Patent ID: 8173714

Claim:
An expanded styrene polymer having a density in the range from 7 to 20 g/l and a thermal conductivity λ, determined at 10° C. in accordance with DIN 52612, in the range from 27 to 31 mW/m*K, which comprises from 1 to 4% by weight of natural graphite having a mean particle size in the range from 1 to 50 μm, and which has been obtained by pre-foaming, and welding of an expandable styrene polymer, the expandable styrene polymer having been obtained by polymerization of styrene and, optionally, copolymerizable monomers and impregnation with a blowing agent, wherein the polymerization is carried out in the presence of 0.01 to 2% of a nonionic surfactant.