| 摘要 |
PURPOSE:To continuously obtain a copolymer low in a content of low-MW copolymer and excellent in heat resistance, by polymerizing alpha-methylstyrene with styrene and acrylonitrile by using a specified polymerization initiator at a specified polymerization temperature. CONSTITUTION:A monomer mixture comprising 30-60wt% alpha-methylstyrene (A), 20-40wt% acrylonitrile (B) and 50-5wt% styrene (C) is continuously fed to a single-tank complete mixing type of reaction tank containing 0.05-0.0015mol%, based on component A, t-butylperoxy 2-ethylhexanoate as a polymerization initiator and is polymerized at 100-130 deg.C for 1-5hr to a conversion of 30-60wt%. Unreacted monomers are recovered by partial condensation, and part or the whole of the recovered monomers are continuously fed to said reaction tank to obtain an alpha-methylstyrene/acrylonitrile/styrene copolymer of a reduced viscosity (as measured in a solution of 0.5g of polymer in 100mol of dimethylformamide at 30 deg.C)>=0.45.
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