Patent ID: 6271272
Filing Date: 2001-08-07
Classification: C08J

Abstract:
A homogeneous composition of an expandable styrene polymer in the form of beads, comprising:(a) 100 parts by weight of a styrene polymer having a weight-average molecular mass, M.sub.w, of 150,000 to 300,000 and a residual monomer content of less than 2000 ppm;(b) from 2 to 9 parts by weight of at least one blowing agent comprising n-pentane;(c) from 0.1 to less than 1.0 parts by weight of a petroleum wax comprising a mixture of C.sub.18 to C.sub.80 alkanes; and(d) from 0 to 1.0 part by weight of a nucleating agent chosen from synthetic Fischer-Tropsch or polyolefin waxes,wherein the petroleum wax is distributed substantially uniformly throughout the composition, said composition being prepared in part by polymerizing styrene in an aqueous suspension to obtain the styrene polymer in the presence of the petroleum wax, the petroleum wax being introduced into the aqueous suspension at a time when the conversion of the styrene into styrene polymer is from 0 to 35%.