Propylene-ethylene-butene block copolymer and molded article thereof

A propylene-ethylene-butene block copolymer is provided which includes from 60 to 85% by weight of a polypropylene portion and from 15 to 40% by weight of a propylene-ethylene-butene random copolymer portion, wherein the copolymer satisfies the requirements (1) and (2) given below. In addition, a molded article including such a propylene-ethylene-butene block copolymer is provided. (1) The random copolymer portion includes a propylene-ethylene random copolymer component (EP) and a propylene-ethylene-butene random copolymer component (EPB) and the copolymer component (EP) has an intrinsic viscosity of from 1.5 to 8 dl/g and an ethylene unit content of from 20 to 50% by weight, and the copolymer component (EPB) has an intrinsic viscosity of from 0.5 to 8 dl/g, an ethylene unit content of from 47 to 77% by weight and a butene unit component of from 3 to 33% by weight and the total of the ethylene unit content and the butene unit content is from 50 to 80% by weight. (2): The propylene-ethylene-butene block copolymer has a melt flow rate of from 5 to 120 g/10 min.