METHOD OF PRODUCTION FOR POLYOLEFIN PRE-EXPANDED BEADS AND PRE-EXPANDED BEADS OBTAINED BY THE METHOD

摘要

PROBLEM TO BE SOLVED: To obtain polyolefin pre-expanded beads excellent in foaming magnification and dispersion of foaming magnification without using a volatile foaming agent, carbon dioxide, etc. SOLUTION: The method of pre-expanding the polyolefin beads by dispersing beads of a polyolefin resin composition in an aqueous dispersion medium in a pressure vessel, heating/pressurizing the resin composition beads to the temperature higher than the softening point of the polyolefin resin and then releasing into a vessel with pressure lower than the inner pressure of the pressure vessel, the pre-expanding beads released from the releasing part are contacted with a gas with temperature≥60°C and set to clash from the releasing part to a clash board or a wall of the vessel. COPYRIGHT: (C)2003,JPO