Patent ID: 7901602

Claim:
A method for producing expandable styrene-modified olefin-based resin particles comprising steps of: impregnating styrene-modified olefin-based resin particles with an easily volatile blowing agent to obtain expandable resin particles, and impregnating 100 parts by weight of the expandable resin particles with 0.1 to 2.0 parts by weight of a surfactant at a temperature of 10 to 30° C. and an internal pressure of 0.05 to 0.30 MPa, to obtain expandable styrene-modified olefin-based resin particles, wherein the surfactant is represented by the following general formula (1): [(R1) 4 N] + C 2 H 5 OSO 3 —, and R1 is the same or different, and optionally branched alkyl group of a carbon number of 1 to 17; where the styrene-modified olefin-based resin particles comprise a polyolefin-based resin and a polystyrene-based resin, the polyolefin-based resin being selected from a low-density polyethylene, a medium-density polyethylene, a high-density polyethylene, a linear low-density polyethylene, an ethylene-vinyl acetate copolymer, a polypropylene, a propylene-ethylene copolymer, and a propylene-1-butene copolymer.