JP4587091B2

JP4587091B2 - Blow molding method, apparatus therefor and die head used therefor

Info

Publication number: JP4587091B2
Application number: JP2000320441A
Authority: JP
Inventors: 隆今井; 和義青木
Original assignee: 株式会社プラコー
Priority date: 2000-10-20
Filing date: 2000-10-20
Publication date: 2010-11-24
Anticipated expiration: 2020-10-20
Also published as: JP2002127236A

Description

【０００１】
【産業上の利用分野】
この発明は、ブロー成形する方法とその装置及びこれに使用されるダイヘッドに関する。
【０００２】
【従来の技術】
この種の多層パリソンを形成しブロー成形する装置として、種々の装置が各社で開発され、公開されている。その一例として実開平６−９９１４号公報がある。
【０００３】
【発明が解決しようとする課題】
この発明は、多層パリソンの外層、中間層の分配樹脂路の形状を簡略化し、樹脂の滞留を減少させ、樹脂劣化を少なくするブロー成形方法とその装置及びこれに使用されるダイヘッドを市場に提供することを目的とする。この発明のその他の目的は、ダイヘッドの本体直径を大きくすることなく、パリソンの層数を任意に変更可能とするブロー成形方法とその装置及びこれに使用されるダイヘッドを市場に提供することである。
【０００４】
【課題を解決するための手段】
前記課題を解決するために、特定発明は、少なくとも２つの外層用の樹脂路に最内層用の樹脂路がダイヘッドに同心的に設けてあり、これら樹脂路が前記ダイヘッドの吐出口近傍で合流し、前記吐出口に連通し少なくとも２層のパリソンを前記吐出口から吐出し、ブロー成形するブロー成形方法において、前記ダイヘッドを、少なくとも２個の環状ブロックダイを上下重ね合わせて構成し、隣接する環状ブロックダイ間に平面内で少なくとも１回左右円周方向に分岐した分岐路を通して等角間隔異なる位置より次に全周の環状路より成る分配樹脂路を通じて外層用の樹脂路に外層用の樹脂を供給し、他方マンドレルの外周面に沿い昇降可能なプランジャーにより、ダイ内アキューム室に貯留された最内層用の溶融樹脂を、マンドレルと前記環状ブロックダイ間で形成された合流通路において、前記外層用の溶融樹脂と合流して、これら環状ブロックダイのうち、下側の環状ブロックダイ下面に設けたダイリングとマンドレル間で形成した前記吐出口から前記外層用の樹脂と最内層の樹脂からなる少なくとも２層のパリソンを吐出しブロー成形するとともに、前記環状路の樹脂の合流位置を、前記パリソンを収容しブロー成形する成型金型の合わせ面に概ね符合させることを特徴とするブロー成形方法としてある。
【０００５】
前記課題を解決するために、このブロー成形方法における前記外層用の樹脂路に連なる分配樹脂路の樹脂供給口を、前記環状ブロックダイの側方の上下に重なる前記環状ブロックダイ間に設け、この樹脂供給口にダイ外アキュームレータ室より溶融樹脂を供給し、このダイ外アキュームレータ室より前記樹脂供給口に供給された外層用の溶融樹脂を、この樹脂注入口から平面に見て円周方向へ９０度左右に分岐し、次いで前記分岐路の終端の１８０度異なる位置から環状路全周に分配し、この環状路の全内周縁から前記上下に重なる前記環状ブロックダイ間の扁平ドーナツ盤状樹脂通路を介して、前記外層用の樹脂路に供給するとともに、前記環状路の樹脂の合流位置を、前記パリソンを収容しブロー成形する成型金型の合わせ面に概ね符合させることを特徴とする。
【０００６】
前記課題を解決するために、関連発明は、少なくとも２つの外層用の樹脂路と最内層用の樹脂路がダイヘッドに同心的に設けてあり、これら樹脂路が前記ダイヘッドの吐出口近傍で合流し、前記吐出口に連通し少なくとも２層のパリソンを前記吐出口から吐出し、ブロー成形するブロー成形装置において、前記ダイヘッドは、少なくとも２個の環状ブロックダイを上下重ね合わせて成り、隣接する環状ブロックダイ間に平面内で少なくとも１回左右円周方向に分岐した分岐路が形成され、これら分岐路で分割された等角間隔に設けた分岐路出口部はこれより内側の前記環状ブロックダイ間に設けた環状路及び全内周縁に連なる扁平ドーナツ盤状樹脂通路に連通して外層用樹脂の分配樹脂路は成り、この分配樹脂路は、外層用の樹脂路に連通させてあり、他方マンドレルの外周面に沿い昇降可能なプランジャーが設けて、ダイ内アキューム室に貯留された最内層用の樹脂路は、マンドレルと前記環状ブロックダイ間で形成された内外層合流通路に通じ、この合流路は、前記吐出口に連通しているとともに、前記環状路の樹脂の合流位置は、前記パリソンを収容しブロー成形する成型金型の合わせ面にほぼ符合していることを特徴とするブロー成形装置としてある。
【０００７】
前記課題を解決するために、このブロー成形装置における前記外層用の樹脂路に連なる分配樹脂路の樹脂供給口は、前記環状ブロックダイの側方の上下に重なる前記環状ブロックダイ間に設けてあり、この樹脂供給口はダイ外アキュームレータ室に連通し、この樹脂供給口から平面に見て分配樹脂路は前記９０度円周方向に左右に分岐する第１分岐路と、各第１分岐路から更に９０度左右に第１分岐路よりも内側に分岐した一対の第２分岐路からなり、この一対の第２分岐路の先端は、他側の第２分岐路の先端と、前記樹脂注入口の軸線上乃至上下に重なる位置上で合流させてあり、前記第２分岐路の全域の内縁より内側の上下の前記環状ブロックダイ間には前記合流点に通じる前記扁平ドーナツ盤状樹脂通路が形成してあるとともに、前記環状路の樹脂の合流位置は、前記パリソンを収容しブロー成形する成型金型の合わせ面にほぼ符合していることを特徴とする。
【０００８】
前記課題を解決するために、このブロー成形装置における前記パリソンが３種３層としてあり、前記環状ブロックダイは３個積み重ねられ、最下部と中間部の前記環状ブロックダイ間には、前記外層用の樹脂路に連なる前記分配樹脂路が形成され、最上部と中間部の前記環状ブロックダイ間には、中間層用の樹脂路に連なる中間層用樹脂の分配樹脂路が形成され、これら分配樹脂路は各段共にほぼ同様の形状としてあることを特徴とする。
【０００９】
前記課題を解決するために、関連発明は、少なくとも２個の環状ブロックダイを上下重ね合わせて成り、隣接する環状ブロックダイ間に平面内で少なくとも１回左右円周方向に分岐した分岐路が形成され、これら分岐路で分割された等角間隔に設けた分岐路出口部はこれより内側の前記環状ブロックダイ間に設けた環状路及び全内周縁に連なる扁平ドーナツ盤状樹脂通路に連通して外層用樹脂の分配樹脂路は成り、この分配樹脂路は外層用の樹脂路に連通させてあり、他方マンドレルの外周面に沿い昇降可能なプランジャーが設けて、ダイ内アキューム室に貯留された最内層用の樹脂路は、マンドレルと前記環状ブロックダイ間で形成された合流通路を通り、扁平ドーナツ盤状通路に連なる前記外層用の溶融樹脂路内の外層用の樹脂と合流して吐出口から吐出する形状としてあるとともに、前記環状路内を流れる外層用の樹脂の合流点位置は、前記パリソンを収容しブロー成形する成型金型の合わせ面に符合していることを特徴とするブロー成形装置用のダイヘッドとしてある。
【００１０】
【発明の実施の形態】
請求項６記載のダイヘッドに関する発明の代表的な実施の形態を請求項３，４記載の装置発明の代表的な実施の形態と併せて説明する。
【００１１】
図１において、Ａは、ブロー成形装置全体を示し、このブロー成形装置Ａは外層用及び中間層用の樹脂路１０、１１とに最内層用の樹脂路１２がダイヘッド１３に同心的に設けてあり、これら樹脂路１０、１１、１２が前記ダイヘッド１３の吐出口１４近傍で合流し、前記吐出口７０に連通し３種３層のパリソンＰを前記吐出口７０から吐出し、ブロー成形するものである。前記ダイヘッド１３は、３個の環状ブロックダイ１５、１６、１７を上下重ね合わせて成り、最下部と中間部の環状ブロックダイ１５、１６間に平面内で１回左右円周方向に分岐した分岐路１８が形成され、これら分岐路１８で分割された等角間隔に設けた分岐路出口部１９はこれより内側の前記環状ブロックダイ１５、１６間に設けた環状路２０及び全内周縁に連なる扁平ドーナツ盤状樹脂通路２１に連通して外層用の分配樹脂路Ｂ１は成り、このように形成して分配樹脂路Ｂ１は外層用の樹脂路１０に連なる（図２、図３、参照）。
【００１２】
更に詳述すれば前記外層用の樹脂路１０に連なる前記分配樹脂路の樹脂供給口２６は、前記環状ブロックダイ１５、１６、１７の側方で上下に重なる前記環状ブロックダイ１５、１６間に設けてあり、この樹脂供給口２６はダイ外アキュームレータ室（図示せず）に連通し、この樹脂供給口２６から平面に見て前記分配樹脂路は前記９０度円周方向に左右に分岐する分岐路１８と、各分岐路１８から更に９０度左右に分けて分岐路１８の吐出口よりも内側で円周方向に設けた前記環状路２０に連なり、この環状路２０の全域の内縁より内側の上下の前記環状ブロックダイ１５、１６間には前記外層用の樹脂路１０に通じる扁平ドーナツ状樹脂通路２１が形成してあり（図３参照）、前記環状路２０の中を流れる溶融樹脂の合流位置は、前記パリソンを収容しブロー成形する成型金型（図示せず）の合わせ面にほぼ符合している。
【００１３】
最上部と中間部の前記環状ブロックダイ１７、１６間には、中間層用の樹脂路１１に連なる分配樹脂路Ｂ２が形成され、この分配樹脂路Ｂ２は外層用の分配樹脂路Ｂ１とほぼ同様の形状としてあり、分配樹脂路Ｂ１と同一の符号は同一の構成を示す（図４参照）。
【００１４】
他方マンドレル２２の外周面に沿い昇降可能なプランジャー２３が設けて、ダイ内アキューム室２４に貯留された最内層用の溶融樹脂路は、マンドレル２２と環状ブロックダイ間で形成された３層合流通路２５に通じ、この合流路は、前記吐出口１３に連通している（図１参照）。前記プランジャー２３の外側でダイ本体の内側に同心に配置した環状スリーブ２７の外周面に、押出機（図示せず）からの樹脂流入口２８に連通する分岐路の下流に連なる円筒面樹脂分配路はこのダイヘッド１３の軸線方向に対称となるようにコートハンガー状の円筒面樹脂分配路として形成され、この円筒面樹脂分配路２９の上流方向である分岐路３０においてはダイ本体Ｄと環状スリーブ２７は密嵌し分岐路に沿い流れる周方向の流れを生じさせ、この円筒面樹脂分配路２９においてはダイ本体Ｄと環状スリーブ２７間に間隙が形成され、この円筒面樹脂分配路２９に沿い流れる周方向流と併せてこの間隙を流れる軸線方向流れを生じさせる形状としてある（図１参照）。
【００１５】
前記プランジャー２２の外周面に付着した溶融樹脂膜を、パリソンＰの吐出毎に上下動するプランジャー２２の外周面から剥離する溶融樹脂膜剥離用環状体５０が、プランジャーの外周面を取り囲んで前記スリーブ２７の上端に固定されている（図１、図５、図６、図７参照）。この溶融樹脂剥離用環状体５０は、扁平にリング体から成り、その中心には、前記プランジャーが貫通する貫通孔５１が明けてあり、この貫通孔５１の周囲に円周方向に間隔を置いて複数の取付孔５２が前記溶融樹脂剥離用環状体５０の軸線方向に設けてあり、隣接する取付孔５２間で、この溶融樹脂剥離用環状体５０の下面５３側には、このリング体の外周面から貫通孔５１にわたり殺ぎ落として形成した溶融樹脂膜排出口部５４が形成してあり、各溶融樹脂膜排出口部５４は前記貫通孔５１にその全内縁で連通し、前記取付穴５２の周縁を避けて、前記溶融樹脂剥離用環状体５０の外周面に開放している（図４、図６及び図７参照）。
前記溶融樹脂膜排出口部５４は前記スリーブ２７の上端面との間に放射状に形成された扁平な間隙口を形成して、前記スリーブ２７の上端に前記溶融樹脂剥離用環状体５０は固定されている。前記貫通穴５１には、段差部５５が設けてあり、前記リング体の上面５６側の直径が、このリング体の下面５３側の直径より小さくしてあり、このリング体の上面側の直径は前記プランジャー２３の外形とほぼ符合し、前記段差部５５は、溶融樹脂膜剥離エッジを形成している（図６参照）。この実施の形態の作用を請求項１、２記載の方法発明の代表的な実施の形態として説明する。
【００１６】
前記分配樹脂路Ｂ１、Ｂ２を通じて外層用および中間層の樹脂路１０、１１に外層用の樹脂及び中間層の樹脂を別々に供給する。他方マンドレル２０の外周面に沿い昇降可能なプランジャー２３により、ダイ内アキューム室２４に貯留された最内層用の溶融樹脂を、マンドレル２２と環状ブロックタイ間で形成された前記合流通路２５において、前記外層用、中間層用の溶融樹脂と合流して、下側の環状ブロックダイ１５に取り付けたダイリング６０とマンドレル２２間で形成した吐出口７０から前記外層用、中間層用の樹脂と最内層の樹脂からなる３種３層のパリソンＰを吐出しブロー成形する。
【００１７】
更に詳述すれば前記外層、中間層用の樹脂路１０、１１に連なる各分配樹脂路Ｂ１、Ｂ２の樹脂供給口２６にダイ外アキュームレータ室より溶融樹脂を各々供給し、このダイ外アキュームレータ室より前記樹脂供給口２６に供給された外層用、中間層用の溶融樹脂を、この樹脂注入口２６から平面に見て円周方向へ９０度左右に分岐し、次いで前記分岐路１８の終端の１８０度異なる位置から環状路２０全周に分配し、この環状路２０の全内周縁から前記上下に重なる前記環状ブロックダイ間の扁平ドーナツ盤状樹脂通路２１を介して、外層用、中間層用の樹脂路１０、１１に供給する。
【００１８】
前記環状路２０の樹脂の合流位置を、前記パリソンを収容しブロー成形する成型金型（図示せず）の合わせ面に概ね符合させる。このように符合することで、仮にパリソンにフローマークが発生したとしても、前記成型金型の合わせ面に前記フローマークが位置するため、ブロー成形品の外観を損ねることはなく、その外観は良好に維持され、このフローマークが発生した部分を前記合わせ部において喰い切れば、更にブロー成形品の外観を良好に維持される。溶融樹脂の貯留をプランジャー２３の上昇に伴い、前記環状スリーブ２７の下端を通りダイ内アキューム室２４内に下方から徐々に貯留し、このプランジャー２３下端を前記環状スリーブ２７の下端より若干下位まで下降させ、ダイ内アキューム室２４内の溶融樹脂全量を余すことなく、前記合流点２５へ供給し、前記外層用、中間層用樹脂と合流させて、３種３層のパリソンＰを吐出口７０から吐出しブロー成形する。前記プランジャー２３の上昇毎に前記プランジャー２３の外周面に付着している内層用の溶融樹脂は前記溶融樹脂剥離用環状体５０の貫通穴５１に形成された段差部５５のエッジにより剥離され、この剥離した樹脂は、前記排出口部５４を通して、外部へ放射状に排出される（図６参照）。前記溶融樹脂剥離用環状体５０の作用は、多層樹脂よりなるパリソン成形用ダイヘッドでなくとも、ダイ内アキューム型のものであれば、単層でも同様の作用を為すが、現在は多層パリソンが一般的であり、利用価値は大きい。
【００１９】
実施の形態２
この実施の形態は、図８に示すもので、請求項６記載のダイヘッドに関する別の形態で請求項３．４記載の装置発明の代表的な実施の形態と併せて説明する。
実施の形態１と異なる構成は次の通りである。実施の形態１の分岐路１８が第１分岐路１８ａによって２分割され、第２分岐路１８ｂにおいて４分割され、それぞれの出口部において９０度各間隔で、内側に設けた円周方向の前記環状路２０の連通されている。この環状路２０内を流れる溶融樹脂の分岐点は４点有るが、そのうち１８０度離れた位置の合流点は前記パリソンを収容しブロー成形する成型金型（図示せず）の合わせ面に概ね符合させてある。その他、実施の形態１と同一の符号は同一の構成を示し、同様の作用を為す。
【００２０】
【発明の効果】
請求項１、２記載の方法発明においては、前記ダイヘッドを、少なくとも２個の環状ブロックダイを上下重ね合わせて構成し、隣接する環状ブロックダイ間に平面内で少なくとも１回左右に分岐した、分岐路を通して等角間隔異なる位置より次に全周の環状路より成る分配樹脂路を通じて外層用の樹脂路に外層用の樹脂を供給し、他方マンドレルの外周面に沿い昇降可能なプランジャーにより、ダイ内アキューム室に貯留された最内層用の溶融樹脂を、マンドレルとリング部材間で形成された合流通路において、前記外層用の溶融樹脂と合流するため、前記外装用の溶融樹脂を平面内で順次分配して前記合流部に供給でき、樹脂を円滑に流すことができ、その滞留を減少でき、樹脂劣化を低減し、更に色路替えを含む材料替えを迅速にできる。
前記環状路の樹脂の合流位置を、前記パリソンを収容しブロー成形する成型金型の合わせ面に概ね符合させることにより、仮にパリソンにフローマークが発生したとしても、前記成型金型の合わせ面に前記フローマークが位置するため、ブロー成形品の外観を損ねることはなく、その外観を良好に維持でき、このフローマークが発生した部分を前記合わせ部において喰い切れば、更にブロー成形品の外観を良好に維持できる。
【００２１】
請求項２記載の方法発明においては、殊に、前記外層用の樹脂路に連なる分配樹脂路の樹脂供給口を、前記環状ブロックダイの側方の上下に重なる前記環状ブロックダイ間に設け、この樹脂供給口にダイ外アキュームレータ室より溶融樹脂を供給し、このダイ外アキュームレータ室より前記樹脂供給口に供給された外層用の溶融樹脂を、この樹脂注入口から平面に見て円周方向へ９０度左右に分岐し、次いで前記分岐路の終端の１８０度異なる位置から環状路全周に分配し、この環状路の全内周縁から前記上下に重なる前記環状ブロックダイ間の扁平ドーナツ盤状樹脂通路を介して、外層用の樹脂路に供給することを特徴により、供給された外層用の樹脂を１回に分岐し分配した後、前記合流点にその全周から均一に供給することができる。
【００２２】
請求項３記載の装置発明においては、請求項１記載の方法発明を実施でき、その効果を奏する。
【００２３】
請求項４記載の装置発明においては、請求項２記載の方法発明を実施でき、その効果を奏する。
【００２４】
請求項５記載の装置発明においては、前記パリソンを３種３層とし、前記環状ブロックダイを３個積み重ね、最下部と中間部の前記環状ブロックダイ間には、前記外層用の樹脂路に連なる前記分配樹脂路を形成し、最上部と中間部の前記環状ブロックダイ間には、中間層用の樹脂路に連なる前記分配樹脂路を形成し、これら分配樹脂路をほぼ同様の形状とすることにより、請求項３、４記載の装置発明の効果を３種３層のパリソンを利用し、ブロー成形する際に有効に発揮できる。
【００２５】
請求項６記載の発明において、請求項１、２記載の方法発明を実施でき、その効果を奏する。
【００２６】
実施の形態においては、前記溶融樹脂剥離用環状体５０により、プランジャー２３の上昇毎にプランジャー２３外周面を自動的にクリーニングできる。
前記各実施の形態においては、ブロー成形装置をダイレクトブロー（押出）方式として説明したが、インジェクション（射出）方式としても、この発明の技術的範囲に属する。
【図面の簡単な説明】
【図１】実施の形態１の概略縦断面図である。
【図２】図１一部破断斜視図である。
【図３】図１の下側の環状ブロックダイの斜視図である。
【図４】図１の中間の環状ブロックダイの平面図である。
【図５】溶融樹脂離間環状体の底面図である。
【図６】溶融樹脂剥離用環状体の使用状態を示す概略縦断面図である。
【図７】図５の正面図である。
【図８】実施の形態２の環状ブロックダイの平面図である。
【符号の説明】
１５、１６、１７環状ブロックダイ
Ｂ１、Ｂ２分配樹脂路[0001]
[Industrial application fields]
The present invention relates to a blow molding method, an apparatus therefor, and a die head used therefor.
[0002]
[Prior art]
Various apparatuses have been developed and disclosed by various companies as apparatuses for forming and blow-molding this type of multilayer parison. One example is Japanese Utility Model Publication No. 6-9914.
[0003]
[Problems to be solved by the invention]
This invention provides the market with a blow molding method and apparatus for reducing the resin deterioration by simplifying the shape of the distribution resin path of the outer layer and the intermediate layer of the multilayer parison, and reducing the resin deterioration. The purpose is to do. Another object of the present invention is to provide to the market a blow molding method and apparatus capable of arbitrarily changing the number of parison layers without increasing the main body diameter of the die head, and a die head used therefor. .
[0004]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the specific invention is such that at least two outer resin paths are concentrically provided with a resin path for the innermost layer, and these resin paths merge in the vicinity of the discharge port of the die head. In the blow molding method in which at least two layers of parison are communicated with the discharge port and are blow-molded from the discharge port, the die head is formed by stacking at least two annular block dies vertically and adjacent to each other. The resin for the outer layer is put into the resin path for the outer layer through the distribution resin path composed of the annular path of the entire circumference through the branch path branched at least once in the left and right circumferential directions in the plane between the block dies and from the position different from the equiangular interval. The molten resin for the innermost layer stored in the accumulation chamber in the die is supplied to the mandrel and the ring by a plunger that can be fed up and down along the outer peripheral surface of the mandrel. In the joining passage formed between the block dies, the discharge port formed between the die ring and the mandrel provided on the lower surface of the lower annular block die out of these annular block dies by joining with the molten resin for the outer layer. The at least two layers of parison made of the outer layer resin and the innermost layer resin are discharged and blow-molded, and the joining position of the resin in the annular path is set to the mating surface of the molding die that accommodates and blow-molds the parison The blow molding method is characterized by substantially matching the above.
[0005]
In order to solve the above-mentioned problem, a resin supply port of a distribution resin path that is continuous with the resin path for the outer layer in this blow molding method is provided between the annular block dies that overlap the upper and lower sides of the annular block die. The molten resin is supplied to the resin supply port from the external accumulator chamber, and the molten resin for the outer layer supplied from the external die accumulator chamber to the resin supply port is 90 in the circumferential direction when viewed in plan from the resin injection port. A flat donut disk-shaped resin passage between the annular block dies that branches to the left and right and then distributes to the entire circumference of the annular path from a position 180 degrees different from the end of the branch path, and overlaps the upper and lower sides from the entire inner periphery of the annular path. The resin passage for the outer layer is supplied to the resin passage for the outer layer, and the joining position of the resin in the annular passage substantially coincides with the mating surface of the molding die for containing the parison and blow-molding. And characterized in that.
[0006]
In order to solve the above-mentioned problems, in the related invention, at least two resin paths for the outer layer and the resin path for the innermost layer are provided concentrically on the die head, and these resin paths merge near the discharge port of the die head. In the blow molding apparatus for discharging at least two layers of the parison from the discharge port and performing blow molding, the die head is formed by stacking at least two annular block dies vertically, and adjacent annular blocks. A branch path branched at least once in the left-right circumferential direction in the plane is formed between the dies, and the branch path exit portions provided at equiangular intervals divided by these branch paths are between the annular block dies on the inner side. A resin distribution path for the outer layer resin is formed in communication with the provided annular path and a flat donut disk-shaped resin path connected to the entire inner periphery, and this distribution resin path is connected to the resin path for the outer layer. On the other hand, a plunger that can be moved up and down along the outer peripheral surface of the mandrel is provided, and the resin path for the innermost layer stored in the accumulator chamber in the die is an inner / outer layer merging passage formed between the mandrel and the annular block die The joint flow path communicates with the discharge port, and the joining position of the resin in the annular passage substantially coincides with the mating surface of the molding die for accommodating and blow-molding the parison. As a featured blow molding device.
[0007]
In order to solve the above-mentioned problem, a resin supply port of a distribution resin path connected to the resin path for the outer layer in this blow molding apparatus is provided between the annular block dies that overlap vertically on the side of the annular block die. The resin supply port communicates with the accumulator chamber outside the die, and the distribution resin path from the resin supply port in a plan view is divided into a first branch path branching left and right in the 90 ° circumferential direction, and each first branch path. Further, it is composed of a pair of second branch paths that branch 90 degrees to the left and inside of the first branch path. The ends of the pair of second branch paths are connected to the tip of the second branch path on the other side and the resin injection port. The flat donut disk-shaped resin passage leading to the joining point is formed between the upper and lower annular block dies inside the inner edge of the entire area of the second branch path. And said Merging position of the resin Jo path, characterized in that it substantially conforms to the mating surface of the mold to blow molding housing the parison.
[0008]
In order to solve the above-mentioned problem, the parison in this blow molding apparatus has three types and three layers, and three annular block dies are stacked, and the outer layer is between the annular block dies at the lowermost part and the middle part. The distribution resin path that is continuous with the resin path is formed, and the distribution resin path for the intermediate layer resin that is continuous with the resin path for the intermediate layer is formed between the annular block dies at the uppermost part and the intermediate part. The road is characterized by substantially the same shape at each stage.
[0009]
In order to solve the above-mentioned problem, the related invention is formed by stacking at least two annular block dies vertically, and a branch path branched at least once in the left-right circumferential direction in a plane is formed between adjacent annular block dies. The branch passage outlet portions provided at equiangular intervals divided by these branch passages communicate with the annular passage provided between the annular block dies on the inner side and the flat donut disk-shaped resin passage connected to the entire inner peripheral edge. A distribution resin path for the outer layer resin is formed, and this distribution resin path is communicated with the resin path for the outer layer. On the other hand, a plunger that can be raised and lowered along the outer peripheral surface of the mandrel is provided and stored in the accumulator chamber in the die. The resin path for the innermost layer merges with the resin for the outer layer in the molten resin path for the outer layer that passes through the merge passage formed between the mandrel and the annular block die and is connected to the flat donut disk-shaped passage. The shape is a shape that is discharged from a discharge port, and the joining point position of the resin for the outer layer that flows in the annular path is coincident with a mating surface of a molding die that accommodates and blow-molds the parison. As a die head for blow molding equipment.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
A typical embodiment of the invention relating to the die head according to the sixth aspect will be described together with a typical embodiment of the apparatus invention according to the third and fourth aspects.
[0011]
In FIG. 1, A shows the whole blow molding apparatus, and this blow molding apparatus A has resin paths 12 for the inner layer and resin paths 12 for the inner layer provided concentrically on the die head 13. Yes, these resin passages 10, 11 and 12 merge in the vicinity of the discharge port 14 of the die head 13, communicate with the discharge port 70, discharge three types and three layers of parison P from the discharge port 70, and perform blow molding It is. The die head 13 is composed of three annular block dies 15, 16, and 17 that are stacked one above the other, and is branched between the bottom and middle annular block dies 15, 16 once in the left-right circumferential direction within a plane. The path 18 is formed, and the branch path exit portions 19 provided at equiangular intervals divided by the branch paths 18 are connected to the annular path 20 provided between the annular block dies 15 and 16 on the inner side and the entire inner peripheral edge. The distribution resin path B1 for the outer layer is formed in communication with the flat donut disk-shaped resin path 21, and the distribution resin path B1 formed in this way is connected to the resin path 10 for the outer layer (see FIGS. 2 and 3).
[0012]
More specifically, the resin supply port 26 of the distribution resin passage connected to the resin passage 10 for the outer layer is located between the annular block dies 15, 16 that overlap vertically on the sides of the annular block dies 15, 16, 17. The resin supply port 26 communicates with a non-die accumulator chamber (not shown), and the distribution resin path branches from the resin supply port 26 to the left and right in the 90-degree circumferential direction when viewed in plan. It is connected to the annular path 20 provided in the circumferential direction on the inner side of the discharge path of the branch path 18 by dividing the path 18 further 90 degrees left and right from each branch path 18, and inside the inner edge of the entire area of the annular path 20. Between the upper and lower annular block dies 15, 16, a flat donut-shaped resin passage 21 is formed (see FIG. 3) communicating with the outer layer resin passage 10 (see FIG. 3). The position is It is substantially conforms to the mating surface of the mold (not shown) to blow molding houses Son.
[0013]
A distribution resin path B2 connected to the resin path 11 for the intermediate layer is formed between the annular block dies 17 and 16 in the uppermost part and the intermediate part, and this distribution resin path B2 is substantially the same as the distribution resin path B1 for the outer layer. The same reference numerals as those of the distribution resin path B1 indicate the same configuration (see FIG. 4).
[0014]
On the other hand, a plunger 23 that can move up and down along the outer peripheral surface of the mandrel 22 is provided, and the molten resin path for the innermost layer stored in the in-die accumulator chamber 24 is a three-layer confluence formed between the mandrel 22 and the annular block die. This joint channel communicates with the passage 25 and communicates with the discharge port 13 (see FIG. 1). Cylindrical surface resin distribution connected to the outer peripheral surface of an annular sleeve 27 arranged concentrically inside the die body outside the plunger 23 and downstream of a branch passage communicating with a resin inlet 28 from an extruder (not shown). The path is formed as a coat hanger-shaped cylindrical surface resin distribution path so as to be symmetric with respect to the axial direction of the die head 13. In the branch path 30 upstream of the cylindrical surface resin distribution path 29, the die body D and the annular sleeve are formed. In the cylindrical surface resin distribution path 29, a gap is formed between the die body D and the annular sleeve 27, and along the cylindrical surface resin distribution path 29 Along with the flowing circumferential flow, an axial flow that flows through this gap is formed (see FIG. 1).
[0015]
A molten resin film peeling annular body 50 for peeling the molten resin film adhering to the outer peripheral surface of the plunger 22 from the outer peripheral surface of the plunger 22 that moves up and down every time the parison P is discharged surrounds the outer peripheral surface of the plunger. And is fixed to the upper end of the sleeve 27 (see FIGS. 1, 5, 6, and 7). The molten resin peeling annular body 50 is formed of a flat ring body, and a through hole 51 through which the plunger penetrates is opened at the center, and a circumferential interval is provided around the through hole 51. A plurality of mounting holes 52 are provided in the axial direction of the molten resin peeling annular body 50, and between the adjacent mounting holes 52, the ring resin 50 on the bottom surface 53 side of the molten resin peeling annular body 50 is provided. A molten resin film discharge port portion 54 formed by slashing from the outer peripheral surface to the through hole 51 is formed, and each molten resin film discharge port portion 54 communicates with the through hole 51 at its entire inner edge, and the mounting hole The outer periphery of 52 is opened to the outer peripheral surface of the molten resin peeling annular body 50 (see FIGS. 4, 6, and 7).
The molten resin film discharge port portion 54 forms a flat gap opening formed radially between the upper end surface of the sleeve 27, and the molten resin peeling annular body 50 is fixed to the upper end of the sleeve 27. ing. The through hole 51 is provided with a stepped portion 55, the diameter of the ring body on the upper surface 56 side is smaller than the diameter of the ring body on the lower surface 53 side, and the diameter of the upper surface side of the ring body is The stepped portion 55 substantially coincides with the outer shape of the plunger 23 and forms a molten resin film peeling edge (see FIG. 6). The operation of this embodiment will be described as a typical embodiment of the method invention described in claims 1 and 2.
[0016]
The outer layer resin and the intermediate layer resin are separately supplied to the outer layer and intermediate layer resin paths 10 and 11 through the distribution resin paths B1 and B2. On the other hand, the innermost layer of molten resin stored in the accumulator chamber 24 is moved by the plunger 23 that can be moved up and down along the outer peripheral surface of the mandrel 20 in the merging passage 25 formed between the mandrel 22 and the annular block tie. The outer layer and the intermediate layer resin are merged with the molten resin for the outer layer and the intermediate layer and discharged from the discharge port 70 formed between the die ring 60 attached to the lower annular block die 15 and the mandrel 22. Three types and three layers of parison P made of an inner layer resin are discharged and blow-molded.
[0017]
More specifically, molten resin is supplied from the outside accumulator chamber to the resin supply ports 26 of the distribution resin passages B1 and B2 connected to the outer and intermediate layer resin passages 10 and 11, respectively. The molten resin for the outer layer and the intermediate layer supplied to the resin supply port 26 branches from the resin injection port 26 to the left and right by 90 degrees in the circumferential direction as viewed in a plane, and then to the end 180 of the branch path 18. It is distributed to the entire circumference of the annular path 20 from different positions, and for the outer layer and the intermediate layer via the flat donut disk-shaped resin passage 21 between the annular block dies that overlap the upper and lower sides from the entire inner periphery of the annular path 20. It supplies to the resin paths 10 and 11.
[0018]
The joining position of the resin in the annular path 20 is generally matched with a mating surface of a molding die (not shown) that accommodates and blow-molds the parison. By matching in this way, even if a flow mark is generated in the parison, the flow mark is located on the mating surface of the molding die, so that the appearance of the blow molded product is not impaired and the appearance is good. If the portion where the flow mark is generated is cut off at the mating portion, the appearance of the blow-molded product is further favorably maintained. As the plunger 23 moves up, the molten resin is gradually stored from below through the lower end of the annular sleeve 27 into the in-die accumulator chamber 24. The lower end of the plunger 23 is slightly lower than the lower end of the annular sleeve 27. The molten resin in the die accumulator 24 is supplied to the junction 25 without leaving the remainder, and is merged with the outer layer and intermediate layer resins to discharge the three-layer / three-layer parison P to the discharge port. 70 is discharged and blow-molded. Each time the plunger 23 is raised, the inner layer molten resin adhering to the outer peripheral surface of the plunger 23 is peeled off by the edge of the step portion 55 formed in the through hole 51 of the molten resin peeling annular body 50. The peeled resin is discharged radially outward through the discharge port portion 54 (see FIG. 6). The operation of the molten resin peeling annular body 50 is not limited to a parison molding die head made of a multilayer resin, but can be a single layer as long as it is an accumulator in a die, but currently a multilayer parison is generally used. The utility value is great.
[0019]
Embodiment 2
This embodiment is shown in FIG. 8, and will be described in conjunction with a typical embodiment of the apparatus invention described in claim 3.4 in another form relating to the die head described in claim 6.
The configuration different from the first embodiment is as follows. The branch path 18 of the first embodiment is divided into two by the first branch path 18a, and is divided into four at the second branch path 18b. The road 20 is in communication. There are four branch points of the molten resin flowing in the annular path 20, and the junction point 180 degrees apart is substantially coincident with the mating surface of a molding die (not shown) that accommodates the parison and blow-molds it. I'm allowed. In addition, the same reference numerals as those in the first embodiment indicate the same configuration and perform the same operation.
[0020]
【The invention's effect】
The method invention according to claim 1 or 2, wherein the die head is constituted by stacking at least two annular block dies vertically, and branching between the adjacent annular block dies at least once in the right and left in a plane. The resin for the outer layer is supplied to the resin path for the outer layer through the distribution resin path composed of the annular path of the entire circumference from the position where the equiangular spacing is different through the path, and on the other hand, the plunger is movable up and down along the outer peripheral surface of the mandrel. In order to join the molten resin for the innermost layer stored in the inner accumulation chamber with the molten resin for the outer layer in the merged passage formed between the mandrel and the ring member, the molten resin for the exterior layer is sequentially placed in a plane. Can be distributed and supplied to the junction, the resin can flow smoothly, the retention can be reduced, the resin deterioration can be reduced, and the material change including color change can be made quickly.
Even if a flow mark is generated in the parison, the joining position of the resin in the annular path is substantially matched with the mating surface of the molding die that accommodates and blow-molds the parison. Since the flow mark is located, the appearance of the blow-molded product is not impaired, and the appearance can be maintained satisfactorily. If the portion where the flow mark is generated is cut off at the mating portion, the appearance of the blow-molded product is further improved. It can be maintained well.
[0021]
In the method invention according to claim 2, in particular, a resin supply port of a distribution resin passage that is continuous with the resin passage for the outer layer is provided between the annular block dies that are vertically overlapped on the side of the annular block die. The molten resin is supplied to the resin supply port from the external accumulator chamber, and the molten resin for the outer layer supplied from the external die accumulator chamber to the resin supply port is 90 in the circumferential direction when viewed in plan from the resin injection port. A flat donut disk-shaped resin passage between the annular block dies that branches to the left and right and then distributes to the entire circumference of the annular path from a position 180 degrees different from the end of the branch path, and overlaps the upper and lower sides from the entire inner periphery of the annular path. In this case, the supplied outer layer resin can be branched and distributed at a time, and then can be uniformly supplied from the entire circumference to the junction.
[0022]
In the apparatus invention according to the third aspect, the method invention according to the first aspect can be carried out, and the effect is obtained.
[0023]
In the device invention according to the fourth aspect, the method invention according to the second aspect can be carried out, and the effect is obtained.
[0024]
In the apparatus invention according to claim 5, the parison has three types and three layers, the three annular block dies are stacked, and the resin path for the outer layer is connected between the annular block dies at the lowermost part and the middle part. The distribution resin path is formed, and the distribution resin path connected to the resin path for the intermediate layer is formed between the annular block dies at the uppermost part and the intermediate part, and these distribution resin paths have substantially the same shape. Thus, the effects of the device inventions of claims 3 and 4 can be effectively exhibited when blow molding is performed using a three-layer / three-layer parison.
[0025]
In the invention according to claim 6, the method invention according to claims 1 and 2 can be carried out, and the effect is achieved.
[0026]
In the embodiment, the outer peripheral surface of the plunger 23 can be automatically cleaned every time the plunger 23 is raised by the molten resin peeling annular body 50.
In each of the above embodiments, the blow molding apparatus has been described as a direct blow (extrusion) system, but an injection (injection) system also belongs to the technical scope of the present invention.
[Brief description of the drawings]
FIG. 1 is a schematic longitudinal sectional view of a first embodiment.
FIG. 2 is a partially broken perspective view of FIG.
FIG. 3 is a perspective view of the lower annular block die of FIG.
4 is a plan view of the intermediate annular block die of FIG. 1. FIG.
FIG. 5 is a bottom view of a molten resin separating annular body.
FIG. 6 is a schematic longitudinal sectional view showing a use state of a molten resin peeling annular body.
7 is a front view of FIG. 5. FIG.
8 is a plan view of an annular block die according to a second embodiment. FIG.
[Explanation of symbols]
15, 16, 17 Ring block die B1, B2 Distribution resin path

Claims

The resin path for the innermost layer is concentrically provided in the die head in at least two resin paths for the outer layer, and these resin paths merge in the vicinity of the discharge port of the die head, communicate with the discharge port, and have at least two layers of parisons In the blow molding method, the die head is formed by superimposing at least two annular block dies on the upper and lower sides, and the left and right circles at least once in a plane between adjacent annular block dies. The outer layer resin can be supplied to the outer layer resin path through the distribution resin path consisting of an annular path around the circumference from the position where the equiangular distance is different through the branch path branched in the circumferential direction, and can be moved up and down along the outer peripheral surface of the mandrel. The innermost layer of molten resin stored in the die accumulator chamber is transferred to the merging passage formed between the mandrel and the annular block die. The outer layer resin and the innermost layer from the discharge port formed between the die ring and the mandrel provided on the lower surface of the lower annular block die, of the annular block dies, joined with the molten resin for the outer layer. And at least two layers of the parison made of the resin are discharged and blow-molded, and the joining position of the resin in the annular path is made to substantially coincide with the mating surface of the molding die for accommodating and blow-molding the parison. Blow molding method.

A resin supply port of a distribution resin path that is continuous with the resin path for the outer layer is provided between the annular block dies that overlap the upper and lower sides of the annular block die, and molten resin is supplied to the resin supply port from an accumulator chamber outside the die. The outer layer molten resin supplied from the die accumulator chamber to the resin supply port is branched from the resin injection port to the left and right by 90 degrees in the circumferential direction as viewed in a plane, and then at the end of the branch path. It distributes to the entire circumference of the annular path from a position different by 180 degrees, and supplies it to the resin path for the outer layer through the flat donut disk-shaped resin path between the annular block dies that overlap the upper and lower sides from the entire inner periphery of the annular path. The blow molding method according to claim 1, wherein the joining position of the resin in the annular path is substantially matched with a mating surface of a molding die that accommodates and blow-molds the parison.

At least two outer-layer resin paths and an innermost-layer resin path are provided concentrically on the die head, and these resin paths merge in the vicinity of the discharge port of the die head, communicate with the discharge port, and have at least two layers of parisons. In the blow molding apparatus, the die head is formed by superimposing at least two annular block dies on the upper and lower sides, and circumferentially at least once in a plane between adjacent annular block dies. A branch path that is branched in a direction is formed, and the branch path exit portions provided at equiangular intervals divided by these branch paths are an annular path provided between the annular block dies on the inner side and a flat donut connected to the entire inner periphery. A distribution resin path for the outer layer resin is formed in communication with the disk-shaped resin path, and this distribution resin path is connected to the resin path for the outer layer, and along the outer peripheral surface of the mandrel. A plunger that can be lowered is provided, and the resin path for the innermost layer stored in the accumulator chamber in the die communicates with an inner / outer layer joining passage formed between a mandrel and the annular block die. A blow molding apparatus, wherein the blow molding apparatus is in communication with an outlet, and a joining position of the resin in the annular path substantially coincides with a mating surface of a molding die for housing and parsing the parison.

The resin supply port of the distribution resin path that is continuous with the resin path for the outer layer is provided between the annular block dies that are overlapped on the upper and lower sides of the annular block die, and this resin supply port communicates with the accumulator chamber outside the die. When viewed in plan from the resin supply port, the distribution resin path is branched to the left and right in the 90-degree circumferential direction, and further to the left and right from each first branch path 90 degrees to the inside of the first branch path. It consists of a pair of branched second branch passages, and the tip ends of the pair of second branch passages merge with the tip end of the second branch passage on the other side on a position overlapping the axis of the resin inlet or vertically. And the flat donut disk-shaped resin passage leading to the junction is formed between the upper and lower annular block dies inside the inner edge of the entire area of the second branch path, and the resin junction position of the annular path Houses the parison and blows Blow molding apparatus according to claim 3, characterized in that it substantially conforms to the mating surface of the mold to form.

The parison has three layers and three layers, and the three annular block dies are stacked, and the distribution resin passage that is continuous with the resin passage for the outer layer is formed between the annular block dies at the bottom and the middle. Between the annular block dies at the uppermost part and the intermediate part, a distribution resin path for the intermediate layer resin connected to the resin path for the intermediate layer is formed, and these distribution resin paths have almost the same shape at each stage. The blow molding apparatus according to claim 3 or 4, characterized in that:

At least two annular block dies are stacked one on top of the other, and a branch path branched at least once in the left-right circumferential direction in the plane is formed between adjacent annular block dies, and equiangular intervals divided by these branch paths The outlet of the branch path provided on the outer side communicates with the annular path provided between the annular block dies on the inner side and the flat donut disk-shaped resin path connected to the entire inner peripheral edge to form a resin distribution path for the outer layer resin. The resin path communicates with the resin path for the outer layer, and on the other hand, a plunger that can be moved up and down along the outer peripheral surface of the mandrel is provided, and the resin path for the innermost layer stored in the accumulator chamber in the die has the mandrel and the annular shape. With a shape that passes through the merge passage formed between the block dies, merges with the resin for the outer layer in the molten resin passage for the outer layer connected to the flat donut disk-shaped passage, and is discharged from the discharge port. To the confluence point of the resin for the outer layer flowing through the annular passage, the die head for blow molding apparatus characterized in that it conforms to the mating surface of the mold to blow molding housing the parison.