HYDROXYL GROUP-CONTAINING AROMATIC VINYL POLYMERS AND RESIN EXPANDABLE PARTICLES INCLUDING THE SAME, PRE-EXPANDED PARTICLES, AND FOAM MOLDED BODY

摘要

PROBLEM TO BE SOLVED: To provide aromatic vinyl polymers which can be uniformly dispersed in expandable particles or in a foam molded body; resin expandable particles and pre-expanded particles, which contain the polymers, have a uniform and controllable air bubble diameter, reduce aging time after a foaming agent impregnation process in a pre-expanded particle foaming method, and have a suppressed quality change due to a temperature history until foam molding; and a foam molded body having excellent physical properties, surface appearance, dimensional stability, and moldability.SOLUTION: Provided is an aromatic vinyl polymer having a hydroxyl group on a side chain, which has a GPC pattern area, in a range of a polystyrene-equivalent molecular weight of 5 million or more, amounting to 0.1 to 30% of the total pattern area, and is soluble in a liquid medium having a value of solubility parameter SP, of 8 to 11 (cal/cm). By blending a small amount of the aromatic vinyl polymer in a polystyrene (PS) resin, a polyolefin (PO) resin, and a PS/polyolefin (PO) alloy resin, there are provided resin expandable particles and pre-expanded particles, which can reduce an aging time after a foaming agent impregnation process in a foaming method and suppress a quality change due to a temperature history until foam molding, and there are provided a foam molded body.