なお、前述した実施形態の吹込口弁付紙袋１０では、口部に封緘部１３を形成する際に、一枚の当て紙１２を用いたが、特に袋本体４の口部端４ａにおける端縁４ｂに沿う範囲についてもう一枚の当て紙を重ねて貼り合わせ、部分的に二重にしてもよい。
【００４１】
また、前述した実施形態の吹込口弁付紙袋１０では、底部閉鎖部１９が、底部端を巻き込むように２回折り曲げてなる折曲げ部１７を跨ぐように開封テープ付当て紙１８で包囲固定して形成されていたが、この発明は底部閉鎖部を要旨とするものではないので、この底部閉鎖部の構造には特に限定されるものではない。
【００４２】
従って、この吹込口弁付紙袋１０の底部閉鎖部１９を、容易に開封できる構造とせずに、厳重に封緘してしまう場合には、口部の封緘部１３と同様な構造を採用して底部閉鎖部としてもよい。すなわち、底部端の端縁から糊代部を飛び出させるように一方の壁面に接着した当て紙の両端を袋本体の両側部から突出させ、この突出片を壁面側に巻き込むように折り返して接着する。
【００４３】
次いで、底部端と共に当て紙を折り曲げて他方の壁面に糊代部を接着して底部閉鎖部とすることができる。このように底部閉鎖部を口部の封緘部１３と同様な方式で構成すれば、底部端が１回の折り曲げでも内容物の漏れの起こらない閉鎖ができるため、使用紙量の節約が可能となる。
【００４４】
最後に、この吹込口弁付紙袋１０では、前述したように当該紙袋に内容物を吹き込んだ時に口部端において当て紙１２の突出片１２ｂの巻き込みによりまち部２を扁平状態に押さえている当て紙１２の突出片折り返し部が膨張によって下側から強い引裂き力が働く時、例えば繊維配向等に工夫をする等して容易に切れる程度の性質を備えたものであることが望ましい。
【００４５】
このように、この発明の吹込口弁付紙袋１０では、口部端に封緘部を形成する際に、袋本体の口部端における吹込口とは反対側の側部における横断面ほぼ横Ｍ字形の幅方向最も側方に位置する上端開口を当て紙の突出片で側方から巻き込んで完全に閉鎖することにより、例えば扁平状態にある吹込口弁付紙袋に空気圧送で粉体等を吹き込んだ時に従来のこの種の紙袋で生じていた前述の上端開口からの粉体の漏れを完全に防止することができる。
【００４６】
【発明の効果】
以上説明したように、この発明の吹込口弁付紙袋によれば、袋本体の口部端における吹込口とは反対側の側部における横断面ほぼ横Ｍ字形の幅方向最も側方に位置する上端開口を当て紙の突出片で側方から巻き込んで完全に閉鎖するようにして口部端に封緘部を形成するという非常に簡単な構成により、粉体等の吹き込み時或いは粉体が充填されたこの吹込口弁付紙袋の荷扱い時に、前記上端開口から内容物の漏れを完全に防止することができる。
【図面の簡単な説明】
【図１】この発明の一実施形態に係る吹込口弁付紙袋を扁平状態にして示す平面図である。
【図２】図１に示される吹込口弁付紙袋を２−２線で切断してその断面構造を模式的に示す構成説明図である。
【図３】図１に示される吹込口弁付紙袋の口部端に封緘部を、また底部端に底部閉鎖部を形成するため、それぞれ当て紙を一壁面に貼り付けて配置した状態を示す平面図である。
【図４】図３に示される吹込口弁付紙袋形成前の口部端における吹込口とは反対側の側部を上方から見た概略的な構成説明図である。
【図５】図１に示される吹込口弁付紙袋の口部端に封緘部を形成する直前の状態を示す部分的な平面図である。
【図６】図１に示される吹込口弁付紙袋の口部端における吹込口とは反対側の側部まち部を扁平状態に押さえている当て紙の突出片の折り返し部がこの吹込口弁付紙袋に内容物を充填した時の膨張力により引き裂かれる状態を概略的に示す部分的な斜視図である。
【図７】図１に示される吹込口弁付紙袋に内容物を充填することにより、口部端における吹込口とは反対側の側部まち部を扁平状態に押さえている当て紙の突出片の折り返し部が引き裂かれて通常の角形に成型された状態を概略的に示す部分的な斜視図である。
【図８】この発明の他の実施形態に係る吹込口弁付紙袋であって、その口部端を封緘する際に当て紙の突出片をまち部の中折り部に入り込ませるように折り返してまち部の片側半分の上端口部を包むようにする状態を示す部分的な斜視図である。
【図９】従来の吹込口弁付袋の口部端を扁平状態にして示す平面図である。
【図１０】従来の吹込口弁付袋及びこの発明の吹込口弁付紙袋における基本構成要素となるまち部付の袋本体を扁平状態で示す平面図である。
【図１１】図１０に示される袋本体の吹込口弁となる突起部を台形状に開披した状態を示す斜視図である。
【図１２】図１１に示される袋本体の台形状に開披した突起部を開披状態から内側へ折り込んだ状態を示す斜視図である。
【符号の説明】
２ まち部
３ 突起部
４ 袋本体
４ａ 袋本体の口部端
４ｂ 袋本体口部端の端縁
６ 吹込口弁
８ａ、８ｂ 壁面
１０ 吹込口弁付紙袋
１１ 折返し部
１２ 当て紙
１２ａ 糊代部
１２ｂ 突出片
１３ 封緘部
１４ａ 熱可塑性接着剤
１４ｂ 水溶性接着剤
１５ 上端開口
１６ 折り返し線
１７ 折曲げ部
１８ 開封テープ付当て紙
１９ 底部閉鎖部
２０ 接着剤
２１ 開封テープ
２２ 膨張方向を示す矢印
２３ 引裂き開始部
２４ 引裂き範囲[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a paper bag with a blow-in valve, and more specifically, a paper bag with a blow-in valve that has a gusset on both sides and is provided with a blow-in valve that is folded inward on one side in the width direction on the mouth end side. About.
[0002]
[Prior art]
Conventionally, this type of bag with a blow-in valve is disclosed in, for example, Japanese Patent Publication No. 1-50662 and many other patent publications, and is well known. Therefore, the configuration of a conventional bag with a blow-in valve disclosed in Japanese Patent Publication No. 1-50662 will be briefly described with reference to FIGS.
[0003]
The bag 1 with a blow-in valve disclosed in the aforementioned patent publication was configured as follows. In other words, the bag with a blow-in valve 1 shown in FIG. 9 has a bag body 4 as a basic component. As shown in FIG. 10, the bag body 4 is a cylindrical body formed on both sides with a gusset 2 that can be folded in a V-shaped cross section, and includes the gusset 2 on one side end opening. A protrusion 3 having a width is provided. And the bag 1 with a blow-in valve has centered on the valley fold line 2a of the town part 2 while forming the folding line 5 of the protrusion part 3 of this bag main body 4 with respect to the side edge from the base P. As shown in FIG.
[0004]
Thereafter, the portion opened in a substantially trapezoidal shape is folded inward as shown in FIG. 12 to form the blow-in valve 6 in the bag body 4, and the mouth edge of the bag body 4 (shown in the figure). 9, the bottom edge is also folded back, and a backing sheet 7 as a reinforcing sheet is disposed across the folded portion as shown in FIG. 9, and this backing sheet 7 is bonded to both wall surfaces 8 of the bag body 4. By forming the sealing part 9, the bag with a blow-in valve 1 is configured.
[0005]
[Problems to be solved by the invention]
The bag with a blow-in valve 1 disclosed in the above-mentioned patent gazette has been used for many years for transportation and storage of powders such as flour and granular materials such as grains because it has a very excellent structure. It has been continued. However, it has been found that there is a problem that “leakage” occurs when the bag with a blow-off valve is used for transportation and storage of powders and the like for many years.
[0006]
This point will be described in detail. When the air bag 1 with a blow-in valve is automatically filled with powder such as wheat flour, a pneumatic transport method is used. That is, the nozzle for filling the contents is inserted into the bag 1 with the blow-in valve from the blow-in opening formed between the blow-in valve 6 folded inside and the backing paper 7, and the powder is blown on the compressed air. It is out.
[0007]
In this filling operation, transport air blown at the same time passes through the gap around the content filling nozzle inserted into the blow-in opening and the air-permeable bag body (town portion 2 and both wall surfaces 8 connected to this). Thus, only the powder is stored in the bag with the blow-in valve so that it is filled.
[0008]
The filling of the powder into the bag with the air inlet valve by such air transportation is completed in about 13 to 14 seconds in the case of the bag with the air inlet valve of the standard size. At the filling pressure, powder leakage sometimes occurred from the side opposite to the blowing port at the upper end of the bag. Of course, during powder filling, powder is blown out of the bag through the gap around the content filling nozzle at the blowing port. For such powder, a powder recovery device installed on the powder filling side, that is, near the blowing port It is not a problem because it is collected in
[0009]
The problem is the leakage of powder from the side opposite to the top of the bag. This point will be described in more detail. A sealing portion 9 is formed at the upper end of the bag 1 with a blow-in valve, and this sealing portion 9 turns the flat edge of the mouth one time and turns it back. It is configured so as to be covered with the sheet 7 across the part.
[0010]
At this time, the side of the bag body 4 on the side opposite to the blowing port at the mouth end is flattened by folding the town part 2 into a V-shaped cross section inside the valley fold line 2a at the center in the width direction. In addition, the shape or the cross-sectional shape seen from the upper direction in a state including the wall surfaces 8 on both sides connected to the town portion 2 has a substantially horizontal M shape.
[0011]
The upper end opening located on the most lateral side in the width direction of the transverse cross section, that is, the upper end of the mountain fold portion between the wall surface and one half of the folded town portion 2 is located at the end of the backing paper 7. Therefore, it is a place where the closing function is difficult to be demonstrated. In addition, the flat end of the mouth is only folded once.
[0012]
Therefore, when the powder is blown into the bag 1 with the air inlet valve in the flat state by pneumatic feeding, the air bag with the air inlet valve swells at a stretch with the filling pressure for the first few seconds, and the above-mentioned cross-section is almost the same. The upper end opening located in the lateral direction of the lateral M-shape is slightly opened, and the closing function of the backing paper 7 for this portion is not effectively exhibited. I found it leaking out.
[0013]
The leakage of the powder from this part is not only in the powder filling, but in the warehouse, the bag 1 with the blow-in valve is filled with the powder and the blow-in valve 6 is bonded to the backing paper 7 by hot melt. It may occur depending on the way of handling even when the work of loading at a predetermined position is performed. That is, when the operator holds the bag 1 with powder filling and puts it on the transport pallet or puts it on another bag with valve already loaded on the transport pallet. In some cases, the bag with the blow-in valve with the wall facing down is placed so as to drop quite quickly.
[0014]
Then, the pressure applied to the wall surface 8 when the bag with the air inlet valve is shockedly dropped causes the internal pressure in the air bag 1 with the air inlet valve to rapidly increase, and the same phenomenon as in the above-described powder filling occurs. As a result, the upper end opening located on the most lateral side in the width direction of the transverse cross-section described above slightly opens, so that the powder leaks out from the momentary on the pressurized internal air. is there.
[0015]
For this reason, when a large number of bags with inlet valves are continuously filled with powder, or when a large number of bags with inlet valves filled with powder are loaded and stored in a warehouse, etc. Personnel sometimes became white due to the leaked powder. When the powder is wheat flour, it is not harmful to the human body itself, so that the clothes of the workers are simply soiled and there is no problem.
[0016]
However, when the powder is cement or the like, it is assumed that the working environment is extremely deteriorated, so it is necessary to reduce the air pressure feeding force to the bag with the blow-in valve. If the pneumatic feeding force is lowered, the filling time becomes longer, so that the working efficiency of filling is lowered. In addition, when the powder is cement or the like, care must be taken to prevent rough handling of the bag with a blow-in valve after filling.
[0017]
In order to eliminate the occurrence of such powder leakage, it has been proposed to fold the end of the mouth twice as in the case of the bottom closed portion where the end is bent twice and is surrounded and fixed by the application paper. Improve the sealing part 9 formed at the upper end of the bag with a blow-in valve therewith to a structure using a double-layered application paper, and thicken the pressure applied to the sealing part 7 during filling The above-mentioned leakage could not be prevented.
[0018]
An object of the present invention is to solve such a conventional problem, and is an improved inlet valve that does not cause leakage of contents from the side opposite to the inlet during filling or handling. The purpose is to provide a paper bag.
[0019]
[Means for Solving the Problems]
In the present invention, one end of a cylindrical body having a foldable portion having a V-shaped cross section on both sides is processed and closed to form a bottom closed portion, and the other end in the width direction on the mouth end side is the same. A bag body provided with a protrusion on the upper edge of one side of the town part and a part of both wall surfaces connected to the town part, and a substantially trapezoidal shape around the valley fold line at the center of the town part. The air inlet valve formed by folding inside and the mouth end of the bag body is folded back to one wall surface, and the backing paper is placed across the folded portion, and the backing paper is placed on both wall surfaces. In a paper bag with a blow-off valve provided with a sealing part formed by bonding, the sealing part is formed so that a part of the patch protrudes from the edge of the mouth end to form a margin part. When first adhering to the other wall surface, the end of the backing paper opposite to the inlet valve protrudes from the bag body. The protruding piece is folded back in a lateral direction so as to wrap all or one half of the flat area of the bag body, and the end of the mouth is folded back together with the backing paper on one wall surface, and the adhesive margin of the backing paper is placed on one wall surface. It is characterized by being bonded.
[0020]
Further, in the paper bag with a blow-in valve according to the present invention, the protruding piece in which the end of the backing paper opposite to the blow-off valve is protruded from the bag body is folded so as to wrap all or one half of the flat town part. When folded back in the lateral direction, the folded back projecting piece is adhered to the adhesive margin portion of the facing paper and one wall surface or gusset portion of the bag body.
[0021]
Furthermore, in the paper bag with a blow-in valve according to the present invention, the bottom closing portion formed by processing one end of the bag body turns back at least one end of the bag main body and straddles the folded portion. And the adhesive tape attached with the opening tape is adhered to both wall surfaces.
[0022]
Furthermore, the paper bag with a blow-in valve according to the present invention is characterized in that it has a moisture-proof performance provided with an inner bag made of a resin film that is disposed so as to overlap the inside of the bag body. In addition, the bag main body may be comprised from the cylindrical body formed from the kraft paper.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Next, the bag with a blow-in valve according to the present invention will be described in more detail with respect to a preferred embodiment shown in the drawings. 1 shows a paper bag 10 with a blow-in valve according to an embodiment of the present invention, and FIG. 2 shows a longitudinal sectional structure of the paper bag 10 with a blow-in valve taken along the line 2-2 in FIG. FIG. 3 to FIG. 7 are partial configuration explanatory diagrams schematically showing a procedure for forming the paper bag 10 with a blow-in valve according to the present embodiment.
[0024]
By the way, since the basic structure of the paper bag 10 with an air inlet valve concerning this embodiment is substantially the same as the conventional bag 1 with an air inlet valve, about the basic structure of this paper bag 10 with an air inlet valve, it is conventional. It demonstrates with reference to FIGS. 10-12 which shows the basic part of the bag 1 with an inlet valve.
[0025]
As shown in FIG. 1, a paper bag 10 with a blow-in valve according to an embodiment of the present invention processes and closes one end of a cylindrical body 4 having a gusset 2 on both sides, thereby closing a bottom portion (bottom portion). The closing portion will be described later), and the projection is formed on the upper edge of one of the wall portions 2 on one side in the width direction on the mouth end side, which is the other end, and on the upper edge of a part of both wall surfaces 8 connected to the town portion 2 A bag body 4 having a portion 3 is provided.
[0026]
And the projection part 3 of this bag main body 4 is as shown in FIG. 11 centering on the valley fold line 2a of the town part 2, forming the fold curve 5 of about 45 degree | times with respect to the side edge from the base P. It will be shown in a trapezoidal shape. Thereafter, the portion opened in a substantially trapezoidal shape is folded inward as shown in FIG.
[0027]
The paper bag 10 with a blow-in valve according to this embodiment is a reinforcing sheet that folds the mouth end 4a of the bag body 4 configured as described above and straddles the folded portion 11 as shown in FIG. The backing paper 12 is disposed, and the sealing paper 13 is formed by adhering the backing paper 12 to both wall surfaces 8 a and 8 b of the bag body 4.
[0028]
The paper bag 10 with a blow-in valve of this embodiment is characterized by the structure of the sealing part 13. The structure of the sealing portion 13 will be described according to the formation procedure. As shown in FIG. 3, the sealing portion 13 of the paper bag 10 with the blow-in valve has a patch 12, a part of which protrudes from the edge 4 b at the mouth end 4 a of the bag body 4 to form an adhesive margin 12 a. First, it adheres to the other wall surface 8b.
[0029]
At that time, the end of the backing paper 12 opposite to the blow-off valve 6 is protruded from the bag body 4, and an adhesive is applied to the adhesive margin 12a and the protruding piece 12b, and the protruding piece 12b is shown in FIGS. As shown in FIG. 5, the bag body 4 is folded back so as to wrap around the entire other side in the width direction of the flat mouth end 4 a, that is, the entire town portion 2 (all in the thickness direction) on the one wall surface 8 a side. The part end 4 a and the adhesive margin 12 a of the backing paper 12 are overlapped and bonded.
[0030]
As a result, at the side of the bag body 4 on the side opposite to the blowing port at the mouth end 4a, as shown in FIG. The upper end opening 15 located on the side, that is, the upper end opening of the mountain fold portion between the wall surface 8a, 8b and each half of the folded city portion 2 is the projecting piece 12b of the backing paper 12, and the entire city portion is wound from the side. As a result, it is sandwiched in a sandwich shape, and the top portion of the upper opening 15 is completely closed by mutual adhesion between the adhesive margin 12a of the application paper 12 and the protruding piece 12b overlapping therewith.
[0031]
Thereafter, in the protruding piece 12b that is polymerized and bonded to the mouth end 4a and the adhesive margin 12a of the backing paper 12, the area overlapping the adhesive margin 12a of the backing paper 12 becomes a new adhesive margin 12a as it is. Adhesive is also applied to this area as shown in FIG. At that time, a thermoplastic adhesive 14a such as a hot-melt adhesive is applied to a region corresponding to the blow-in valve 6 in the adhesive margin 12a of the backing paper 12, that is, a region covering the blow-in valve 6 (FIG. 3). A portion indicated by a shadow line in FIG. 2) is coated with a water-soluble or heat-resistant adhesive 14b on the entire surface other than the thermoplastic adhesive application portion.
[0032]
The reason why the thermoplastic adhesive 14a is applied to the region covering the blow-in valve 6 in the adhesive margin 12a of the backing paper 12 and the water-soluble adhesive 14b is applied to the other region is that the contents from the blow-off port When the adhesive 14a is reactivated by applying heat to close the blowing port after filling the paper bag, the adhesive of the adhesive margin 12a already used for adhesion melts when the heat is applied, and the paper 12 This is in order not to cause peeling.
[0033]
Finally, the mouth end 4a of the bag body 4 is folded back to the wall surface 8a along the folding line 16 together with the backing paper 12, and the adhesive margin portion 12a of the backing paper 12 is adhered to the wall surface 8a, whereby the bag body A sealing portion 13 is formed at the four mouths. On the other hand, the bottom side of the bag body 4 is bent twice so as to wind the bottom end in accordance with a conventional method, and is then surrounded and fixed with an opening tape application paper 18 so as to straddle the bent portion 17 to be a bottom closing portion 19. ing.
[0034]
Specifically, when the cover paper 18 with the opening tape is arranged so as to straddle the bent portion 17, both end portions located in the longitudinal direction of the bag body 4 are respectively attached to the wall surfaces 8 a and 8 b of the bag body 4 by the adhesive 20. Glued and fixed. In addition, when the opening tape-attached paper 18 is disposed so as to straddle the folded portion 17, the opening tape 21 attached to the inside of the applied paper 18 is positioned substantially on the upper surface side of the folded portion 17. It is good to do.
[0035]
When the air bag is filled with powder from the air inlet, the paper bag 10 with the air inlet valve gradually expands as shown by an arrow 22 in FIG. The town part 2 that is V-shaped in a horizontal plane is opened to form a square as shown in FIG. 7, and as a result, from the lower side of the sheet 12 holding the town part 2 flat as shown in FIG. 6. Strong tearing force works.
[0036]
The mountain fold portion where the protruding piece 12b of the backing paper 12 is folded back by this tearing force is torn (the tearing start portion is indicated by reference numeral 23), and there is no problem in forming the paper bag 10 with the air inlet valve into the final square shape. Done without. The range (length) at which the mountain fold portion where the protruding piece 12b of the backing paper 12 is folded is torn is a range 24 between the lower edge 12c of the backing paper 12 and the mouth end folding line 16 as shown in the state of FIG. It is. Therefore, there is no effect on the folded portion of the backing paper 12 that closes the upper end opening 15 located in the laterally most lateral direction in the width M direction at the folded end 4a.
[0037]
In the paper bag 10 with the blow-in valve according to the embodiment described above, when the mouth end 4a is sealed, the protruding piece 12b of the backing paper 12 is formed in the width direction of the flat mouth end 4a as shown in FIGS. The other side part, that is, the entire town part 2 (the whole in the thickness direction) is folded back so as to wrap, and is overlapped and bonded to the mouth end 4a and the adhesive margin part 12a of the backing paper 12. However, the present invention is not limited to this form.
[0038]
For example, as shown in FIG. 8, when sealing the mouth end 4 a, the protruding piece 12 b of the backing paper 12 is placed on one side half of the town part 2, that is, on one side half of the town part 2 folded halfway with the wall surface 8 b. It may be folded back sideways so as to wrap only the upper end of the mountain fold. In short, when the protruding piece 12b of the backing paper 12 is folded back to the side, the folded piece 12b is not folded so as to overlap the wall surface 8a of the bag body 4, but is folded into the middle folded portion of the town portion 2 folded in a V-shaped cross section. It folds to the side so that it can enter.
[0039]
In this case, in the case of such a paper bag, the wall surface 8b and the inside of the paper bag 12 may only be wrapped from the side by the protruding piece 12b of the backing paper 12 from the side. This is because the contents are most likely to wrap around the upper end of the mountain fold with the half on one side of the folded town 2. That is, the wall surface 8a and the half of the half-folded town portion 2 connected to the wall surface 8a are bent almost 180 degrees on the wall surface 8a side by the fold line 16, so that it is difficult for the contents to wrap around the upper end. This is because the wall surface 8b and the half of the half-folded town portion 2 connected to the wall surface 8b are not bent when the contents are filled and the paper bag is inflated into a square shape.
[0040]
In addition, in the paper bag 10 with the blow-in valve according to the above-described embodiment, when the sealing portion 13 is formed in the mouth portion, the single sheet 12 is used. In particular, the edge at the mouth end 4a of the bag body 4 is used. Another sheet of paper may be overlapped and pasted in the range along 4b and partially doubled.
[0041]
Moreover, in the paper bag 10 with the blow-in valve according to the above-described embodiment, the bottom closing portion 19 is surrounded and fixed by the application paper 18 with the opening tape so as to straddle the folded portion 17 that is bent twice so as to wind the bottom end. However, the present invention is not limited to the structure of the bottom closing portion because the bottom closing portion is not the subject of the present invention.
[0042]
Therefore, when the bottom closing part 19 of the paper bag 10 with the air inlet valve is not tightly sealed without being easily opened, a structure similar to that of the sealing part 13 at the mouth is adopted. It is good also as a closure part. That is, both ends of the backing paper bonded to one wall surface are protruded from both side portions of the bag body so that the glue margin portion protrudes from the edge of the bottom end, and the protruding pieces are folded back and bonded to the wall surface side. .
[0043]
Then, the sheet can be folded together with the bottom end, and the adhesive margin can be adhered to the other wall surface to form the bottom closed portion. In this way, if the bottom closing part is configured in the same manner as the sealing part 13 at the mouth part, the bottom end can be closed without being leaked even if the bottom end is bent once, so the amount of paper used can be saved. Become.
[0044]
Finally, in the paper bag 10 with a blow-off valve, as described above, when the contents are blown into the paper bag, the gusset 2 is held flat by the protrusion 12b of the paper 12 at the mouth end. It is desirable that the protruding portion folded portion of the paper 12 has such a property that it can be easily cut when, for example, the fiber orientation is devised when a strong tearing force is exerted from the lower side due to expansion.
[0045]
Thus, in the paper bag 10 with a blow-in valve of this invention, when forming a sealing part in a mouth end, the cross section in the side part on the opposite side to the blow-in opening in the mouth part end of a bag main body is substantially horizontal M shape. For example, powder was blown into the paper bag with a blow-in valve in a flat state by pneumatic feeding, for example, by completely closing the upper end opening located on the side in the width direction with the protruding piece of the paper from the side. It is possible to completely prevent the leakage of powder from the above-mentioned upper end opening, which has sometimes occurred in this type of conventional paper bag.
[0046]
【The invention's effect】
As described above, according to the paper bag with a blow-in valve of the present invention, the lateral side of the side of the bag body opposite to the blow-in port is located on the most lateral side of the transverse M-shaped cross section. With a very simple configuration in which the upper end opening is wound from the side with a projecting piece of the paper and completely closed so that the sealing portion is formed at the end of the mouth, powder or the like is filled with powder. When handling the paper bag with the air inlet valve, leakage of contents from the upper end opening can be completely prevented.
[Brief description of the drawings]
FIG. 1 is a plan view showing a paper bag with a blow-in valve according to an embodiment of the present invention in a flat state.
FIG. 2 is a structural explanatory view schematically showing a cross-sectional structure of the paper bag with a blow-in valve shown in FIG. 1 cut along line 2-2.
3 shows a state in which a sealing paper is attached to one wall surface to form a sealing portion at the mouth end and a bottom closing portion at the bottom end of the paper bag with a blow-in valve shown in FIG. It is a top view.
4 is a schematic configuration explanatory view of a side portion on the opposite side to the blowing port at the mouth end before forming the paper bag with the blowing port valve shown in FIG. 3 as viewed from above.
FIG. 5 is a partial plan view showing a state immediately before forming a sealing portion at the mouth end of the paper bag with a blow-in valve shown in FIG. 1;
6 is a fold-back portion of a protruding piece of a sheet of paper that presses a side gusset opposite to the blow-off port at the mouth end of the paper bag with the blow-off valve shown in FIG. 1 in a flat state. It is a fragmentary perspective view which shows roughly the state torn by the expansion force when a paper bag is filled with the content.
FIG. 7 is a projecting piece of a backing paper that presses the side part of the mouth end opposite to the blow-off port into a flat state by filling the paper bag with the blow-in valve shown in FIG. It is a partial perspective view which shows roughly the state by which the folding | turning part of this was torn and shape | molded in the normal square shape.
FIG. 8 is a paper bag with a blow-off valve according to another embodiment of the present invention, and when the end of the mouth portion is sealed, the protruding piece of the application paper is folded back so as to enter the middle folding portion of the town portion. It is a fragmentary perspective view which shows the state which wraps up the upper end opening part of the one side half of a town part.
FIG. 9 is a plan view showing the mouth end of a conventional bag with a blow-in valve in a flat state.
FIG. 10 is a plan view showing, in a flat state, a bag body with a gusset as a basic component in a conventional bag with a blow-in valve and a paper bag with a blow-in valve according to the present invention.
11 is a perspective view showing a state in which a protrusion serving as a blow-in valve of the bag body shown in FIG. 10 is opened in a trapezoidal shape.
12 is a perspective view showing a state in which the protruding portion of the bag main body shown in FIG. 11 which is opened in a trapezoidal shape is folded inward from the opened state.
[Explanation of symbols]
2 Machi part 3 Protruding part 4 Bag body 4a Bag body end 4b Edge of bag body mouth end 6 Blow-in valve 8a, 8b Wall surface 10 Blow-in valve bag 11 Folding part 12 Paper 12a Paste margin 12b Projection piece 13 Sealing portion 14a Thermoplastic adhesive 14b Water-soluble adhesive 15 Upper end opening 16 Folding line 17 Bending portion 18 Opening tape attaching paper 19 Bottom closing portion 20 Adhesive 21 Opening tape 22 Arrow 23 indicating expansion direction Start of tearing Part 24 Tear range

Claims (5)

両側部に断面Ｖ字状に中折り可能なまち部を備える筒状体の一端を加工して閉鎖することにより底部閉鎖部とし、他端である口部端側の幅方向一側部における一方の前記まち部上縁とこのまち部に連接する両壁面の一部の上縁に突起部を備える袋本体と、この突起部を前記まち部中央の谷折り線を中心としてほぼ台形状に開披すると共に内側に折り込んで形成された吹込口弁と、前記袋本体の前記口部端を一方の前記壁面側に折り返し、その折返し部を跨いで当て紙を配置し、その当て紙を前記両壁面に接着して形成された封緘部とを備える吹込口弁付紙袋において、
前記封緘部が、前記当て紙の一部を前記口部端の端縁から飛び出させて糊代部を形成するように当該当て紙を他方の前記壁面に最初に接着する時に前記吹込口弁とは反対側の前記当て紙の端部を前記袋本体から突出させ、この突出片を前記袋本体の扁平な前記まち部の全部又は片側半分を包み込むように側方に折り返し、前記口部端を一方の前記壁面側に前記当て紙と共に折り返して前記当て紙の前記糊代部を一方の前記壁面に接着して構成されていることを特徴とする吹込口弁付紙袋。One end of one end of the width direction side of the mouth end side which is the other end is formed by closing one end of a cylindrical body which is provided with a town part which can be folded in a V-shaped cross section on both side parts. A bag body having a protrusion on the upper edge of the town part and a part of both wall surfaces connected to the town part, and the protrusion is opened substantially in a trapezoidal shape around the valley fold line at the center of the town part. The blow-in valve formed by folding inside and the mouth end of the bag body is folded back to the one wall surface side, and the backing paper is arranged across the folded-back portion, In a paper bag with a blow-in valve provided with a sealing part formed by bonding to a wall surface,
When the sealing part first bonds the pad to the other wall surface so that a part of the pad is ejected from the edge of the mouth end to form a glue margin, Projecting the end of the backing paper on the opposite side from the bag body, folding the protruding piece sideways so as to wrap all or one half of the flat side of the bag body, and the mouth end A paper bag with a blow-in valve, wherein the paper bag is configured to be folded together with the pad on one of the wall surfaces and adhere the adhesive margin of the pad to the one wall. 前記吹込口弁とは反対側の前記当て紙の端部を前記袋本体から突出させた前記突出片を折り返して扁平な前記まち部の全部又は片側半分を包み込むように側方に折り返す時、折り返された前記突出片が、対面する前記当て紙の前記糊代部と前記袋本体の一方の前記壁面又は前記まち部に接着されていることを特徴とする請求項１に記載の吹込口弁付紙袋。When the projecting piece with the end of the backing paper on the side opposite to the blow-off valve projecting from the bag body is folded back and folded back sideways so as to wrap all or one half of the flat town part 2. The blow-off valve attached according to claim 1, wherein the protruding piece is bonded to the glue margin portion of the facing paper and the one wall surface or the gusset portion of the bag body facing each other. paper bag. 前記袋本体の一端を加工して形成された前記底部閉鎖部が、前記袋本体の一端を少なくとも２回折り返して、その折返し部を跨いで開封テープ付当て紙を配置し、その開封テープ付当て紙を前記両壁面に接着して形成されていることを特徴とする請求項１又は２に記載の吹込口弁付紙袋。The bottom closing part formed by processing one end of the bag main body turns at least one end of the bag main body twice, arranges an opening tape application paper across the folded part, and applies the opening tape application The paper bag with a blow-in valve according to claim 1 or 2, wherein paper is adhered to both the wall surfaces. 前記吹込口弁付紙袋が、前記袋本体の内側に重ねて配置された樹脂フィルム製の内袋を備えた防湿性能付きであることを特徴とする請求項１〜３のいずれかに記載の吹込口弁付紙袋。The blower according to any one of claims 1 to 3, wherein the paper bag with a blow-in valve has a moisture-proof performance provided with an inner bag made of a resin film that is disposed so as to overlap the inside of the bag body. Paper bag with mouth valve. 前記袋本体が、クラフト紙から形成された前記筒状体から構成されていることを特徴とする請求項１〜４のいずれかに記載の吹込口弁付紙袋。The said bag main body is comprised from the said cylindrical body formed from the kraft paper, The paper bag with a blower valve in any one of Claims 1-4 characterized by the above-mentioned.

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