JP4081510B2

JP4081510B2 - Regeneration treatment system for reclaimable polystyrene resin particles and treatment method thereof

Info

Publication number: JP4081510B2
Application number: JP2002160832A
Authority: JP
Inventors: 研了西元; 和人浜石; 好孝神野; 宗典古賀; 誠一塚本; 強長野; 純一郎谷山; 哲郎高木; 一成児島; 嘉啓本村; 博行茶圓; 稔横山; 真一松山; 一隆雄城
Original assignee: 株式会社スタイロジャパン
Priority date: 2002-05-31
Filing date: 2002-05-31
Publication date: 2008-04-30
Anticipated expiration: 2022-05-31
Also published as: JP2004002572A

Description

【０００１】
【発明の属する技術分野】
本発明は、再生発泡性ポリスチレン系樹脂粒子の再生処理システム、及びその処理法に関する。特に、使用済み発泡ポリスチレンの減容物に対して減容剤抽出と発泡剤の含浸をひとつの工程で行うことで、溶剤の分離回収と再生発泡性ポリスチレン系樹脂粒子の製造を効率良く行えるようにした、再生発泡性ポリスチレン系樹脂粒子の再生処理システム及びその処理法に関するものである。また、再度発泡ポリスチレン成形体を作ることのできる再生発泡性ポリスチレン系樹脂粒子を製造する工程における減容物の粒状化技術に関するものである。
【０００２】
【従来の技術】
国際公開ＷＯ０１／６８７５９Ａ１（以下、先行技術１という。）には、使用済みの発泡ポリスチレンを溶剤で減容処理した減容物から減容剤を回収し、発泡剤の含浸処理を行う方法について記載されている。この方法は、特定範囲のハンセン溶解度パラメータを持つ溶剤を減容剤として使用し、減容物を発泡剤に浸漬処理し、減容剤の回収、発泡剤の含浸を行い発泡性樹脂粒子を製造するものである。この中に減容物の凝着性を低下させるための工程として減容物を発泡剤と撹拌または混練して減容物中の減容剤を抽出しその含有量を減らし、粒状物への成形を容易にすることの記載がある。
【０００３】
高粘度液の混合撹拌では、アンカー翼やリボン翼などの大きな翼を有する撹拌翼を比較的低速で回転させて、撹拌槽全体を層流状態で強引に混合する場合が一般的である。一方、低粘度液では、傾斜パドル翼やタービン翼などの比較的小さな翼を高速回転させて乱流状態で混合する場合が多い。また異なる粘度の液体を効率よく撹拌混合するために、特定の撹拌翼を用いて撹拌槽全体の混合特性を改良した種々の撹拌装置が考案され提案されている。
【０００４】
例えば特開平５−４９８９０号公報には、上段のパドル翼を隣接する下段のパドル翼より交差角度４５〜７５度で回転方向に先行させて配置し、上下のパドル翼を外端部で部分的に重複させ、最下段のパドル翼の外端部を後退羽根に形成した撹拌装置の記載がある。特開平７−１２４４５６号公報には上段に略台形状で下部中央に凹部を備えた翼と、略長方形で上部中央部に凹部を備えた下段翼を直交して配置し、下段翼の下部を後退羽根に形成した撹拌装置の記載がある。特開平９−７５６９９号公報、特開２０００−２１０５４９号公報には、回転軸線と傾斜して半径方向かつ上方に伸びる板状の第１の上段翼と、傾斜して半径方向かつ下方に伸びる板状の第２の上段翼を、第１の上段翼下辺部と第２の上段翼上辺部を重複させて配置し、さらに下方かつ半径方向に延びる板状の下段翼で構成された撹拌装置の記載がある。
【０００５】
また、先行技術１には、ポリスチレンペレット中間体を経由せずに、減容剤を含み膨潤した減容物から常温・常圧条件下で直接減容剤と発泡剤の溶剤置換を行い、再生発泡性ポリスチレン系樹脂粒子を製造する方法が記載されている。この製造方法によると、減容物をプランジャー型押し出し機やスクリュー式押し出し機等で紐状に押し出し、これをポリエチレンやフッ素樹脂等の不粘着性の板あるいは棒状の基材に巻いて保持し発泡剤に浸漬後、硬化させてからストランドカッター等の切断機で切断し、再生発泡性ポリスチレン系樹脂粒子を製造するとの記載がある。
【０００６】
他方、溶剤を含まない溶融樹脂の粒状化技術は、特開平７−１８６２３６号公報（以下、先行技術２という。）に、押出口から吐出された混練物を切断する回転切断刃と切断された溶融ペレットを前記回転切断刃の回転領域外に同伴させる水を噴出する水噴出孔と固化したペレットを前記水と共に排出する排出口とを備えてなるカッター装置との記載がある。
【０００７】
特開平６−８７９７３号公報（以下、先行技術３という。）には、発泡スチレン系樹脂成形品の収縮物を無延伸熱溶融して得られるスチレン系樹脂粒子に有機分散剤を含む水性媒体を分散し、１００℃以上１４０℃以下の温度で易揮発性炭化水素を含浸させて再生発泡性スチレン系樹脂を製造している記載がある。
【０００８】
特開平５−９８０６２号（以下、先行技術４という。）には、粉砕された発泡スチレン系樹脂成形体を押出機中で加熱溶融して押出し、切断してスチレン系樹脂粒子とし、このスチレン系粒子を純水中に分散させ、ベンゾイルパ−オキサイドを融解したスチレン単量体溶液を添加することにより、スチレン系樹脂粒子に吸収重合させた後、更に発泡剤であるブタンを含浸させて発泡性スチレン系樹脂粒子を得るとの記載がある。
【０００９】
特開平９−２０８７３４号公報（以下、先行技術５という。）には、懸濁重合によって得られる発泡性スチレン系樹脂粒子であって、平均粒子径が０．４ｍｍ以下、又は、１．３ｍｍ以上の規格外品を、スチレン系樹脂、発泡剤と共に押出し機に投入し、加圧加熱液中に押出し即時切断して再生発泡性粒子を得るとの記載がある。
【００１０】
先行技術１には、廃棄物である発泡ポリスチレン系樹脂成形体を、発泡ポリスチレン系樹脂成形体に対して溶解性を有し、かつ発泡剤とは相互溶解性がある減容剤に溶解させて減容物を作り、減容物と減溶剤を抽出するための抽出溶剤とを分散・混錬して、減容剤を抽出して固形物を作り、固形物を粒単位である樹脂粒子に成形して、常温で樹脂粒子であるポリスチレン系樹脂を発泡させるための発泡剤に浸漬させると同時に、減容物を更に抽出して発泡ポリスチレン系樹脂を再生するとの記載がある。
【００１１】
【発明が解決しようとする課題】
この減容物からの減容剤抽出操作では、高濃度高分子溶液とこれと相溶しない発泡剤の混合撹拌を行う。高濃度の高分子溶液である減容物は、高粘度物質であり、これに含まれる減容剤を抽出するための発泡剤は、低粘度の有機溶剤である。また減容物すなわち高分子相からの減容剤の抽出が進行し、その含有量が低下するにつれて高分子相の粘度はさらに増加するという性質がある。
【００１２】
このように粘度が異なる複数種の物質で、しかも相溶しないものの混合撹拌において、アンカー翼やリボン翼の低速回転型撹拌機を用いた場合、高粘度液部分は混合するが低粘度液部分に対して混合性能が低く、混合攪拌槽の全体に循環流が形成されず均一に混合撹拌できない欠点がある。一方、傾斜パドル翼やタービン翼などの中速回転型撹拌機を用いた場合は、撹拌翼の近傍のみが撹拌され全体の循環流が形成されず均一に混合撹拌できない欠点がある。
そこで、形状、攪拌機能が異なる翼を組合せた特定の撹拌翼で、撹拌槽全体の混合特性を改良した撹拌装置を用い、撹拌槽全体に循環流を形成する十分な回転数で撹拌すると、粘度が異なる物質の混合でも撹拌槽全体の均一混合が可能である。ところが、減容物からの減容剤抽出操作では、撹拌槽全体を均一混合すると、高粘性物質である減容物は、急激に増粘し、撹拌翼により引きちぎられ、はじめ塊状であった高分子相が不定形に細分化され、発泡剤相中を流動した状態となる。さらに抽出が進行すると断片状になった減容物は、撹拌翼や撹拌槽へ付着し、撹拌槽からの著しく排出が困難になるという問題点がある。
【００１３】
先行技術１で提案されたものは、紐状の減容物をストランドカッター等の切断機で切断できるほどの硬さになるまで時間を要する等の問題があり生産性が低いものである。また、先行技術２で提案されたものは、水噴射口から水を噴射しても減容物の粘着性を落とすことはできないため切断できないものである。減容物を一旦は切断できるが、切断された粒子は非常に粘着性を有しているため、高速カッターによる遠心力だけでは個々の粒子に分離して飛散させることができず、瞬時に粒子同士が再付着し団子状の塊になるので目的とする粒子を得ることが出来ない。
【００１４】
先行技術３と先行技術５での提案は、揮発性炭化水素を含浸させるとき、オ−トクレ−ブ等の反応圧力容器内で行う必要がある。廃棄物が発生する現場でのこれらの機器の利用は困難であり、かつ生産性も低い。先行技術４での提案も、分散剤の使用量が多いため、この廃水処理にコストがかかり実用性に問題がある。しかも、加熱による熱収縮のためのエネルギ−損失、又熱収縮のため押出機等により加熱溶融押出してポリスチレン系樹脂を減容する方法は熱履歴により樹脂を劣化させてしまう問題がある。
【００１５】
先行技術１に記載されたものは、実験室レベルの製造方法を提案したものであるので、再生発泡性ポリスチレン系樹脂粒子を、工業レベルで大量にかつ経済的に生産できる製造方法に展開する必要がある。本発明は、以上のような技術背景のもので発明されたものであり、以下の目的を達成するものである。
本発明の目的は、常温・常圧条件下で溶剤置換法による再生発泡性ポリスチレン系樹脂粒子を製造するものにおいて、発泡剤及び減容剤も再利用できる、再生発泡性ポリスチレン系樹脂粒子の再生処理システム及びその処理法を提供することである。
本発明の他の目的は、予備含浸工程により、減容物を発泡剤と効率的に撹拌または混練して、減容物中の減容剤を抽出して減容剤含有量を減らして、後工程である造粒化を容易にした、再生発泡性ポリスチレン系樹脂粒子の再生処理システム及びその処理法を提供することである。
本発明の更に他の目的は、常温・常圧条件下で溶剤置換法による再生発泡性ポリスチレン系樹脂粒子を製造するものにおいて、減容物において造粒後の粒状物を相互付着させることなく粒状化できる、再生発泡性ポリスチレン系樹脂粒子の再生処理システム及びその処理法を提供するものである。
【００１６】
また、本発明の利点は、工業レベルで、使用済み発泡ポリスチレン系樹脂成形体を減容剤で減容した減容物から、常温・常圧条件下で減容剤の抽出及び発泡剤の含浸を同時に行うので、再生発泡性ポリスチレン系樹脂粒子が熱履歴を受けることもなく、しかも回収された発泡剤及び減容剤も再利用できる。
【００１７】
【課題を解決するための手段】
本願発明者は、前記課題を鋭意研究した結果、以下の発明を完成するに至った。すなわち、本発明の再生発泡性ポリスチレン系樹脂粒子の再生処理法は、発泡ポリスチレン系樹脂を再生するために減容剤に溶解させて減容物を作る減容工程と、前記減容物に発泡剤を含浸させる発泡剤含浸工程からなる、発泡性ポリスチレン系樹脂粒子の再生処理法において、
前記発泡剤含浸工程は、
前記減容物中の前記減容剤を抽出すると同時に、前記発泡剤を含浸させるための予備含浸工程と、
前記予備含浸工程を経た後に前記減容物を粒状物にする粒状物造粒工程と、
前記粒状物造粒工程を経た後に前記粒状物中の前記減容剤を抽出すると同時に、前記発泡剤を含浸させるための本含浸工程とからなり、
前記本含浸工程の後に、
前記粒状物と前記粒状物の表面に付着している過剰発泡剤を蒸発させて除去する乾燥工程を含むことを特徴とする。
【００１８】
本発明の再生発泡性ポリスチレン系樹脂粒子の再生処理システムは、
発泡ポリスチレン系樹脂を再生するために減容剤に溶解させた減容物に発泡剤を含浸させる発泡剤含浸を行うことができる、発泡性ポリスチレン系樹脂粒子の再生処理システムにおいて、
前記減容物中の前記減容剤を抽出すると同時に、前記発泡剤を含浸させる予備含浸工程のための予備含浸槽と、
前記予備含浸工程を経た後に、前記減容物を粒状物にする粒状物工程のための粒状化手段と、
前記粒状物造粒工程を経た後に前記粒状物中の前記減容剤を抽出すると同時に、前記発泡剤を含浸させるための本含浸槽とからなり、
前記本含浸工程の後に、
前記粒状物と前記粒状物の表面に付着している過剰発泡剤を蒸発させて除去する乾燥手段を含むことを特徴とする。
【００１９】
本発明の前記予備含浸工程は、異種翼の組合せによる特定の撹拌翼を低速回転させ、減容物と発泡剤を２層に分離したまま撹拌し、減容物中の減容剤抽出を行い、底部に開閉弁を有する予備含浸槽を用いることで、減容剤含有量を減らした減容物を予備含浸槽底部から容易に取り出す新規な減容剤抽出方法を実現したものである。
本発明の前記予備含浸工程後の減容物の粒状化は、ダイス表面に円周上に等間隔に配置された押し出し穴から減容物、予備的に減容物表面の減容剤を発泡剤で洗浄・抽出し粘着性を落とした減容物を押し出し、カッター刃面及びダイス表面に発泡剤を噴射させながら、高速回転するカッター刃で切断し、切断後の粒子同士が再付着せず独立した粒子を得る方法である。
【００２０】
本発明再生発泡性ポリスチレン系樹脂粒子の再生処理システムは、予備含浸槽と粒状化手段及び本含浸槽を主な構成とし、常温・常圧のもとで、再生発泡性ポリスチレン系樹脂粒子の製造と同時に溶剤の回収も行う。本発明にいう特定の撹拌翼とは、下段にパドル翼を有する撹拌翼であり、上段翼の形状は特にこだわらず一般的な傾斜パドル翼、スクリュー翼、パドル翼、タービン翼、プロペラ翼、及びこれらを組み合わせた攪拌翼で構成される多段翼をいう。好ましくは、前記攪拌翼は、下部に矩形板材である垂直パドル翼が配置され、上部に楕円板材を長軸、短軸で４分割した形であり、この分割した楕円板材を含む面と、攪拌翼の駆動軸線とを傾斜させた状態で固定したものであるものが良い。
【００２１】
本発明で使用する貧溶媒としては、ポリスチレン樹脂の溶解度が小さい有機溶剤であり、ペンタン、ヘキサンなどの易揮発性炭化水素やアルコール類、多価アルコール類を用いることができる。本発明で使用する減容物は、使用済み発泡ポリスチレン及び/又は発泡ポリスチレンを減容剤で収縮・脱泡させたものであり、減容剤を５０〜７０重量％程度含むものである。
【００２２】
本発明で使用する減容剤は、ポリスチレン系樹脂と溶解性を有し、発泡剤とは相互溶解性がある極性溶剤であり、ハンセン溶解度パラメ−タ−の水素結合項δｈ、極性項δｐがその単位を（Ｊ/ｃｍ³）^1/2として、
【００２３】
［数１］
（δｐ−５．８）²＋（δｈ−４．３）²＜５０
かつ
δｐ²＋δｈ²＞４６
の条件を満足する溶媒を少なくとも１つ以上含むものである。例えば、コハク酸ジメチル、アジピン酸ジメチル、グルタル酸ジメチル等の二塩基酸メチルエステル組成物が挙げられる。
【００２４】
本発明で使用する発泡剤とは、発泡性ポリスチレン系樹脂粒子の発泡剤として通常使用されている易揮発性低級炭化水素化合物の内、常温・常圧において液体であるペンタン、ヘキサン、若しくはこれらの異性体を１種で単独、又は２種以上を混合したものである。本発明で製造される再生発泡性ポリスチレン系樹脂粒子は、ポリスチレン系樹脂に対して減容剤及び発泡剤濃度が５〜２５重量％であり、好ましくは、８〜１３重量％である。
【００２５】
本発明にいう予備含浸とは、減容物から減容剤を抽出し発泡剤を同時に含浸するために攪拌混合するものである。高粘度搬送ポンプは、この予備含浸のための予備含浸槽で得られた減容物を搬送昇圧するポンプであり、例えばギアポンプ、プランジャ−ポンプ等が挙げられる。本発明の粒状化装置は、予備含浸槽で得られた減容物を、最大長さが１００μｍ〜２ｍｍに粒状化する手段をいう。
【００２６】
本発明の本含浸は、粒状化手段で得られた粒状物に残存している減容剤をさらに抽出して、発泡剤を含浸させることをいう。この本含浸槽は、粒状物を投入し本含浸のために減容剤及び発泡剤の濃度を５〜２５重量％程度にする攪拌槽である。本発明の乾燥機は、本含浸槽中の粒状物を分離回収し、主として粒状物表面に付着する過剰な発泡剤を除去する手段である。本発明の回分式小型蒸留装置とは、予備含浸槽及び本含浸槽内の減容剤と発泡剤を分離回収する回分式の小型蒸留装置をいう。
【００２７】
本発明の予備含浸のための減容剤抽出方法は、減容物と発泡剤を２層に分離したまま撹拌し、塊状の高分子相の表面更新と発泡剤相の均一混合の作用により、高分子相の減容剤を発泡剤相に抽出し、減容剤含有量を減らした減容物を予備含浸槽の底部から容易に排出することを特徴とする。特に、下段にパドル翼を有する撹拌翼を翼の先端周速５０〜２００ｃｍ／ｓで回転させ、減容物と発泡剤の撹拌を行うことで、減容剤含有量が減容物に対し２５〜４０重量％となる減容物を塊状で得ることができる。底部にゲート弁を有する予備含浸槽を用いることで、減容剤含有量を減らした減容物を特別な分離工程を経ずに底部から容易に排出することができる。
【００２８】
本発明の再生発泡性ポリスチレン系樹脂粒子の再生処理システムは、減容物の抽出を予備含浸槽と本含浸槽の２段階から構成され、再生発泡性ポリスチレン系樹脂粒子の残減容剤量を少なくする。本発明の再生発泡性ポリスチレン系樹脂粒子の再生処理システムは、予備含浸槽における減容物からの減容剤抽出と減容物への発泡剤の含浸を同時に効率的に行える板状の攪拌翼を有する。
【００２９】
本発明の粒状化手段は、減容物を紐状に押し出すダイス、それを切断する高速カッター刃、カッター刃面及びダイス表面に発泡剤を噴射する噴射ノズルからなり、減容物を１００μｍ〜２ｍｍに切断し、再付着することなく回転カッター刃の回転領域外に導伴させるものである。本発明の粒状化手段は、高粘度の減容物を、常温の条件下で、直径１００μｍ〜２ｍｍ程度の粒状物とするものである。
【００３０】
本発明の発泡剤の処理法は、予備含浸槽及び本含浸槽内の発泡剤が常温・常圧のもとで液体であることにより減容物に含有される減容剤の抽出と発泡剤の含浸を効率的に行えることを特徴とする。本発明の予備含浸槽の処理法は、高粘度の減容物と低粘度液体発泡剤の２種類の非常に粘度差及び物質の状態の異なるものを、高粘度減容物の固まりが、細分・断片化しないように、効率良く混合攪拌させ減容物から減溶剤を抽出すると同時に発泡剤を含浸することを特徴とする。
【００３１】
本発明の本含浸槽の処理法は、粒状化手段で粒状化された粒状物内の減容剤が、発泡剤相に抽出され粒状物が硬化する迄の間、相互に凝着しやすい粒状物の分散を維持することを特徴とする。本発明は、本含浸の終了後に乾燥機に取出された粒状物の表面には、過剰な発泡剤が含浸されているので、粒状物表面に付着している発泡剤を、乾燥により除去して、市販されているバ−ジンの発泡性ポリスチレン系樹脂粒子と同等の発泡剤の含浸範囲にすることを特徴とする。
【００３２】
【発明の実施の形態】
発泡ポリスチレンを減容剤で収縮脱泡処理した減容物は、通常、５０〜７０重量％の減容剤を含有している。この減容物の凝着性を低下させ粒状物への成形を容易にするためには、減容物に対し２５〜４０重量％程度まで減容剤の含有量を低下させることが好ましい。このための工程として減容物を発泡剤と撹拌または混練して減容物中の減容剤を抽出しその含有量を減らす操作を行う。
【００３３】
本発明の実施形態として、好ましい減容剤含有量の減容物を得るための発泡剤の量は減容物の１．５〜４倍である。混合特性の優れた撹拌装置を用い、予備含浸槽全体に循環流が形成する十分な回転数で撹拌すると、高粘性物質である減溶剤を含浸した減容物は、急激に増粘し、撹拌翼により引きちぎられ、はじめ塊状であったものが不定形に細分化され、発泡剤中を流動した状態となる。さらに抽出が進行すると断片状になった溶剤減容物は、撹拌翼や槽内へ付着し、予備含浸槽からの排出が困難になる。この問題を解決するため、減容物と発泡剤を２層に分離したまま撹拌し、減容物中の減容剤抽出を行うことが好ましい。
【００３４】
この撹拌方法として、形状、機能が異なる複数種の翼の組合せによる特定の撹拌翼を低速回転させて使用すると有効である、ことが実験の結果明らかになった。具体的には、下段にパドル翼を有する撹拌翼を翼の先端周速５０〜２００ｃｍ／ｓで回転させ、減容物と発泡剤の撹拌を行うことで、減容剤含有量が減容物に対し２５〜４０重量％となる減容物を塊状で得ることができる。さらに底部にゲート弁を有する予備含浸槽を用いることで減容剤含有量を減らした減容物を底部から容易に排出することができる。
【００３５】
以下、この発明の実施の形態について図面に基づき詳細に説明する。図１は、本発明の再生発泡性ポリスチレン系樹脂粒子の再生処理システムの一実施の形態であり、システムの概要を示す概略構成図である。この再生発泡性ポリスチレン系樹脂粒子の再生処理システム１０は、予備含浸工程、粒状化工程、本含浸工程、及び乾燥工程の４工程から構成されている。この４工程の回分処理操作により、再生発泡性ポリスチレン系樹脂粒子が製造され、回収発泡剤は、蒸留分離工程により発泡剤と減容剤に分離回収される。
【００３６】
この再生発泡ポリスチレン系樹脂粒子の再生処理システム１０で使用する減容物は、使用済み発泡ポリスチレン及び／又は、発泡ポリスチレンを、主成分が二塩基酸メチルエステル組成物の減容剤で溶解したもので、減容剤含有量が５０〜７０重量％を含む塊状のものである。
予備含浸工程は、前述した減容物から、減容剤の抽出及び発泡剤の含浸を同時に行い、減容剤を抽出された高粘度の塊状固まりを、搬送・昇圧できるようにするための工程である。また、予備含浸工程は、後述するように粒状化を容易にするための前処理工程でもある。予備含浸工程のための機器は、予備含浸槽２１、攪拌機２２、高粘度搬送ポンプ２３等より構成される。予備含浸槽２１には、減容物及び減容物に含有される減容剤の５〜８倍重量の発泡剤を投入され、攪拌機22で攪拌される。
【００３７】
このときの減容剤の液温を８〜２０℃とし、攪拌機22の攪拌翼の外周である先端周速を５０〜２００ｃｍ/ｓとし、含浸時間を１０〜１８０分の条件で、減容剤の抽出及び発泡剤の含浸を同時に行い、減容物中の減容剤濃度を、２５〜４０重量％に制御する。減容剤を抽出した発泡剤の液比重を０．６６〜０．６９の範囲に調整することで、減容物の粘度を高粘度搬送ポンプ２３で搬送可能な粘度、及び粒状化装置３１で粒状化が容易に出来るようにする。なお、減容物の減容剤、及び発泡剤の選択は、ＷＯ０１／６８７５９Ａ１（先行技術１）に記載された通りの方法であり、かつ本発明の要旨でもないのでその詳細な原理の説明は省略する。
【００３８】
予備含浸工程、及び本含浸工程で回収された発泡剤は、発泡剤回収ポンプ６１で回分式小型蒸留装置６２に送られ、蒸留分離されて減容剤は下部のボトムから回収され、発泡剤は凝縮器６３で凝縮液化されて、発泡剤回収タンク６５に回収される。回収された発泡剤は、予備含浸工程の発泡剤として再利用できる。
【００３９】
この予備含浸槽２１で調整すべき減容物の粘度は、後工程の粒状化工程で長さ１００μｍ〜２ｍｍ程度の粒状にカット出来る粘度であり、粘度が高すぎると、薄い円板状にしかならないし、粘度が低すぎると、紐状の塊しか出来なくなってしまう。粒状化工程は予備的に発泡剤に含浸させて、減容剤量を２５〜４０重量％に落とした減容物、又は前処理を行わない減容物から粒子を製造する工程である。
【００４０】
以下、本発明の粒状化するための方法、又は装置は、図面を参照して説明する。ただし、この実施の形態に記載されている構成部品の寸法、形状、その相対的位置等は特に特定的な記載がない限りは、この発明の範囲をそれに限定する趣旨ではなく、単なる説明例にすぎない。以下、図面に基づいて本発明の実施の形態を説明する。
図３は、粒状化装置３１の詳細を示す断面図である。粒状化装置３１は、カッターボックス３３内に、ダイス穴が円周上に配置されたダイス３８、高速回転するカッター取付台３９に取り付けられた回転駆動されるカッター刃３６、及びこのカッター刃３６に貧溶媒を噴射するために、カッターシャフト３４の軸中心部に貫通孔として設けられた貧溶媒流路３５、及びこれに連通して貧溶媒を噴射する貧溶媒噴射口３７等により構成されている。
【００４１】
この粒状化装置３１は、減容物をストランドにするため、また、ダイス３８が円周状に配置されたダイス３８のダイス穴からストランド状に排出された減容物を粒状化するために配置されたものである。このために、貧溶媒噴射口３７はダイス３８と接触しない最も近い位置で、円周方向に高速回転する返りのないカッタ−刃３６、及びカッタ−刃３６に付着する粒状化物を吹き飛ばす目的で設置したものである。貧溶媒噴射口３７には、ペンタン噴射装置３２によりペンタンが加圧されて供給される。高粘度搬送ポンプ２３により昇圧された減容物は、複数個のダイス穴からストランド状に排出され、ダイス３８とカッタ−刃３６が接触しない最も近い位置で、円周方向に１４００〜３２００ｒｐｍで回転するカッタ−刃３６により、粒径１００μｍ〜２ｍｍの粒状物に切断され造粒される。
【００４２】
本含浸工程は、粒状化装置で得られた粒状物に残存している減容剤をさらに抽出する工程であり、減容剤及び発泡剤量を５〜２５重量％程度にする工程で、本含浸槽４1と循環ポンプ４３により構成される。本含浸槽４１に投入された粒状物は、粒子同士がお互いに付着しないようにするために、電動機で回転駆動される攪拌機４２により攪拌回転数を８０〜１５０ｒｐｍで常時流動するように攪拌させる。本含浸槽４１の下部に沈降した粒状物は、循環ポンプ４３で外部循環させることにより、本含浸槽４１の下部に沈降した粒状物のブロッキングにより付着した粒状物の堆積を防止している。本含浸工程である本含浸槽４１での含浸時間は、予備含浸工程で抽出された減容剤の濃度にもよるが、２〜４８時間程度が好ましい。
【００４３】
乾燥工程は、本含浸槽４１で得られた樹脂粒子の表面に付着する過剰な発泡剤を除去する工程をいう。本含浸工程終了後、循環ポンプ４３により樹脂粒子を含む本含浸槽４１内の液を乾燥機５１に送り、乾燥機５１の内部に設置されている４０メッシュ金網により発泡剤と樹脂粒子に分離し、樹脂粒子は金網上に回収され、発泡剤は本含浸槽４１内に回収される。乾燥機５１の内に回収された樹脂粒子は、スポットク−ラ−５２により温度０〜２０℃の冷風で表面に付着している過剰発泡剤を蒸発させて除去し、樹脂粒子の発泡剤含浸量を８〜１３重量％に制御する。
【００４４】
【実施例】
以下に、本発明を実施例及び比較例に基づいて説明する。
〔実施例１〕
小型撹拌装置を用いて減容物とペンタンの撹拌混合を行った。小型撹拌装置としては綜研化学株式会社製Ｈｉ−Ｆミキサーを使用した。撹拌槽は容積３Ｌのガラス製であり、撹拌槽内壁と撹拌翼の間に３枚の邪魔板を有する。攪拌翼は、下部に矩形板材である垂直パドル翼が配置され、上部に楕円板材を長軸、短軸で４分割した形である傾斜四半楕円翼で構成されたものである。各傾斜四半楕円翼は、回転軸の軸線に対してその面が傾斜して配置されたものである。
まず、発泡スチロールを二塩基酸メチルエステル組成物（スタイロジャパン社製スタイロソルブＳＳ６０００）を、減容剤として収縮・脱泡した減容物を調製した。この組成は樹脂１００部に対し減容剤１６３部であった。この減容物を３．０倍量のペンタンと混合撹拌した。撹拌翼の先端周速は、０．８ｍ／ｓとし、液温２５〜２６℃で６０分間撹拌した。混合撹拌操作後の減容物の組成は、樹脂１００部に対し減容剤４０部、ペンタン１７部となった。得られた減容物は塊状であり撹拌槽及び撹拌翼への付着性は小さく、容易に回収できた。また、１．８倍量のペンタンで同様に処理すると、減容剤７５部、ペンタン１７部の組成の減容物が得られた。
【００４５】
〔実施例２〕
図２は、予備含浸槽２１の構造の概略を示す図である。この予備含浸槽２１を用いて発泡スチロール溶剤減容物とペンタンの撹拌混合を行った。減容物の組成は樹脂１００部に対し減容剤１６５部であった。この減容物を３．１倍量のペンタンと混合撹拌した。撹拌翼の先端周速は１０５ｃｍ／ｓとし、液温９〜１１℃で９０分間撹拌した。混合撹拌操作後の減容物の組成は、樹脂１００部に対し減容剤７５部、ペンタン２２部となった。予備含浸槽２１の底部のゲート弁２７を開くと減容物は塊状でサクションホッパー２８に自然落下し、高粘度搬送ポンプ２３での搬送が良好に行われた。予備含浸槽２１の内壁や撹拌翼への減容物の付着はほとんどなかった。
【００４６】
〔比較例１〕
実施例２と同じ装置を用いて減容物とペンタンの撹拌混合を行った。撹拌翼の周速を調整した以外は、実施例２と同様に処理した。先端周速５８ｃｍ／ｓの設定で撹拌を開始し、１５分経過後から周速を徐々に上げた。先端周速１１５ｃｍ／ｓを超えたところで減容物の細片の流動が見られるようになり、先端周速２３０ｃｍ／ｓでは不定形の減容物が激しく流動する状態となった。６０分間撹拌後に抽出液を排出し、ペンタンに更新してさらに６０分間先端周速２３０ｃｍ／ｓで撹拌を続けた。混合撹拌操作後の減容物の組成は、樹脂１００部に対し減容剤４１部、ペンタン１７部となった。底部のゲート弁２７を開き、減容物をサクションホッパー２８を介して、高粘度搬送ポンプ２３での搬送を試みたが搬送不良となった。予備含浸槽２１内では撹拌翼に減容物が著しく付着していた。
【００４７】
〔実施例３〕
使用済みの発泡ポリスチレンを減容剤（二塩基酸メチルエステル化合物、（株）スタイロジャパン製スタイロソルブ６０００）に浸漬し、減容剤の濃度６０％の減容物を得た。この減容物をあらかじめペンタンに２時間攪拌しながら浸漬し、予備的に表面の減容剤を抽出した減容物をポンプで圧送し、ダイス（穴径：１ｍｍ、穴数：１２個）から押し出した。その時のダイスからの吐出量は１２．３ｋｇ／ｈ、吐出圧力は４０ｋｇｆ／ｃｍ²であった。これを鋭利なカッター刃３６を１枚のみ取り付けた粒状化装置３１に送り、カッター刃３６の回転数１８００ｒｐｍ、カッター刃３６の刃面及びダイス表面へのペンタン噴射量１０Ｌ／ｍｉｎで粒状化を行った。粒状化装置下部からステンレス製の受け器で切断されたビーズを受けたところ、短軸径１ｍｍ、長軸径２ｍｍ程度の楕円形の独立した粒子が得られた。
【００４８】
〔実施例４〕
減容物を高粘土搬送ポンプ２３で圧送し、ダイス（穴径：１ｍｍ、穴数：１２個）から押し出した。その時のダイスからの吐出量は１４．１ｋｇ／ｈ、吐出圧力は１４ｋｇｆ／ｃｍ²であった。これを鋭利なカッター刃３６に１枚の刃のみを取り付けた粒状化装置３１に送り、カッター刃３６の回転数２０００ｒｐｍ、カッター刃３６の刃面及びダイス表面へのペンタン噴射量１０Ｌ／ｈで粒状化を行った。粒状化装置下部からステンレス製の受け器で切断されたビーズを受けたところ、短軸径１ｍｍ、長軸径２ｍｍ程度の楕円形の独立した粒子が得られた。予備的に減容物表面の減容剤抽出処理を行わなくても独立した粒子を得ることができた。
【００４９】
〔比較例２〕
カッター刃３６の刃面、及びダイス表面に発泡剤を噴射しない以外は、実施例３と同様の条件下で粒状化を行った。その時のダイス３８からの吐出量は１１．８ｋｇ／ｈ、吐出圧力は４０ｋｇｆ／ｃｍ²であった。粒状化装置下部からステンレス製の受け器で切断されたビーズを受けたところ、直径２ｍｍ、長さ１０ｃｍ程度の紐状物質が得られた。紐状物質の表面は数珠状となっており、一旦カッター刃３６で切断された粒子が再付着して紐状になっていた。
【００５０】
〔比較例３〕
カッター刃３６の刃面、及びダイス３８表面に発泡剤を噴射しない以外は、実施例４と同様の条件下で粒状化を行った。その時のダイスからの吐出量は３．３ｋｇ／ｈ、吐出圧力は４０ｋｇｆ／ｃｍ²であった。粒状化装置３１の下部からステンレス製の受け器で切断されたビーズを受けたところ、直径２ｍｍ、長さ１５ｃｍ程度の紐状物質が得られた。紐状物質の表面は、ねじれており、減容物が切断されずに引き伸ばされていた。
【００５１】
［実施例５］
使用済み発泡ポリスチレン１６ｋｇを減容剤で溶解して減容剤濃度６０％の減容物４０ｋｇを得た。予備含浸槽に投入後、温度１０℃のペンタン３００Ｌを添加して、板状翼を有する攪拌翼先端周速９２ｃｍ/ｓで３時間程度攪拌して減容剤を抽出し、発泡剤を含浸した。この時の、発泡剤の液密度は、０．６５３ｇ／ｃｍ³、減容物中の減容剤は、３２．１重量％であり、発泡剤は１１．８重量％であった。これを、ポンプで搬送し、直径１ｍｍで１２個のダイス穴に押し込んで、ペンタンをカッタ−刃の裏側から噴射し、カッタ−速度１８００ｒｐｍの条件で、センタ−カット方式により、粒状物に切断した。この時の粒状物のサイズは、１〜２ｍｍであり、良好であった。
高粘度搬送ポンプの搬送・昇圧能力は、押出し量が、９．３６ｋｇ／ｈ、ポンプ吐出圧力は、４．０ＭＰａＧであった。使用済み発泡ポリスチレンの溶解条件を表１に示す。予備含浸工程、及び粒状化装置３１でのテスト条件を表２に示す。表３に、予備含浸工程、及び粒状化装置３１でのテスト結果を示す。
【００５２】
この円板状の樹脂粒子を、発泡剤ペンタン８００Ｌの本含浸槽内に投入し、液温を１０〜１５℃とし、攪拌機回転数を８０ｒｐｍとし、槽内の液をポンプで外部循環させながら４１時間程度含浸させた。本含浸終了後、乾燥機に粒子を取出して、スポットク−ラ−を１５℃とし、粒状物表面に付着するペンタンを除去し、発泡ビ−ズ２．２ｋｇを得た。粒径は、１〜２ｍｍの製品が１．１ｋｇ回収され、１ｍｍ以下の微粉末のものが、１ｋｇ回収された。再生発泡性ポリスチレン系樹脂粒子中の減容剤及び発泡剤濃度は、１３．１重量％であり、良好であった。本含浸工程処理条件、及び乾燥機運転条件を表２に示す。テスト結果を表３に示す。
【００５３】
［実施例６］
使用済み発泡ポリスチレン２４ｋｇを減容剤で溶解して減容剤濃度６０％の減容物６０ｋｇを得た。予備含浸槽に投入後、温度１０℃のペンタン３００Ｌを添加して、板状翼を有する攪拌翼先端周速１０５ｃｍ/ｓで２時間程度攪拌して減溶剤を抽出し、発泡剤を含浸した。この時の、発泡剤の液密度は、０．６５３ｇ／ｃｍ³であり、減容物中の減容剤は、３８．８重量％であり、発泡剤は１２．７重量％であった。
これを、高粘度搬送ポンプで搬送・昇圧し、直径１ｍｍで１２個のダイス穴に押し込んで、ペンタンをカッタ−刃３６の裏側から噴射し、カッタ−速度２０００ｒｐｍの条件で、センタ−カット方式により粒状物に切断した。この時の粒状物のサイズは、１〜２ｍｍであり、良好であった。高粘度搬送ポンプの搬送・昇圧能力は、押出し量が、１４．１ｋｇ／ｈ、ポンプ吐出圧力は、２．０ＭＰａＧであった。使用済み発泡ポリスチレンの溶解条件を表１に示す。予備含浸及び粒状化措置でのテスト条件を表２に示す。表３に、予備含浸及び粒状化措置でのテスト結果を示す。
【００５４】
この円板状の粒状物を、発泡剤ペンタン９５０Ｌの本含浸槽内に投入し、液温を１０〜１５℃とし、攪拌機回転数を８０ｒｐｍとし、槽内の液をポンプで外部循環させながら２４時間程度含浸させた。本含浸終了後、乾燥機に粒子を取出して、スポットク−ラ−を１５℃とし、粒状物表面に付着するペンタンを除去し、発泡ビ−ズ１．８ｋｇを得た。粒径は、１〜２ｍｍの製品が１．５ｋｇ回収され、１ｍｍ以下の微粉末のものが、０．３ｋｇ回収された。再生発泡性ポリスチレン系樹脂粒子中の減容剤及び発泡剤濃度は、１４．７重量％あり、良好であった。本含浸工程処理条件、及び乾燥機運転条件を表２に示す。テスト結果を表3に示す。
【００５５】
【表１】

【００５６】
【表２】

【００５７】
【表３】

【００５８】
［比較例４］
予備含浸工程を実施しない以外は、実施例１と同様に粒状化テストを実施した。使用済み発泡ポリスチレンの溶解条件を表４に示す。テスト条件を表５に、粒状化のテスト結果を表６に示す。この時の粒状物は、粒子サイズ５〜６ｍｍ程度のゴムくずであり、実施例1に比較すると、かなり劣るものであった。従って、本含浸及び乾燥運転は実施することが、出来なかった。
【００５９】
［比較例５］
粒状化装置３１でカッタ−刃３６の返りの有る刃２枚及びペンタン噴射の代りに、水を用いて噴射した以外は、実施例１と同様に粒状化テストを実施した。使用済み発泡ポリスチレンの溶解条件を表4に示す。テスト条件を表5に、粒状化のテスト結果表6に示す。この時の粒状物は、粒子サイズ５〜１５ｍｍ程度の紐、紐のダンゴ状の塊に近い物となり、実施例1に比較すると、かなり劣るものであった。従って、本含浸工程、及び乾燥運転は実施することが、出来なかった。
【００６０】
【表４】

【００６１】
【表５】

【００６２】
【発明の効果】
以上説明したように、本発明の再生発泡性ポリスチレン系樹脂粒子の再生処理システム及びその処理法によれば、常温・常圧のもとで、発泡剤を添加して、減容物中の減容剤の抽出と発泡剤の含浸を同時に行うことで、予備含浸された減容物の粒状化が可能となり、更にこの粒状物を発泡剤液中に含浸させ、減容剤を抽出した樹脂粒子を、乾燥させることで、熱履歴を受けない再生発泡性ポリスチレン系樹脂粒子を得ることができる。
また、減容物の減容剤の抽出を予備含浸と本含浸の２段階に分けたことで、粒状化装置で適切な粒子サイズにできる粘度に調整でき、粒状化工程での粒状化条件を最適化できる。予備含浸工程で板状の攪拌翼を用いたので、減容物中の減容剤の抽出と発泡剤の含浸を効率良く行うことができる。
【図面の簡単な説明】
【図１】図１は、本発明の再生発泡性ポリスチレン系樹脂粒子の再生処理システムの実施の形態であり、その概要を示す系統図である。
【図２】図２は、図１に示す本発明の再生発泡性ポリスチレン系樹脂粒子の再生処理システムの予備含浸槽の詳細を示す説明図である。
【図３】図３は、図１に示す本発明の再生発泡性ポリスチレン系樹脂粒子の再生処理システムの粒状化装置を示す断面図である。
【図４】図４は、図３のＡ−Ａ線に沿った矢視方向の断面図である。
【符号の説明】
１０…再生発泡性ポリスチレン系樹脂粒子の再生処理システム
２１…予備含浸槽
２２…予備含浸用攪拌機
２３…高粘度搬送ポンプ
２４…傾斜平板翼
２５…平板翼
２６…邪魔板
２７…ゲート弁
２８…サクションホッパー
３１…粒状化装置
３２…発泡剤噴射装置
３３…カッターボックス
３４…カッターシャフト
３５…貧溶媒流路
３６…カッター刃
３７…貧溶媒噴射口
３８…ダイス
３９…カッター取付台
４１…本含浸槽
４２…本含浸用攪拌機
４３…循環ポンプ
５１…乾燥機
５２…スポットク−ラ−
６１…発泡剤回収ポンプ
６２…回分式小型蒸留搭
６３…凝縮器
６４…回収発泡剤移送ポンプ
６５…発泡剤回収タンク
６６…発泡剤移送ポンプ
６７…回収減容剤移送ポンプ
６８…冷却器
６９…減容剤回収ドラム缶[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a regeneration processing system for recycled expandable polystyrene resin particles and a processing method thereof. In particular, by performing volumetric agent extraction and foaming agent impregnation in a single process on volume-reduced products of used expanded polystyrene, it is possible to efficiently separate and recover the solvent and produce recycled expanded polystyrene resin particles. The present invention relates to a recycled processing system for recycled expandable polystyrene resin particles and a processing method thereof. Moreover, it is related with the granulation technique of the volume-reduction thing in the process of manufacturing the reproduction | regeneration foaming polystyrene-type resin particle which can make an expanded polystyrene molded object again.
[0002]
[Prior art]
International Publication WO 01/68759 A1 (hereinafter referred to as Prior Art 1) describes a method for recovering a volume reducing agent from a volume-reduced product obtained by reducing the volume of used expanded polystyrene with a solvent and impregnating the foaming agent. Has been. This method uses a solvent with a Hansen solubility parameter in a specific range as a volume reducing agent, immerses the volume reduced material in a foaming agent, collects the volume reducing agent, and impregnates the foaming agent to produce expandable resin particles. To do. As a process for reducing the adhesion of the volume-reduced product, the volume-reduced product is stirred or kneaded with a foaming agent to extract the volume-reducing agent in the volume-reduced product, reducing its content, There is a description of facilitating molding.
[0003]
In the mixing and stirring of the high viscosity liquid, a case where the stirring blade having a large blade such as an anchor blade or a ribbon blade is rotated at a relatively low speed and the entire stirring tank is forcibly mixed in a laminar flow state is generally used. On the other hand, low viscosity liquids are often mixed in a turbulent state by rotating relatively small blades such as inclined paddle blades and turbine blades at high speed. Further, in order to efficiently stir and mix liquids having different viscosities, various stirrers have been devised and proposed in which the mixing characteristics of the entire stirring tank are improved using specific stirring blades.
[0004]
For example, in Japanese Patent Laid-Open No. 5-49890, the upper paddle blades are arranged in the rotational direction at an intersecting angle of 45 to 75 degrees from the adjacent lower paddle blades, and the upper and lower paddle blades are partially arranged at the outer ends. And a stirrer in which the outer end portion of the lowermost paddle blade is formed as a retreating blade. In JP-A-7-124456, a wing having a substantially trapezoidal shape in the upper stage and a recess at the center of the lower part and a lower wing having a substantially rectangular shape and having a recess in the upper center part are arranged orthogonally, and the lower part of the lower wing is There is a description of the stirring device formed on the retreating blade. In JP-A-9-75699 and JP-A-2000-210549, a plate-like first upper blade that is inclined with respect to the rotation axis and extends radially and upward, and a plate that is inclined and extends radially and downward. Of the first upper blade lower part and the upper upper blade part of the second upper blade are overlapped with each other, and further the plate-like lower blade that extends downward and in the radial direction is provided. There is a description.
[0005]
Further, in Prior Art 1, the solvent replacement of the volume reducing agent and the foaming agent is performed directly under normal temperature and normal pressure conditions from the reduced volume containing the volume reducing agent and swollen without passing through the polystyrene pellet intermediate, and recycled. A method for producing expandable polystyrene resin particles is described. According to this manufacturing method, the volume-reduced material is extruded in a string shape with a plunger-type extruder, a screw-type extruder, or the like, and this is wound and held on a non-adhesive plate such as polyethylene or fluororesin or a rod-like substrate. There is a description that, after being immersed in a foaming agent, it is cured and then cut with a cutting machine such as a strand cutter to produce recycled expandable polystyrene resin particles.
[0006]
On the other hand, a molten resin granulation technique that does not contain a solvent was disclosed in Japanese Patent Laid-Open No. 7-186236 (hereinafter referred to as Prior Art 2) and a rotary cutting blade that cuts the kneaded material discharged from the extrusion port. There is a description of a cutter device comprising a water ejection hole for ejecting water that entrains molten pellets outside the rotation region of the rotary cutting blade and a discharge port for discharging the solidified pellet together with the water.
[0007]
In JP-A-6-87973 (hereinafter referred to as Prior Art 3), an aqueous medium containing an organic dispersant in styrene resin particles obtained by non-stretching heat melting a shrinkage of a foamed styrene resin molded product. There is a description that a regenerated foamable styrene resin is produced by dispersing and impregnating a readily volatile hydrocarbon at a temperature of 100 ° C. to 140 ° C.
[0008]
In JP-A-5-98062 (hereinafter referred to as Prior Art 4), a pulverized foamed styrene resin molded product is heated and melted in an extruder, extruded, cut into styrene resin particles. After the particles are dispersed in pure water and a styrene monomer solution in which benzoyl peroxide is melted is added, the styrene-based resin particles are absorbed and polymerized, and further impregnated with butane as a foaming agent to expand foamed styrene. There is a description of obtaining resin particles.
[0009]
JP-A-9-208734 (hereinafter referred to as Prior Art 5) discloses expandable styrene resin particles obtained by suspension polymerization, having an average particle diameter of 0.4 mm or less, or 1.3 mm or more. The non-standard product is put into an extruder together with a styrenic resin and a foaming agent, extruded into a pressurized heating liquid, and immediately cut to obtain regenerated expandable particles.
[0010]
In Prior Art 1, a foamed polystyrene resin molded article, which is a waste, is dissolved in a volume reducing agent that is soluble in the foamed polystyrene resin molded article and is mutually soluble with the foaming agent. Make a volume-reducing material, disperse and knead the volume-reducing material and the extraction solvent to extract the solvent-reducing agent, extract the volume-reducing agent, create a solid, and turn the solid into resin particles There is a description that it is molded and immersed in a foaming agent for foaming polystyrene-based resin that is resin particles at room temperature, and at the same time, the reduced volume is further extracted to regenerate the expanded polystyrene-based resin.
[0011]
[Problems to be solved by the invention]
In the volume reducing agent extraction operation from the volume reduction product, a high concentration polymer solution and a foaming agent that is incompatible with the high concentration polymer solution are mixed and stirred. The volume-reduction product which is a high concentration polymer solution is a high-viscosity substance, and the foaming agent for extracting the volume-reducing agent contained therein is a low-viscosity organic solvent. Further, the extraction of the volume-reducing agent from the volume-reduced product, that is, the polymer phase proceeds, and the viscosity of the polymer phase further increases as its content decreases.
[0012]
In the case of mixing and stirring a plurality of kinds of substances having different viscosities and incompatible with each other, when a low-speed rotating stirrer with an anchor blade or a ribbon blade is used, the high-viscosity liquid portion is mixed but the low-viscosity liquid portion is mixed. On the other hand, the mixing performance is low, and there is a disadvantage that a circulating flow is not formed in the entire mixing and stirring tank and uniform mixing and stirring cannot be performed. On the other hand, when a medium-speed rotating stirrer such as an inclined paddle blade or a turbine blade is used, only the vicinity of the stirring blade is stirred, and the entire circulation flow is not formed, so that there is a disadvantage that uniform mixing and stirring cannot be performed.
Therefore, with a specific stirring blade that combines blades with different shapes and stirring functions, using a stirring device that improves the mixing characteristics of the entire stirring tank, and stirring with a sufficient number of revolutions to form a circulating flow in the entire stirring tank, the viscosity However, it is possible to uniformly mix the entire stirring tank even when mixing different substances. However, in the operation of extracting the volume reducing agent from the volume-reduced product, when the entire stirring tank is uniformly mixed, the volume-reduced material, which is a highly viscous substance, suddenly thickens and is torn off by the stirring blades. The molecular phase is subdivided into an indeterminate shape and flows in the blowing agent phase. Further, as the extraction proceeds, the volume-reduced material that has become fragmented adheres to the stirring blade and the stirring tank, and there is a problem that it is difficult to discharge from the stirring tank.
[0013]
What was proposed in the prior art 1 has a problem that it takes time until the volume-reduced material becomes hard enough to be cut by a cutting machine such as a strand cutter, and the productivity is low. Moreover, what was proposed by the prior art 2 cannot be cut | disconnected since the adhesiveness of a volume reduction material cannot be dropped even if water is injected from a water injection port. Although the volume-reduced material can be cut once, the cut particles are very sticky, so the particles cannot be separated and scattered by centrifugal force with a high-speed cutter alone. Since the particles reattach to each other to form a dumpling lump, the intended particles cannot be obtained.
[0014]
The proposals in the prior art 3 and the prior art 5 need to be performed in a reaction pressure vessel such as an autoclave when impregnated with volatile hydrocarbons. Use of these devices at the site where waste is generated is difficult and productivity is low. The proposal in Prior Art 4 also has a problem in practicality due to the cost of this wastewater treatment because of the large amount of dispersant used. In addition, there is a problem that energy loss due to heat shrinkage due to heating, and a method of reducing the volume of polystyrene resin by heat melting and extruding with an extruder or the like due to heat shrinkage deteriorates the resin due to heat history.
[0015]
Since what is described in Prior Art 1 is a laboratory-level production method, it is necessary to develop recycled foamed polystyrene resin particles in a production method that can be produced in large quantities and economically at an industrial level. There is. The present invention has been invented with the above technical background, and achieves the following objects.
The purpose of the present invention is to produce regenerated expandable polystyrene resin particles by solvent replacement under normal temperature and normal pressure conditions. Recycling of regenerated expandable polystyrene resin particles can also be reused as a foaming agent and a volume reducing agent. It is to provide a processing system and a processing method thereof.
Another object of the present invention is to efficiently agitate or knead the volume-reducing material with the foaming agent by the pre-impregnation step, extract the volume-reducing agent in the volume-reduced material, and reduce the content of the volume-reducing agent, It is an object of the present invention to provide a recycled processing system for recycled expandable polystyrene resin particles and a method for processing the same, which facilitates granulation as a subsequent process.
Still another object of the present invention is to produce regenerated expandable polystyrene resin particles by a solvent substitution method under normal temperature and normal pressure conditions. In the volume-reduced product, the granules after granulation are not adhered to each other. The present invention provides a regeneration processing system and a processing method for recycled expandable polystyrene resin particles.
[0016]
In addition, the advantages of the present invention are that, on an industrial level, the volume-reducing agent is extracted from a volume-reduced product obtained by reducing the volume of a used expanded polystyrene-based resin molded article with a volume-reducing agent. Since the recycled foamed polystyrene resin particles are not subjected to a heat history, the recovered foaming agent and volume reducing agent can be reused.
[0017]
[Means for Solving the Problems]
  As a result of earnest research on the above problems, the present inventor has completed the following invention. That is, the regeneration processing method of the regenerated expandable polystyrene resin particles of the present invention includes a volume reducing step of dissolving a polystyrene foam resin in a volume reducing agent to regenerate the expanded polystyrene resin, and foaming the reduced volume product. In the regeneration treatment method of expandable polystyrene resin particles, comprising a blowing agent impregnation step for impregnating the agent,
  The foaming agent impregnation step includes
  A pre-impregnation step for impregnating the foaming agent simultaneously with extracting the volume-reducing agent in the volume-reducing material;
  A granule granulation step for converting the volume-reduced product into a granular material after the preliminary impregnation step;
  A main impregnation step for impregnating the foaming agent at the same time as extracting the volume reducing agent in the granule after passing through the granule granulation step;Consists of
  After the main impregnation step,
  The method includes a drying step of evaporating and removing the granular material and excess foaming agent adhering to the surface of the granular material.
[0018]
  The regeneration processing system of the regenerated expandable polystyrene resin particles of the present invention,
  In the regeneration processing system for expandable polystyrene resin particles, the foaming agent impregnation can be performed by impregnating the foaming agent into the volume-reduced product dissolved in the volume reducing agent in order to regenerate the expanded polystyrene resin.
  A pre-impregnation tank for the pre-impregnation step of impregnating the foaming agent simultaneously with extracting the volume reducing agent in the volume-reduced product;
  Granulating means for a granular material process for converting the volume-reduced material into a granular material after the preliminary impregnation step;
  A main impregnation tank for impregnating the foaming agent at the same time as extracting the volume reducing agent in the granular material after passing through the granule granulating step;Consists of
  After the main impregnation step,
  It comprises drying means for evaporating and removing the excess foaming agent adhering to the surface of the particulate matter and the particulate matter.
[0019]
  In the pre-impregnation step of the present invention, a specific stirring blade made of a combination of different types of blades is rotated at a low speed, and the volume reduction product and the foaming agent are stirred while being separated into two layers, and the volume reduction agent is extracted from the volume reduction product. By using a pre-impregnation tank having an open / close valve at the bottom, a novel volume-reducing agent extraction method for easily taking out a volume-reduced material with a reduced volume-reducing agent content from the bottom of the pre-impregnation tank is realized.
  In the granulation of the volume-reduced material after the pre-impregnation step of the present invention, the volume-reduced material and the volume-reducing agent on the surface of the volume-reduced material are foamed from the extrusion holes arranged at equal intervals on the circumference of the die surface. After extruding a reduced-volume product that has been washed and extracted with an agent and sprayed with foaming agent on the cutter blade surface and the die surface, it is cut with a cutter blade that rotates at high speed, and the particles after cutting do not reattach This is a method for obtaining independent particles.
[0020]
The reclaimed polystyrene resin particle regeneration system of the present invention mainly comprises a pre-impregnation tank, a granulating means, and a main impregnation tank, and is capable of producing regenerated expandable polystyrene resin particles at room temperature and normal pressure. At the same time, the solvent is recovered. The specific stirring blade referred to in the present invention is a stirring blade having a paddle blade in the lower stage, and the shape of the upper blade is not particularly limited, and a general inclined paddle blade, screw blade, paddle blade, turbine blade, propeller blade, and A multistage blade composed of a stirring blade combining these. Preferably, the stirring blade has a vertical paddle blade, which is a rectangular plate material, arranged in the lower part, and an elliptical plate material divided into four parts along the major axis and the minor axis in the upper part. What fixed with the drive axis line of the wing | blade inclined is good.
[0021]
The poor solvent used in the present invention is an organic solvent having low polystyrene resin solubility, and readily volatile hydrocarbons such as pentane and hexane, alcohols, and polyhydric alcohols can be used. The volume-reducing material used in the present invention is a product obtained by shrinking and defoaming used expanded polystyrene and / or expanded polystyrene with a volume-reducing agent, and contains about 50 to 70% by weight of the volume-reducing agent.
[0022]
The volume reducing agent used in the present invention is a polar solvent that is soluble in polystyrene resin and mutually soluble in the foaming agent, and the hydrogen bond term δh and polar term δp of the Hansen solubility parameter are The unit is (J / cm^Three)^1/2As
[0023]
[Equation 1]
(Δp-5.8)²+ (Δh-4.3)²<50
And
δp²+ Δh²> 46
It contains at least one solvent that satisfies the above conditions. Examples thereof include dibasic acid methyl ester compositions such as dimethyl succinate, dimethyl adipate, and dimethyl glutarate.
[0024]
The foaming agent used in the present invention is pentane, hexane, or these which are liquids at room temperature and normal pressure among easily volatile lower hydrocarbon compounds usually used as foaming agents for expandable polystyrene resin particles. One isomer is used alone, or two or more isomers are mixed. The recycled expandable polystyrene resin particles produced in the present invention have a volume reducing agent and foaming agent concentration of 5 to 25% by weight, preferably 8 to 13% by weight, based on the polystyrene resin.
[0025]
The pre-impregnation referred to in the present invention is to stir and mix in order to extract a volume reducing agent from the volume-reduced product and impregnate the foaming agent simultaneously. The high-viscosity transport pump is a pump that transports and pressurizes the reduced volume obtained in the pre-impregnation tank for pre-impregnation, and examples thereof include a gear pump and a plunger pump. The granulating apparatus of the present invention refers to a means for granulating the reduced volume obtained in the pre-impregnation tank to a maximum length of 100 μm to 2 mm.
[0026]
The main impregnation of the present invention means that a volume reducing agent remaining in the granular material obtained by the granulating means is further extracted and impregnated with a foaming agent. This main impregnation tank is an agitation tank in which granular materials are introduced and the concentration of the volume reducing agent and the foaming agent is about 5 to 25% by weight for the main impregnation. The dryer of the present invention is a means for separating and recovering the particulate matter in the impregnation tank and removing excess foaming agent adhering mainly to the surface of the particulate matter. The batch type small distillation apparatus of the present invention refers to a batch type small distillation apparatus that separates and recovers a pre-impregnation tank and a volume reducing agent and a foaming agent in the main impregnation tank.
[0027]
The volume reducing agent extraction method for pre-impregnation of the present invention is performed by stirring the volume-reduced material and the foaming agent while separating them into two layers, and by renewing the surface of the bulk polymer phase and uniformly mixing the foaming agent phase, It is characterized in that the volume reducing agent in the polymer phase is extracted into the foaming agent phase, and the volume reducing material with a reduced volume reducing agent content is easily discharged from the bottom of the pre-impregnation tank. In particular, by rotating a stirring blade having a paddle blade in the lower stage at a tip peripheral speed of 50 to 200 cm / s and stirring the volume-reducing product and the foaming agent, the content of the volume-reducing agent is 25 with respect to the volume-reduced product. A reduced volume of ˜40% by weight can be obtained in bulk. By using a pre-impregnation tank having a gate valve at the bottom, the volume-reduced material with a reduced volume reducing agent content can be easily discharged from the bottom without going through a special separation step.
[0028]
The regeneration treatment system for regenerated expandable polystyrene resin particles according to the present invention is composed of two stages of pre-impregnation tank and main impregnation tank for extracting the volume-reduced material. Reduce. The regeneration processing system for regenerated expandable polystyrene resin particles according to the present invention is a plate-like stirring blade capable of efficiently and simultaneously extracting a volume reducing agent from a reduced volume in a pre-impregnation tank and impregnating the reduced volume with a blowing agent. Have
[0029]
The granulating means of the present invention comprises a die for extruding a volume-reduced material into a string shape, a high-speed cutter blade for cutting it, a cutter blade surface and an injection nozzle for injecting a foaming agent onto the surface of the die, and the volume-reduced material is 100 μm to 2 mm. In this case, it is guided outside the rotation region of the rotary cutter blade without being attached again. The granulating means of the present invention converts a high-viscosity volume-reduced material into a granular material having a diameter of about 100 μm to 2 mm under normal temperature conditions.
[0030]
The foaming agent treatment method of the present invention includes extraction of a volume reducing agent contained in a volume-reduction product and a foaming agent because the foaming agent in the pre-impregnation tank and the main impregnation tank is liquid at normal temperature and normal pressure. It is characterized by being able to efficiently impregnate. The treatment method of the pre-impregnation tank of the present invention is divided into two types of high viscosity reduction products and low viscosity liquid foaming agents with very different viscosity and different material states. -It is characterized by efficiently mixing and stirring so as to prevent fragmentation, and extracting the solvent-reducing solvent from the reduced volume and simultaneously impregnating the foaming agent.
[0031]
The treatment method of the present impregnation tank of the present invention is such that the volume reducing agent in the granulated material granulated by the granulating means is easily adhered to each other until the granular material is cured by extraction into the foaming agent phase. It is characterized by maintaining the dispersion of objects. In the present invention, since the surface of the particulate matter taken out by the dryer after the completion of the impregnation is impregnated with an excessive foaming agent, the foaming agent adhering to the surface of the particulate matter is removed by drying. It is characterized by having an impregnation range of a blowing agent equivalent to that of commercially available virgin expandable polystyrene resin particles.
[0032]
DETAILED DESCRIPTION OF THE INVENTION
A volume-reduced product obtained by shrink-defoaming foamed polystyrene with a volume-reducing agent usually contains 50 to 70% by weight of a volume-reducing agent. In order to reduce the adhesion of the volume-reduced product and facilitate molding into a granular material, it is preferable to reduce the content of the volume-reducing agent to about 25 to 40% by weight with respect to the volume-reduced product. For this purpose, the volume-reducing material is stirred or kneaded with the foaming agent to extract the volume-reducing agent in the volume-reduced material and reduce its content.
[0033]
As an embodiment of the present invention, the amount of the foaming agent for obtaining a volume-reduced material having a preferable volume-reducing agent content is 1.5 to 4 times that of the volume-reduced material. When a stirring device with excellent mixing characteristics is used and stirring is performed at a sufficient number of revolutions that a circulating flow forms in the entire pre-impregnation tank, the volume-reduced product impregnated with the solvent-reducing solvent, which is a highly viscous substance, rapidly increases in viscosity and stirred. It is torn off by the wing and is initially agglomerated and is subdivided into an indeterminate shape, which flows into the foaming agent. Further, as the extraction proceeds, the solvent-reduced material that has become fragmented adheres to the stirring blade and the tank, and it becomes difficult to discharge from the pre-impregnation tank. In order to solve this problem, it is preferable that the volume reducing agent and the foaming agent are stirred while being separated into two layers and the volume reducing agent is extracted from the volume reducing material.
[0034]
As a result of experiments, it has been clarified that, as this stirring method, it is effective to use a specific stirring blade by combining a plurality of types of blades having different shapes and functions while rotating at a low speed. Specifically, the volume reducing agent content is reduced by rotating a stirring blade having a paddle blade in the lower stage at a tip peripheral speed of 50 to 200 cm / s and stirring the volume reducing agent and the foaming agent. On the other hand, a reduced volume of 25 to 40% by weight can be obtained as a lump. Furthermore, by using a pre-impregnation tank having a gate valve at the bottom, it is possible to easily discharge the volume-reduced material having a reduced volume reducing agent content from the bottom.
[0035]
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an outline of a system, which is an embodiment of a regeneration processing system for recycled expandable polystyrene resin particles according to the present invention. The regeneration processing system 10 for regenerated expandable polystyrene resin particles is composed of four steps: a pre-impregnation step, a granulation step, a main impregnation step, and a drying step. By this four-step batch processing operation, regenerated expandable polystyrene resin particles are produced, and the recovered foaming agent is separated and recovered into a foaming agent and a volume reducing agent by a distillation separation process.
[0036]
The volume-reduced material used in the regenerated processing system 10 for regenerated expanded polystyrene-based resin particles is obtained by dissolving used expanded polystyrene and / or expanded polystyrene with a volume-reducing agent whose main component is a dibasic acid methyl ester composition. And the bulking agent content is 50 to 70% by weight.
The pre-impregnation step is a step for simultaneously conveying and pressurizing a high-viscosity lump that has been extracted from the volume-reducing material, and simultaneously extracting the volume-reducing agent and impregnating the foaming agent. It is. The pre-impregnation step is also a pretreatment step for facilitating granulation as will be described later. The equipment for the pre-impregnation step includes a pre-impregnation tank 21, a stirrer 22, a high viscosity transport pump 23, and the like. The pre-impregnation tank 21 is charged with a volume reducing agent and a foaming agent 5 to 8 times the weight of the volume reducing agent contained in the volume reducing agent, and stirred by the stirrer 22.
[0037]
At this time, the liquid temperature of the volume reducing agent is set to 8 to 20 ° C., the tip peripheral speed which is the outer periphery of the stirring blade of the stirrer 22 is set to 50 to 200 cm / s, and the impregnation time is set to 10 to 180 minutes. The volume reduction agent concentration in the volume reduction product is controlled to 25 to 40% by weight. By adjusting the liquid specific gravity of the foaming agent from which the volume reducing agent is extracted to a range of 0.66 to 0.69, the viscosity of the volume reducing material can be conveyed by the high viscosity conveying pump 23, and the granulating device 31 Make it easy to granulate. Note that the selection of the volume reducing agent and the foaming agent is a method as described in WO 01/68759 A1 (Prior Art 1) and is not the gist of the present invention, so the detailed explanation of the principle is as follows. Omitted.
[0038]
The foaming agent recovered in the pre-impregnation step and the main impregnation step is sent to a batch-type small distillation apparatus 62 by a foaming agent recovery pump 61, separated by distillation, and the volume reducing agent is recovered from the bottom at the bottom. It is condensed and liquefied by the condenser 63 and recovered in the foaming agent recovery tank 65. The recovered foaming agent can be reused as the foaming agent in the pre-impregnation step.
[0039]
The viscosity of the volume-reduced material to be adjusted in the pre-impregnation tank 21 is a viscosity that can be cut into granules having a length of about 100 μm to 2 mm in a subsequent granulation step. If the viscosity is too low, only string-like lumps can be made. The granulation step is a step of producing particles from a volume-reduced product that is preliminarily impregnated with a foaming agent and the volume-reducing agent amount is reduced to 25 to 40% by weight, or a volume-reduced product that is not subjected to pretreatment.
[0040]
Hereinafter, the granulating method or apparatus of the present invention will be described with reference to the drawings. However, the dimensions, shapes, relative positions, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, and are merely illustrative examples. Only. Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 3 is a cross-sectional view showing details of the granulating device 31. In the cutter box 33, the granulating device 31 includes a die 38 having a die hole arranged on the circumference, a cutter blade 36 that is rotationally driven attached to a cutter mounting base 39 that rotates at a high speed, and the cutter blade 36. In order to inject the poor solvent, it is constituted by a poor solvent flow path 35 provided as a through hole in the axial center portion of the cutter shaft 34, a poor solvent injection port 37 for injecting the poor solvent in communication therewith, and the like. .
[0041]
This granulating device 31 is arranged to make the volume-reduced material into strands, and to granulate the volume-reduced material discharged in strands from the die holes of the dies 38 in which the dies 38 are circumferentially arranged. It has been done. For this reason, the poor solvent injection port 37 is installed at the nearest position not in contact with the die 38 for the purpose of blowing away the non-returning cutter blade 36 rotating at high speed in the circumferential direction and the granulated material adhering to the cutter blade 36. It is a thing. Pentane is pressurized and supplied to the poor solvent injection port 37 by the pentane injection device 32. The volume-reduced material pressurized by the high-viscosity transport pump 23 is discharged in a strand form from a plurality of die holes, and rotated at 1400 to 3200 rpm in the circumferential direction at the nearest position where the die 38 and the cutter blade 36 do not contact each other. The cutter blade 36 is cut into granules having a particle diameter of 100 μm to 2 mm and granulated.
[0042]
The impregnation step is a step of further extracting the volume reducing agent remaining in the granular material obtained by the granulating apparatus, and is a step of reducing the amount of the volume reducing agent and the foaming agent to about 5 to 25% by weight. An impregnation tank 4 1 and a circulation pump 43 are included. The granular material put into the impregnation tank 41 is agitated so as to constantly flow at a stirring speed of 80 to 150 rpm by a stirrer 42 driven to rotate by an electric motor in order to prevent the particles from adhering to each other. The particulate matter that has settled in the lower part of the main impregnation tank 41 is externally circulated by the circulation pump 43 to prevent accumulation of particulate matter that has adhered to the lower part of the impregnation tank 41 due to blocking of the particulate matter that has settled. The impregnation time in the main impregnation tank 41 which is the main impregnation step is preferably about 2 to 48 hours, although it depends on the concentration of the volume reducing agent extracted in the preliminary impregnation step.
[0043]
The drying step refers to a step of removing excess foaming agent adhering to the surface of the resin particles obtained in the impregnation tank 41. After completion of the impregnation step, the liquid in the main impregnation tank 41 containing the resin particles is sent to the dryer 51 by the circulation pump 43 and separated into the blowing agent and the resin particles by a 40 mesh wire net installed inside the dryer 51. The resin particles are collected on the wire mesh, and the foaming agent is collected in the main impregnation tank 41. The resin particles recovered in the dryer 51 are removed by evaporating and removing excess foaming agent adhering to the surface with cold air of 0 to 20 ° C. by a spot cooler 52, and impregnating the resin particles with the foaming agent. The amount is controlled to 8-13% by weight.
[0044]
【Example】
Below, this invention is demonstrated based on an Example and a comparative example.
[Example 1]
The reduced volume and pentane were stirred and mixed using a small stirrer. A Hi-F mixer manufactured by Soken Chemical Co., Ltd. was used as a small stirring device. The stirring tank is made of glass having a volume of 3 L, and has three baffle plates between the stirring tank inner wall and the stirring blade. The stirring blade is composed of an inclined quarter-elliptical blade in which a vertical paddle blade, which is a rectangular plate material, is arranged at the lower part and an elliptical plate material is divided into four parts by a major axis and a minor axis at the upper part. Each inclined quarter-elliptical wing is arranged with its surface inclined with respect to the axis of the rotation axis.
First, a volume-reduced product was prepared by shrinking and degassing foamed styrene using a dibasic acid methyl ester composition (Stylosolv SS6000 manufactured by Styro Japan) as a volume-reducing agent. This composition was 163 parts of volume reducing agent with respect to 100 parts of resin. This volume-reduced product was mixed and stirred with 3.0 times the amount of pentane. The tip peripheral speed of the stirring blade was 0.8 m / s, and stirring was performed at a liquid temperature of 25 to 26 ° C. for 60 minutes. The composition of the volume-reduced material after the mixing and stirring operation was 40 parts of volume reducing agent and 17 parts of pentane with respect to 100 parts of resin. The obtained volume-reduced material was in the form of a lump and had little adhesion to the stirring tank and stirring blade, and could be easily recovered. Further, when the same treatment was performed with 1.8 times the amount of pentane, a volume-reduced product having a composition of 75 parts of a volume reducing agent and 17 parts of pentane was obtained.
[0045]
[Example 2]
FIG. 2 is a diagram showing an outline of the structure of the pre-impregnation tank 21. The pre-impregnation tank 21 was used to stir and mix the styrene solvent volume-reduced product and pentane. The composition of the volume-reducing material was 165 parts of volume-reducing agent with respect to 100 parts of resin. This volume-reduced product was mixed and stirred with 3.1 times the amount of pentane. The tip peripheral speed of the stirring blade was 105 cm / s, and stirring was performed at a liquid temperature of 9 to 11 ° C. for 90 minutes. The composition of the reduced volume after the mixing and stirring operation was 75 parts of a volume reducing agent and 22 parts of pentane with respect to 100 parts of the resin. When the gate valve 27 at the bottom of the pre-impregnation tank 21 was opened, the volume-reduced material was agglomerated and spontaneously dropped onto the suction hopper 28, and the conveyance with the high viscosity conveyance pump 23 was performed well. There was almost no adhesion of the reduced volume to the inner wall of the pre-impregnation tank 21 or the stirring blade.
[0046]
[Comparative Example 1]
Using the same apparatus as in Example 2, the volume-reduced product and pentane were mixed with stirring. The same treatment as in Example 2 was performed except that the peripheral speed of the stirring blade was adjusted. Stirring was started at a tip peripheral speed of 58 cm / s, and the peripheral speed was gradually increased after 15 minutes. When the tip peripheral speed exceeded 115 cm / s, the flow of small pieces of the volume-reduced material was observed. At the tip peripheral speed of 230 cm / s, the amorphous volume-reduced material flowed violently. After stirring for 60 minutes, the extract was discharged, renewed to pentane, and further stirred for 60 minutes at a tip peripheral speed of 230 cm / s. The composition of the volume-reduced material after the mixing and stirring operation was 41 parts of volume reducing agent and 17 parts of pentane with respect to 100 parts of resin. The gate valve 27 at the bottom was opened, and the reduced volume was transported by the high viscosity transport pump 23 through the suction hopper 28, but transport failed. In the pre-impregnation tank 21, the volume-reducing material was remarkably adhered to the stirring blade.
[0047]
Example 3
The used expanded polystyrene was immersed in a volume-reducing agent (dibasic acid methyl ester compound, Styrosolv 6000 manufactured by Styro Japan Co., Ltd.) to obtain a volume-reduced material having a volume-reducing agent concentration of 60%. This volume-reduced material is immersed in pentane in advance for 2 hours, and the volume-reduced material preliminarily extracted from the surface volume-reducing agent is pumped with a pump, and from a die (hole diameter: 1 mm, number of holes: 12) Extruded. The discharge rate from the die at that time is 12.3 kg / h, the discharge pressure is 40 kgf / cm²Met. This is sent to the granulating device 31 to which only one sharp cutter blade 36 is attached, and is granulated at a rotation speed of the cutter blade 36 of 1800 rpm, a pentane injection amount of 10 L / min to the blade surface of the cutter blade 36 and the die surface. It was. When beads cut by a stainless steel receiver were received from the lower part of the granulating apparatus, independent elliptical particles having a minor axis diameter of 1 mm and a major axis diameter of about 2 mm were obtained.
[0048]
Example 4
The reduced volume was pumped by the high clay transport pump 23 and extruded from a die (hole diameter: 1 mm, number of holes: 12). The discharge rate from the die at that time is 14.1 kg / h, the discharge pressure is 14 kgf / cm²Met. This is sent to a granulating device 31 in which only one blade is attached to a sharp cutter blade 36, and is granulated at a rotation speed of the cutter blade 36 of 2000 rpm, a pentane injection amount of 10 L / h onto the blade surface of the cutter blade 36 and the die surface. Made. When beads cut by a stainless steel receiver were received from the lower part of the granulating apparatus, independent elliptical particles having a minor axis diameter of 1 mm and a major axis diameter of about 2 mm were obtained. Independent particles could be obtained without preliminarily performing a volume reducing agent extraction treatment on the surface of the volume reduction material.
[0049]
[Comparative Example 2]
Granulation was performed under the same conditions as in Example 3 except that the foaming agent was not sprayed onto the blade surface of the cutter blade 36 and the die surface. The discharge rate from the die 38 at that time is 11.8 kg / h, and the discharge pressure is 40 kgf / cm.²Met. When beads cut by a stainless steel receiver were received from the lower part of the granulating apparatus, a string-like substance having a diameter of about 2 mm and a length of about 10 cm was obtained. The surface of the string-like substance was beaded, and particles once cut by the cutter blade 36 were reattached to form a string.
[0050]
[Comparative Example 3]
Granulation was performed under the same conditions as in Example 4 except that the foaming agent was not sprayed onto the blade surface of the cutter blade 36 and the surface of the die 38. The discharge rate from the die at that time is 3.3 kg / h, the discharge pressure is 40 kgf / cm²Met. When beads cut by a stainless steel receiver were received from the lower part of the granulating apparatus 31, a string-like substance having a diameter of about 2 mm and a length of about 15 cm was obtained. The surface of the string-like substance was twisted, and the volume reduction material was stretched without being cut.
[0051]
[Example 5]
16 kg of used expanded polystyrene was dissolved with a volume reducing agent to obtain 40 kg of a volume reduced product having a volume reducing agent concentration of 60%. After charging into the pre-impregnation tank, 300 L of pentane at a temperature of 10 ° C. was added, and the volume reducing agent was extracted by stirring for about 3 hours at a stirring blade tip peripheral speed of 92 cm / s having a plate blade, and impregnated with a foaming agent. . The liquid density of the foaming agent at this time is 0.653 g / cm.^ThreeThe volume-reducing agent in the volume-reduced product was 32.1% by weight, and the foaming agent was 11.8% by weight. This was transported by a pump, pushed into 12 die holes with a diameter of 1 mm, and pentane was sprayed from the back side of the cutter blade, and cut into granular materials by a center-cut method under the condition of a cutter speed of 1800 rpm. . The size of the granular material at this time was 1 to 2 mm, which was good.
The high-viscosity conveyance pump had a conveyance / pressure increase capacity of 9.36 kg / h of extrusion amount and a pump discharge pressure of 4.0 MPaG. Table 1 shows the dissolution conditions of the used expanded polystyrene. Table 2 shows the pre-impregnation step and the test conditions in the granulating apparatus 31. Table 3 shows test results in the pre-impregnation step and the granulating apparatus 31.
[0052]
The disc-like resin particles are put into a main impregnation tank of 800 L of foaming agent pentane, the liquid temperature is set to 10 to 15 ° C., the agitator rotation speed is set to 80 rpm, and the liquid in the tank is externally circulated by a pump 41 Impregnation for about an hour. After completion of the impregnation, the particles were taken out into a dryer, the spot cooler was set to 15 ° C., pentane adhering to the surface of the granular material was removed, and 2.2 kg of foam beads were obtained. As for the particle size, 1.1 kg of a product having a diameter of 1 to 2 mm was recovered, and 1 kg of a fine powder having a particle size of 1 mm or less was recovered. The volume reducing agent and the blowing agent concentration in the regenerated expandable polystyrene resin particles were 13.1% by weight, which was good. Table 2 shows the treatment conditions for the impregnation step and the operating conditions of the dryer. Table 3 shows the test results.
[0053]
[Example 6]
24 kg of used expanded polystyrene was dissolved with a volume reducing agent to obtain 60 kg of a reduced volume material having a volume reducing agent concentration of 60%. After feeding into the pre-impregnation tank, 300 L of pentane at a temperature of 10 ° C. was added, and the solvent was extracted by stirring for about 2 hours at a stirring blade tip peripheral speed of 105 cm / s having a plate-like blade, and impregnated with a blowing agent. The liquid density of the foaming agent at this time is 0.653 g / cm.^ThreeThe volume-reducing agent in the volume-reduced product was 38.8% by weight, and the foaming agent was 12.7% by weight.
This is transported and pressurized by a high-viscosity transport pump, pressed into 12 die holes with a diameter of 1 mm, and pentane is sprayed from the back side of the cutter blade 36, under the condition of a cutter speed of 2000 rpm by a center-cut method. Cut into granules. The size of the granular material at this time was 1 to 2 mm, which was good. The high-viscosity conveyance pump had a conveyance / pressure increase capability of 14.1 kg / h of extrusion and a pump discharge pressure of 2.0 MPaG. Table 1 shows the dissolution conditions of the used expanded polystyrene. Table 2 shows the test conditions for the pre-impregnation and granulation measures. Table 3 shows the test results for the pre-impregnation and granulation measures.
[0054]
This disc-shaped granular material is put into a main impregnation tank of 950 L of a foaming agent pentane, the liquid temperature is set to 10 to 15 ° C., the rotation speed of the stirrer is set to 80 rpm, and the liquid in the tank is externally circulated by a pump. Impregnation for about an hour. After completion of the impregnation, the particles were taken out into a dryer, the spot cooler was set to 15 ° C., pentane adhering to the surface of the granular material was removed, and 1.8 kg of foam beads were obtained. As for the particle size, 1.5 kg of a 1 to 2 mm product was recovered, and 0.3 kg of a fine powder of 1 mm or less was recovered. The volume reducing agent and foaming agent concentration in the regenerative foamable polystyrene resin particles was 14.7% by weight, which was good. Table 2 shows the treatment conditions for the impregnation step and the operating conditions of the dryer. Table 3 shows the test results.
[0055]
[Table 1]

[0056]
[Table 2]

[0057]
[Table 3]

[0058]
[Comparative Example 4]
A granulation test was performed in the same manner as in Example 1 except that the pre-impregnation step was not performed. Table 4 shows the dissolution conditions of the used expanded polystyrene. Table 5 shows the test conditions, and Table 6 shows the granulation test results. The granular material at this time was a rubber scrap having a particle size of about 5 to 6 mm, which was considerably inferior to Example 1. Therefore, this impregnation and drying operation could not be carried out.
[0059]
[Comparative Example 5]
A granulation test was carried out in the same manner as in Example 1 except that water was used instead of the two blades having the cutter blade 36 returned by the granulating device 31 and pentane injection. Table 4 shows the dissolution conditions of the used expanded polystyrene. Table 5 shows the test conditions, and Table 6 shows the granulation test results. The granular material at this time was close to a string having a particle size of about 5 to 15 mm and a dango-like lump of string, and was considerably inferior to Example 1. Therefore, the impregnation step and the drying operation could not be performed.
[0060]
[Table 4]

[0061]
[Table 5]

[0062]
【The invention's effect】
As described above, according to the reclaimable polystyrene resin particle regeneration system and treatment method of the present invention, a foaming agent is added at room temperature and normal pressure to reduce the volume in the volume-reduced product. By simultaneously performing the extraction of the volume and the impregnation of the foaming agent, it becomes possible to granulate the pre-impregnated volume-reduced material, and further the resin particles are extracted by impregnating the granular material in the foaming agent liquid. By drying the above, it is possible to obtain regenerated expandable polystyrene resin particles that do not receive a thermal history.
In addition, by dividing the extraction of the volume reducing agent into two stages of pre-impregnation and main impregnation, the viscosity can be adjusted to an appropriate particle size by the granulating device, and the granulating conditions in the granulating process can be adjusted. Can be optimized. Since the plate-like stirring blade is used in the pre-impregnation step, extraction of the volume reducing agent in the volume reduction material and impregnation of the foaming agent can be performed efficiently.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a system diagram showing an outline of an embodiment of a regeneration processing system for recycled expandable polystyrene resin particles according to the present invention.
FIG. 2 is an explanatory view showing details of a pre-impregnation tank of the reclaimable polystyrene resin particle regeneration treatment system of the present invention shown in FIG. 1;
FIG. 3 is a cross-sectional view showing a granulating apparatus of the reclaimable polystyrene-based resin particle regeneration processing system of the present invention shown in FIG.
4 is a cross-sectional view taken along the line AA in FIG. 3 in the direction of the arrows.
[Explanation of symbols]
10 ... Regeneration processing system of regenerated expandable polystyrene resin particles
21 ... Pre-impregnation tank
22 ... Stirrer for pre-impregnation
23 ... High viscosity conveying pump
24 ... Inclined flat plate wing
25 ... Flat wing
26 ... Baffle plate
27 ... Gate valve
28 ... Suction hopper
31 ... Granulating device
32 ... Foaming agent injection device
33 ... Cutter box
34 ... Cutter shaft
35 ... Poor solvent flow path
36 ... Cutter blade
37 ... Poor solvent jet
38 ... Dice
39 ... Cutter mounting base
41 ... This impregnation tank
42. Stirrer for impregnation
43 ... circulation pump
51 ... Dryer
52. Spot cooler
61 ... Foaming agent recovery pump
62 ... Batch type small distillation tower
63 ... Condenser
64 ... Recovery foaming agent transfer pump
65 ... Blowing agent recovery tank
66 ... Blowing agent transfer pump
67 ... Recovery volume reducing agent transfer pump
68 ... Cooler
69 ... Volume reducing agent recovery drum

Claims

An expandable polystyrene resin particle comprising a volume reduction step of dissolving a foamed polystyrene resin into a volume reducing agent to produce a volume reduction product, and a foaming agent impregnation step of impregnating the volume reduction product with the foaming agent. In the regeneration processing method,
The foaming agent impregnation step includes
A pre-impregnation step for impregnating the foaming agent simultaneously with extracting the volume-reducing agent in the volume-reducing material;
A granule granulation step for converting the volume-reduced product into a granular material after the preliminary impregnation step;
It comprises the main impregnation step for impregnating the foaming agent at the same time as extracting the volume reducing agent in the granule after passing through the granule granulation step ,
After the main impregnation step,
A drying process for evaporating and removing the granular material and excess foaming agent adhering to the surface of the granular material.

In the reproduction | regeneration processing method of the expandable polystyrene-type resin particle of Claim 1 ,
The pre-impregnation step includes
The volume-reducing material and the foaming agent are stirred while being separated into upper and lower layers, and the volume-reducing agent in the volume-reducing material is extracted, and at the same time, the volume-reducing material is impregnated with the volume-reducing agent. A method for regenerating regenerated expandable polystyrene resin particles, characterized in that the content is reduced.

In the reproduction | regeneration processing method of the reproduction | regeneration foaming polystyrene-type resin particle of Claim 2 ,
Agitation in the pre-impregnation step
The stirring blade is rotated at a tip peripheral speed of 50 to 200 cm / s, the volume-reduced product and the foaming agent are stirred, the liquid temperature of the foaming agent is 8 to 20 ° C., and the impregnation time is 10 to 180 minutes. Then, the weight composition of the volume reducing agent in the foaming agent and the volume reducing material is mixed and stirred in a range of 2: 1 to 8: 1, and the concentration of the volume reducing agent in the volume reducing material is 25 to 40 wt. % Of the recycled foamed polystyrene resin particles.

In the reproduction | regeneration processing method of the reproduction | regeneration foaming polystyrene-type resin particle of Claim 2 ,
The main impregnation step includes
After the liquid temperature was set to 0 to 36 ° C., the stirrer rotation speed was set to 80 to 200 rpm, and the impregnation time was set to 2 to 48 hours, the particles granulated by the granulating apparatus in the foaming agent were mixed and stirred. Take out to a dryer, dry at a temperature of 0 to 20 ° C., and reduce the concentration of the volume reducing agent and the blowing agent in the resin particles to 5 to 25% by weight. Regeneration processing method.

In the reproduction | regeneration processing method of the reproduction | regeneration foaming polystyrene-type resin particle of Claim 3 ,
Agitation in the pre-impregnation step
A method for regenerating regenerated expandable polystyrene resin particles, characterized in that a vertical paddle blade, which is a rectangular plate material, is arranged at the bottom, and an elliptical plate material is stirred at the top with a stirring blade divided into four with a major axis and a minor axis.

In the regeneration processing system for expandable polystyrene resin particles, the foaming agent impregnation can be performed by impregnating the foaming agent into the volume-reduced product dissolved in the volume reducing agent in order to regenerate the expanded polystyrene resin.
A pre-impregnation tank for a pre-impregnation step in which the foam-reducing agent is impregnated simultaneously with extracting the volume-reducing agent in the volume-reducing material;
Granulating means for a granular material process for converting the volume-reduced material into a granular material after the preliminary impregnation step;
It comprises the main impregnation tank for impregnating the foaming agent at the same time as extracting the volume reducing agent in the granular material after passing through the granular material granulation step ,
After the main impregnation step,
A regeneration means for regenerating expandable polystyrene resin particles, comprising drying means for evaporating and removing the granular material and excess foaming agent adhering to the surface of the granular material.

In the reproduction | regeneration processing system of the reproduction | regeneration foaming polystyrene-type resin particle of Claim 6 ,
Regeneration treatment of regenerated expandable polystyrene resin particles, characterized in that the pre-impregnation tank has an outer peripheral speed of 50 to 200 cm / s and a stirring blade for stirring the volume-reducing material and the foaming agent. system.

In the reproduction | regeneration processing system of the reproduction | regeneration foaming polystyrene-type resin particle of Claim 6 ,
The granulating means includes
Regeneration of regenerated expandable polystyrene resin particles, comprising: a cutter for cutting the volume-reduced material extruded from a die; and a poor solvent spraying means for spraying a poor solvent onto the cutter blade surface and the die surface. Processing system.

In the reproduction | regeneration processing system of the reproduction | regeneration foaming polystyrene-type resin particle of Claim 6 ,
In the preliminary impregnation tank, the liquid temperature is 8 to 20 ° C., the stirring blade tip peripheral speed is 50 to 200 cm / s, and the impregnation time is 10 to 180 minutes. Regenerative foamable polystyrene system characterized by mixing and stirring the weight reducing agent in a range of 2: 1 to 8: 1 so that the concentration of the reducing agent in the reduced volume is 25 to 40% by weight. Resin particle regeneration system.

In the reproduction | regeneration processing system of the reproduction | regeneration foaming polystyrene-type resin particle of Claim 6 ,
In this impregnation tank, the liquid temperature was set to 0 to 36 ° C., the rotation speed of the stirrer was set to 80 to 200 rpm, and the impregnation time was set to 2 to 48 hours. After that, the granular material is taken out into a dryer, and dried at a temperature of 0 to 20 ° C., so that the concentration of the volume reducing agent and the foaming agent in the resin particles is 5 to 25% by weight. Recycling system for conductive polystyrene resin particles.

In the reproduction | regeneration processing system of the reproduction | regeneration foaming polystyrene-type resin particle of Claim 7 ,
The stirring blade is
A recycling system for recycled expandable polystyrene resin particles, characterized in that a vertical paddle blade, which is a rectangular plate material, is arranged at the bottom, and an elliptical plate material is divided into four at the top and the long axis and the short axis.