JP3741638B2

JP3741638B2 - Double-sided vacuum / pressure forming method and double-sided vacuum / pressure forming device

Info

Publication number: JP3741638B2
Application number: JP2001330383A
Authority: JP
Inventors: 光生吉村; 博樹布瀬; 元彰伊藤
Original assignee: Panasonic Corp; Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Corp; Panasonic Holdings Corp
Priority date: 2001-10-29
Filing date: 2001-10-29
Publication date: 2006-02-01
Anticipated expiration: 2021-10-29
Also published as: JP2003127216A

Description

【０００１】
【発明の属する技術分野】
本発明は、冷蔵庫等の家庭用電気機器の外装筐体に加飾等の目的からＰＥＴ（ｐｏｌｙｅｔｈｙｌｅｎｅｔｅｒｅｐｈｔｈａｌａｔｅ）シートを被覆する両面真空圧空成形方法と両面真空圧空成形装置に関するものである。
【０００２】
【従来の技術】
従来、冷蔵庫等の家庭用電気機器の外装筐体は加飾等の目的からＰＥＴシートを被覆することがあり、そのために、１２０℃程度に加熱した厚さ２００ミクロン程度の無延伸ＰＥＴシートを圧縮空気により真空圧空成形機を用いて外装筐体等の成形品に押し付ける両面真空圧空成形方法が考えられている（特開昭５９−８３６１３号、特開昭５９−２０１８１６号参照）。
【０００３】
図４、図５、図６は従来の両面真空圧空成形方法の各工程における両面真空圧空成形装置の状態図を示す。図４（ａ）はワークセットの状態図であり、近赤外線ヒータ１を内蔵した上室２と、上下動できる駆動軸３上に設けたテーブル４とその上に被覆する面の高さが異なる被覆製品、例えば、階段状の上面を有する被覆製品５を取り付ける治具６とを内蔵した下室７と、前記上室２と下室７との間に上枠８とをセットした状態を示し、図４（ｂ）はシートセットの状態図であり、図４（ａ）の下室７と上枠８の間に、被覆製品５に被覆する厚さ２００ミクロン程度の無延伸ＰＥＴシート９をセットした状態を示し、図４（ｃ）は上枠８が下降したシートクランプの状態図であり、図４（ｂ）の上枠８が下降して、下室７と上枠８の間に無延伸ＰＥＴシート９を挟持クランプした状態を示し、図５（ａ）は上室２と下室７の内部を真空に引いている両面真空引きの状態図であり、上室２と下室７とを閉じ、上室２はバルブ１０およびバランスバルブ１１を介して、下室７はバルブ１２を介してそれぞれ真空タンク１３−真空ポンプ１４に接続し、さらに、上室２はバルブ１０を介して、下室７はバルブ１２およびバランスバルブ１１を介してそれぞれ圧空タンク１５−コンプレッサ１６に接続し、無延伸ＰＥＴシート９によって隔てられた上室２と下室７の内部の真空度が同じになるように、バランスバルブ１１を調整しながら、真空タンク１３および真空ポンプ１４で減圧し、その後、バルブ１０およびバルブ１２を閉じて上室２と下室７を真空のまま分離独立させている状態を示し、図５（ｂ）は無延伸ＰＥＴシート９を加熱する状態図であり、上室２と下室７の間に張られた無延伸ＰＥＴシート９を、上室２内の近赤外線ヒータ１により１２０℃程度に加熱し、軟化させる状態を示し、図５（ｃ）は無延伸ＰＥＴシート９のドローダウン状態図であり、図５（ｂ）における加熱により、無延伸ＰＥＴシート９がドローダウンし、加熱が終了した状態を示し、図６（ａ）は被覆製品５が上昇する状態図であり、下室７内を上下動する駆動軸３により、治具６に取り付けられた被覆製品５が上昇し、図５（ｃ）のドローダウン状態図に示す軟化ドローダウンした無延伸ＰＥＴシート９が、被覆製品５の階段状の上面では面状に接触し、被覆製品５の段部には空間を持って張られた状態を示し、図６（ｂ）は上室２を大気に開放した状態図であり、軟化ドローダウンした無延伸ＰＥＴシート９が、大気に繋がったバルブ１７を開いて導かれた上室２内の大気圧により、被覆製品５の階段状の上面に押し付けれれるとともに、被覆製品５の段部の空間が小さくなるように、被覆製品５の段部により近づく状態を示し、図６（ｃ）は軟化ドローダウンした無延伸ＰＥＴシート９の圧空成形状態図であり、バルブ１０を開いて圧空タンク１５−コンプレッサ１６により、上室２内の気圧を高め、無延伸ＰＥＴシート９が図６（ｂ）よりも強く被覆製品５の階段状の上面および段部に押し付けられ、階段状の凸凹した上面を持つ被覆製品５に完全に密着した状態を示している。
【０００４】
上記従来の両面真空圧空成形方法により、無延伸ＰＥＴシート９を被覆製品５に被覆するには、図６（ａ）に示すように、軟化ドローダウンした無延伸ＰＥＴシート９が、被覆製品５の階段状の上面では面状に接触し、被覆製品５の段部に空間を持って張られた状態となり、次いで、図６（ｂ）に示すように、上室２が大気に開放された場合でも、無延伸ＰＥＴシート９の部分で被覆製品５と接触しているのは、被覆製品５の階段状の上面だけであり、被覆製品５の段部は無延伸ＰＥＴシート９との間に空間がある。このことは、被覆製品５と接触している無延伸ＰＥＴシート９の部分は被覆製品５と軟化接着しており、図６（ａ）に示す被覆製品５の上昇時に伸展した以上は伸展できず、図６（ａ）の状態でほぼ決まるのに対し、被覆製品５の段部に対向する無延伸ＰＥＴシート９の部分は、図６（ａ）の状態以降も、図６（ｃ）になるまで伸展の余地があり、被覆製品５の表面に被覆された無延伸ＰＥＴシート９が部分によって厚さが異なるものになることを意味する。この傾向は被覆製品５の表面に凸凹があればある程、強くなる。
【０００５】
【発明が解決しようとする課題】
上記のように、従来の両面真空圧空成形方法による場合は、被覆する面の高さが異なる被覆製品の表面に被覆された無延伸ＰＥＴシートは部分によって厚さが異なり、均一な被覆ができなかったり、無延伸ＰＥＴシートで模様をつけようとする場合は模様が歪んだり、ゆがんだりする問題があった。
【０００６】
本発明は上記の課題を解決するもので、被覆する面の高さが異なる被覆製品の表面に無延伸ＰＥＴシートを被覆する場合、被覆する部分によって無延伸ＰＥＴシートの厚さが異なり、均一な被覆ができなかったり、また、無延伸ＰＥＴシートで模様をつけようとする場合、模様が歪んだり、ゆがんだりすることのない両面真空圧空成形方法と両面真空圧空成形装置を提供することを目的とするものである。
【０００７】
【課題を解決するための手段】
上記の課題を解決するために、本発明は、内部圧力を変えるための圧力容器がバルブを介してそれぞれ接続され、厚さ２００ミクロンの無延伸ＰＥＴシートで仕切られた上室と下室が真空になった状態で、無延伸ＰＥＴシートを１２０℃〜１４０℃で加熱軟化させ、その後、その温度変化を２℃以内に保つことができる時間内に、前記バルブを開閉することにより前記圧力容器によって前記上室と下室の容量を変化させて前記上室と下室の間に０．１ｋｇｆ／ｃｍ²以内の圧力差をつけ、無延伸ＰＥＴシートを圧力の低い室内に予備的に膨張させ、その後、予備的に膨張した無延伸ＰＥＴシートに被覆する面の高さが異なる被覆製品の表面を押し付け、その後、圧縮空気により、予備的に膨張した無延伸ＰＥＴシートを高さが異なる被覆製品の表面に押し付け密着させる両面真空圧空成形方法であり、被覆する面の高さが異なる被覆製品の表面に無延伸ＰＥＴシートを被覆しても、被覆する部分によって無延伸ＰＥＴシートの厚さが異なって、不均一な被覆ができたり、また、無延伸ＰＥＴシートで模様をつける場合、模様が歪んだり、ゆがんだりすることがなくなるものである。
【０００８】
【発明の実施の形態】
本発明の請求項１に記載の発明は、内部圧力を変えるための圧力容器がバルブを介してそれぞれ接続され、厚さ２００ミクロンの無延伸ＰＥＴシートで仕切られた上室と下室が真空になった状態で、無延伸ＰＥＴシートを１２０℃〜１４０℃で加熱軟化させ、その後、その温度変化を２℃以内に保つことができる時間内に、前記バルブを開閉することにより前記圧力容器によって前記上室と下室の容量を変化させて前記上室と下室の間に０．１ｋｇｆ／ｃｍ²以内の圧力差をつけ、無延伸ＰＥＴシートを圧力の低い室内に予備的に膨張させ、その後、予備的に膨張した無延伸ＰＥＴシートに被覆する面の高さが異なる被覆製品の表面を押し付け、その後、圧縮空気により、予備的に膨張した無延伸ＰＥＴシートを高さが異なる被覆製品の表面に押し付け密着させる両面真空圧空成形方法であり、予備的に伸展させた無延伸ＰＥＴシートを圧縮空気で高さが異なる被覆製品の表面に密着させることにより、予備的に伸展した無延伸ＰＥＴシートは、すでに、均一な厚さで伸展しているので、圧縮空気による押し付けによってもそれ以上の伸展は少なく、高さが異なる被覆製品の表面にほぼ均一な厚さで密着するという作用を有する。
また、本発明の請求項２に記載の発明は、内部圧力を変えるための圧力容器がバルブを介してそれぞれ接続され、無延伸ＰＥＴシートで仕切られた上室と下室が真空になった状態で、前記無延伸ＰＥＴシートを加熱軟化させ、その後、その温度変化を所定範囲以内に保つことができる時間内に、前記バルブを開閉することにより前記圧力容器によって前記上室と下室の容量を変化させて前記上室と下室の間に圧力差をつけ、前記無延伸ＰＥＴシートを圧力の低い室内に予備的に膨張させ、その後、予備的に膨張した前記無延伸ＰＥＴシートに被覆する面の高さが異なる被覆製品の表面を押し付け、その後、圧縮空気により、予備的に膨張した前記無延伸ＰＥＴシートを高さが異なる被覆製品の表面に押し付け密着させる両面真空圧空成形方法である。
【０００９】
本発明の請求項３に記載の発明は、上室と、
前記上室との間に配置された厚さ２００ミクロンの無延伸ＰＥＴシートを挟んで配置される下室と、
バルブを介して前記上室及び下室にそれぞれ接続し、前記無延伸ＰＥＴシートで仕切られた上室と下室を真空にする真空タンクと、
前記上室内に設けられ前記無延伸ＰＥＴシートを１２０℃〜１４０℃で加熱軟化させるヒーターと、
前記上室及び下室にそれぞれバルブを介して接続され、前記ヒーターによって加熱された前記無延伸ＰＥＴシートの温度変化を２℃以内に保つことができる時間内にバルブを開閉することよって前記上室と下室の容量を変化させて前記上室と下室の間に０．１ｋｇｆ／ｃｍ²以内の圧力差をつけ、前記無延伸ＰＥＴシートを圧力の低い室内に予備的に膨張させるための圧力容器と、
前記下室内に前記被覆製品を載置し上下動可能に構成され、上昇することによって予備的に膨張した前記無延伸ＰＥＴシートに被覆する前記被覆製品の表面を押し付ける治具と、
前記上室及び下室にバルブを介してそれぞれ接続され前記予備的に膨張した前記無延伸ＰＥＴシートを前記被覆製品の表面に密着させる圧空タンクとを備えることを特徴とする、両面真空圧空成形装置であり、上室または下室に、その内部容量を変えるための容器を接続することにより、上室または下室の内部の容量を微妙に調整でき、上室内と下室内との間に０．１ｋｇｆ／ｃｍ²以内の圧力差がつき、厚さ２００ミクロンの無延伸ＰＥＴシートを成形前に均一な厚さに予備伸展ができるという作用を有する。
また、本発明の請求項４に記載の発明は、上室と、
前記上室との間に配置された無延伸ＰＥＴシートを挟んで配置される下室と、
バルブを介して前記上室及び下室にそれぞれ接続し、前記無延伸ＰＥＴシートで仕切られた上室と下室を真空にする真空タンクと、
前記上室内に設けられ前記無延伸ＰＥＴシートを加熱軟化させるヒーターと、
前記上室及び下室にそれぞれバルブを介して接続され、前記ヒーターによって加熱された前記無延伸ＰＥＴシートの温度変化を所定範囲以内に保つことができる時間内にバルブを開閉することよって前記上室と下室の容量を変化させて前記上室と下室の間に圧力差をつけ、前記無延伸ＰＥＴシートを圧力の低い室内に予備的に膨張させるための圧力容器と、
前記下室内に前記被覆製品を載置し上下動可能に構成され、上昇することによって予備的に膨張した前記無延伸ＰＥＴシートに被覆する前記被覆製品の表面を押し付ける治具と、
前記上室及び下室にバルブを介してそれぞれ接続され前記予備的に膨張した前記無延伸ＰＥＴシートを前記被覆製品の表面に密着させる圧空タンクとを備えることを特徴とする、両面真空圧空成形装置である。
【００１１】
以下、本発明の実施の形態について図面を参照して説明する。
【００１２】
（実施の形態）
図１、図２、図３は本発明の実施の形態における両面真空圧空成形方法の各工程における両面真空圧空成形装置の状態図であり、従来例を示す図４、図５、図６と構成的に異なるところは、上室２内の容量または圧力を微妙に調整し、上室２と下室７の間に０．１ｋｇｆ／ｃｍ²以内の圧力差をつけ、上室２と下室７の間に張られ、軟化ドローダウンした厚さ２００ミクロンの無延伸ＰＥＴシート９を下室７内に予備伸展させる下方伸展用の圧力容器１８を上室２に接続し、同様に、下室７内の容量または圧力を微妙に調整し、上室２と下室７の間に０．１ｋｇｆ／ｃｍ²以内の圧力差をつけ、上室２と下室７の間に張られ、軟化ドローダウンした厚さ２００ミクロンの無延伸ＰＥＴシート９を上室２内に予備伸展させる上方伸展用の圧力容器１９を下室７に接続した点であり、その他の点は従来例を示す図４、図５、図６と同じであるので、同じ符号を付し説明する。
【００１３】
図１（ａ）は、図４（ａ）のワークセットの状態図と同様のワークセットの状態図であり、下方伸展用の圧力容器１８を接続し、近赤外線ヒータ１を内蔵した上室２と、上方伸展用の圧力容器１９を接続し、駆動軸３上のテーブル４とその上の被覆する面の高さが異なる被覆製品５を内蔵した下室７と、前記上室２と下室７との間に上枠８とをセットした状態を示し、図１（ｂ）、図１（ｃ）、図２（ａ）、図２（ｂ）、図２（ｃ）は、図４、図５における各状態図と同様、前記図１（ａ）の後に続く工程におけるシートセットの状態図、シートクランプの状態図、両面真空引きの状態図、加熱状態図、ドローダウン状態図であり、図２（ｄ）は、下室７に接続した上方伸展用の圧力容器１９により、下室７内の容量または圧力を微妙に調整し、上室２と下室７の間に０．１ｋｇｆ／ｃｍ²以内の圧力差をつけ、上室２と下室７の間に張られ、軟化ドローダウンした無延伸ＰＥＴシート９を上室２内に予備伸展させた予備伸展状態図であり、図３（ａ）は下室７内を上下動する駆動軸３により、治具６に取り付けられた被覆製品５が上昇し、図２（ｄ）の予備伸展状態図に示す予備伸展した無延伸ＰＥＴシート９が、被覆製品５の階段状の上面では面状に接触し、被覆製品５の段部に空間を持って張られた状態を示す被覆製品上昇状態図であり、図３（ｂ）は被覆製品５の階段状の上面に面状に接触し、被覆製品５の段部には空間を持って張られた無延伸ＰＥＴシート９が、大気に繋がったバルブ１７を開いて導かれた上室２内の大気圧により、被覆製品５の階段状の上面に押し付けられるとともに、被覆製品５の段部の空間が小さくなるように、被覆製品５の段部により近づく大気開放状態図であり、図３（ｃ）はバルブ１０を開いて圧空タンク１５−コンプレッサ１６により、上室２内の気圧を高め、無延伸ＰＥＴシート９が図３（ｂ）よりも強く被覆製品５の階段状の上面および段部に押し付けられ、階段状の凸凹した上面を持つ被覆製品５に完全に密着被覆された圧空成形状態図を示している。
【００１４】
上記本実施の形態における両面真空圧空成形方法により、無延伸ＰＥＴシート９を階段状の凸凹した上面を持つ被覆製品５に被覆するには、初期の工程では従来例を示す図４、図５の場合と同様、図１（ａ）から図２（ｃ）に示す両面真空圧空成形装置の状態図のように、ワークセット、シートセット、シートクランプ、両面真空引き、加熱の各工程を経て無延伸ＰＥＴシート９が下室７内に軟化ドローダウンし、次に、図２（ｄ）の予備伸展状態図に示すように、下室７に接続した上方伸展用の圧力容器１９により、下室７内の容量または圧力を微妙に調整し、上室２と下室７の間に０．１ｋｇｆ／ｃｍ²以内の圧力差をつけ、上室２と下室７の間に張られ、軟化ドローダウンした厚さ２００ミクロンの無延伸ＰＥＴシート９を上室２内に予備伸展させ、以降の工程は、図３（ａ）の被覆製品上昇状態図に示すように、下室７内を上下動する駆動軸３により、治具６に取り付けられた被覆製品５が上昇し、上室２内に予備伸展した無延伸ＰＥＴシート９に、被覆製品５の階段状の上面が面状に接触し、被覆製品５の段部が空間を持って対向する形となり、次に、図３（ｂ）の大気開放状態図に示すように、大気に繋がったバルブ１７を開いて導かれた上室２内の大気圧により、無延伸ＰＥＴシート９は被覆製品５の階段状の上面に押し付けられるとともに、被覆製品５の段部の空間が小さくなるように、被覆製品５の段部により近づくことになる、最後に、図３（ｃ）の圧空成形状態図に示すように、バルブ１０を開いて圧空タンク１５−コンプレッサ１６により、上室２内の気圧をさらに高め、無延伸ＰＥＴシート９が図３（ｂ）よりもさらに強く被覆製品５の階段状の上面および段部に押し付けられ、階段状の凸凹した上面を持つ被覆製品５に完全に密着被覆することになる。
【００１５】
なお、上記両面真空圧空成形方法とその装置において、無延伸ＰＥＴシート９を１２０℃〜１４０℃に加熱して、その温度変化が２℃の範囲内にある間に成形を行うのは、図７に示す２００ミクロン厚の無延伸ＰＥＴシート９の温度−抗張力関係図から分かるように、無延伸ＰＥＴシートの抗張力（ｋｇｆ／ｃｍ²）は１２０℃〜１４０℃の狭い範囲で０に近くなり、この抗張力（ｋｇｆ／ｃｍ²）≒０を維持できる温度範囲、例えば、（１２０℃〜１４０℃）±２℃の狭い温度領域内で圧空成形作業を行うことにより、無延伸ＰＥＴシート９の伸展が容易な状態で作業ができることになるからである。
【００１６】
また、下室７の体積Ｖ＝２２８７５０ｃｃ、無延伸ＰＥＴシート９の伸び率を１２４％とした時の上室２内へ予備伸展する無延伸ＰＥＴシート９の体積増分ΔＶ＝１８４００ｃｃ、下室７に接続した上方伸展用の圧力容器１９内の圧力Ｐ₀＝１ｋｇｆ／ｃｍ²、圧力容器１９の体積Ｖ₀、上室２と下室７の内部圧力差ΔＰ＝０．１ｋｇｆ／ｃｍ²とすると、
Ｐ₀＊Ｖ₀＝ΔＰ（Ｖ＋Ｖ₀＋ΔＶ）
Ｖ₀（Ｐ₀−ΔＰ）＝ΔＰ（Ｖ＋ΔＶ）
Ｖ₀＝ΔＰ（Ｖ＋ΔＶ）／（Ｐ₀−ΔＰ）
となり、圧力容器１９の体積Ｖ₀は２７４６１ｃｃとなる。
【００１７】
また、伸び率１２４％程度の無延伸ＰＥＴシート９を軟化ドローダウンした状態で予備伸展させるためには、０．１ｋｇｆ／ｃｍ²以内の小さな圧力で可能である。
【００１８】
上記仕様により、本実施の形態における両面真空圧空成形方法とその装置による予備伸展が可能になるが、厳密には上室２と下室７内が真空になっていないことや、上室２と下室７内の温度条件による誤差、重力の影響を考慮すると、上記によって導き出された体積Ｖ₀も変るため、圧力容器１９の容量や圧力は変えられるようにしてある。
【００１９】
また、上記説明では、無延伸ＰＥＴシート９の予備伸展を上室２内に行った例で説明したが、下方伸展用の圧力容器１８により下室７内に予備伸展させた場合にも、上室２に導入した圧縮空気により予備伸展した無延伸ＰＥＴシート９を被覆製品５に押し付け密着させ得ることは申すまでもない。
【００２０】
以上のように、本実施の形態の両面真空圧空成形方法とその装置によれば、圧力容器１９により、上室２と下室７間に０．１ｋｇｆ／ｃｍ²以内の微妙な圧力差がつくられているので、上室２と下室７間に張られた無延伸ＰＥＴシート９が均一に予備伸展し、その後の工程で被覆製品５に圧縮空気により押し付けた場合でも、無延伸ＰＥＴシート９は、すでに、均一の厚さで伸展しているので、それ以上の伸展は少なく、高さが異なる被覆製品５の表面に均一な厚さで密着し、また、無延伸ＰＥＴシート９で模様をつけようとする場合、模様が歪んだり、ゆがんだりすることがなくなるものである。
【００２１】
【発明の効果】
以上のように、本発明の両面真空圧空成形方法とその装置によれば、上室と下室の何れかに接続した圧力容器により、上室と下室間に微妙な圧力差をつくることにより、上室と下室間に張られた無延伸ＰＥＴシートを被覆製品に完全に密着させる前に予備伸展させることができ、被覆する面の高さが異なる被覆製品の表面に無延伸ＰＥＴシートを被覆しても、被覆する部分によって無延伸ＰＥＴシートの厚さが異なって、不均一な被覆ができたり、また、無延伸ＰＥＴシートで模様をつける場合、模様が歪んだり、ゆがんだりすることがなくなるという効果が得られる。
【図面の簡単な説明】
【図１】（ａ）本発明の実施の形態における両面真空圧空成形装置のワークセットの状態図
（ｂ）同シートセットの状態図
（ｃ）同シートクランプの状態図
【図２】（ａ）本発明の実施の形態における両面真空圧空成形装置の両面真空引きの状態図
（ｂ）同加熱状態図
（ｃ）同ドローダウン状態図
（ｄ）同予備伸展状態図
【図３】（ａ）本発明の実施の形態における両面真空圧空成形装置の被覆製品上昇状態図
（ｂ）同大気開放状態図
（ｃ）同圧空成形状態図
【図４】（ａ）従来の両面真空圧空成形装置のワークセットの状態図
（ｂ）同シートセットの状態図
（ｃ）同シートクランプの状態図
【図５】（ａ）従来の両面真空圧空成形装置の両面真空引きの状態図
（ｂ）同加熱状態図
（ｃ）同ドローダウン状態図
【図６】（ａ）従来の両面真空圧空成形装置の被覆製品上昇状態図
（ｂ）同大気開放状態図
（ｃ）同圧空成形状態図
【図７】無延伸ＰＥＴシートの温度−抗張力関係図
【符号の説明】
１近赤外線ヒータ
２上室
３駆動軸
４テーブル
５被覆製品
６治具
７下室
８上枠
９無延伸ＰＥＴシート
１０，１２，１７バルブ
１１バランスバルブ
１３真空タンク
１４真空ポンプ
１５圧空タンク
１６コンプレッサ
１８，１９圧力容器[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a double-sided vacuum / pressure forming method and a double-sided vacuum / pressure forming apparatus for coating a PET (polyethylene terephthalate) sheet for the purpose of decoration or the like on an exterior housing of a domestic electric device such as a refrigerator.
[0002]
[Prior art]
Conventionally, exterior casings of household electric appliances such as refrigerators may be coated with PET sheets for the purpose of decoration, etc. For this purpose, unstretched PET sheets with a thickness of about 200 microns heated to about 120 ° C are compressed. There has been considered a double-sided vacuum / pressure forming method in which air is pressed against a molded product such as an outer casing using a vacuum / pressure forming machine (see Japanese Patent Laid-Open Nos. 59-83613 and 59-201816).
[0003]
4, 5 and 6 show state diagrams of the double-sided vacuum / pressure forming apparatus in each step of the conventional double-sided vacuum / pressure forming method. FIG. 4A is a state diagram of the work set, and the height of the upper chamber 2 in which the near-infrared heater 1 is built, the table 4 provided on the drive shaft 3 capable of moving up and down, and the surface covered thereon are different. Shown is a state in which a lower chamber 7 in which a coated product, for example, a jig 6 for mounting a coated product 5 having a stepped upper surface is built, and an upper frame 8 is set between the upper chamber 2 and the lower chamber 7 are shown. 4B is a state diagram of the sheet set, and an unstretched PET sheet 9 having a thickness of about 200 microns covering the coated product 5 is provided between the lower chamber 7 and the upper frame 8 of FIG. 4 (c) is a state diagram of the sheet clamp in which the upper frame 8 is lowered, and the upper frame 8 is lowered between the lower chamber 7 and the upper frame 8 in FIG. 4 (b). FIG. 5A shows a state in which the non-stretched PET sheet 9 is clamped and clamped. FIG. 5A shows the inside of the upper chamber 2 and the lower chamber 7 being evacuated. It is a state diagram of surface vacuuming, the upper chamber 2 and the lower chamber 7 are closed, the upper chamber 2 is connected via a valve 10 and a balance valve 11, and the lower chamber 7 is connected via a valve 12 to a vacuum tank 13-vacuum pump. 14, and the upper chamber 2 is connected to the compressed air tank 15 -compressor 16 via the valve 10 and the lower chamber 7 via the valve 12 and the balance valve 11, and is separated by the unstretched PET sheet 9. While adjusting the balance valve 11 so that the degree of vacuum inside the upper chamber 2 and the lower chamber 7 is the same, the pressure is reduced by the vacuum tank 13 and the vacuum pump 14, and then the valve 10 and the valve 12 are closed to close the upper chamber. 2 and the lower chamber 7 are separated and independent in a vacuum state, and FIG. 5B is a state diagram for heating the non-stretched PET sheet 9, and is stretched between the upper chamber 2 and the lower chamber 7. Unstretched The ET sheet 9 is heated to about 120 ° C. by the near-infrared heater 1 in the upper chamber 2 to be softened, and FIG. 5C is a draw-down state diagram of the unstretched PET sheet 9. FIG. FIG. 6A shows a state in which the unstretched PET sheet 9 is drawn down by the heating in b) and the heating is finished, and FIG. The coated product 5 attached to the jig 6 is lifted by the shaft 3, and the soft stretched-down unstretched PET sheet 9 shown in the drawdown state diagram of FIG. 5C is formed on the stepped upper surface of the coated product 5. FIG. 6 (b) is a state diagram in which the upper chamber 2 is opened to the atmosphere, and it is unstretched after being softened and drawn down. The PET sheet 9 opens the valve 17 connected to the atmosphere. The atmospheric pressure in the upper chamber 2 thus guided is pressed against the stepped upper surface of the coated product 5 and approaches the stepped portion of the coated product 5 so that the space of the stepped portion of the coated product 5 is reduced. FIG. 6 (c) is a diagram showing a pressure forming state of the non-stretched PET sheet 9 that has been softened and drawn down. The valve 10 is opened and the pressure in the upper chamber 2 is increased by the pressure tank 15-compressor 16 so that it is not stretched. 6 shows a state in which the PET sheet 9 is pressed more strongly against the stepped upper surface and the stepped portion of the coated product 5 than in FIG. 6B and is completely adhered to the coated product 5 having a stepped uneven upper surface.
[0004]
In order to coat the unstretched PET sheet 9 on the coated product 5 by the above-mentioned conventional double-sided vacuum / pressure forming method, as shown in FIG. When the upper surface of the stepped surface comes into contact with the surface and is stretched with a space in the stepped portion of the coated product 5, and then the upper chamber 2 is opened to the atmosphere as shown in FIG. 6 (b) However, only the stepped upper surface of the coated product 5 is in contact with the coated product 5 at the portion of the unstretched PET sheet 9, and the stepped portion of the coated product 5 is a space between the unstretched PET sheet 9. There is. This means that the portion of the non-stretched PET sheet 9 that is in contact with the coated product 5 is softly bonded to the coated product 5 and cannot be stretched beyond the extent that the coated product 5 as shown in FIG. 6 (a), the portion of the non-stretched PET sheet 9 that faces the stepped portion of the coated product 5 becomes FIG. 6 (c) after the state of FIG. 6 (a). This means that the unstretched PET sheet 9 coated on the surface of the coated product 5 varies in thickness depending on the portion. This tendency becomes stronger as the surface of the coated product 5 has unevenness.
[0005]
[Problems to be solved by the invention]
As described above, in the case of the conventional double-sided vacuum / pressure forming method, the non-stretched PET sheet coated on the surface of the coated product with different height of the coated surface varies depending on the part and cannot be uniformly coated. Or, when trying to apply a pattern with an unstretched PET sheet, there was a problem that the pattern was distorted or distorted.
[0006]
The present invention solves the above-mentioned problem. When a non-stretched PET sheet is coated on the surface of a coated product having a different height of the surface to be coated, the thickness of the non-stretched PET sheet varies depending on the portion to be coated. It is an object to provide a double-sided vacuum / pressure forming method and a double-sided vacuum / pressure forming device that do not cause the pattern to be distorted or distorted when it is impossible to coat or to form a pattern with an unstretched PET sheet. To do.
[0007]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention is configured such that a pressure vessel for changing an internal pressure is connected via a valve, and an upper chamber and a lower chamber partitioned by an unstretched PET sheet having a thickness of 200 microns are vacuumed. In such a state, the non-stretched PET sheet is heated and softened at 120 ° C. to 140 ° C., and then the valve is opened and closed by the pressure vessel within a time during which the temperature change can be kept within 2 ° C. By changing the volume of the upper and lower chambers to create a pressure difference within 0.1 kgf / cm ² between the upper and lower chambers, the unstretched PET sheet is preliminarily expanded into a low-pressure chamber, Thereafter, the surface of the coated product having a different surface height is pressed against the pre-expanded unstretched PET sheet, and then the pre-expanded unstretched PET sheet is coated with a different height by compressed air. It is a double-sided vacuum pressure forming method that presses and adheres to the surface, and even if the surface of the coated product with different surface heights is coated with an unstretched PET sheet, the thickness of the unstretched PET sheet varies depending on the portion to be coated When the pattern is formed with a non-stretched PET sheet, the pattern is not distorted or distorted.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
According to the first aspect of the present invention, the pressure chamber for changing the internal pressure is connected through a valve, and the upper chamber and the lower chamber partitioned by a non-stretched PET sheet having a thickness of 200 microns are evacuated. In such a state, the unstretched PET sheet is softened by heating at 120 ° C. to 140 ° C., and then the valve is opened and closed by the pressure vessel within a time during which the temperature change can be kept within 2 ° C. By changing the volume of the upper chamber and the lower chamber to create a pressure difference within 0.1 kgf / cm ² between the upper chamber and the lower chamber, the unstretched PET sheet is preliminarily expanded into a low pressure chamber, The surface of the coated product having a different surface height is pressed against the pre-expanded unstretched PET sheet, and then the pre-expanded non-stretched PET sheet is coated with a different height by compressed air. Non-stretched PET sheet preliminarily stretched by adhering the unstretched PET sheet preliminarily stretched to the surface of a coated product having a different height with compressed air. Since it has already been extended with a uniform thickness, there is little further extension even by pressing with compressed air, and it has the effect of adhering to the surface of a coated product having a different height with a substantially uniform thickness.
In the invention according to claim 2 of the present invention, the pressure chamber for changing the internal pressure is connected through the valve, and the upper chamber and the lower chamber partitioned by the non-stretched PET sheet are in a vacuum state. In the time when the unstretched PET sheet is softened by heating, and then the temperature change can be kept within a predetermined range, the pressure vessel is used to open and close the valve, thereby reducing the volume of the upper chamber and the lower chamber. A surface that is changed to create a pressure difference between the upper chamber and the lower chamber, preliminarily expand the unstretched PET sheet into a low-pressure chamber, and then cover the prestretched unstretched PET sheet Double-sided vacuum / pressure forming method in which the surfaces of coated products having different heights are pressed, and then the unstretched PET sheet preliminarily expanded is pressed against the surface of the coated products having different heights by compressed air. A.
[0009]
The invention according to claim 3 of the present invention includes an upper chamber,
A lower chamber disposed with an unstretched PET sheet having a thickness of 200 microns disposed between the upper chamber and the upper chamber;
A vacuum tank that connects to the upper chamber and the lower chamber via a valve, and vacuums the upper chamber and the lower chamber partitioned by the unstretched PET sheet;
A heater provided in the upper chamber for heating and softening the unstretched PET sheet at 120 ° C to 140 ° C;
The upper chamber is connected to the upper chamber and the lower chamber via a valve, and the valve is opened and closed within a time period during which the temperature change of the unstretched PET sheet heated by the heater can be kept within 2 ° C. The pressure for pre-expanding the non-stretched PET sheet into a low-pressure chamber by changing the volume of the lower chamber and creating a pressure difference within 0.1 kgf / cm ² between the upper chamber and the lower chamber A container,
A jig that presses the surface of the coated product that covers the unstretched PET sheet that is preliminarily expanded by placing the coated product in the lower chamber and configured to be movable up and down;
Characterized in that it comprises a compressed air tank for adhering the unstretched PET sheet are connected via respective valves to the upper chamber and the lower chamber expands the preliminarily on the surface of the coating product, double-sided vacuum pressure forming By connecting a container for changing the internal capacity of the upper chamber or the lower chamber to the upper chamber or the lower chamber, the internal volume of the upper chamber or the lower chamber can be finely adjusted. The pressure difference is within 1 kgf / cm ^{2, and} the non-stretched PET sheet having a thickness of 200 microns can be pre-stretched to a uniform thickness before molding.
The invention according to claim 4 of the present invention includes an upper chamber,
A lower chamber disposed across an unstretched PET sheet disposed between the upper chamber;
A vacuum tank that connects to the upper chamber and the lower chamber via a valve, and vacuums the upper chamber and the lower chamber partitioned by the unstretched PET sheet;
A heater provided in the upper chamber for heating and softening the unstretched PET sheet;
The upper chamber is connected to the upper chamber and the lower chamber via a valve, and the valve is opened and closed within a time period during which the temperature change of the unstretched PET sheet heated by the heater can be kept within a predetermined range. And a pressure vessel for pre-expanding the unstretched PET sheet into a low-pressure chamber by changing the volume of the lower chamber to create a pressure difference between the upper chamber and the lower chamber,
A jig that presses the surface of the coated product that covers the unstretched PET sheet that is preliminarily expanded by placing the coated product in the lower chamber and configured to be movable up and down;
Characterized in that it comprises a compressed air tank for adhering the unstretched PET sheet are connected via respective valves to the upper chamber and the lower chamber expands the preliminarily on the surface of the coating product, double-sided vacuum pressure forming Device.
[0011]
Embodiments of the present invention will be described below with reference to the drawings.
[0012]
(Embodiment)
1, 2, and 3 are state diagrams of a double-sided vacuum / pressure forming apparatus in each step of the double-sided vacuum / pressure forming method according to the embodiment of the present invention. The difference is that the capacity or pressure in the upper chamber 2 is finely adjusted, and a pressure difference within 0.1 kgf / cm ² is established between the upper chamber 2 and the lower chamber 7. A pressure container 18 for downward extension that preliminarily stretches the unstretched PET sheet 9 having a thickness of 200 microns that has been softened and drawn down into the lower chamber 7 is connected to the upper chamber 2. The internal volume or pressure is finely adjusted to create a pressure difference within 0.1 kgf / cm ² between the upper chamber 2 and the lower chamber 7, and is stretched between the upper chamber 2 and the lower chamber 7 to soften draw down Pressure vessel for upward extension that pre-extends the unstretched PET sheet 9 having a thickness of 200 microns into the upper chamber 2 19 is connected to the lower chamber 7, and the other points are the same as those in FIGS. 4, 5, and 6 showing the conventional example.
[0013]
FIG. 1A is a state diagram of a work set similar to the state diagram of the work set of FIG. 4A, and an upper chamber 2 in which a pressure vessel 18 for downward extension is connected and a near-infrared heater 1 is incorporated. And a lower chamber 7 in which a pressure vessel 19 for upward extension is connected and a table 4 on the drive shaft 3 and a coated product 5 having different heights to be coated thereon are built in, and the upper chamber 2 and the lower chamber. 7 shows a state in which the upper frame 8 is set between FIG. 1 (b), FIG. 1 (c), FIG. 2 (a), FIG. 2 (b), and FIG. Like each state diagram in FIG. 5, a sheet set state diagram, a sheet clamp state diagram, a double-sided vacuum state diagram, a heating state diagram, and a drawdown state diagram in the process following FIG. FIG. 2 (d) shows that the capacity or pressure in the lower chamber 7 is finely adjusted by the pressure container 19 for upward extension connected to the lower chamber 7. , With a pressure difference within 0.1 kgf / cm ² between the upper chamber 2 and the lower chamber 7, is established between the upper chamber 2 and the lower chamber 7, the upper chamber unstretched PET sheet 9 softened drawdown 2 FIG. 3 (a) is a diagram illustrating a preliminary extension state in which the coated product 5 attached to the jig 6 is raised by the drive shaft 3 that moves up and down in the lower chamber 7. FIG. The pre-stretched non-stretched PET sheet 9 shown in the pre-stretched state diagram of FIG. 2) is in contact with the surface of the stepped upper surface of the coated product 5 and is stretched with a space in the stepped portion of the coated product 5 FIG. 3 (b) is a diagram showing a state where the coated product is raised, and FIG. By pressing the valve 17 connected to the atmosphere, the atmospheric pressure in the upper chamber 2 led to press against the stepped upper surface of the coated product 5 Fig. 3 (c) is a diagram showing an open state of the atmosphere closer to the stepped portion of the coated product 5 so that the space of the stepped portion of the coated product 5 becomes smaller. The pressure inside the upper chamber 2 is increased, and the unstretched PET sheet 9 is pressed more strongly against the stepped upper surface and the stepped portion of the coated product 5 than in FIG. 3B, and the coated product 5 having a stepped uneven upper surface. FIG. 2 shows a pressure forming state diagram in which the film is completely and closely coated.
[0014]
In order to coat the non-stretched PET sheet 9 on the coated product 5 having a stepped uneven upper surface by the double-sided vacuum / pressure forming method in the present embodiment, the conventional process shown in FIGS. As in the case, as shown in the state diagram of the double-sided vacuum / pressure forming apparatus shown in FIGS. 1 (a) to 2 (c), the work set, the sheet set, the sheet clamp, the double-sided vacuum drawing, and the heating process are not stretched. The PET sheet 9 is softened and drawn down into the lower chamber 7, and then, as shown in the preliminary extension state diagram of FIG. 2 (d), the upper chamber 7 is connected to the lower chamber 7 by the upward extension pressure vessel 19. The internal volume or pressure is finely adjusted to create a pressure difference within 0.1 kgf / cm ² between the upper chamber 2 and the lower chamber 7, and is stretched between the upper chamber 2 and the lower chamber 7 to soften draw down The non-stretched PET sheet 9 having a thickness of 200 microns is placed in the upper chamber 2. In the subsequent steps, the coated product 5 attached to the jig 6 is lifted by the drive shaft 3 that moves up and down in the lower chamber 7 as shown in the coated product rising state diagram of FIG. Then, the non-stretched PET sheet 9 preliminarily stretched in the upper chamber 2 comes into contact with the stepped upper surface of the coated product 5 in a planar shape, and the steps of the coated product 5 are opposed to each other with a space. 3 (b), the non-stretched PET sheet 9 has a stepped shape of the coated product 5 due to the atmospheric pressure in the upper chamber 2 guided by opening the valve 17 connected to the atmosphere. As it is pressed against the upper surface, the stepped portion of the coated product 5 will be closer so that the space of the stepped portion of the coated product 5 becomes smaller. The valve 10 is opened and the air pressure in the upper chamber 2 is increased by the compressed air tank 15 -compressor 16. The non-stretched PET sheet 9 is pressed more strongly against the stepped upper surface and the stepped portion of the coated product 5 than in FIG. 3 (b), and is completely adhered to the coated product 5 having a stepped uneven upper surface. Will do.
[0015]
In the double-sided vacuum / pressure forming method and apparatus, the unstretched PET sheet 9 is heated to 120 ° C. to 140 ° C. and the molding is performed while the temperature change is within the range of 2 ° C. FIG. As can be seen from the temperature-tension relationship diagram of the 200-micron-thick unstretched PET sheet 9 shown in FIG. ² , the unstretched PET sheet has a tensile strength (kgf / cm ² ) close to 0 in a narrow range of 120 ° C to 140 ° C. Easy stretching of non-stretched PET sheet 9 by performing pressure forming in a temperature range where tensile strength (kgf / cm ² ) ≈0 can be maintained, for example, (120 ° C. to 140 ° C.) ± 2 ° C. This is because the work can be performed in a stable state.
[0016]
Further, when the volume V of the lower chamber 7 is 228750 cc and the elongation rate of the unstretched PET sheet 9 is 124%, the volume increment ΔV of the unstretched PET sheet 9 preliminarily extended into the upper chamber 2 is 18400 cc, When the pressure P ₀ = 1 kgf / cm ² in the connected upward extension pressure vessel 19, the volume V ₀ of the pressure vessel 19, and the internal pressure difference ΔP = 0.1 kgf / cm ² between the upper chamber 2 and the lower chamber 7,
P ₀ * V ₀ = ΔP (V + V ₀ + ΔV)
V ₀ (P ₀ −ΔP) = ΔP (V + ΔV)
V ₀ = ΔP (V + ΔV) / (P ₀ −ΔP)
Thus, the volume V ₀ of the pressure vessel 19 is 27461 cc.
[0017]
Further, in order to pre-stretch the non-stretched PET sheet 9 having an elongation rate of about 124% in a softened down state, a small pressure within 0.1 kgf / cm ² is possible.
[0018]
According to the above specifications, the double-sided vacuum / pressure forming method and the apparatus according to the present embodiment can be used for preliminary extension, but strictly speaking, the upper chamber 2 and the lower chamber 7 are not evacuated, Considering an error due to temperature conditions in the lower chamber 7 and the influence of gravity, the volume V ₀ derived as described above also changes, so that the capacity and pressure of the pressure vessel 19 can be changed.
[0019]
In the above description, the example in which the pre-stretching of the non-stretched PET sheet 9 is performed in the upper chamber 2 has been described. However, when the pre-stretching is performed in the lower chamber 7 by the pressure container 18 for downward stretching, Needless to say, the non-stretched PET sheet 9 preliminarily stretched by the compressed air introduced into the chamber 2 can be pressed against and closely adhered to the coated product 5.
[0020]
As described above, according to the double-sided vacuum / pressure forming method and apparatus of the present embodiment, the pressure vessel 19 creates a subtle pressure difference within 0.1 kgf / cm ² between the upper chamber 2 and the lower chamber 7. Therefore, even when the non-stretched PET sheet 9 stretched between the upper chamber 2 and the lower chamber 7 is uniformly pre-stretched and pressed against the coated product 5 with compressed air in the subsequent process, the non-stretched PET sheet 9 Has already been stretched with a uniform thickness, so there is little further stretching, and it adheres to the surface of the coated product 5 having a different height with a uniform thickness. When trying to apply, the pattern will not be distorted or distorted.
[0021]
【The invention's effect】
As described above, according to the double-sided vacuum / pressure forming method and apparatus of the present invention, by creating a delicate pressure difference between the upper chamber and the lower chamber by the pressure vessel connected to either the upper chamber or the lower chamber. The unstretched PET sheet stretched between the upper chamber and the lower chamber can be pre-stretched before being completely adhered to the coated product. Even if it is coated, the thickness of the unstretched PET sheet varies depending on the portion to be coated, and a non-uniform coating can be made, or when a pattern is formed with an unstretched PET sheet, the pattern may be distorted or distorted. The effect of disappearing is obtained.
[Brief description of the drawings]
1A is a state diagram of a work set of a double-sided vacuum / pressure forming apparatus according to an embodiment of the present invention. FIG. 1B is a state diagram of the sheet set. FIG. 1C is a state diagram of the sheet clamp. FIG. 3B is a diagram showing a state of double-sided vacuum drawing of a double-sided vacuum / pressure forming apparatus according to an embodiment of the present invention. FIG. 3B is a diagram showing a heating state. FIG. FIG. 4B is a view showing the state of rising of the coated product of the double-sided vacuum / pressure forming apparatus according to the embodiment of the invention. FIG. (B) State diagram of the sheet set (c) State diagram of the sheet clamp [FIG. 5] (a) State diagram of double-sided vacuuming of a conventional double-sided vacuum / pressure forming apparatus (b) State of heating state ( c) Drawdown state diagram [Figure 6] (a) Conventional double-sided vacuum Coated product increased state diagram of the air-forming device (b) the temperature of the atmosphere release state diagram (c) the pressure forming state diagram 7 unstretched PET sheet - tensile strength relationship diagram EXPLANATION OF REFERENCE NUMERALS
1 near infrared heater 2 upper chamber 3 drive shaft 4 table 5 coated product 6 jig 7 lower chamber 8 upper frame 9 unstretched PET sheet 10, 12, 17 valve 11 balance valve 13 vacuum tank 14 vacuum pump 15 pressurized air tank 16 compressor 18 , 19 Pressure vessel

Claims

Pressure vessels for changing the internal pressure were connected to each other via valves, and the upper and lower chambers partitioned by a 200-micron-thick unstretched PET sheet were evacuated and the unstretched PET sheet was placed at 120 ° C. The volume of the upper chamber and the lower chamber is changed by the pressure vessel by opening and closing the valve within a time period during which the temperature change can be kept within 2 ° C. by heating and softening at ˜140 ° C. A pressure difference of 0.1 kgf / cm ^{2 or} less is applied between the upper chamber and the lower chamber, and the unstretched PET sheet is preliminarily expanded in a low-pressure chamber, and then the pre-expanded unstretched PET sheet is coated. Double-sided vacuum compressed air that presses the surface of the coated product with different heights on the surface to be pressed, and then presses the pre-expanded unstretched PET sheet against the surface of the coated product with different heights by compressed air Form method.

Pressure vessels for changing the internal pressure are respectively connected via valves, and in the state where the upper chamber and the lower chamber partitioned by the non-stretched PET sheet are in a vacuum, the unstretched PET sheet is heated and softened, and then Within a time period during which the temperature change can be kept within a predetermined range, the pressure vessel changes the volume of the upper chamber and the lower chamber by opening and closing the valve, and the pressure difference between the upper chamber and the lower chamber is changed. The unstretched PET sheet is pre-expanded into a low-pressure chamber, and then the pre-expanded unstretched PET sheet is pressed against the surface of the coated product having a different surface height, A double-sided vacuum / pressure forming method in which the unstretched PET sheet, which has been pre-expanded, is pressed and adhered to the surface of a coated product having a different height by compressed air.

Upper room,
A lower chamber disposed with an unstretched PET sheet having a thickness of 200 microns disposed between the upper chamber and the upper chamber;
A vacuum tank that connects to the upper chamber and the lower chamber via a valve, and vacuums the upper chamber and the lower chamber partitioned by the unstretched PET sheet;
A heater provided in the upper chamber for heating and softening the unstretched PET sheet at 120 ° C to 140 ° C;
The upper chamber is connected to the upper chamber and the lower chamber via a valve, and the valve is opened and closed within a time period during which the temperature change of the unstretched PET sheet heated by the heater can be kept within 2 ° C. The pressure for pre-expanding the non-stretched PET sheet into a low-pressure chamber by changing the volume of the lower chamber and creating a pressure difference within 0.1 kgf / cm ² between the upper chamber and the lower chamber A container,
A jig that presses the surface of the coated product that covers the unstretched PET sheet that is preliminarily expanded by placing the coated product in the lower chamber and configured to be movable up and down;
Characterized in that it comprises a compressed air tank for adhering the unstretched PET sheet are connected via respective valves to the upper chamber and the lower chamber expands the preliminarily on the surface of the coating product, double-sided vacuum pressure forming apparatus.

Upper room,
A lower chamber disposed across an unstretched PET sheet disposed between the upper chamber;
A vacuum tank that connects to the upper chamber and the lower chamber via a valve, and vacuums the upper chamber and the lower chamber partitioned by the unstretched PET sheet;
A heater provided in the upper chamber for heating and softening the unstretched PET sheet;
The upper chamber is connected to the upper chamber and the lower chamber via a valve, and the valve is opened and closed within a time period during which the temperature change of the unstretched PET sheet heated by the heater can be kept within a predetermined range. And a pressure vessel for pre-expanding the unstretched PET sheet into a low-pressure chamber by changing the volume of the lower chamber to create a pressure difference between the upper chamber and the lower chamber,
A jig that presses the surface of the coated product that covers the unstretched PET sheet that is preliminarily expanded by placing the coated product in the lower chamber and configured to be movable up and down;
Characterized in that it comprises a compressed air tank for adhering the unstretched PET sheet are connected via respective valves to the upper chamber and the lower chamber expands the preliminarily on the surface of the coating product, double-sided vacuum pressure forming apparatus.