PROCESS FOR PRODUCING EXPANDED POLYOLEFIN RESIN PARTICLES AND EXPANDED POLYOLEFIN RESIN PARTICLES

摘要

A process for producing expanded polyolefin resin particles with use as a foaming agent of water contained in an aqueous dispersion medium. The process includes dispersing polyolefin resin particles together with the aqueous dispersion medium into a closed vessel; heating the polyolefin resin particles up to or above a softening temperature of the polyolefin resin particles and pressurizing the polyolefin resin particles; and releasing the polyolefin resin particles into a zone whose pressure is lower than an internal pressure of the closed vessel. The polyolefin resin particles are composed of a polyolefin resin composition including polyolefin resin, a water-absorbing substance, and a foam nucleating agent.