Abstract: Supported stereospecific catalysts and processes for the stereotactic propagation of a polymer chain derived from ethylenically unsaturated monomers which contain three or more carbon atoms or which are substituted vinyl compounds, specifically alpha olefins, particularly the polymerization of propylene to produce syndiotactic or isotactic polypropylene. The supported metallocene catalyst comprises a stereospecific metallocene catalyst and a co-catalyst component comprising at least one of an alkyl alumoxane and an alkylaluminum compound. Both the metallocene catalyst and the co-catalyst are supported on a particulate silica support comprising silica particles having an average particle size of 5-40 microns and an average effective pore size of 50-200 angstroms. The silica support further has a differential pore size distribution of a pore volume of at least 0.01 cm3/g. within a range having a maximum pore width of no more than 300 angstroms.

Abstract: Supported stereospecific catalysts and processes for the stereotactic propagation of a polymer chain derived from ethylenically unsaturated monomers which contain three or more carbon atoms or which are substituted vinyl compounds, specifically alpha olefins, particularly the polymerization of propylene to produce syndiotactic or isotactic polypropylene. The supported metallocene catalyst comprises a stereospecific metallocene catalyst and a co-catalyst component comprising at least one of an alkyl alumoxane and an alkylaluminum compound. Both the metallocene catalyst and the co-catalyst are supported on a particulate silica support comprising silica particles having an average particle size of 5-40 microns and an average effective pore size of 50-200 angstroms. The silica support further has a differential pore size distribution of a pore volume of at least 0.01 cm3/g. within a range having a maximum pore width of no more than 300 angstroms.

Abstract: Supported stereospecific catalysts and processes for the stereotactic propagation of a polymer chain derived from ethylenically unsaturated monomers which contain three or more carbon atoms or which are substituted vinyl compounds, specifically alpha olefins, particularly the polymerization of propylene to produce syndiotactic or isotactic polypropylene. The supported metallocene catalyst comprises a stereospecific metallocene catalyst and a co-catalyst component comprising at least one of an alkyl alumoxane and an alkylaluminum compound. Both the metallocene catalyst and the co-catalyst are supported on a particulate silica support comprising silica particles having an average particle size of 5–40 microns and an average effective pore size of 50–200 angstroms. The silica support further has a differential pore size distribution of a pore volume of at least 0.01 cm3/g. within a range having a maximum pore width of no more than 300 angstroms.

Abstract: Disclosed is a method of polymerizing olefin using a compatible combination of a multi-site catalyst and a single-site catalyst. The catalysts may be a Ziegler-Natta catalyst and a metallocene catalyst. The resulting polymer, which may be a homopolymer or a random copolymer, may exhibit a molecular weight distribution which is intermediate than that resulting for polymers prepared using either catalyst alone.

Abstract: The present invention includes a bimodal polyethylene polymerization process wherein metallocene catalyst to is used to adjust the hydrogen response of a Ziegler-Natta catalyst. The polymerization may be carried out in a single reactor or in two or more reactors in series, preferably two or more continuously stirred tank reactors in series. In an embodiment having two or more reactors, the Zeigler-Natta catalyst is added to a first reactor and the metallocene catalyst is added to a downstream reactor. In another embodiment having two or more reactors, the Zeigler-Natta catalyst and metallocene catalyst are added to the same reactor, preferably an upstream reactor. A preferred Zeigler-Natta catalyst comprises TiCl4, and a preferred metallocene catalyst comprises bis(cyclopentadienyl) titanium dichloride.

Abstract: Supported stereospecific catalysts and processes for the stereotactic propagation of a polymer chain derived from ethylenically unsaturated monomers which contain three or more carbon atoms or which are substituted vinyl compounds, specifically alpha olefins, particularly the polymerization of propylene to produce syndiotactic or isotactic polypropylene. The supported metallocene catalyst comprises a stereospecific metallocene catalyst and a co-catalyst component comprising at least one of an alkyl alumoxane and an alkylaluminum compound. Both the metallocene catalyst and the co-catalyst are supported on a particulate silica support comprising silica particles having an average particle size of 5-40 microns and an average effective pore size of 50-200 angstroms. The silica support further has a differential pore size distribution of a pore volume of at least 0.01 cm3/g. within a range having a maximum pore width of no more than 300 angstroms.

Abstract: A method of modifying a Ziegler-Natta type polyolefin catalyst comprises contacting the Ziegler-Natta catalyst with olefin monomer to form a prepolymerized catalyst. The prepolymerized catalyst can comprise a reduced number of catalyst particles having a size of 40 microns or less. The prepolymerized catalyst can be used in a polymerization process to produce polymer fluff particles with a reduced number of polymer fluff fines than the Ziegler-Natta type catalyst.