JP4035979B2 - Expandable polystyrene resin particles and method for producing the same - Google Patents
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Description
【０００１】
【発明の属する技術分野】
発泡性ポリスチレン系樹脂粒子は、水蒸気や熱風等の加熱手段で加熱されると、粒子内に多数の小気泡が生成して予備発泡粒子となる。そして、この予備発泡粒子を金型内に充填して再び加熱すると、上記予備発泡粒子が二次発泡し、互いに融着し合って、金型内の型形状に忠実な発泡ポリスチレン系樹脂成形体を成形することができる。従ってこのようにして得られた発泡ポリスチレン系樹脂成形体は建築用断熱材、盛土等として利用することができる。
【０００２】
本発明は、発泡性ポリスチレン系樹脂粒子の製造時にハロゲン系難燃剤と気泡調節剤として脂肪族ビスアマイド、メチルメタクリレート・ブタジエン・スチレン共重合体、スチレン・ブタジエン共重合体を組み合わせることにより、製造直後から約１ヶ月以上経過させても、得られた発泡性ポリスチレン系樹脂粒子を型内で二次発泡させ、成形して得られる成形体の切断面気泡径の変化が少なく、しかもこれら成形体の切断面気泡径の平均弦長を９０〜２００μｍの間で任意にコントロールすることができ、断熱性能に優れ、かつ難燃性を有する発泡性ポリスチレン系樹脂粒子及びその製造方法に関するものである。
【０００３】
【従来の技術】
周知のように、発泡ポリスチレン系樹脂成形体は広い範囲の用途に使用されているが特に建材や盛土分野には難燃化された発泡成形体の供給が必須である。最近、従来以上に大きな成形体や厚みのある成形体あるいは高倍化された成形体が要求される場合があり、より優れた寸法安定性、機械的強度のある難燃性発泡ポリスチレン系樹脂を得る事が必要となってきている。特に建材分野で壁や床の断熱材に使用される発泡ポリスチレン系成形体は、省エネルギーの観点から断熱性能に優れた難燃性のものが切望されている。
【０００４】
一般に発泡ポリスチレン系樹脂成形体の断熱効果は、特開平２−３０５８３９にも記載の如く発泡体の気泡寸法がｍｍ当たり約５から１０個の気泡（即ち、平均弦長で約１００から２００μｍに相当する）である場合に最良の断熱効果を示す事が知られている。
【０００５】
一方、発泡性ポリスチレン系樹脂粒子の難燃化には、（ａ）難燃剤をスチレン系モノマーと共に重合時に添加する方法、（ｂ）ポリスチレン系樹脂に発泡剤を含浸させる際に難燃剤を添加する方法、の何れかが採用されてきた。これらの方法に於いて製造されるポリスチレン系重合体粒子は、難燃剤自体が造核作用を有するため熟成が非常に短期間で進むと同時に、一般に熟成は粒子表面付近から起こることから表面の気泡から微細化が進行するため粒子の大きさによって気泡状態の異なる、いわゆる粒子間ムラが発生していた。
【０００６】
このため、任意の気泡径を有し、かつ均一な気泡は得難く最終的には超微細な気泡になるという欠点が認識されていた。この為、高圧側で成形した時は成形体表面が溶融してしまい成形幅が狭く取り扱い難い傾向を有し、また、気泡膜が薄いため破れ易く高倍化しにくいと云う欠点が指摘されている。
【０００７】
難燃性の発泡ポリスチレン系樹脂成形体のセル径を調整する技術としては、特開平２−３０５８３９には気泡調節剤としてアンモニウム塩と有機アミンを併用する技術が開示されている。また、 ＷＯ９７／１７３９６では、界面活性剤種の選択により気泡径を調整している。
【０００８】
【発明が解決しようとする課題】
しかしながら、特開平２−３０５８３９で気泡調整剤として使用している有機アミンは毒性上の問題が懸念され好ましくなく、ＷＯ９７／１７３９６では、界面活性剤の選択により気泡径を調整し、気泡調節剤を含有させていないので、気泡の熟成期間が長くかかりリードタイムが長くなると言う問題があり、また、記載された熱伝導率の発泡ポリスチレン系樹脂成形体を工業的に量産するのは困難であった。
【０００９】
この為、毒性上懸念が無く、成形して得られる成形体の切断面気泡の経時変化が少なく、しかも任意に気泡径をコントロールすることができる表面性および断熱性能の優れた難燃発泡性ポリスチレン系樹脂粒子が切望されていた。
【００１０】
【課題を解決するための手段】
かかる問題を解決する為に鋭意研究を重ねた結果、発泡性ポリスチレン系樹脂粒子にハロゲン系難燃剤と特定の気泡調節剤を適当量含有させる事により、発泡体の気泡が製造直後から平均弦長９０−２００μｍという断熱性能に有効な気泡径を有し、かつ時間の経過によっても気泡径が変化しにくい発泡性ポリスチレン系樹脂粒子が得られる事を見出し、本発明を完成させた。
【００１１】
即ち、本発明は、（１）ポリスチレン系樹脂１００重量部に、ヘキサブロモシクロドデカンをハロゲン系難燃剤として０．１〜６重量部及び脂肪族ビスアマイドを０．００１〜０．３重量部含有させることを特徴とする発泡性ポリスチレン系樹脂粒子。
【００１２】
（２）ポリスチレン系樹脂１００重量部に、ヘキサブロモシクロドデカンをハロゲン系難燃剤として０．１〜６重量部及びメチルメタクリレート・ブタジエン・スチレン共重合体及び又はスチレン・ブタジエン共重合体を０．０１〜１重量部含有させることを特徴とする発泡性ポリスチレン系樹脂粒子。
【００１３】
（３）発泡成形したときの成形体の切断面気泡径の平均弦長が９０〜２００μｍの範囲であることを特徴とする（１）又は（２）記載の発泡性ポリスチレン系樹脂粒子。
【００１４】
（４）発泡性ポリスチレン系樹脂粒子を製造するに際し、重合系中にスチレン系単量体１００重量部に対して、ヘキサブロモシクロドデカンをハロゲン系難燃剤として０．１〜６重量部及び脂肪族ビスアマイドを０．００１〜０．３重量部存在させると共に、重合途中又は重合後に発泡剤を添加することを特徴とする発泡性ポリスチレン系樹脂粒子の製造方法。
【００１５】
（５）発泡性ポリスチレン系樹脂粒子を製造するに際し、重合系中にスチレン系単量体１００重量部に対して、ヘキサブロモシクロドデカンをハロゲン系難燃剤として０．１〜６重量部及びメチルメタクリレート・ブタジエン・スチレン共重合体及び又はスチレン・ブタジエン共重合体を０．０１〜１重量部存在させると共に、重合途中又は重合後に発泡剤を添加することを特徴とする発泡性ポリスチレン系樹脂粒子の製造方法である。
【００１６】
【発明の実施の形態】
本発明は、例えば、発泡性ポリスチレン系樹脂粒子を製造するに際し、重合系中にハロゲン系難燃剤をスチレン系単量体１００重量部に対して０．１〜６重量部及び脂肪族ビスアマイドを０．００１〜０．３重量部存在させることを特徴とする発泡性ポリスチレン系樹脂粒子を提供するものである。
【００１７】
本発明で用いられるスチレン系単量体としては、スチレンを主成分とし、α―メチルスチレン、ビニルトルエン等のスチレン以外のスチレン系単量体を混合して使用できる。スチレン系単量体の一部をそれ以外のビニル単量体、例えばアクリロニトリル等のシアン化ビニル系単量体、ブチルアクリレート等のアクリレート系単量体、メチルメタクリレート等のメタクリレート系単量体などスチレン系単量体と共重合可能な単量体に置き換えてもよい。
【００１８】
上記スチレン系単量体を懸濁重合する際に重合系である懸濁系に添加される配合剤としては、分散剤、重合開始剤、発泡剤、難燃剤およびその助剤、気泡調節剤、他に、必要により分散助剤、可塑剤などが加えられる。
【００１９】
本発明に使用する分散剤としては、例えばポリビニールアルコール、ポリビニルピロリドン、ポリアクリルアミド等の高分子分散剤、例えば燐酸カルシウム、ハイドロキシアパタイト、ピロリン酸マグネシウム等の水に難溶な無機塩等を用いる事ができる。また水に難溶な無機塩を用いる場合には、α―オレフィンスルホン酸ソーダ、ドデシルベンゼンスルホン酸ソーダなどのアニオン界面活性剤を併用するのが好ましい。
【００２０】
本発明に使用する重合開始剤としては、一般にスチレン系単量体のラジカル重合に用いられている重合開始剤、例えば過酸化ベンゾイル、ｔ−ブチルパーオキシベンゾエート、イソプロピル-t-ブチルパーオキシカーボネート、過安息香酸ブチル、１，１−ビス（ｔ−ブチルパーオキシ）３，３，５―トリメチルシクロヘキサンのような有機過酸化物やアゾビスイソブチロニトリル等のアゾ化合物が使用でき、併用しても何ら差し支えない。
【００２１】
本発明で使用する発泡剤としては、Ｃ3からＣ5炭化水素であるプロパン、ブタン、ペンタン等の脂肪族炭化水素類およびトリフロロモノクロロエタン、ジフロロジクロロメタン等のハロゲン化炭化水素等の沸点が８０℃以下の揮発性発泡剤が使用できる。また、これらの発泡剤を併用しても何ら差し支えない。使用量としては、ポリスチレン系樹脂１００重量部に対して、３〜１０重量部、好ましくは５〜９重量部である。
【００２２】
本発明で使用される可塑剤としては、ステアリン酸トリグリセライド、パルミチン酸トリグリセライド、ラウリン酸トリグリセライド、ステアリン酸ジグリセライド、ステアリン酸モノグリセライド等の脂肪酸グリセライド、ヤシ油、パーム油、パーム核油等の植物性油脂、ジオクチルアジペート等の脂肪族エステル、シクロヘキサン、トルエン、キシレン等の有機炭化水素類や流動パラフィンなどが使用される。また、これらを併用しても良い。
【００２３】
本発明で使用されるハロゲン系難燃剤としては、その分解温度と発泡体の燃焼温度との兼ね合いにより発泡体用途における難燃性に極めて優れる点からハロゲン化脂肪族炭化水素化合物が好ましく、特にその５０％分解温度が３５０℃以下であるヘキサブロモシクロドデカンが好ましい。
【００２４】
また、ハロゲン系難燃剤は、慣用の有効量、すなわち０．１から６重量部、特に好ましは０．５から３重量部である。上記範囲未満では充分な難燃性が得難く、６重量部を越えると得られる発泡性ポリスチレン系樹脂粒子の成形体の物性面での低下が生じる傾向となる。
【００２５】
必要に応じては、難燃助剤を０．０１から３重量部、好ましくは０．１から２重量部が添加される。難燃助剤としては、クメンハイドロパーオキサイド、ジクミルパーオキサイド、ターシャルブチルハイドロパーオキサイド、２，３−ジメチルー２，３−ジフェニルブタン等の高温分解型開始剤が使用される。
【００２６】
本発明で使用される気泡調整剤としては、脂肪族ビスアマイド、メチルメタクリレート・ブタジエン・スチレン共重合体（ＭＢＳ）、スチレン・ブタジエン共重合体が挙げられ、単独で又は、２種以上併用できる。
【００２７】
本発明に用いられる脂肪族ビスアマイドは、式１に表す構造式で示される脂肪族ビスアマイドである。
【００２８】
【化１】
【００２９】
具体的にはメチレンビスステアリン酸アマイド、メチレンビスミリスチン酸アマイド、エチレンビスステアリン酸アマイド、ヘキサメチレンビスパルミチン酸アマイド、エチレンビスオレイン酸アマイド、エチレンビスラウリン酸アマイド等が好ましく、その内でもメチレンビスステアリン酸アマイド、エチレンビスステアリン酸アマイド、エチレンビスオレイン酸アマイド等がより好ましい。さらに、エチレンビスステアリン酸アマイドが最も好ましい。これらは単独または数種併用しても差し支えない。
【００３０】
その添加量は０．００１〜０．３重量部、好ましくは０．０１〜０．１５重量部であり、この添加量を調節することによって成形して得られる成形体の切断面気泡径を任意にコントロールすることができる。上記範囲未満では十分な気泡調節効果は得にくい傾向となり、０．３重量部を越えて添加すると、成形して得られる成形体の切断面気泡サイズが過剰に微細になりやすく、好ましくない。
【００３１】
本発明に用いられるメチルメタクリレート・ブタジエン・スチレン系共重合体樹脂は、具体的にはスチレン・ブタジエンゴムにメチルメタクリレート、スチレン及び、或いはブチルアクリレート、アクリロニトリルをグラフト重合してなる共重合体樹脂やポリブタジエンゴムにメチルメタアクリレート、スチレン及び、或いはブチルアクリレート、アクリロニトリルをグラフト重合してなる共重合体樹脂よりなる群から選ばれる。その添加量は０．０１〜１重量部、好ましくは０．０２〜０．５重量部である。上記範囲未満では十分な気泡調節効果は得られず、１重量部を越えて添加すると、気泡サイズが過剰に微細となるため、好ましくない。
【００３２】
本発明で用いられるスチレン・ブタジエン共重合体としては、一般に市販されているハイインパクトポリスチレンを使用する事ができ、特に制限はない。その添加量は０．０１〜１重量部、好ましくは０．０２〜０．５重量部である。上記範囲未満では十分な気泡調節効果は得られず、１重量部を越えて添加すると、気泡サイズが過剰に微細となるため、好ましくない。
【００３３】
また、一般に用いられているポリエチレンワックスは、難燃剤を併用すると短期間で、成形して得られる成形体切断面気泡が超微細化するため目的とする気泡径に調節はできないことが判った。
【００３４】
本発明における重合法は、前記特定の難燃剤と特定の気泡径調節剤を用いる以外は前記した公知特許公報中に記載された方法等を含む公知の発泡性スチレン系重合体粒子を得る懸濁重合法およびシード重合法等が、特に制限されることなく採用し得る。
【００３５】
例えば、懸濁重合法は分散剤を含む水性媒体中に、有機過酸化物などを溶解したスチレン系モノマーを分散させて懸濁液を調整し、その後加熱してラジカルを発生させて重合を完結させるものである。また、シード重合法は分散剤を含む水性媒体中に種粒子としてスチレン系樹脂粒子を分散させ、所定の温度に制御しながらスチレン系モノマーと有機過酸化物などを単独或いは混合して、連続または断続的に重合系に添加して重合を完結させるものである。そして、発泡性ポリスチレン系樹脂粒子はこれら重合中または重合後に前記した発泡剤を添加することで得られる。尚本発明における重合系中に存在させるとは、発泡性ポリスチレン系樹脂粒子を製造する重合の途中にその重合系内に存在させることをいう。
【００３６】
【実施例】
以下に実施例および比較例を挙げるが、これによって本発明は限定されるものではない。
【００３７】
（実施例１）
３Ｌの回転撹拌機付きオートクレーブ内に、蒸留水１０００ｇ、第三リン酸カルシュウム２．５ｇ、α―オレフィンスルホン酸ソーダ０．０５ｇ、エチレンビスステアリン酸アマイド０．１ｇを仕込み、次いで、スチレン１０００ｇにベンゾイルパーオキサイド２ｇ、安息香酸ブチル０．５ｇ、ヘキサブロモシクロドデカン（ＨＢＣＤ）１０ｇ、ジオクチルフタレート０．５ｇを溶解させて仕込んだ。
【００３８】
次に、該オートクレーブを９０℃の温度まで昇温し、同温度で６時間スチレンを重合させた後、ブタンを８０ｇを圧入し、その後、オートクレーブを１１０℃の温度まで昇温させて、生成重合体粒子中にブタンを４時間かけて含浸させた。この後、反応系を３０℃の温度にまで徐冷し、重合を終了させた。
【００３９】
得られた発泡性ポリスチレン系樹脂粒子を、遠心分離器にて脱水し、乾燥後、粒径０．８４〜１．１９ｍｍで分級し、熟成を行わずに嵩倍率８０倍に予備発泡させて予備発泡粒子を得た。 この予備発泡粒子の気泡は均一であった。
【００４０】
次に、この予備発泡粒子を室温で１日養生させた後、３００×６００×２５ｍｍの金型キャビ内に充填し、０．７ｋｇｆ／ｃｍ2の水蒸気で１５秒間加熱して型物成形して発泡成形品を得た。
（評価）
＜気泡径の測定＞
成形体の平均気泡径はＡＳＴＭ―Ｄ−２８４２−９７に準じて、発泡体の切断面を撮影した走査型電子顕微鏡写真から、切断面の一直線上（６０ｍｍ）にかかる気泡数から平均弦長を測定した。
【００４１】
＜熱伝導率の測定＞
成形体を乾燥後２００×２００ｍｍに切り出し５０℃×５日間アニーリングを施した後、ＪＩＳ Ａ １４１２に基つき熱伝導率計（英弘精機…ＨＣ−０７３）を用いて、２０℃における熱伝導率を測定した。
【００４２】
＜自己消火性＞
難燃性能は、ＪＩＳ Ａ ９５１１に準じて成形体の燃焼試験を測定した。
【００４３】
＜表面性＞
成形体の表面性は、成形したものを約３５℃の乾燥室で一昼夜保管したものを目視観察で下記５段階に評価した。
【００４４】
５；粒子間隙がほとんど無く綺麗である。
【００４５】
４；粒子間隙は若干見られる。
【００４６】
３；粒子間隙はあるが実用上問題ない最低レベルである。
【００４７】
２；粒子間隙が多数あり問題がある。
【００４８】
１；使用できないレベルである、
＜気泡径の経時変化＞
気泡径の経時変化を調べるため上記で得た粒子の一部を密閉容器に入れ、 室温で４週間保管した後取り出し、前記同様に成形体の切断面気泡状態および表面性を調べた。
【００４９】
これらの結果を表１に示す。
（実施例２）
ジオクチルフタレート０．５ｇを椰子油１ｇに変更し、気泡調整剤エチレンビスステアリン酸アマイド量を０．５ｇに変更する以外は実施例１と同様に実施した。
（実施例３〜１０および比較例１〜９）
気泡調整剤種、気泡調整剤量及び難燃剤量を表１に示す用に変更する以外は実施例１と同様に実施した。表中の記号を下記に説明する。
ＥＢＳ：エチレンビスステアリリン酸アマイド
Ｂ１２：鐘淵化学工業（株）製カネエースＢ１２
Ｂ５６１：鐘淵化学工業（株）製カネエースＢ５６１
ＥＸＧ１１：エーアンドエムスチレン（株）製ＥＸＧ１１
ＰＥＷ：ポリエチレンワックス
ＨＢＣＤ：ヘキサブロモシクロドデカン
（評価）
得られた発泡性ポリスチレン系樹脂粒子は、実施例１と同様に分級、予備発泡、成形して表１に示す物性の型内発泡成形品を得た。
【００５０】
【表１】
【発明の効果】
以上説明し、かつ実証した通り、本発明は、製造直後から約一ヶ月以上にかけて発泡させて成形して得られる成形体の切断面気泡径の経時変化が少なく、かつ成形体切断面気泡径の平均弦長を９０〜２００μの範囲内としうることにより、優れた断熱性能と表面性を有する難燃性発泡性ポリスチレン系樹脂粒子を提供することができる。[0001]
BACKGROUND OF THE INVENTION
When the expandable polystyrene resin particles are heated by a heating means such as water vapor or hot air, a large number of small bubbles are generated in the particles and become pre-expanded particles. Then, when the pre-expanded particles are filled in the mold and heated again, the pre-expanded particles are secondarily expanded and fused to each other, and the expanded polystyrene resin molded product faithful to the mold shape in the mold Can be molded. Therefore, the foamed polystyrene-based resin molded body thus obtained can be used as a heat insulating material for buildings, embankment and the like.
[0002]
The present invention combines a halogenated flame retardant and an aliphatic bisamide, a methyl methacrylate / butadiene / styrene copolymer, and a styrene / butadiene copolymer as a foam control agent in the production of expandable polystyrene resin particles. Even after about 1 month or more, the foamed polystyrene resin particles obtained are subjected to secondary foaming in the mold and molded, and there is little change in the cell diameter of the cut surface of the molded product. The present invention relates to an expandable polystyrene resin particle having an average chord length of a surface cell diameter of 90 to 200 μm, having excellent heat insulation performance and flame retardancy, and a method for producing the same.
[0003]
[Prior art]
As is well known, expanded polystyrene-based resin molded products are used in a wide range of applications, but it is essential to supply flame-retardant expanded molded products, particularly in the field of building materials and embankments. Recently, there is a case where a molded body that is larger, thicker or higher-magnified than before is required, and a flame-retardant foamed polystyrene resin with better dimensional stability and mechanical strength is obtained. Things have become necessary. In particular, in the building material field, a foamed polystyrene-based molded body used as a heat insulating material for walls and floors is highly desired from the viewpoint of energy saving.
[0004]
In general, the thermal insulation effect of a polystyrene foam resin molding is equivalent to a bubble size of about 5 to 10 bubbles per mm (that is, an average chord length of about 100 to 200 μm as described in JP-A-2-305839). It is known that the best thermal insulation effect is exhibited.
[0005]
On the other hand, for flame retardancy of expandable polystyrene resin particles, (a) a method of adding a flame retardant together with a styrene monomer during polymerization, and (b) adding a flame retardant when impregnating a polystyrene resin with a foaming agent. One of the methods has been adopted. Polystyrene polymer particles produced by these methods have a nucleating action because the flame retardant itself has a nucleating action. At the same time, aging usually occurs from the vicinity of the particle surface. Therefore, the so-called non-particle unevenness in which the bubble state differs depending on the size of the particles has occurred.
[0006]
For this reason, it has been recognized that it is difficult to obtain a uniform bubble having an arbitrary bubble diameter, and eventually becomes an ultrafine bubble. For this reason, it has been pointed out that when the molding is performed on the high-pressure side, the surface of the molded body is melted and the molding width is narrow and difficult to handle.
[0007]
As a technique for adjusting the cell diameter of the flame-retardant foamed polystyrene resin molded article, Japanese Patent Laid-Open No. 2-305839 discloses a technique in which an ammonium salt and an organic amine are used in combination as a cell regulator. In WO97 / 17396, the bubble diameter is adjusted by selecting the surfactant type.
[0008]
[Problems to be solved by the invention]
However, organic amines used as bubble regulators in JP-A-2-305839 are not preferred due to concerns about toxicity, and WO97 / 17396 adjusts the bubble diameter by selecting a surfactant and uses a bubble regulator. Since it is not contained, there is a problem that the aging period of the bubbles is long and the lead time is long, and it is difficult to industrially mass-produce the foamed polystyrene resin molded body having the described thermal conductivity. .
[0009]
For this reason, there is no concern about toxicity, there is little change over time in the cut surface bubbles of the molded product obtained by molding, and flame retardant foamed polystyrene with excellent surface properties and heat insulation properties that can arbitrarily control the bubble diameter System resin particles have been eagerly desired.
[0010]
[Means for Solving the Problems]
As a result of intensive research to solve such problems, by adding an appropriate amount of a halogen-based flame retardant and a specific cell regulator to the expandable polystyrene resin particles, the average chord length of the foam bubbles immediately after production is increased. The inventors have found that expandable polystyrene resin particles having a bubble diameter effective for heat insulation performance of 90-200 μm and hardly changing the bubble diameter over time can be obtained, and the present invention has been completed.
[0011]
That is, the present invention includes (1) 0.1 to 6 parts by weight of hexabromocyclododecane as a halogen-based flame retardant and 0.001 to 0.3 parts by weight of aliphatic bisamide in 100 parts by weight of a polystyrene resin. Expandable polystyrene resin particles characterized by the above.
[0012]
(2) To 100 parts by weight of polystyrene resin , 0.1 to 6 parts by weight of hexabromocyclododecane as a halogen-based flame retardant and 0.01 mg of methyl methacrylate / butadiene / styrene copolymer and / or styrene / butadiene copolymer. Expandable polystyrene resin particles characterized by containing ˜1 part by weight.
[0013]
(3) The expandable polystyrene resin particles according to (1) or (2), wherein an average chord length of a bubble diameter of a cut surface of the molded product when foamed is in a range of 90 to 200 μm.
[0014]
(4) When producing expandable polystyrene resin particles, 0.1 to 6 parts by weight of hexabromocyclododecane as a halogen flame retardant and aliphatic with respect to 100 parts by weight of styrene monomer in the polymerization system A method for producing expandable polystyrene resin particles, comprising adding 0.001 to 0.3 parts by weight of bisamide and adding a foaming agent during or after polymerization.
[0015]
(5) When producing expandable polystyrene resin particles, 0.1 to 6 parts by weight of hexabromocyclododecane as a halogen flame retardant and methyl methacrylate with respect to 100 parts by weight of styrene monomer in the polymerization system -Production of expandable polystyrene resin particles characterized by containing 0.01 to 1 part by weight of butadiene / styrene copolymer and / or styrene / butadiene copolymer and adding a foaming agent during or after polymerization. Is the method.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, for example, when producing expandable polystyrene resin particles, 0.1 to 6 parts by weight of a halogen-based flame retardant and 100 parts by weight of a styrene monomer and 0 to aliphatic bisamide are added in a polymerization system. The present invention provides expandable polystyrene resin particles characterized by the presence of 0.001 to 0.3 parts by weight.
[0017]
As the styrene monomer used in the present invention, styrene can be used as a main component and styrene monomers other than styrene such as α-methylstyrene and vinyltoluene can be mixed and used. A part of the styrene monomer is a vinyl monomer other than that, for example, a vinyl cyanide monomer such as acrylonitrile, an acrylate monomer such as butyl acrylate, a methacrylate monomer such as methyl methacrylate, and the styrene. It may be replaced with a monomer copolymerizable with the system monomer.
[0018]
As a compounding agent added to the suspension system which is a polymerization system when the styrene monomer is subjected to suspension polymerization, a dispersant, a polymerization initiator, a foaming agent, a flame retardant and its auxiliary agent, a bubble regulator, In addition, a dispersion aid, a plasticizer, etc. are added if necessary.
[0019]
Examples of the dispersant used in the present invention include polymer dispersants such as polyvinyl alcohol, polyvinyl pyrrolidone, and polyacrylamide, such as inorganic salts that are hardly soluble in water such as calcium phosphate, hydroxyapatite, and magnesium pyrophosphate. Can do. When an inorganic salt that is hardly soluble in water is used, it is preferable to use an anionic surfactant such as α-olefin sulfonic acid soda and dodecylbenzene sulfonic acid soda together.
[0020]
As the polymerization initiator used in the present invention, polymerization initiators generally used for radical polymerization of styrenic monomers, such as benzoyl peroxide, t-butyl peroxybenzoate, isopropyl-t-butyl peroxycarbonate, Organic peroxides such as butyl perbenzoate and 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane and azo compounds such as azobisisobutyronitrile can be used in combination. There is no problem.
[0021]
Examples of the blowing agent used in the present invention include C 3 to C 5 hydrocarbons such as propane, butane, pentane and other aliphatic hydrocarbons and halogenated hydrocarbons such as trifluoromonochloroethane and difluorodichloromethane. A volatile foaming agent of 80 ° C. or lower can be used. Moreover, there is no problem even if these foaming agents are used in combination. As a usage-amount, it is 3-10 weight part with respect to 100 weight part of polystyrene-type resin, Preferably it is 5-9 weight part.
[0022]
As plasticizers used in the present invention, fatty acid glycerides such as stearic acid triglyceride, palmitic acid triglyceride, lauric acid triglyceride, stearic acid diglyceride, stearic acid monoglyceride, vegetable oils such as coconut oil, palm oil, palm kernel oil, Aliphatic esters such as dioctyl adipate, organic hydrocarbons such as cyclohexane, toluene and xylene, and liquid paraffin are used. These may be used in combination.
[0023]
The halogen-based flame retardant used in the present invention is preferably a halogenated aliphatic hydrocarbon compounds from very excellent points flame retardant in the foam applications by balance with the combustion temperature of the foam and its decomposition temperature, in particular the Hexabromocyclododecane having a 50% decomposition temperature of 350 ° C. or lower is preferred.
[0024]
The halogen-based flame retardant is a conventional effective amount, that is, 0.1 to 6 parts by weight, particularly preferably 0.5 to 3 parts by weight. When the amount is less than the above range, it is difficult to obtain sufficient flame retardancy, and when it exceeds 6 parts by weight, the resulting foamed polystyrene resin particles tend to be deteriorated in physical properties.
[0025]
If necessary, 0.01 to 3 parts by weight, preferably 0.1 to 2 parts by weight of a flame retardant aid is added. As the flame retardant aid, a high temperature decomposition type initiator such as cumene hydroperoxide, dicumyl peroxide, tertiary butyl hydroperoxide, 2,3-dimethyl-2,3-diphenylbutane is used.
[0026]
Examples of the air conditioner used in the present invention include aliphatic bisamide, methyl methacrylate / butadiene / styrene copolymer (MBS), and styrene / butadiene copolymer, which can be used alone or in combination of two or more.
[0027]
The aliphatic bisamide used in the present invention is an aliphatic bisamide represented by the structural formula shown in Formula 1.
[0028]
[Chemical 1]
[0029]
Specifically, methylene bis stearic acid amide, methylene bis myristic acid amide, ethylene bis stearic acid amide, hexamethylene bis palmitic acid amide, ethylene bis oleic acid amide, ethylene bis lauric acid amide, etc. are preferable, and among them, methylene bis stearic acid amide. Acid amide, ethylene bis stearic acid amide, ethylene bis oleic acid amide and the like are more preferable. Furthermore, ethylene bis stearic acid amide is most preferred. These may be used alone or in combination of several kinds.
[0030]
The amount of addition is 0.001 to 0.3 parts by weight, preferably 0.01 to 0.15 parts by weight. By adjusting the amount of addition, the cell diameter of the cut surface of the molded body obtained by molding can be arbitrarily set. Can be controlled. If the amount is less than the above range, a sufficient bubble control effect tends to be difficult to obtain, and if it exceeds 0.3 parts by weight, the cell size of the cut surface of the molded product obtained by molding tends to become excessively fine, such being undesirable.
[0031]
Specifically, the methyl methacrylate / butadiene / styrene copolymer resin used in the present invention is a copolymer resin or polybutadiene obtained by graft polymerization of methyl methacrylate, styrene and / or butyl acrylate and acrylonitrile on a styrene / butadiene rubber. The rubber is selected from the group consisting of copolymer resins obtained by graft polymerization of methyl methacrylate, styrene and / or butyl acrylate and acrylonitrile. The addition amount is 0.01 to 1 part by weight, preferably 0.02 to 0.5 part by weight. If the amount is less than the above range, a sufficient bubble adjusting effect cannot be obtained, and if the amount exceeds 1 part by weight, the bubble size becomes excessively fine, which is not preferable.
[0032]
As the styrene / butadiene copolymer used in the present invention, commercially available high impact polystyrene can be used, and there is no particular limitation. The addition amount is 0.01 to 1 part by weight, preferably 0.02 to 0.5 part by weight. If the amount is less than the above range, a sufficient bubble adjusting effect cannot be obtained, and if the amount exceeds 1 part by weight, the bubble size becomes excessively fine, which is not preferable.
[0033]
In addition, it has been found that the commonly used polyethylene wax cannot be adjusted to the target cell diameter because the molded product cut surface bubbles obtained by molding become ultrafine in a short period of time when a flame retardant is used in combination.
[0034]
The polymerization method in the present invention is a suspension for obtaining known expandable styrenic polymer particles including the method described in the above-mentioned known patent publication except that the specific flame retardant and the specific cell diameter regulator are used. A polymerization method, a seed polymerization method, and the like can be employed without any particular limitation.
[0035]
For example, in the suspension polymerization method, a suspension is prepared by dispersing a styrene monomer in which an organic peroxide or the like is dissolved in an aqueous medium containing a dispersant, and then heated to generate radicals to complete the polymerization. It is something to be made. In the seed polymerization method, styrene resin particles are dispersed as seed particles in an aqueous medium containing a dispersant, and a styrene monomer and an organic peroxide are used alone or mixed while being controlled at a predetermined temperature. It is intermittently added to the polymerization system to complete the polymerization. The expandable polystyrene resin particles can be obtained by adding the foaming agent described above during or after the polymerization. In addition, making it exist in the polymerization system in this invention means making it exist in the polymerization system in the middle of the superposition | polymerization which manufactures an expandable polystyrene resin particle.
[0036]
【Example】
Examples and Comparative Examples are given below, but the present invention is not limited thereby.
[0037]
Example 1
In a 3 L autoclave equipped with a rotary stirrer, 1000 g of distilled water, 2.5 g of calcium triphosphate, 0.05 g of α-olefin sulfonic acid sodium, and 0.1 g of ethylene bis-stearic acid amide were added, and then benzoyl was added to 1000 g of styrene. 2 g of peroxide, 0.5 g of butyl benzoate, 10 g of hexabromocyclododecane (HBCD), and 0.5 g of dioctyl phthalate were dissolved and charged.
[0038]
Next, the autoclave is heated to a temperature of 90 ° C., styrene is polymerized at the same temperature for 6 hours, 80 g of butane is injected, and then the autoclave is heated to a temperature of 110 ° C. The coalesced particles were impregnated with butane for 4 hours. Thereafter, the reaction system was gradually cooled to a temperature of 30 ° C. to complete the polymerization.
[0039]
The obtained expandable polystyrene resin particles are dehydrated with a centrifuge, dried, classified with a particle size of 0.84 to 1.19 mm, pre-foamed at a bulk magnification of 80 times without aging, and preliminarily prepared. Expanded particles were obtained. The pre-expanded particles had uniform air bubbles.
[0040]
Next, after the pre-expanded particles are cured at room temperature for 1 day, they are filled in a mold cabinet of 300 × 600 × 25 mm and heated with 0.7 kgf / cm 2 of steam for 15 seconds to form a mold. A foam molded product was obtained.
(Evaluation)
<Measurement of bubble diameter>
According to ASTM-D-2842-97, the average cell diameter of the molded body is calculated from the scanning electron micrograph obtained by photographing the cut surface of the foam, and the average chord length is calculated from the number of bubbles applied on a straight line (60 mm) of the cut surface. It was measured.
[0041]
<Measurement of thermal conductivity>
After the molded body was dried and cut into 200 × 200 mm and annealed at 50 ° C. for 5 days, the thermal conductivity at 20 ° C. was measured using a thermal conductivity meter (Eihiro Seiki… HC-073) based on JIS A 1412. It was measured.
[0042]
<Self-extinguishing>
For the flame retardancy, a fire test of the molded product was measured according to JIS A 9511.
[0043]
<Surface property>
The surface property of the molded product was evaluated by visual observation of the molded product stored overnight in a drying room at about 35 ° C. in the following five stages.
[0044]
5: It is beautiful with almost no particle gaps.
[0045]
4; Some particle gaps are seen.
[0046]
3; lowest level at which there is a particle gap but no practical problem.
[0047]
2: There are many particle gaps and there is a problem.
[0048]
1: Level that cannot be used
<Change in bubble diameter over time>
In order to examine the change with time of the bubble diameter, a part of the particles obtained above was put in a sealed container, stored for 4 weeks at room temperature, and then taken out.
[0049]
These results are shown in Table 1.
(Example 2)
The same procedure as in Example 1 was performed except that 0.5 g of dioctyl phthalate was changed to 1 g of coconut oil and the amount of the bubble regulator ethylene bis stearic acid amide was changed to 0.5 g.
(Examples 3 to 10 and Comparative Examples 1 to 9)
The same procedure as in Example 1 was carried out except that the type of bubble regulator, the amount of bubble regulator and the amount of flame retardant were changed as shown in Table 1. The symbols in the table are explained below.
EBS: Ethylene bis stearyl phosphate amide B12: Kane Ace B12 manufactured by Kaneka Chemical Co., Ltd.
B561: Kane Ace B561 manufactured by Kaneka Chemical Co., Ltd.
EXG11: EXG11 manufactured by A & M Styrene Co., Ltd.
PEW: Polyethylene wax HBCD: Hexabromocyclododecane (evaluation)
The obtained expandable polystyrene resin particles were classified, prefoamed and molded in the same manner as in Example 1 to obtain in-mold foam molded products having physical properties shown in Table 1.
[0050]
[Table 1]
【The invention's effect】
As described above and demonstrated, the present invention has little change over time in the cell diameter of the cut surface of a molded product obtained by foaming and molding for about one month or more immediately after production, By setting the average chord length within the range of 90 to 200 μm, it is possible to provide flame-retardant expandable polystyrene resin particles having excellent heat insulation performance and surface properties.
Claims (5)
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| JP2001320904A JP4035979B2 (en) | 2000-10-20 | 2001-10-18 | Expandable polystyrene resin particles and method for producing the same |
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| JP2000-321551 | 2000-10-20 | ||
| JP2000321551 | 2000-10-20 | ||
| JP2001320904A JP4035979B2 (en) | 2000-10-20 | 2001-10-18 | Expandable polystyrene resin particles and method for producing the same |
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| JP4035979B2 true JP4035979B2 (en) | 2008-01-23 |
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|---|---|---|---|---|
| US9079342B2 (en) | 2009-03-30 | 2015-07-14 | Sekisui Plastics Co., Ltd. | Expandable polystyrene resin particles and method for producing the same |
| US10358538B2 (en) | 2009-10-27 | 2019-07-23 | Sekisui Plastics Co., Ltd. | Foamable polystyrene resin particles and polystyrene resin prefoamed particles |
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|---|---|---|---|---|
| JP2008525572A (en) * | 2004-12-22 | 2008-07-17 | アルベマール・コーポレーシヨン | Flame retardant foamed polystyrene foam composition |
| MX2007007548A (en) * | 2004-12-22 | 2007-07-20 | Albemarle Corp | Flame retardant extruded polystyrene foam compositions. |
| CN101087818A (en) * | 2004-12-22 | 2007-12-12 | 雅宝公司 | Flame retardant polystyrene foam compositions |
| JP5188083B2 (en) * | 2007-03-26 | 2013-04-24 | 積水化成品工業株式会社 | Method for producing flame retardant expandable polystyrene resin particles |
| IT1395379B1 (en) * | 2009-09-07 | 2012-09-14 | Polimeri Europa Spa | PROCEDURE FOR THE PREPARATION OF EXPANDABLE VINYLAROMATIC POLYMERS WITH REDUCED THERMAL CONDUCTIVITY BY MEANS OF SUSPENSION POLYMERIZATION |
| US20120214885A1 (en) | 2009-10-27 | 2012-08-23 | Hiroyuki Tarumoto | Foamable polystyrene resin particles and process for production thereof, polystyrene resin prefoamed particles, polystyrene resin foam-molded article, heat-insulating material for building material, banking member, and vehicle interior material |
| JP5909903B2 (en) * | 2011-07-15 | 2016-04-27 | 株式会社カネカ | Method for producing flame retardant foamable styrene resin particles |
| JP6135791B2 (en) * | 2016-03-30 | 2017-05-31 | 株式会社カネカ | Method for producing flame retardant foamable styrene resin particles |
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2001
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9079342B2 (en) | 2009-03-30 | 2015-07-14 | Sekisui Plastics Co., Ltd. | Expandable polystyrene resin particles and method for producing the same |
| US10358538B2 (en) | 2009-10-27 | 2019-07-23 | Sekisui Plastics Co., Ltd. | Foamable polystyrene resin particles and polystyrene resin prefoamed particles |
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| JP2002194130A (en) | 2002-07-10 |
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