Patent ID: 8729143

Claim:
An expandable, thermoplastic polymer bead material comprising A) from 45 to 89.5 percent by weight of a standard polystyrene (GPPS) polymer, B1) from 5 to 20 percent by weight of a polyolefin with a melting point in the range from 105 to 140° C., B2) from 1 to 15 percent by weight of a copolymer composed of ethylene and octene with a melting point below 105° C., C1) from 3 to 25 percent by weight of a styrene-butadiene or styrene-isoprene block copolymer, C2) from 0.5 to 5 percent by weight of a styrene-ethylene-butylene block copolymer, D) from 1 to 15 percent by weight of a blowing agent, and E) from 0 to 5 percent by weight of a nucleating agent, where the entirety composed of the components A) to E) gives 100% by weight wherein the entirety of components C1) and C2) lies within the range from 3.5 to 30 percent by weight, and wherein the expandable thermoplastic polymer bead material is composed of a multiphase polymer mixture which comprises blowing agent and consists of one continuous phase and two disperse phases P 1 and P 2 dispersed in the continuous phase, where a) the continuous phase consists essentially of component A, b) the first disperse phase P 1 consists essentially of components B1 and B2, and c) the second disperse phase P 2 consists essentially of component C1, and wherein the component C2 forms an interface between the disperse phase P 1 and the continuous phase.