EXPANDABLE POLYSTYRENE RESIN, PRE-EXPANDED RESIN AND EXPANDED COMPACT

摘要

Expandable polystyrene resin beads which can give expanded moldings having beautiful surface appearance and high strength even when the molding steam pressure is low and which permit shorter molding time. The expandable polystyrene resin beads can be produced by conducting the first polymerization step (1) of introducing 7.0 to 80.0 parts by mass of a styrenic monomer and 2.0 to 12.0 parts by mass of an acrylic ester monomer into an aqueous dispersion of seed particles of polystyrene resin per 100 parts by mass of the seed particles and making these monomers absorbed by the seed particles and polymerized to grow the seed particles; the second polymerization step (2) of introducing only a styrenic monomer into the dispersion and making the monomer absorbed by the seed particles and polymerized to grow resin particles; and the impregnation step (3) of impregnating the resulting particles with a blowing agent after or during the step (2).