MULTI-LAYER EXPANSION-MOLDED ARTICLE OF POLYPROPYLENE RESIN, PRODUCTION PROCESS THEREOF, AND CONTAINER, SHOCK-ABSORBING MATERIAL FOR AUTOMOBILE AND AUTOMOTIVE MEMBER FORMED OF THE MULTI-LAYER EXPANSION-MOLDED ARTICLE OF POLYPROPYLENE RESIN

摘要

A multi-layer expansion-molded article of a polypropylene resin, which is obtained by molding a multi-layer parison comprising a foamed resin layer and a resin layer provided on the outer side of the foamed resin layer in a mold in such manner that at least part of the opposed inner surfaces of foamed resin layer in the parison are fusion-bonded to each other, and has a polypropylene resin layer on the surface of a foamed polypropylene resin layer, wherein a melt tension, MT_fr (gf) and a melt flow rate, MFR_fr (g/10 min) obtained by measurement to a polypropylene resin forming the foamed resin layer in the expansion-molded article satisfy the relationship [log MT_fr−0.74 log MFR_fr+0.66], and a melt tension, MT_ur (gf) and a melt flow rate, MFR_ur (g/10 min) obtained by measurement to a polypropylene resin forming the resin layer on the surface of the foamed resin layer satisfy the relationship [log MT_ur−1.02 log MFR_ur+0.47].