Patent ID: 8044144

Claim:
A propylene-ethylene block copolymer having a propylene homopolymer block and a copolymer block, and satisfying the following requisites: (1) triad chain ratio f EEE of [EEE]: ≦0.1 (mole %), (2) product (Re·Rp) of reactivity ratios of ethylene and propylene: ≧0.5, (3) molecular weight distribution (Mw/Mn): ≦3.5, (4) enthalpy of melting (ΔH): 10 to 60 J/g, (5) melting point (Tm): ≧105° C. and (6) ethylene content: ≦10 mole wherein the propylene homopolymer block is provided by polymerization of propylene in a first step and the copolymer block is provided by copolymerization of propylene and ethylene in a second step.