STUDY ON STEAM CHEST MOLDING PROCESS FOR EPP BEAD FOAM

摘要

This paper deals with the basic principles and procedures of the steam chest molding process for expanded polypropylene (EPP) bead foam. Steam chest molding is an integral process for EPP technology. However, little research has been carried out regarding the processing condition of steam chest molding. The characteristics of EPP foam are energy absorption, multiple impact protection, lightweight, structural strength and durability. In this study, the steam pressure in the steam chest molding was varied to find the optimum condition for manufacturing EPP foam. Moreover, annealing after EPP foam molding was put into practice to prevent the shrinkage of the steam-molded product. It was possible to verify the mechanism of foam shrinkage by observing the weight change with time at different annealing temperatures. A tensile test and scanning electron microscopy (SEM) analysis were also executed to support these experimental results. The dimensional stability was investigated for each molded product from different steam pressures.