Polypropylene resin pre-expanded beads, manufacturing method thereof and expansion-molding method using said beads.

摘要

The present invention provides polypropylene resin pre-expanded beads formed by shrinking polypropylene resin pre-expanded beads originally having a bulk density of not higher than 0.0930 g/cm<3> 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.