JP4782931B2

JP4782931B2 - Method for producing open cell foam

Info

Publication number: JP4782931B2
Application number: JP2001064731A
Authority: JP
Inventors: 豊繁門石; 和三郎猪田
Original assignee: Sekisui Chemical Co Ltd
Current assignee: Sekisui Chemical Co Ltd
Priority date: 2001-03-08
Filing date: 2001-03-08
Publication date: 2011-09-28
Anticipated expiration: 2021-03-08
Also published as: KR20020072217A; JP2002265661A

Description

【０００１】
【発明の属する技術分野】
本発明は、ポリオレフィン系樹脂発泡体の如き独立気泡発泡体を連続気泡化する連続気泡発泡体の製造方法に関する。
【０００２】
【従来の技術】
従来から架橋ポリオレフィン系樹脂発泡体を製造する方法としては、有機分解型発泡剤を用いる方法が広く用いられている。詳細には、ポリオレフィン系樹脂に有機過酸化物を添加し或いはポリオレフィン系樹脂に電子線を照射してポリオレフィン系樹脂を架橋させた後、ポリオレフィン系樹脂に含有させた有機分解型発泡剤を分解させて架橋ポリオレフィン系樹脂発泡体を製造している。
【０００３】
上記の如くして得られたポリオレフィン系樹脂発泡体は、その気泡構造が非常に微細な独立気泡構造である。これは、ポリオレフィン系樹脂が非常に強靱であるために有機分解型発泡剤の分解によって生じた気泡の膜が破壊されないためである。
【０００４】
一方、従来から連続気泡発泡体が多数提供されているが、この殆どはポリウレタン樹脂発泡体であって、ポリオレフィン系樹脂発泡体に比して耐候性、耐薬品性、耐水性に劣り、連続気泡のポリオレフィン系樹脂発泡体が所望されていた。
【０００５】
そこで、特開昭５７−１９１０２７号公報には、ゲル分率ゼロの状態のポリオレフィン系樹脂を所望の形状に成形した後、常圧下にて加熱することによって架橋と発泡とを同時進行的に行わせた上で圧縮変形を加えることにより連続気泡化したポリオレフィン系樹脂発泡体の製造方法が提案されている。
【０００６】
しかしながら、上記ポリオレフィン系樹脂発泡体の製造方法では、上記の如く、ポリオレフィン系樹脂は非常に強靱であるため、ポリオレフィン系樹脂発泡体に機械的変形を施した場合、独立気泡の連続気泡化が不均一となり、又、連続気泡率を向上させるために大きな力を加えると、ポリオレフィン系樹脂発泡体の表面に皺や凹凸等が生じて外観性が低下してしまうといった問題点があった。
【０００７】
更に、上記ポリオレフィン系樹脂発泡体の製造方法では、工程の管理が難しく、連続気泡化したポリオレフィン系樹脂発泡体を容易に且つ連続的に得られないといった問題点もあった。
【０００８】
【発明が解決しようとする課題】
本発明は、独立気泡発泡体、特に、ポリオレフィン系樹脂発泡体の独立気泡を連続気泡にして連続気泡発泡体を容易に且つ連続的に製造することができる連続気泡発泡体の製造方法を提供する。
【０００９】
【課題を解決するための手段】
請求項１に記載の連続気泡発泡体の製造方法は、少なくとも一方の回転ロール表面に多数の針状物が植設された一対の回転ロール間に独立気泡発泡体を連続的に供給し、上記回転ロール表面の針状物を上記独立気泡発泡体に突き刺して該独立気泡発泡体の独立気泡を互いに連通させて連続気泡化することを特徴とする連続気泡発泡体の製造方法において、上記独立気泡発泡体を加熱して上記独立気泡発泡体の独立気泡内の空気を膨張させて上記独立気泡が膨らんだ状態とした上で、上記独立気泡発泡体を上記一対の回転ロール間に供給することを特徴とする。
【００１０】
又、請求項２に記載の連続気泡発泡体の製造方法は、請求項１に記載の連続気泡発泡体の製造方法において、回転ロール間の間隔を独立気泡発泡体の厚み以下にして、これらの一対の回転ロール間で独立気泡発泡体を挟圧しつつ回転ロール表面の針状物を独立気泡発泡体の厚み方向に貫通させて独立気泡発泡体の独立気泡を連通させることを特徴とする。
【００１１】
更に、請求項３に記載の連続気泡発泡体の製造方法は、請求項１又は請求項２に記載の連続気泡発泡体の製造方法において、双方の回転ロール表面に針状物を植設していることを特徴とする。
【００１２】
最後に、請求項４に記載の連続気泡発泡体の製造方法は、請求項１乃至請求項３の何れか１項に記載の連続気泡発泡体の製造方法において、他方の回転ロール表面に、一方の回転ロール表面に植設した針状物の先端部を受け入れる受入凹部を凹設していることを特徴とする。
【００１３】
【作用】
本発明の連続気泡発泡体の製造方法によれば、少なくとも一方の回転ロール表面に植設された多数の針状物を独立気泡発泡体に突き刺すことによって独立気泡を互いに連通させ連続気泡化していることから、発泡体表面の外観を損なうことなく独立気泡を全体的に且つ均一に連続気泡化することができる。
【００１４】
しかも、本発明の連続気泡発泡体の製造方法では、少なくとも一方の回転ロール表面に多数の針状物が植設された一対の回転ロール間に独立気泡発泡体を連続的に供給することによって独立気泡発泡体の独立気泡を連続的に連続気泡化しており、独立気泡発泡体を高効率で連続気泡発泡体に加工することができる。
【００１５】
【発明の実施の形態】
本発明の連続気泡発泡体の製造方法の一例を図面を参照しつつ説明する。先ず、連続気泡発泡体の製造方法で用いられる製造装置について説明する。図１に示したように、連続気泡発泡体の製造装置Ａは、連続気泡化する独立気泡発泡体Ｆの厚みよりも狭い間隔、好ましくは、独立気泡発泡体Ｆの厚みの１／２〜１／１２の間隔を存して上下方向に配設された一対の円柱状の上下回転ロール１、２からなる。そして、上側回転ロール１は、その表面が金属等の硬質材料から形成されている一方、下側回転ロール２は、その表面が硬質ゴム等の弾性材料から形成され、後述する上側回転ロール２の針状物11の先端部による押圧によって弾性的に凹み、上記針状物11の先端部を受け入れ可能に構成されている。
【００１６】
なお、上記上下回転ロール１、２は、その対向面間の間隔を独立気泡発泡体Ｆの厚みに合わせて広げたり狭めたりすることができるように構成されており、又、上記上下回転ロール１、２の直径は、適宜調整され、具体的には５ｃｍ以上のものが好ましく、幅も適宜調整されるが、具体的には５ｃｍ以上のものが好ましい。
【００１７】
更に、上記上下回転ロール１、２の回転速度は、速いと、独立気泡発泡体の連続気泡化が不十分となることがあり、又、遅いと、連続気泡発泡体の製造効率が低下することがあるので、３〜７０ｍ／ｍｉｎが好ましく、２５〜５０ｍ／ｍｉｎがより好ましい。なお、上記上下回転ロール１、２の回転速度は同一であっても異なってもよい。
【００１８】
そして、上記上側回転ロール１の外周面全面には、上下回転ロール１、２の対向面間の間隔よりも若干長い長さを有する多数本の針状物11が上側回転ロール１の周方向及び幅方向に好ましくは等間隔毎に且つ上下回転ロール１、２の径方向に植設されている。又、隣接する針状物11、11間の間隔は、適宜設定されるが、広いと、独立気泡発泡体の連続気泡化が不十分となることがあるので、３ｍｍ以下が好ましく、２ｍｍ以下がより好ましい。なお、上記上側回転ロール１の外周面全面に針状物11を植設する代わりに上記下側回転ロール２の外周面全面に上記の要領で針状物を植設してもよい。
【００１９】
なお、上記針状物11の形状は、独立気泡発泡体Ｆを厚み方向に貫通可能であれば、特に限定されず、例えば、針状（円錐状）、角錐状、円筒状、角柱状等が挙げられ、又、上記針状物11の材質も、鉄、銅、チタン、亜鉛、錫、鉛、金、銀、白金等の何れの材質であってもよく、上記針状物11の表面にはメッキ、樹脂コーティングが施されていてもよい。
【００２０】
次に、上記連続気泡発泡体の製造装置Ａを用いて独立気泡発泡体Ｆから連続気泡発泡体Ｇを製造する要領について説明する。なお、上記連続気泡発泡体の製造装置Ａに適用可能な独立気泡発泡体Ｆとしては、特に限定されず、例えば、低密度ポリエチレン樹脂、中密度ポリエチレン樹脂、高密度ポリエチレン樹脂、エチレン−ブテン共重合体、エチレン−１−ヘキセン共重合体、エチレン−４−メチル−１−ペンテン共重合体、エチレン−１−オクテン共重合体、エチレン−１−ペンテン共重合体、エチレン−酢酸ビニル共重合体、エチレン−エチルアクリレート共重合体等のポリエチレン系樹脂；ホモポリプロピレン、エチレン−プロピレン共重合体等のポリプロピレン系樹脂；ポリブテン等からなる独立気泡発泡体が挙げられる。
【００２１】
先ず、好ましくは、独立気泡発泡体Ｆを構成する合成樹脂の軟化温度〜溶融温度に加熱された独立気泡発泡体Ｆを上記上下回転ロール１、２間に供給する。このように、独立気泡発泡体Ｆをこれを構成する合成樹脂の軟化温度〜溶融温度に加熱することによって、独立気泡発泡体Ｆの独立気泡F1内の空気を膨張させて独立気泡F1を膨らんだ内圧の大きな状態とし、この内圧の大きな状態の独立気泡F1に上記上側回転ロール１の針状物11を突き刺すことによって独立気泡F1の膜を容易に破壊させて隣接する独立気泡F1、F1同士を連通化し、独立気泡F1を円滑に且つ確実に連続気泡化することができる。
【００２２】
すると、上記独立気泡発泡体Ｆは上記上下回転ロール１、２の対向面間によって厚み方向に挟圧されると同時に、上側回転ロール１の針状物11が独立気泡発泡体Ｆにその厚み方向に貫通した状態に突き刺さり、独立気泡発泡体Ｆの独立気泡膜が破壊されて、上記独立気泡発泡体Ｆの独立気泡F1、F1・・・は互いに連通した連続気泡G1となって連続気泡化される。
【００２３】
この際、上記独立気泡発泡体Ｆの独立気泡F1は、独立気泡発泡体Ｆの厚み方向に押し潰されて偏平に近い状態とされ、独立気泡発泡体の厚み方向から見た投影面積が大きくなった状態とされていることから、上記独立気泡発泡体Ｆの独立気泡F1は、上側回転ロール１の針状物11によって確実に突き刺されて独立気泡F1の膜が破壊されて連続気泡化される。
【００２４】
しかも、上記独立気泡発泡体Ｆの独立気泡F1は、独立気泡発泡体Ｆの厚み方向に押し潰されて圧縮された状態となっていることから、上記独立気泡F1内の圧力は大きくなっている。そして、このように内圧の大きくなった独立気泡F1に上側回転ロール１の針状物11を突き刺すことによって、独立気泡F1の膜を円滑に且つ確実に破壊させて、隣接する独立気泡F1、F1同士を連通させて独立気泡F1を円滑に且つ確実に連続気泡化することができる。
【００２５】
しかして、独立気泡発泡体Ｆを上側回転ロール１の針状物11で突き刺すことによって得られた連続気泡発泡体Ｇは、上下回転ロール１、２の回転に伴って上下回転ロール１、２間から連続的に排出され、連続気泡発泡体Ｇを連続的に効率良く製造することができる。
【００２６】
上記では、一対の上下回転ロール１、２のうちの上側回転ロール１にのみ針状物11を植設した場合を説明したが、図２に示したように、上下回転ロール１、２を金属等の硬質材料から形成するとともに、上下回転ロール１、２の外周面の夫々に上下回転ロール１、２の対向面間の間隔よりも若干長い長さを有する針状物11、21を上下回転ロール１、２の周方向及び幅方向に好ましくは等間隔毎に且つ上下回転ロール１、２の径方向に植設してなるものであってもよく、この際、上下回転ロール１、２の針状物11、21同士が衝突しないように互いにずらした状態に植設されている。
【００２７】
更に、上記上下回転ロール１、２の針状物11、11（21、21）間の夫々には、上下回転ロール２（１）の針状物21（11）の先端部を受け入れ可能な受入凹部12（22）が凹設されている。
【００２８】
そして、上記の如き上下回転ロール１、２によれば、独立気泡発泡体Ｆに上下回転ロール１、２の針状物11、21を両面から同時に確実に突き刺すことができ、しかも、独立気泡発泡体Ｆの両面から針状物11、21を突き刺すので、独立気泡発泡体Ｆに対する針状物11、21の突き刺し密度を高くすることができ、よって、独立気泡発泡体Ｆの連続気泡化をより確実に行うことができる。
【００２９】
しかも、上記上下回転ロール１、２の針状物11、21は、上下回転ロール１、２の対向面間において、その先端部が一方の回転ロール１、２の受入凹部12、22に受け入れられた状態となるので、独立気泡発泡体Ｆをその両面において上下回転ロール１、２の外周面で確実に受止しつつ、上記上下回転ロール１、２の針状物11、21を独立気泡発泡体Ｆの厚み方向に完全に貫通した状態に突き刺すことができ、独立気泡発泡体Ｆの連続気泡化をより確実に行うことができる。
【００３０】
最後に、上記では、一対の上下回転ロール１、２を一組だけ用い、この一組の上下回転ロール１、２間に独立気泡発泡体Ｆを供給して連続気泡G1化する場合を説明したが、図３及び図４に示したように、上記一対の上下回転ロール１、２を一組とし、これら一対の上下回転ロール１、２を複数組、発泡体の排出方向に所定間隔毎に並設し、独立気泡発泡体Ｆをこれら複数組の上下回転ロール１、２間に順次供給し、独立気泡発泡体Ｆに上側回転ロール１の針状物11或いは上下回転ロール１、２の針状物11、21を順次、突き刺して独立気泡F1を連続気泡G1化して連続気泡発泡体Ｇを製造してもよい。なお、図４において、上下回転ロール１、２の受入凹部12、22は省略した。
【００３１】
【実施例】
（実施例１）
図３に示したように、上下方向に所定間隔を存して配設された直径３０ｃｍで且つ幅が１００ｃｍの円柱状の上下回転ロール１、２を一組とし、これら一対の上下回転ロール１、２を４組、水平方向に所定間隔毎に並設するとともに、各上側回転ロール１の外周面全面に、周方向及び幅方向に２ｍｍ間隔毎に針状物11を多数、上側回転ロール１の径方向に突設してなる連続気泡発泡体の製造装置Ａを用いた。なお、上記上下回転ロールの対向面間の間隔は、独立気泡発泡体の厚みの１／１０となるように調整されているとともに、上記上側回転ロール１の針状物11の長さは上下回転ロール１、２の対向面間の間隔よりも若干長い長さを有しており、更に、上記下側回転ロール２の外周面は硬質ゴムから形成されており、針状物11の押圧によって弾性的に凹んで針状物11の先端部を受け入れ可能に構成している。
【００３２】
そして、各上下回転ロールを３０ｍ／ｍｉｎの同一速度で互いに反対方向（図３において上側回転ロールを反時計回り、下側回転ロールを時計回り）に回転させる一方、１２０℃に加熱保持した独立気泡発泡体を上流側の上下回転ロール1a、2aの対向面間に供給し、独立気泡発泡体Ｆを厚み方向に圧縮させながら、上側回転ロール1aの針状物11を独立気泡発泡体Ｆにその厚み方向に貫通状態に突き刺して独立気泡F1を連続気泡化した後、更に、発泡体を下流側の上下回転ロール1b、2b、1c、2c、1d、2d間に順次、連続的に供給し、上記と同様の要領で、発泡体に上側回転ロールの針状物11を厚み方向に突き刺して独立気泡F1を連続気泡化して連続気泡発泡体Ｇを得た。
【００３３】
なお、上記独立気泡発泡体Ｆとして、発泡倍率が３０倍で且つゲル分率が２５重量％のシート状のポリプロピレン製発泡体であって、厚みを６、１０、２０、３０、４０ｍｍと変化させた五種類のポリプロピレン製発泡体（軟化温度＝１２０℃、溶融温度＝１４７℃）を用いた。
【００３４】
（実施例２）
図４に示したように、上下方向に所定間隔を存して配設された直径３０ｃｍで且つ幅が１００ｃｍの円柱状の上下回転ロール１、２を一組とし、これら一対の上下回転ロール１、２を４組、水平方向に所定間隔毎に並設する一方、各上下回転ロール１、２の外周面全面に、周方向及び幅方向に２ｍｍ間隔毎に針状物11、21を多数、上下回転ロール１、２の径方向に突設しているとともに、上下回転ロール１、２の外周面における針状物11、11、21、21間の夫々には上記針状物11、21の先端部を受け入れ可能な受入凹部が凹設されてなる連続気泡発泡体の製造装置Ａを用いた。なお、上記上下回転ロール１、２の対向面間の間隔は、独立気泡発泡体Ｆの厚みの１／１０となるように調整しているとともに、上記上下回転ロール１、２の針状物11、21の長さは上下回転ロール１、２の対向面間の間隔よりも若干長い長さを有している。
【００３５】
そして、各上下回転ロールを３０ｍ／ｍｉｎの同一速度で互いに反対方向（図４において上側回転ロールを反時計回り、下側回転ロールを時計回り）に回転させる一方、１２０℃に加熱保持した独立気泡発泡体Ｆを上流側の上下回転ロール1a、2aの対向面間に供給し、独立気泡発泡体Ｆを厚み方向に圧縮させながら、上側回転ロール1a、2aの針状物11、21を独立気泡発泡体Ｆに両面から厚み方向に貫通状態に突き刺して独立気泡F1を連続気泡化した後、更に、発泡体を下流側の上下回転ロール1b、2b、1c、2c、1d、2d間に順次、連続的に供給し、上記と同様の要領で、発泡体に上下回転ロール１、２の針状物11、21を厚み方向に突き刺して独立気泡F1を連続気泡化して連続気泡発泡体Ｇを得た。
【００３６】
なお、上記独立気泡発泡体Ｆとしては、発泡倍率が３０倍で且つゲル分率が２５重量％のシート状のポリプロピレン製発泡体であって、厚みを６、１０、２０、３０、４０ｍｍと変化させた五種類のポリプロピレン製発泡体（軟化温度＝１２０℃、溶融温度＝１４７℃）を用いた。
【００３７】
（比較例１）
上下方向に所定間隔を存して配設された直径３０ｃｍで且つ幅が１００ｃｍの外周面が平滑な円柱状の上下回転ロールを一組とし、これら一対の上下回転ロールを４組、水平方向に所定間隔毎に並設してなる連続気泡発泡体の製造装置を用いた。なお、上記上下回転ロールの対向面間の間隔は、独立気泡発泡体の厚みの１／１０となるように調整している。
【００３８】
そして、各上下回転ロールを３０ｍ／ｍｉｎの同一速度で互いに反対方向（上側回転ロールを反時計回り、下側回転ロールを時計回り）に回転させる一方、１２０℃に加熱保持した独立気泡発泡体を上流側の上下回転ロールの対向面間に供給し、独立気泡発泡体を厚み方向に圧縮させて独立気泡を連続気泡化した後、更に、発泡体を下流側の３組の上下回転ロール間に順次、連続的に供給し、上記と同様の要領で、発泡体を厚み方向に圧縮して独立気泡を連続気泡化して連続気泡発泡体を得た。
【００３９】
なお、上記独立気泡発泡体としては、発泡倍率が３０倍で且つゲル分率が２５重量％のシート状のポリプロピレン製発泡体であって、厚みを６、１０、２０、３０、４０ｍｍと変化させた五種類のポリプロピレン製発泡体（軟化温度＝１２０℃、溶融温度＝１４７℃）を用いた。
【００４０】
上記の要領で製造した連続気泡発泡体の連続気泡率、２５％圧縮強さ、残存厚み及び外観性を下記に示した要領で測定し、その結果を表１乃至表６に示した。なお、連続気泡率及び２５％圧縮強さについては、４組ある上下回転ロールの夫々を通過した後ごとの各ポリプロピレン製発泡体について測定した。
【００４１】
（連続気泡率）
発泡体の連続気泡率をＡＳＴＭ−Ｄ−２８５６に基づいて測定した。
【００４２】
（２５％圧縮強さ）
発泡体から縦５０ｍｍ×横５０ｍｍ×厚さ２．５ｍｍの試験片を切り出し、この試験片を温度２０℃且つ湿度６５％の雰囲気下において圧縮速度１０ｍｍ／ｍｉｎで元の厚さの２５％を圧縮し、その圧縮時における圧縮荷重（Ｗ）を測定し、下記式により算出した。なお、Ａは、圧縮面積（ｃｍ²）である。
２５％圧縮強さ（Ｎ／ｃｍ²）＝Ｗ／Ａ
【００４３】
（残存厚み）
４組全ての上下回転ロール間を通して得られた連続気泡発泡体の厚みを測定した。
【００４４】
（外観性）
４組全ての上下回転ロール間を通して得られた連続気泡発泡体の外観性を下記の基準に基づいて測定した。
○・・・連続気泡発泡体表面には凹凸や皺は発生しなかった。
×・・・連続気泡発泡体表面に多数の凹凸や皺が発生した。
【００４５】
【表１】

【００４６】
【表２】

【００４７】
【表３】

【００４８】
【表４】

【００４９】
【表５】

【００５０】
【表６】

【００５１】
【発明の効果】
請求項１に記載の連続気泡発泡体の製造方法は、少なくとも一方の回転ロール表面に多数の針状物が植設された一対の回転ロール間に独立気泡発泡体を連続的に供給し、上記回転ロール表面の針状物を上記独立気泡発泡体に突き刺して該独立気泡発泡体の独立気泡を互いに連通させて連続気泡化することを特徴とする連続気泡発泡体の製造方法において、上記独立気泡発泡体を加熱して上記独立気泡発泡体の独立気泡内の空気を膨張させて上記独立気泡が膨らんだ状態とした上で、上記独立気泡発泡体を上記一対の回転ロール間に供給することを特徴とするので、発泡体表面に凹凸や皺を生じさせることなく、独立気泡発泡体の隣接する独立気泡同士を回転ロールの針状物によって確実に互いに連通させて連続気泡化することができる。
【００５２】
しかも、独立気泡発泡体を一対の回転ロール間に連続的に供給し、回転ロールの針状物によって独立気泡発泡体の独立気泡を連続的に連続気泡化することができ、独立気泡発泡体の連続気泡化を高効率で行うことができる。
【００５３】
又、請求項２に記載の連続気泡発泡体の製造方法は、請求項１に記載の連続気泡発泡体の製造方法において、回転ロール間の間隔を独立気泡発泡体の厚み以下にして、これらの一対の回転ロール間で独立気泡発泡体を挟圧しつつ回転ロール表面の針状物を独立気泡発泡体の厚み方向に貫通させて独立気泡発泡体の独立気泡を連通させることを特徴とするので、独立気泡発泡体の独立気泡を該独立気泡発泡体の厚み方向に押圧して独立気泡を偏平な状態とし、独立気泡発泡体の厚み方向からみた独立気泡の投影面積を大きくした上で回転ロールの針状物を独立気泡発泡体の独立気泡に確実に突き刺すことができ、よって、独立気泡発泡体の連続気泡化を円滑に且つ確実に行うことができる。
【００５４】
しかも、上述の如く、独立気泡発泡体の独立気泡を該独立気泡発泡体の厚み方向に押圧して独立気泡を偏平な状態としているので、独立気泡内の圧力は大きくなっている。そして、このような状態で回転ロールの針状物を独立気泡に突き刺しているので、独立気泡の膜は円滑に且つ確実に破壊されて隣接する独立気泡同士は連通し、よって、連続気泡発泡体を円滑に且つ確実に得ることができる。
【００５５】
更に、請求項３に記載の連続気泡発泡体の製造方法は、請求項１又は請求項２に記載の連続気泡発泡体の製造方法において、双方の回転ロール表面に針状物を植設していることを特徴とするので、独立気泡発泡体に対する回転ロールの針状物の突き刺し密度を高くすることができ、よって、独立気泡発泡体をより確実に連続気泡化することができる。
【００５６】
最後に、請求項４に記載の連続気泡発泡体の製造方法は、請求項１乃至請求項３の何れか１項に記載の連続気泡発泡体の製造方法において、他方の回転ロール表面に、一方の回転ロール表面に植設した針状物の先端部を受け入れる受入凹部を凹設していることを特徴とするので、独立気泡発泡体をその両面において上下回転ロール表面によって確実に受止しつつ、独立気泡発泡体に針状物を厚み方向に確実に貫通させた状態に突き刺すことができ、独立気泡発泡体の連続気泡化をより確実に行うことができる。
【図面の簡単な説明】
【図１】本発明の連続気泡発泡体の製造方法で用いられる製造装置を示した模式側面図である。
【図２】本発明の連続気泡発泡体の製造方法で用いられる他の製造装置を示した模式側面図である。
【図３】本発明の連続気泡発泡体の製造方法で用いられる他の製造装置を示した模式側面図である。
【図４】本発明の連続気泡発泡体の製造方法で用いられる他の製造装置を示した模式側面図である。
【符号の説明】
１上側回転ロール
11 針状物
12 受入凹部
２下側回転ロール
21 針状物
22 受入凹部
Ａ連続気泡発泡体の製造装置
Ｆ独立気泡発泡体
F1 独立気泡
Ｇ連続気泡発泡体
G1 連続気泡[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing an open cell foam in which closed cell foam such as polyolefin resin foam is made into open cells.
[0002]
[Prior art]
Conventionally, as a method for producing a crosslinked polyolefin resin foam, a method using an organic decomposable foaming agent has been widely used. Specifically, after adding an organic peroxide to the polyolefin resin or irradiating the polyolefin resin with an electron beam to crosslink the polyolefin resin, the organic decomposable foaming agent contained in the polyolefin resin is decomposed. To produce crosslinked polyolefin resin foam.
[0003]
The polyolefin resin foam obtained as described above has a closed cell structure in which the cell structure is very fine. This is because the polyolefin-based resin is very tough so that the bubble film generated by the decomposition of the organic decomposable foaming agent is not destroyed.
[0004]
On the other hand, many open-cell foams have been provided, but most of them are polyurethane resin foams, which are inferior in weather resistance, chemical resistance and water resistance compared to polyolefin resin foams. The polyolefin resin foam was desired.
[0005]
Japanese Patent Application Laid-Open No. 57-191027 discloses that a polyolefin resin having a zero gel fraction is molded into a desired shape and then heated under normal pressure to simultaneously perform crosslinking and foaming. There has been proposed a method for producing a polyolefin resin foam that has been made open-celled by applying compressive deformation after being subjected to compression.
[0006]
However, in the method for producing a polyolefin resin foam, as described above, the polyolefin resin is very tough, and therefore, when the polyolefin resin foam is mechanically deformed, closed cells cannot be made continuous. If a large force is applied in order to improve uniformity and open cell ratio, wrinkles, irregularities, and the like are generated on the surface of the polyolefin resin foam, resulting in a decrease in appearance.
[0007]
Furthermore, in the method for producing a polyolefin resin foam, there is a problem that it is difficult to manage the process, and a polyolefin resin foam having open cells cannot be easily and continuously obtained.
[0008]
[Problems to be solved by the invention]
The present invention provides a method for producing an open-cell foam, in particular, an open-cell foam that can be easily and continuously produced by making closed-cells of a polyolefin resin foam into open-cells. .
[0009]
[Means for Solving the Problems]
The method for producing an open-cell foam according to claim 1, wherein the closed-cell foam is continuously supplied between a pair of rotating rolls in which a large number of needle-like objects are implanted on the surface of at least one rotating roll, In the method for producing an open-cell foam, the closed-cell foam is characterized in that a needle-like object on the surface of a rotating roll is pierced into the closed-cell foam and the closed cells of the closed-cell foam are communicated with each other to form open cells. Heating the foam to expand the air in the closed cells of the closed cell foam so that the closed cells are expanded, and then supplying the closed cell foam between the pair of rotating rolls. Features.
[0010]
Moreover, the manufacturing method of the open-cell foam of Claim 2 WHEREIN: The manufacturing method of the open-cell foam of Claim 1 makes the space | interval between rotary rolls below the thickness of a closed-cell foam, These While the closed cell foam is sandwiched between a pair of rotating rolls, the needle-like material on the surface of the rotating roll is penetrated in the thickness direction of the closed cell foam to allow the closed cells of the closed cell foam to communicate with each other.
[0011]
Furthermore, the manufacturing method of the open-cell foam of Claim 3 is a manufacturing method of the open-cell foam of Claim 1 or Claim 2, and implants a needle-like object on both rotary roll surfaces. It is characterized by being.
[0012]
Finally, the method for producing an open-cell foam according to claim 4 is the method for producing an open-cell foam according to any one of claims 1 to 3, wherein The receiving recessed part which receives the front-end | tip part of the needle-shaped object planted on the surface of this rotation roll is recessed, It is characterized by the above-mentioned.
[0013]
[Action]
According to the method for producing an open-cell foam of the present invention, a plurality of needle-like objects implanted on the surface of at least one rotating roll are pierced into the closed-cell foam, thereby allowing the closed cells to communicate with each other to form open cells. Therefore, the closed cells can be made into continuous cells uniformly and uniformly without impairing the appearance of the foam surface.
[0014]
And in the manufacturing method of the open-cell foam of this invention, it is independent by supplying a closed-cell foam continuously between a pair of rotary roll by which many needlelike objects were planted on the surface of at least one rotary roll. The closed cells of the cell foam are continuously made into open cells, and the closed cell foam can be processed into an open cell foam with high efficiency.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
An example of the manufacturing method of the open-cell foam of this invention is demonstrated referring drawings. First, the manufacturing apparatus used with the manufacturing method of an open-cell foam is demonstrated. As shown in FIG. 1, the apparatus A for producing open-cell foam has an interval narrower than the thickness of the closed-cell foam F that becomes open-cell, preferably ½ to 1 of the thickness of the closed-cell foam F. It consists of a pair of cylindrical up-and-down rotating

rolls

1 and 2 arranged in the up-and-down direction with an interval of / 12. The upper rotary roll 1 has a surface made of a hard material such as metal, while the lower rotary roll 2 has a surface made of an elastic material such as hard rubber. The needle-shaped object 11 is configured to be elastically recessed by being pressed by the distal end portion thereof so that the distal end portion of the needle-shaped object 11 can be received.
[0016]
The upper and lower

rotary rolls

1 and 2 are configured such that the interval between the opposing surfaces can be expanded or narrowed according to the thickness of the closed cell foam F, and the vertical rotary roll 1 The diameter of 2 is adjusted as appropriate, specifically 5 cm or more is preferable, and the width is also adjusted as appropriate, but specifically 5 cm or more is preferable.
[0017]
Furthermore, if the rotational speeds of the upper and lower

rotary rolls

1 and 2 are high, the closed cell foam may not be formed into continuous cells, and if it is slow, the production efficiency of the open cell foam may be reduced. Therefore, 3-70 m / min is preferable, and 25-50 m / min is more preferable. The rotational speeds of the upper and lower

rotary rolls

1 and 2 may be the same or different.
[0018]
A large number of needles 11 having a length slightly longer than the distance between the opposing surfaces of the upper and lower

rotary rolls

1 and 2 are formed on the entire outer peripheral surface of the upper rotary roll 1 in the circumferential direction of the upper rotary roll 1. Preferably, it is planted in the width direction at equal intervals and in the radial direction of the upper and lower

rotary rolls

1 and 2. Further, the interval between the adjacent needle-

like objects

11 and 11 is appropriately set, but if it is wide, the closed cell foam may be insufficiently formed into open cells. Therefore, it is preferably 3 mm or less, and preferably 2 mm or less. More preferred. In addition, instead of implanting the needle-like object 11 over the entire outer peripheral surface of the upper rotary roll 1, the needle-like object may be implanted over the entire outer peripheral surface of the lower rotary roll 2 as described above.
[0019]
The shape of the needle-like material 11 is not particularly limited as long as it can penetrate the closed-cell foam F in the thickness direction. For example, the shape of the needle-like material F may be a needle shape (conical shape), a pyramid shape, a cylindrical shape, a prism shape, or the like. In addition, the material of the needle-like object 11 may be any material such as iron, copper, titanium, zinc, tin, lead, gold, silver, platinum, etc. May be plated or resin coated.
[0020]
Next, the point which manufactures the open-cell foam G from the closed-cell foam F using the said open-cell foam manufacturing apparatus A is demonstrated. In addition, it does not specifically limit as the closed cell foam F applicable to the said manufacturing apparatus A of an open cell foam, For example, a low density polyethylene resin, a medium density polyethylene resin, a high density polyethylene resin, ethylene-butene copolymer weight Polymer, ethylene-1-hexene copolymer, ethylene-4-methyl-1-pentene copolymer, ethylene-1-octene copolymer, ethylene-1-pentene copolymer, ethylene-vinyl acetate copolymer, Examples thereof include polyethylene resins such as ethylene-ethyl acrylate copolymers; polypropylene resins such as homopolypropylene and ethylene-propylene copolymers; closed-cell foams such as polybutene.
[0021]
First, preferably, the closed cell foam F heated to the softening temperature to the melting temperature of the synthetic resin constituting the closed cell foam F is supplied between the upper and lower

rotating rolls

1 and 2. Thus, by heating the closed cell foam F from the softening temperature to the melting temperature of the synthetic resin constituting the closed cell foam F, the air in the closed cell F1 of the closed cell foam F is expanded to expand the closed cell F1. A state where the internal pressure is large, and the closed cell F1 in the state where the internal pressure is large is pierced with the needle-like object 11 of the upper rotary roll 1 so that the membrane of the closed cell F1 is easily broken, and the adjacent closed cells F1, F1 are separated from each other. By communicating, the closed cell F1 can be made into a continuous cell smoothly and reliably.
[0022]
Then, the closed cell foam F is sandwiched between the opposing surfaces of the upper and lower rotary rolls 1 and 2 in the thickness direction, and at the same time, the needles 11 of the upper rotary roll 1 are applied to the closed cell foam F in the thickness direction. The closed cell membrane of the closed cell foam F is destroyed, and the closed cells F1, F1,... Of the closed cell foam F become open cells G1 that are communicated with each other to be formed into open cells. The
[0023]
At this time, the closed cell F1 of the closed cell foam F is crushed in the thickness direction of the closed cell foam F to be almost flat, and the projected area viewed from the thickness direction of the closed cell foam is increased. Therefore, the closed cell F1 of the closed cell foam F is surely pierced by the needle-like object 11 of the upper rotating roll 1, and the film of the closed cell F1 is broken to be continuous. .
[0024]
In addition, since the closed cells F1 of the closed cell foam F are in a compressed state by being crushed in the thickness direction of the closed cell foam F, the pressure in the closed cells F1 is increased. . Then, the needle-like object 11 of the upper rotary roll 1 is pierced into the closed cell F1 having the increased internal pressure in this way, so that the membrane of the closed cell F1 is smoothly and reliably broken, and the adjacent closed cells F1, F1 By communicating with each other, the closed cells F1 can be smoothly and reliably made into continuous cells.
[0025]
Thus, the open-cell foam G obtained by piercing the closed cell foam F with the needles 11 of the upper rotary roll 1 is formed between the upper and lower rotary rolls 1 and 2 as the vertical rotary rolls 1 and 2 rotate. The continuous-cell foam G can be continuously and efficiently produced.
[0026]
In the above description, the case where the needle-like object 11 is implanted only in the upper rotary roll 1 of the pair of vertical rotary rolls 1 and 2 has been described. However, as shown in FIG. The needle-

like objects

11 and 21 having a length slightly longer than the distance between the opposing surfaces of the upper and lower rotary rolls 1 and 2 are rotated up and down. The

rolls

1 and 2 may be implanted in the circumferential direction and the width direction, preferably at regular intervals and in the radial direction of the upper and lower rotary rolls 1 and 2. The

needles

11 and 21 are planted so as to be shifted from each other so as not to collide with each other.
[0027]
Furthermore, between the needle-like objects 11 and 11 (21, 21) of the above-described vertical

rotating rolls

1 and 2, receiving the tip of the needle-like object 21 (11) of the vertical rotating roll 2 (1) is acceptable. A recess 12 (22) is provided.
[0028]
Then, according to the vertical

rotating rolls

1 and 2 as described above, the needle-

like objects

11 and 21 of the vertical

rotating rolls

1 and 2 can be reliably pierced simultaneously from both sides into the closed cell foam F, and the closed cell foaming is possible. Since the

needles

11 and 21 are pierced from both sides of the body F, the piercing density of the

needles

11 and 21 with respect to the closed-cell foam F can be increased, and thus the closed-cell foam F can be made more continuous. It can be done reliably.
[0029]
Moreover, the needle-

like objects

11 and 21 of the upper and lower rotary rolls 1 and 2 are received by the receiving recesses 12 and 22 of one

rotary roll

1 and 2 between the opposing surfaces of the vertical rotary rolls 1 and 2. Since the closed cell foam F is reliably received by the outer peripheral surfaces of the upper and lower rotary rolls 1 and 2 on both sides, the needle-

like objects

11 and 21 of the upper and lower rotary rolls 1 and 2 are closed cell foamed. It can stab in the state penetrated completely in the thickness direction of the body F, and the closed cell foam F can be made into open cells more reliably.
[0030]
Finally, in the above description, a case where only one pair of the vertical

rotating rolls

1 and 2 is used and the closed cell foam F is supplied between the pair of vertical

rotating rolls

1 and 2 to form an open cell G1 has been described. However, as shown in FIG. 3 and FIG. 4, the pair of upper and lower rotary rolls 1 and 2 is set as one set, and a plurality of sets of the pair of vertical rotary rolls 1 and 2 are set at predetermined intervals in the foam discharge direction. The closed cell foam F is supplied in parallel between the plurality of upper and lower rotary rolls 1 and 2 and the needles 11 of the upper rotary roll 1 or the needles of the vertical rotary rolls 1 and 2 are supplied to the closed cell foam F. The open-cell foam G may be manufactured by sequentially piercing the

articles

11 and 21 to convert the closed cells F1 into open cells G1. In FIG. 4, the receiving recesses 12 and 22 of the upper and lower rotary rolls 1 and 2 are omitted.
[0031]
【Example】
Example 1
As shown in FIG. 3, a pair of cylindrical up-and-down

rotating rolls

1 and 2 having a diameter of 30 cm and a width of 100 cm arranged at predetermined intervals in the up-and-down direction is set as a pair, and the pair of up-and-down rotating rolls 1 4 are arranged in parallel at predetermined intervals in the horizontal direction, and a large number of needles 11 are provided on the entire outer peripheral surface of each upper rotary roll 1 at intervals of 2 mm in the circumferential direction and the width direction. An apparatus for producing an open-cell foam formed by projecting in the radial direction was used. In addition, while the space | interval between the opposing surfaces of the said up-and-down rotating roll is adjusted so that it may become 1/10 of the thickness of a closed-cell foam, the length of the needle-like object 11 of the said upper rotating roll 1 rotates up and down. It has a length slightly longer than the distance between the opposing surfaces of the

rolls

1 and 2, and the outer peripheral surface of the lower rotary roll 2 is made of hard rubber and is elastic when pressed by the needle 11. The tip portion of the needle-like object 11 is configured to be recessed so that it can be received.
[0032]
Each of the up-and-down rotating rolls is rotated at the same speed of 30 m / min in opposite directions (in FIG. 3, the upper rotating roll is rotated counterclockwise and the lower rotating roll is rotated clockwise), and the closed cells heated and held at 120 ° C. The foam is supplied between the opposed surfaces of the upper and lower rotary rolls 1a and 2a on the upstream side, and the needle-like object 11 of the upper rotary roll 1a is compressed into the closed-cell foam F while compressing the closed-cell foam F in the thickness direction. After piercing in the penetrating state in the thickness direction and making the closed cells F1 into continuous cells, the foam is further supplied sequentially and continuously between the upper and lower rotary rolls 1b, 2b, 1c, 2c, 1d, 2d on the downstream side, In the same manner as described above, the needle-like object 11 of the upper rotating roll was pierced in the thickness direction into the foam to make the closed cells F1 open cells, whereby an open cell foam G was obtained.
[0033]
The closed cell foam F is a sheet-like polypropylene foam having a foaming ratio of 30 times and a gel fraction of 25% by weight, and the thickness is changed to 6, 10, 20, 30, 40 mm. Five types of polypropylene foams (softening temperature = 120 ° C., melting temperature = 147 ° C.) were used.
[0034]
(Example 2)
As shown in FIG. 4, a pair of cylindrical up-and-down

rotating rolls

1 and 2 having a diameter of 30 cm and a width of 100 cm arranged at predetermined intervals in the up-and-down direction are set as a pair, and the pair of up-and-down rotating rolls 1 4 sets, 2 in parallel, at a predetermined interval in the horizontal direction, on the entire outer peripheral surface of each of the upper and lower rotary rolls 1, 2, a large number of

needles

11, 21 at intervals of 2mm in the circumferential direction and width direction, The upper and lower rotary rolls 1 and 2 protrude in the radial direction, and the needle-

like objects

11, 11, 21, 21 on the outer peripheral surface of the vertical rotary rolls 1, 2 are respectively provided with the needle-

like objects

11, 21. An apparatus A for producing an open-cell foam in which a receiving recess capable of receiving the tip is provided. In addition, while adjusting the space | interval between the opposing surfaces of the said up-and-down

rotating rolls

1 and 2 so that it may become 1/10 of the thickness of the closed-cell foam F, the needlelike object 11 of the above-mentioned up-and-down

rotating rolls

1 and 2 , 21 has a length slightly longer than the distance between the opposing surfaces of the up and down rotary rolls 1 and 2.
[0035]
Each of the up-and-down rotating rolls is rotated at the same speed of 30 m / min in opposite directions (in FIG. 4, the upper rotating roll is counterclockwise and the lower rotating roll is rotated clockwise), and the closed cells heated and held at 120 ° C. The foam F is supplied between the opposed surfaces of the upstream upper and lower rotary rolls 1a and 2a, and the needle-

like objects

11 and 21 of the upper rotary rolls 1a and 2a are closed by compressing the closed cell foam F in the thickness direction. After piercing the foam F from both sides in the thickness direction to make the closed cells F1 into continuous cells, the foam is further sequentially placed between the up and down

rotating rolls

1b, 2b, 1c, 2c, 1d, 2d on the downstream side, Continuously supplied, and in the same manner as above, the

needles

11 and 21 of the upper and lower rotary rolls 1 and 2 are pierced in the thickness direction to make the closed cells F1 into open cells, thereby obtaining an open cell foam G. It was.
[0036]
The closed-cell foam F is a sheet-like polypropylene foam having a foaming ratio of 30 times and a gel fraction of 25% by weight, and the thickness is changed to 6, 10, 20, 30, 40 mm. Five types of polypropylene foams (softening temperature = 120 ° C., melting temperature = 147 ° C.) were used.
[0037]
(Comparative Example 1)
A set of cylindrical up-and-down rotating rolls having a diameter of 30 cm and a width of 100 cm and having a smooth outer peripheral surface arranged at predetermined intervals in the up-and-down direction, and four pairs of these up-and-down rotating rolls in the horizontal direction. An apparatus for producing an open-cell foam formed in parallel at predetermined intervals was used. In addition, the space | interval between the opposing surfaces of the said up-and-down rotating roll is adjusted so that it may become 1/10 of the thickness of a closed-cell foam.
[0038]
Each of the vertical rotating rolls is rotated at the same speed of 30 m / min in opposite directions (the upper rotating roll is counterclockwise and the lower rotating roll is rotated clockwise), while the closed cell foam heated and held at 120 ° C. After the closed cell foam is compressed in the thickness direction to make the closed cells continuous, the foam is further inserted between the three sets of the upper and lower rotary rolls on the downstream side. In the same manner as described above, the foam was compressed in the thickness direction to make closed cells into open cells to obtain an open cell foam.
[0039]
The closed cell foam is a sheet-like polypropylene foam having a foaming ratio of 30 times and a gel fraction of 25% by weight, and the thickness is changed to 6, 10, 20, 30, 40 mm. Five types of polypropylene foams (softening temperature = 120 ° C., melting temperature = 147 ° C.) were used.
[0040]
The open cell ratio, 25% compressive strength, residual thickness and appearance of the open cell foam produced as described above were measured as shown below, and the results are shown in Tables 1 to 6. In addition, about the open cell ratio and 25% compressive strength, it measured about each polypropylene foam after passing through each of four sets of up-and-down rotating rolls.
[0041]
(Open cell ratio)
The open cell ratio of the foam was measured based on ASTM-D-2856.
[0042]
(25% compression strength)
A test piece having a length of 50 mm, a width of 50 mm, and a thickness of 2.5 mm was cut out from the foam, and the test piece was compressed at a compression rate of 10 mm / min in an atmosphere of a temperature of 20 ° C. and a humidity of 65% to compress 25% of the original thickness. Then, the compression load (W) at the time of compression was measured and calculated by the following formula. A is the compression area (cm ² ).
25% compressive strength (N / cm ² ) = W / A
[0043]
(Remaining thickness)
The thickness of the open-cell foam obtained through all four sets of upper and lower rotating rolls was measured.
[0044]
(Appearance)
The appearance of the open-cell foam obtained through all four sets of upper and lower rotating rolls was measured based on the following criteria.
○: No irregularities or wrinkles were generated on the surface of the open-cell foam.
X: Many irregularities and wrinkles occurred on the surface of the open-cell foam.
[0045]
[Table 1]

[0046]
[Table 2]

[0047]
[Table 3]

[0048]
[Table 4]

[0049]
[Table 5]

[0050]
[Table 6]

[0051]
【The invention's effect】
The method for producing an open-cell foam according to claim 1, wherein the closed-cell foam is continuously supplied between a pair of rotating rolls in which a large number of needle-like objects are implanted on the surface of at least one rotating roll, In the method for producing an open-cell foam, the closed-cell foam is characterized in that a needle-like object on the surface of a rotating roll is pierced into the closed-cell foam and the closed cells of the closed-cell foam are communicated with each other to form open cells. Heating the foam to expand the air in the closed cells of the closed cell foam so that the closed cells are expanded, and then supplying the closed cell foam between the pair of rotating rolls. Because of the feature , the closed cells adjacent to the closed cell foam can be reliably communicated with each other by the needles of the rotating roll without causing irregularities or wrinkles on the surface of the foam, thereby forming continuous cells.
[0052]
In addition, the closed cell foam can be continuously supplied between a pair of rotating rolls, and the closed cells of the closed cell foam can be continuously opened by the needles of the rotating roll. Open cell formation can be performed with high efficiency.
[0053]
Moreover, the manufacturing method of the open-cell foam of Claim 2 WHEREIN: The manufacturing method of the open-cell foam of Claim 1 makes the space | interval between rotary rolls below the thickness of a closed-cell foam, These Since the closed cell foam is sandwiched between a pair of rotating rolls, the needles on the surface of the rotating roll are penetrated in the thickness direction of the closed cell foam so that the closed cells of the closed cell foam communicate with each other. The closed cells of the closed cell foam are pressed in the thickness direction of the closed cell foam to make the closed cells flat, and the projected area of the closed cell viewed from the thickness direction of the closed cell foam is increased, and then the rotating roll The needle-like object can be reliably pierced into the closed cells of the closed cell foam, and thus the closed cell foam can be smoothly and reliably made open.
[0054]
Moreover, as described above, the closed cells of the closed cell foam are pressed in the thickness direction of the closed cell foam to make the closed cells flat, so that the pressure in the closed cells is increased. In this state, the needle-like object of the rotating roll is pierced into the closed cells, so that the closed cell membrane is smoothly and reliably destroyed and the adjacent closed cells communicate with each other. Can be obtained smoothly and reliably.
[0055]
Furthermore, the manufacturing method of the open-cell foam of Claim 3 is a manufacturing method of the open-cell foam of Claim 1 or Claim 2, and implants a needle-like object on both rotary roll surfaces. Therefore, it is possible to increase the piercing density of the needles of the rotating roll with respect to the closed cell foam, and thus it is possible to more reliably form the closed cell foam into continuous cells.
[0056]
Finally, the method for producing an open-cell foam according to claim 4 is the method for producing an open-cell foam according to any one of claims 1 to 3, wherein Since the receiving concave portion for receiving the tip of the needle-like material implanted on the surface of the rotating roll is recessed, the closed cell foam is reliably received by the upper and lower rotating roll surfaces on both sides thereof. In addition, the closed cell foam can be pierced in a state in which the needle-like object is reliably penetrated in the thickness direction, and the closed cell foam can be more reliably formed into an open cell.
[Brief description of the drawings]
FIG. 1 is a schematic side view showing a production apparatus used in the method for producing an open-cell foam of the present invention.
FIG. 2 is a schematic side view showing another manufacturing apparatus used in the method for manufacturing an open-cell foam according to the present invention.
FIG. 3 is a schematic side view showing another manufacturing apparatus used in the method for manufacturing an open-cell foam according to the present invention.
FIG. 4 is a schematic side view showing another manufacturing apparatus used in the method for manufacturing an open-cell foam according to the present invention.
[Explanation of symbols]
1 Upper rotating roll
11 needles
12 Receiving recess 2 Lower rotating roll
21 needles
22 Receiving recess A Open cell foam manufacturing equipment F Closed cell foam
F1 closed cell G open cell foam
G1 open cell

Claims

A closed cell foam is continuously supplied between a pair of rotating rolls in which a large number of needles are implanted on the surface of at least one rotating roll, and the needles on the surface of the rotating roll are pierced into the closed cell foam. In the method for producing an open cell foam, the closed cells of the closed cell foam are heated to communicate with each other to form open cells. The closed cell foam is supplied between the pair of rotating rolls after expanding the closed air so that the closed cells are expanded.

The interval between the rotating rolls is set to be equal to or less than the thickness of the closed cell foam, and the needle-like material on the surface of the rotating roll is penetrated in the thickness direction of the closed cell foam while sandwiching the closed cell foam between the pair of rotating rolls. The closed-cell foam manufacturing method according to claim 1, wherein closed-cells of the closed-cell foam are communicated.

The method for producing an open-cell foam according to claim 1 or 2, wherein needle-like objects are implanted on both rotating roll surfaces.

4. A receiving recess for receiving a tip of a needle-like object implanted on the surface of one of the rotating rolls is provided on the surface of the other rotating roll, according to any one of claims 1 to 3. A process for producing the open-cell foam described.