To obtain a propylene block copolymer having excellent mechanical strength, especially balance between rigidity and low-temperature impact resistance, extremely effective as a resin for injection molding or extrusion molding.
This propylene block copolymer substantially comprises (A) a block which is a propylene homopolymer or a random copolymer of propylene and a 2-20C α-olefin and has ≤10 mol.% α-olefin content in the case of the copolymer of propylene and the 2-20C α-olefin and (B) a block which is a copolymer of at least two or more kinds of monomers selected from the 2-20C α-olefins and comprises ≥75 wt.% of a low crystalline component (a dissolved component when a solution of the copolymer in orthodichlorobenzene (135°C) is cooled to 5°C) and has ≤12 wt.% content of a component having a molecular weight ≤1/10 the weight-average molecular weight of the low crystalline component.
SHIBATA OSAMU
MARUYAMA YASUO
SUZUKI TORU
SUGANO TOSHIHIKO
