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: 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.

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, such as styrene and vinyl chloride. One application is the stereospecific propagation of C3-C4 alpha olefins, particularly the polymerization of propylene to produce syndiotactic polypropylene over a supported metallocene catalyst comprising a stereospecific metallocene catalyst component incorporating a metallocene ligand structure having two sterically dissimilar cyclopentadienyl ring structures coordinated with the central transition metal atom. Both of the cyclopentadienyl groups are in a relationship with one another by virtue of bridge or substituent groups, which provide a stereorigid relationship relative to the coordinating transition metal atom to prevent rotation of said ring structures.

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.

Abstract: A process of forming a polyolefin catalyst component includes contacting a metal compound of the formula MR2 with a diketone to form a metal bis(diketonate) having the formula M(OCRCR′CRO)2, wherein M is a Group IIA or Group VIIB metal, and wherein R and R′ are each hydrocarbyls or substituted hydrocarbyls having from 1 to 20 carbons atoms. Catalyst components, catalysts, polyolefin polymers, catalysts systems, and methods of preparing same are disclosed.

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.

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: 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: A process of forming a polyolefin catalyst component includes contacting a metal compound of the formula MR2 with a diketone to form a metal bis(diketonate) having the formula M(OCRCR′CRO)2, wherein M is a Group IIA or Group VIIB metal, and wherein R and R′ are each hydrocarbyls or substituted hydrocarbyls having from 1 to 20 carbons atoms. Catalyst components, catalysts, polyolefin polymers, catalysts systems, and methods of preparing same are disclosed.

Abstract: Processes for the formulation of Ziegler-type catalysts from a plurality of catalyst components including transition metal, organosilicon electron donor, and organoaluminum co-catalyst components. The components are mixed together in the course of formulating the Ziegler-type catalyst to be charged to an olefin polymerization reactor. Several orders of addition of the catalyst components can be used in formulating the Ziegler catalyst. One involves mixing of the transition metal component with the organoaluminum co-catalyst to formulate a mixture having an aluminum/transition metal mole ratio of at least 200. This mixture is combined with the organosilicon electron donor component to produce a Ziegler-type catalyst formulation having an aluminum/silicon mole ratio of no more than 50. There may be an initial pre-polymerization of the catalyst prior to introducing the catalyst into an olefin polymerization reactor.

Abstract: The present invention provides polypropylene having xylene solubles from 0.6 to 1.5 weight percent and isotacticity equal to or greater than about 98.0 percent. The polypropylene is obtained by contacting propylene monomer under suitable polymerization conditions with (a) a Ziegler-Natta catalyst, (b) a co-catalyst, and (c) an electron donor.

Abstract: The present invention provides a catalyst system that exhibits control of desired properties in the polymer product. The catalyst system includes a conventional supported Ziegler-Natta catalyst in combination with an electron donor having the general formula SiRm(OR′)4-m where R is selected from the group consisting of an alkyl group, a cycloalkyl group, an aryl group and a vinyl group; R′ is an alkyl group; and m is 0-3, wherein when R is an alkyl group, R may be identical with R′; when m is 0, 1 or 2, the R′ groups may be identical or different; and when m is 1, 2 or 3, the R groups may be identical or different. The system easily achieves efficiencies over 30 kg/g-cat·h. The system also exhibits good control over the xylene solubles of the polymer products and produces a highly crystalline polymer product.

Abstract: A polyolefin metallocene catalyst which includes two metallocene components, a stereorigid isospecific metallocene catalyst component and a stereorigid syndiospecific metallocene catalyst component, both of which are supported upon the same support. A method of forming a catalyst system includes contacting the above catalyst with a cocatalyst or Lewis acid. A method of polymerization includes contacting an olefin with the catalyst system.

Abstract: Processes for the polymerization of olefins with Zeigler-type catalyst systems which involve transition metal catalyst components comprising 4, 5 or 6 transition metals incorporating internal electron donors to provide desired polymerization characteristics, including yield and polymer characteristics. Specific olefins used in the polymerization process are C2-C4 alpha olefins such as propylene in the production of stereoregular polypropylene. The catalyst system comprised a transition metal component having an internal electron donor in an amount providing an internal donor/transition metal mole ratio of no more than 2/3. This is combined with an organoaluminum co-catalyst component to provide a precusor mixture having an aluminum/transition metal mole ration of at least 100. The precusor mixture is combined with an organosilicon external electron donor component in an amount to provide an aluminum/silicon mole ration of no more than 200.

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, such as styrene and vinyl chloride. One application is the stereospecific propagation of C3-C4 alpha olefins, particularly the polymerization of propylene to produce syndiotactic polypropylene over a supported metallocene catalyst comprising a stereospecific metallocene catalyst component incorporating a metallocene ligand structure having two sterically dissimilar cyclopentadienyl ring structures coordinated with the central transition metal atom. Both of the cyclopentadienyl groups are in a relationship with one another by virtue of bridge or substituent groups, which provide a stereorigid relationship relative to the coordinating transition metal atom to prevent rotation of said ring structures.

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, such as styrene and vinyl chloride. One application is the stereospecific propagation of C3-C4 alpha olefins, particularly the polymerization of propylene to produce syndiotactic polypropylene over a supported metallocene catalyst comprising a stereospecific metallocene catalyst component incorporating a metallocene ligand structure having two sterically dissimilar cyclopentadienyl ring structures coordinated to the central transition metal atom. Both of the cyclopentadienyl groups are in a relationship with one another by virtue of bridge or substituent groups, which provide a stereorigid relationship relative to the coordinating transition metal atom to prevent rotation of said ring structures.

Abstract: The present invention provides a catalyst system that exhibits unexpected control of desired properties in copolymer product. The catalyst system includes a conventional supported Ziegler-Natta catalyst in combination with an electron donor described by the formula: wherein R1 is a linear alkyl group attached to the silicon atom; R2 and R3 are alkyl or aryl groups and R4 is a linear alkyl attached to the silicon atom, R1 and R4 are the same or different. R1 and R4 are preferably linear carbon groups of 4-13 carbon atoms, more preferably 4-7 carbon atoms; most preferably R1 and R4 are the same and are n-butyl groups. The system exhibits good control over the melt flow index of the copolymer products.

Abstract: Polymer blends of isotactic polypropylene and syndiotactic polypropylene enhance the processability in film applications. Up to a level of 4% by weight of syndiotactic polypropylene will increase the molecular weight distribution. Up to a level of 13.9% by weight of syndiotactic polypropylene the clarity or haze of biaxially oriented film is improved. Within a range from about 2.34% by weight of syndiotactic polypropylene to about 13.9% by weight the melt flow is higher than that for either a syndiotactic homopolymer or an isotactic homopolymer. Within a range from about 2% by weight of syndiotactic polypropylene to about 13.9% by weight the level of xylene solubles is higher than that for either a syndiotactic homopolymer or an isotactic homopolymer. If appropriate catalysts are selected, a reactor blend may be produced of the desired mixture.

Abstract: The invention provides a metallocene catalyst for use in preparing polyolefins having low molecular weight. The catalyst comprises a bridged metallocene in which one of the cyclopentadienyl rings is substituted in a substantially different manner from the other ring.