| 摘要 |
PURPOSE:To obtain expandable resin particles effective in shortening the cooling time in molding, by carrying out suspension polymerization of a styrene monomer in an aqueous medium in the presence of paraffin which is solid at normal temperature and impregnating the polymer with a foaming agent at the latter state or after the completion of the polymerization. CONSTITUTION:An expandable styrene resin particle containing 0.01-0.5wt.% paraffin can be produced by (A) carrying out suspension polymerization of a styrene monomer (containing >=50% styrene or its derivative) in an aqueous medium while adding a paraffin having a melting point of 40-70 deg.C in an amount of 0.01-0.8% (based on the total monomer) to the polymerization system when the polymerization conversion is preferably 50-90% and (B) impregnating the obtained polymer with 1-20% foaming agent which is liquid or gaseous at normal temperature (e.g. propane, butane, etc.) based on the styrene resin particle. The addition of the paraffin is carried out in the form of a solution dissolved in a small amount of a solvent or the styrene monomer.
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