| 摘要 |
PURPOSE:To produce a styrenic polymer having a narrow particle size distribution, by previously making particle diameters of styrenic polymer particles uniform, suspending them in water, adding two polymerization initiators having different decompositions temperatures and carrying out polymerization. CONSTITUTION:Styrenic polymer particles obtained by suspension polymerization are sieved, made uniform so that particles diameters are the average diameter + or -20% average diameter, the particles are suspended in water, a polymerization initiator (e.g. lauroyl peroxide) having 50-80 deg.C decomposition temperature to obtain a half-life of 10hr in an amount to give >=1/2 amount which is required for polymerization of a styrenic monomer to be added to a aqueous suspension system afterward is added to water and the styrenic monomer containing a styrene monomer as a main component, a polymerization initiator (e.g. cyclohexanone peroxide, etc.) having 80-120 deg.C decomposition temperature to obtain a half-life of 10hr and the rest of the polymerization initiator having 50-80 deg.C decomposition temperature is added to the aqueous suspension system, to carry out polymerization.
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