| 摘要 |
PURPOSE:To prepare efficiently the titled particles exhibiting excellent heat and solvent resistance and good expandability and moldability, by bulk polymerization of a specified monomer mixture using specified initiators, followed by suspension polymerization thereof, and impregnation of the obtained polymer with a volatile foaming agent. CONSTITUTION:A monomer mixture comprising 10-80wt% alpha-methylstyrene, 5- 50wt% acrylonitrile, and 0-70wt% compound selected from among styrene, chlorostyrene, t-butylstyrene, methyl methacrylate, etc. is bulk polymerized to a degree of conversion of 15-40wt% at 80-150 deg.C using a polyfunctional organic peroxide having a 10hr half-life temperature of 50-130 deg.C (e.g. di-t-butyl peroxyhexahydro terephthalate) and/or an azo compound (e.g. 2-t-butylazo-2-cyanobutane) as initiator. The obtained copolymer solution is fed into water containing a suspension stabilizer and is suspension polymerized at 80-150 deg.C. During or after suspension polymerization, the polymer particles are impregnated with a volatile foaming agent to produce the titled particles.
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