POLYPROPYLENE BASED RESIN COMPOSITION, EXPANDED MOLDINGS COMPRISING THE SAME AND METHOD FOR PRODUCTION THEREOF

摘要

A polypropylene based resin composition for injection expansion molding, which comprises (A) 50 to 95 parts by weight of a linear polypropylene based resin having a melt flow rate of 10 g/10 min to 100 g/10 min and a melt tension of 2 cN or less, (B) 5 to 50 parts by weight of a modified polypropylene based resin having a melt flow rate of 0.1 g/10 min or more and less than 10 g/10 min and a melt tension of 5 cN or more and exhibiting the strain hardening property (provided that the sun of the linear polypropylene based resin (A) and the linear polypropylene based resin (B) is 100 parts by weight); expanded moldings comprising the resin composition; and a method for producing said expanded moldings. Said expanded moldings are produced along with good injection expansion molding properties and comprises a skin layer having a surface being almost free of silver streaking or the like and an inner core layer being expanded in a high expansion ratio and having uniform and fine pores, and further is excellent in appearance, lightweight property and rigidity.