POLYPROPYLENE RESIN PRE-EXPANDED BEADS, MANUFACTURING METHOD THEREOF AND EXPANSION-MOLDING METHOD USING SAID BEADS

摘要

The present invention provides polypropylene resin preexpanded beads formed by shrinking polypropylene resin preexpanded beads originally having a bulk density of not higher than 0.0930 g/cc to give them a bulk volume ratio of 10 - 75 % at the normal temperature and the normal pressure, a manufacturing method thereof and an expansion-molding method with the aforementioned pre-expanded beads. According to this invention, it is possible to greatly reduce storing and transporting costs per unit weight of pre-expanded beads.