The EPS resin in used for the moulding of EPS products. It is manufactured in the form of very small polystyrene beads with a weight – average molecular weight between 160,000 and 260,000 and contains 4 to 7% blowing agent, usually pentanes or butane.The bead diameter can vary between 0.007 – inches(0.2mm) to 0.11 – inches(3.0 mm).
Ploymerization and Impregnation
The first methods developed involved two step process; polymerization of styrene monomer followed by impregnation of the polymerized polystyrene bead with a blowing agent.
