Abstract: An olefin polymerization catalyst comprising (A) a solid titanium catalyst component containing a magnesium atom, titanium atom, halogen atom and electron donor, in which divalent titanium atom account for not more than 25 atomic % of the whole titanium atom and trivalent titanium atom account for at least 30 atomic % of the whole titanium atom and (B) an organoaluminum compound component having no halogen atom; and an olefin production method which comprises polymerizing an olefin in the presence of the above olefin polymerization catalyst.

Abstract: Disclosed is a propylene-ethylene/butene block copolymer, comprising a polybutene component block-copolymerized with a propylene-ethylene random copolymer component, or with a polypropylene component and a propylene-ethylene random copolymer component, the content of the polybutene component being 0.1 to 10% by weight, the total content of the propylene-ethylene random copolymer component and the polypropylene component being 99.9 to 90% by weight and the content of the polypropylene component being 0 to 30% by weight, wherein the propylene-ethylene random copolymer component is composed of a copolymer comprising 15 to 80 mole % of monomer units based on ethylene and 85 to 20 mole % of monomer units based on propylene, and said block copolymer is a powder having a high molecular weight.