Patent ID: 8961859
Filing Date: 2015-02-24
Classification: B29B,B29C,B29K,C08J

Abstract:
1. Expandable polystyrene resin particles obtained by a melt extrusion method for obtaining expandable polystyrene resin particles by injecting and kneading an expanding agent into a molten polystyrene resin in an extruder, extruding the molten resin containing the expanding agent directly into a liquid for cooling through an orifice of a die installed at the front end of the extruder, and cutting the extrusion product with a rapidly rotating blade simultaneously with the extruding, while solidifying the extrusion product by cooling through contact with the liquid, wherein the weight-average molecular weight Mw of the polystyrene resin after the melt extrusion method is performed is in a range of 120,000 to 270,000, and the expanding agent after the melt extrusion method is performed contains, as an essential component, pentane at a proportion of 3 to 5.5 parts by mass based on 100 parts by mass of the polystyrene resin, and a composition of the pentane is in the range of isopentane:nonnal pentane=10:90 to 80:20 by mass ratio.