Patent ID: 8536240
Filing Date: 2013-09-17
Classification: C08J

Abstract:
1. Pre-expanded beads having a bulk density chosen from a range of from 40 to 190 g/l and containing by weight: (a) 100 parts of a polymer of styrene having a mean molecular mass by weight Mw chosen from a range of from 180,000 to 250,000 and a molecular weight distribution calculated by the ratio of Mw to the mean molecular mass by number, M (b) from 0.5 to less than 3.0 parts of at least one blowing agent, (c) from 0 to 0.4 part of at least one plasticising agent comprising an oil which is liquid at 20° C., having on average from 25 to 38 carbon atoms, a dynamic viscosity at 25° C. of from 110 to 170 mPa·s and a density of from 0.8 to 0.9, and (d) less than 400 ppm of residual styrene monomer, wherein the pre-expanded beads are expandable.