Process for producing propylene resin composition

摘要

Disclosed are processes for producing polypropylene resin compositions including two or three sorts of propylene-based polymeric materials, the processes including a first step of melt-kneading at least a propylene-alpha-olefin block copolymer containing a polymer portion composed mainly of propylene and a propylene-alpha-olefin copolymer portion having a relatively high intrinsic viscosity and a second step of melt-kneading the product of the first step with a propylene-ethylene block copolymer containing a polymer portion composed mainly of propylene and a propylene-ethylene copolymer portion having a relatively low intrinsic viscosity or a polymer portion composed mainly of propylene having a relatively low intrinsic viscosity. In the composition produced by these processes, no or substantially no fish eyes develop.