Ethylene-propylene block-copolymers and process for producing the same.

摘要

An ethylene-propylene block copolymer capable of producong foamed shaped articles with a uniform and fine foam structure even without adding resins comprises a propylene homopolymer portion and an ethylene-propylene (EP) copolymer portion and is characterised in that the homopolymer portion is obtained by polymerizing propylene in two stages so that the propylene homopolymer portion comprises a lower and a higher molecular weight portion, relative to the molecular weight of the propylene homopolymer portion; there is a specified relationship between the melt flow rates under defined conditions; the EP copolymer portion has an ethylene content of 60 to 95 % based on the copolymer portion; and the block copolymer has an ethylene content of 10 to 40 % based on the block copolymer.