Abstract: A process for the polymerization of olefin monomers comprising contacting ethylene or a mixture of ethylene and one or more C4-8 ? olefins with a catalyst composition comprising one or more Group 3-10 transition metal containing, Ziegler-Natta, procatalyst compounds; one or more alkylaluminum cocatalyts; and one or more polymerization control agents, said process being characterized in that at least one such polymerization control agent is an alkyl or aryl. ester of an aliphatic or aromatic (poly)carboxylic acid optionally containing one or more substituents comprising a Group 13, 14, 15, or 16 heteroatom.

Abstract: A supported catalyst composition and process for preparing high molecular weight polymers of one or more addition polymerizable monomers, especially propylene, said composition comprising: 1) a substrate comprising the reaction product of a solid, particulated, high surface area, metal oxide, metalloid oxide, or a mixture thereof and an organoaluminum compound, 2) a hafnium complex of a polyvalent, Lewis base ligand; and optionally, 3) an activating cocatalyst for the metal complex.

Abstract: A catalyst composition, method of formation and process of use in the polymerization of olefin monomers, said composition comprising a catalyst compound, an activator capable of converting said catalyst compound into an active catalyst for addition polymerization, optionally a carrier, further optionally a liquid diluent, and a hydroxycarboxylate metal salt additive.