An olefin polymerization catalyst comprising an organoaluminium oxy-compound (a) and two cyclopentadienyl transition metal compounds (b-I) and (b-II). A process for olefin polymerization in the presence of the catalyst and ethylene/α-olefin copolymer obtainable by copolymerizing ethylene with an α-olefin in the presence of the catalyst.
Graft modified ethylene/α-olefin copolymer obtainable by graft polymerizing the above-mentioned ethylene/α-olefin copolymer with a polar monomer, and composition comprising the graft modified copolymer and polyolefin.
The ethylene/α-olefin copolymer produced is excellent in moldability and has high melt tension and high flowability. A film having high transparency and high mechanical strength can be produced from it.