JP2004161989A5

JP2004161989A5 -

Info

Publication number: JP2004161989A5
Application number: JP2003129890A
Authority: JP
Filing date: 2003-05-08
Publication date: 2006-05-11
Anticipated expiration: 2023-05-08

Description

【特許請求の範囲】
【請求項１】スチレン系単量体の懸濁重合において、
少なくとも重合後期のとき、反応槽内を低酸素濃度に保ちながら重合反応を進め、
重合反応の完了前または重合反応の完了後に、発泡剤を含浸するスチレン系発泡性樹脂粒子の製造方法。
【請求項２】スチレン系単量体の懸濁重合において、
重合開始より、反応槽内を低酸素濃度に保ちながら重合反応を進め、
重合反応の完了前又は重合反応の完了後に、昜揮発性発泡剤を含浸することを特徴とするスチレン系発泡性樹脂粒子の製造方法。
【請求項３】前記低酸素濃度が、７体積％以下であることを特徴とする請求項１又は２記載のスチレン系発泡性樹脂粒子の製造方法。
【請求項４】前記スチレン系単量体の懸濁重合において、水分散液の水素イオン濃度が８〜１０で重合が開始し、
重合率２０％〜５０％で、少なくとも１回以上、難溶性無機塩を加えることを特徴とする請求項１〜３のいずれか一項記載のスチレン系発泡性樹脂粒子の製造方法。
【請求項５】請求項１〜４のいずれか一項記載の製造方法により得られることを特徴とするスチレン系発泡性樹脂粒子。
【請求項６】最表面層発泡セルの重量平均分子量が、表面層発泡セルの重量平均分子量より大きいスチレン系発泡性樹脂粒子。
【請求項７】請求項５又は６記載のスチレン系発泡性樹脂粒子を発泡させて得られることを特徴とするスチレン系発泡ビーズ。
【請求項８】請求項７記載のスチレン系発泡ビーズを成形させて得られることを特徴とするスチレン系発泡成形品。 [Claims]
    1. A suspension polymerization of a styrenic monomer,
  At least during the late stage of the polymerization, the polymerization reaction proceeds while maintaining the inside of the reaction tank at a low oxygen concentration,
  A method for producing styrene-based expandable resin particles in which a foaming agent is impregnated before or after completion of the polymerization reaction.
    2. In the suspension polymerization of a styrene monomer,
  From the start of polymerization, the polymerization reaction is promoted while maintaining the inside of the reaction tank at a low oxygen concentration.
  A method for producing styrenic foamable resin particles, comprising impregnating a readily volatile foaming agent before or after completion of the polymerization reaction.
    3. The method for producing styrene-based expandable resin particles according to claim 1, wherein the low oxygen concentration is 7% by volume or less.
    4. In the suspension polymerization of the styrene-based monomer, polymerization starts when the hydrogen ion concentration of the aqueous dispersion is 8 to 10,
  The method for producing styrenic foamable resin particles according to any one of claims 1 to 3, wherein the sparingly soluble inorganic salt is added at least once or more at a polymerization rate of 20% to 50%.
    5. Styrene-based expandable resin particles obtained by the production method according to claim 1. Description:
    6.   Styrene-based foamable resin particles in which the weight average molecular weight of the outermost layer foam cell is larger than the weight average molecular weight of the surface layer foam cell.
    7.  Claim 5Or 6A styrene-based expanded bead obtained by expanding the styrene-based expandable resin particles described in the above.
    Claim 8.   Claim 7A styrene foam molded article obtained by molding the styrene foam beads.