Production of expandable polystyrene beads with low water content

摘要

The production of expandable polystyrene beads (EPS) with a low internal water content is by (i) polymerisation of styrene in aqueous suspension in presence of blowing agents, then (ii) separation of the aqueous phase to give beads containing the blowing agent, with a water content of up to 5 wt%. This water is then removed by extracting the beads for 1-8 hrs. at 10-60 deg C with an organic liquid (I) with a b.pt. of 20-90 deg C which is a non-solvent for polystyrene (PS).