POLYPROPYLENE RESIN PRE-EXPANDED BEAD

摘要

PURPOSE:To obtain polypropylene resin pre-expanded beads to be moldable without any special pretreatment and facility by setting the bulk density of the pre-expanded beads at a specified value. CONSTITUTION:When the bulk density of the pre-expanded beads is higher than or lower than 0.04g/cm<2>, the melting energy at a peak of higher temp. is 8-12J/g or higher than 8J/g respectively. When molding in a mold is carried out by using these pre-expanded beads, good molding can be thereby done under such a condition that the inner pressure of the pre-expanded beads is almost the same level as the atmospheric pressure and the low in the facility and the cost can be improved. It is also not necessary to continuously connect the forming process of the pre-expanded beads with the molding process for molding the pre-expanded beads.