Abstract: An olefin polymerization process is carried out in the presence of a catalyst system comprising a pre-polymerization catalyst, a boron-based catalyst activator, an alkylaluminoxane co-catalyst, and a hindered phenol compound. The pre-polymerization catalyst is a titanium complex and has an indenoindolyl ligand bridged to a phenoxy ligand via a silyl group. The catalyst system is effective at polymerizing ethylene with alpha-olefins in a solution phase polymerization process at high temperatures and produces ethylene copolymers with high molecular weight and high degrees of alpha-olefin incorporation.

Abstract: Provided in this disclosure are titanium complexes that contain 1) a cyclopentadienyl ligand; 2) an adamantyl-phosphinimine ligand; and 3) at least one activatable ligand. The use of such a complex, in combination with an activator, as an olefin polymerization catalyst is demonstrated. The catalysts are effective for the copolymerization of ethylene with an alpha olefin (such as 1-butene, 1-hexene or 1-octene) and enable the production of high molecular weight copolymers (Mw greater than 25,000) at high productivity under solution polymerization conditions.