To provide a propylene based block copolymer that, when used as a molding material, exhibits an extremely good stiffness-impact resistance balance and has good heat resistance and excellent moldability, and therefore, in molding, good appearance is revealed.
That is, the invention provides a propylene based block copolymer obtained through a preceding stage step of producing a propylene polymer component (PP) and a subsequent stage step of producing a propylene-ethylene copolymer component (EP) using a metallocene catalyst, wherein the block copolymer satisfies specific requisites.
To provide a propylene based block copolymer that, when used as a molding material, exhibits an extremely good stiffness-impact resistance balance and has good heat. resistance and excellent moldability, and therefore, in molding, good appearance is revealed. That is, the invention provides a propylene based block copolymer obtained through a preceding stage step of producing a propylene polymer component (PP) and a subsequent stage step of producing a propylene-ethylene copolymer component (EP) using a metallocene catalyst, wherein the block copolymer satisfies specific requisites.