Patent ID: 9079342
Filing Date: 2015-07-14
Classification: B29C,C08J,C08K,F24F

Abstract:
1. Expandable polystyrene resin particles, which are obtained by supplying a flame-retardant solution into an aqueous suspension before or during impregnating polystyrene resin particles dispersed in the aqueous suspension with a blowing agent, in which the flame-retardant solution is prepared by dissolving in a liquid state plasticizer 33 to 1000 parts by weight of powdery flame retardant relative to 100 parts by weight of the plasticizer and further 20 to 200 parts by weight of a flame retardant aid having one-hour half-life temperature of 100° C. to 250° C. relative to 100 parts by weight of the plasticizer, and impregnating the polystyrene resin particles with the flame retardant and the flame retardant aid, wherein the flame retardant comprises tetrabromocyclooctane that is dry blended with silica fine powders with a Henschel mixer and preliminarily dispersed by silica fine powders, the silica fine powders have the specific surface area of 170 to 330 m the silica fine powders are contained in an amount of 0.3 to 1.5 parts by weight relative to 98.5 to 99.7 parts by weight of the tetrabromocyclooctane, and the flame retardant is absorbed into the central portion of the polystyrene resin particles and the silica fine powders are not absorbed into the polystyrene resin particles.