Expandable styrene resin beads and suspension-polymerization process for producing the same.

摘要

Expandable styrene resin beads are described, which, when expanded to a bulk density of 20 g/ l , give pre-expanded beads in which the number of cells present along those surface parts of radii which range from the bead surface to a depth of 0.2 mm from the surface is from 3 to 20 per mm and the number of cells present along those inner parts of the radii which range from a depth of 1 mm from the bead surface to the bead center is 10 or larger per mm, the number of cells present along said surface parts being smaller than the number of cells present along said inner parts.