STYRENE-BASED POLYMER RESIN COMPOSITION FOR EXTRUSION FOAMING, EXTRUDED AND FOAMED SHEET OF THE SAME RESIN AND PRODUCTION OF EXTRUDED AND FOAMED SHEET OF THE SAME RESIN

摘要

PURPOSE: To provide a resin composition sufficiently forming a foamed film, having a high closed cell ratio and excellent blowing agent retention. ;CONSTITUTION: This rubber modified styrene-based polymer resin composition for extrusion foaming uses a resin comprising (A) a styrene-based polymer having ≥700,000 Z-average molecular weight and (B) a resin selected from a styrene/butadiene block copolymer and its hydrogenated substance as a resin component. The objective extruded and foamed rubber modified styrene-based polymer resin sheet is obtained by extruding and foaming the rubber modified styrene-based polymer resin composition for extrusion foaming containing a volatile blowing agent and has 0.05-0.2g/cm³ and ≥70% closed cell ratio. The objective method for producing the extruded and foamed rubber modified styrene-based polymer resin sheet comprises extruding and foaming the rubber modified styrene based polymer resin composition containing the volatile blowing agent by using a tandem extruder consisting of a uniaxial one-stage extruder and a uniaxial two-stage extruder. The blending ratio of the component A and the component B in the resin component is 5-25 pts.wt. of the latter based on 100 pts.wt. of the former.;COPYRIGHT: (C)1996,JPO