Abstract: The present invention relates to a polymerization process using improved metallocene catalyst systems. Specifically, the catalyst systems of the present invention relate to a metallocene compound having optimized metals loading and activator concentration, and demonstrate improved operability and productivity. In an exemplary embodiment, the improved metallocene catalyst system of the present invention comprises a metallocene catalyst compound activated by methylaluminoxane, and a support material, the methylaluminoxane being present in the range of from 3 to 9 mmole methylaluminoxane per gram of support material, and the metallocene being present in the range of from 0.01 to 1.0 mmole metallocene per gram of support material.

Abstract: Methods of controlling the flow index and/or molecular weight split of a polymer composition are disclosed. The method of producing a polymer composition in one embodiment comprises incorporating a high molecular weight polymer into a low molecular weight polymer to form the polymer composition in a single polymerization reactor in the presence of polymerizable monomers, a bimetallic catalyst composition and at least one control agent; wherein the control agent is added in an amount sufficient to control the level of incorporation of the high molecular weight polymer, the level of low molecular weight polymer, or both. Examples of control agents include alcohols, ethers, amines and oxygen.

Abstract: The invention relates to a polymerization process, the polymerization process includes contacting a cyclic bridged metallocene catalyst represented by the following formula: LA(A)LBMQn wherein A is a divalent group bound to each of LA and LB; each of LA and LB are bound to M, and each Q is bound to M; LA and LB are independently selected from the group consisting of cyclopentadienyl ligands and substituted cyclopentadienyl ligands; A is a divalent bridging group comprising a heterocyclic ring comprising from 3 to 6 carbon atoms and one silyl, thus forming a 4 to 7 member divalent ring; M is a Group 4, 5, or 6 transition metal; Q is independently a halogen, a hydride, or a hydrocarbyl radical having from 1 to 20 carbon atoms; wherein n is 1 or 2; with an activator, and optionally a support, to form an activated catalyst and, subsequently, contacting the activated catalyst with ethylene and optionally, at least one C3-C8 alpha olefin comonomer.

Abstract: The present invention relates to a polymerization process using improved metallocene catalyst systems. Specifically, the catalyst systems of the present invention relate to a metallocene compound having optimized metals loading and activator concentration, and demonstrate improved operability and productivity. In an exemplary embodiment, the improved metallocene catalyst system of the present invention comprises a metallocene catalyst compound activated by methylaluminoxane, and a support material, the methylaluminoxane being present in the range of from 3 to 9 mmole methylaluminoxane per gram of support material, and the metallocene being present in the range of from 0.01 to 1.0 mmole metallocene per gram of support material.

Abstract: Bimetallic catalysts, and methods of producing a bimetallic catalyst comprising a modified Ziegler-Natta catalyst and a metallocene are provided, in one embodiment the method including combining: (a) a Ziegler-Natta catalyst comprising a Group 4, 5 or 6 metal halide and/or oxide, optionally including a magnesium compound, with (b) a modifier compound (“modifier”), wherein the modifier compound is a Group 13 alkyl compound, to form a modified Ziegler-Natta catalyst. Also provided is a method of olefin polymerization using the bimetallic catalyst of the invention. The modified Ziegler-Natta catalyst is preferably non-activated, that is, it is unreactive towards olefin polymerization alone. In one embodiment, the molar ratio of the Group 13 metal (of the modifier) to the Group 4, 5 or 6 metal halide and/or oxide is less than 10:1 in one embodiment.

Abstract: A method of polymerizing olefins comprising combining in one embodiment ethylene and optionally one or more ?-olefins with a catalyst composition in a continuous polymerization reactor at a pressure of less than 10,000 kPa; wherein the catalyst composition comprises a hafnocene; and isolating a polyethylene having a density in the range of from 0.930 to 0.975 g/cm3. Also provided is a method of transitioning a continuous polymerization reactor from production of a low density polyethylene to a medium or high density polyethylene. Also provided is a medium to high density polyethylene suitable for injection or rotomolding applications. Also provided is a single catalyst composition suitable for such needs.

Abstract: The present invention relates to a supported catalyst composition and a method for making the supported catalyst composition and its use in a process for polymerizing olefin(s). In particular, the invention is directed to a method for making a supported catalyst composition by contacting a supported activator with a bulky ligand and a metal compound.

Abstract: A catalyst composition and method for olefin polymerization are provided. In one aspect, the catalyst composition is represented by the formula ?a?b?gMXn wherein M is a metal; X is a halogenated aryloxy group; ? and ? are groups that each comprise at least one Group 14 to Group 16 atom; a is a linking moiety that forms a chemical bond to each of ? and ?; and a, b, g, and n are each integers from 1 to 4.

Abstract: The present invention provides a catalyst precursor, a catalyst system comprising the precursor, and a polymerization method using the catalyst system, an embodiment of the precursor is selected from the following structures: wherein T is a bridging group; M is selected from Groups 3 to 13 atoms, and the Lanthanide series of atoms the Periodic Table of the Elements; Z is a coordination ligand; each L is a monovalent, bivalent, or trivalent anionic ligand; X and Y are each independently selected from nitrogen, oxygen, sulfur, and phosphorus; each R can be the same or different and is a bulky substituent that is sterically hindering with respect to X and Y.

Abstract: A process for preparing a mixed catalyst compound used in the polymerization of polyolefins to produce bimodal polyethylenes is disclosed. In an embodiment, a process of preparing the mixed catalyst system includes: mixing a first catalyst and an activator in a first liquid medium to form a first mixture, combining a support with the first mixture to form a first support slurry, drying the first support slurry in an extent sufficient to provide a dried supported first catalyst, mixing the dried supported first catalyst in a second liquid medium to form a second support slurry, and combining one or more additional catalysts with the second support slurry to provide the mixed catalyst compound.

Abstract: A catalyst composition and method for olefin polymerization are provided. In one aspect, the catalyst composition is represented by the formula ?a?b?gMXn wherein M is a metal; X is a halogenated aryloxy group; ? and ? are groups that each comprise at least one Group 14 to Group 16 atom; ? is a linking moiety that forms a chemical bond to each of ? and ?; and a, b, g, and n are each integers from 1 to 4.

Abstract: Disclosed are various compositions, including but not limited to a high strength bimodal polyethylene composition having a density of 0.940 g/cc or more, the composition comprising a high molecular weight polyethylene component having a higher weight average molecular weight (MwHMW) and a low molecular weight polyethylene component having a lower weight average molecular weight (MwLMW), wherein: the ratio of the higher weight average molecular weight to the lower weight average molecular weight (MwHMW:MwLMW) is 30 or more; and the composition qualifies as a PE 100 material such that in accordance with ISO 1167 a pipe formed from the composition that is subjected to internal pipe resistance has an extrapolated stress of 10 MPa or more when the internal pipe resistance curve is extrapolated to 50 or 100 years in accordance with ISO 9080:2003(E).

Abstract: A polyethylene film having a balance of improved physical and mechanical properties and a method for making the same are provided. In one aspect, the film includes a 1% secant modulus of greater than 25,000 psi, a dart impact resistance of greater than 500 g/mil, and a MD tear strength of greater than 500 g/mil. In one aspect, the method comprises reacting ethylene derived units and a comonomer in the presence of a hafnium-based metallocene at a temperature of from 70° C. and 90° C., an ethylene partial pressure of from 120 psia and 260 psia, and a comonomer to ethylene ratio of from 0.01 to 0.02 to produce an ethylene based polymer. The method further comprises extruding the ethylene based polymer at conditions sufficient to produce a polyethylene film comprising a secant modulus of greater than 25,000 psi, a dart impact resistance of greater than 500 g/mil, and a MD tear strength of greater than 500 g/mil.

Abstract: Bimetallic catalysts, and methods of producing a bimetallic catalyst comprising a modified Ziegler-Natta catalyst and a metallocene are provided, in one embodiment the method including combining: (a) a Ziegler-Natta catalyst comprising a Group 4, 5 or 6 metal halide and/or oxide, optionally including a magnesium compound, with (b) a modifier compound (“modifier”), wherein the modifier compound is a Group 13 alkyl compound, to form a modified Ziegler-Natta catalyst. Also provided is a method of olefin polymerization using the bimetallic catalyst of the invention. The modified Ziegler-Natta catalyst is preferably non-activated, that is, it is unreactive towards olefin polymerization alone. In one embodiment, the molar ratio of the Group 13 metal (of the modifier) to the Group 4, 5 or 6 metal halide and/or oxide is less than 10:1 in one embodiment.

Abstract: A polyethylene film having a balance of improved physical and mechanical properties and a method for making the same are provided. In one aspect, the film includes a 1% secant modulus of greater than 25,000 psi, a dart impact resistance of greater than 500 g/mil, and a MD tear strength of greater than 500 g/mil. In one aspect, the method comprises reacting ethylene derived units and a comonomer in the presence of a hafnium-based metallocene at a temperature of from 70° C. and 90° C., an ethylene partial pressure of from 120 psia and 260 psia, and a comonomer to ethylene ratio of from 0.01 to 0.02 to produce an ethylene based polymer. The method further comprises extruding the ethylene based polymer at conditions sufficient to produce a polyethylene film comprising a secant modulus of greater than 25,000 psi, a dart impact resistance of greater than 500 g/mil, and a MD tear strength of greater than 500 g/mil.

Abstract: A catalyst composition and method for olefin polymerization are provided. In one aspect, the catalyst composition is represented by the formula ?a?b?gMXn wherein M is a metal; X is a halogenated aryloxy group; ? and ? are groups that each comprise at least one Group 14 to Group 16 atom; ? is a linking moiety that forms a chemical bond to each of ? and ?; and a, b, g, and n are each integers from 1 to 4.

Abstract: The present invention relates to a continuous gas phase process comprising polymerizing one or more hydrocarbon monomer(s) in a fluidized bed reactor in the presence of catalyst system or polymerization catalyst and a condensable fluid for a period of at least 12 hours where the bed temperature is less than the Critical Temperature and the dew point temperature of the gas composition in the reactor is within 25° C. of the bed temperature.

Abstract: Methods for controlling a melt viscosity of a polyolefin, controlling comonomer distribution of a polyolefin, achieving a targeted melt viscosity of a polyolefin, and films made from such polyolefins are provided. The methods include contacting an olefin monomer and at least one comonomer with a catalyst system in the presence of a condensable fluid comprising a saturated hydrocarbon having from 2 to 8 carbon atoms. The catalyst system in one embodiment includes a hafnium metallocene catalyst component.

Abstract: Improved catalyst compositions, and polymerization processes using such improved catalyst compositions, are provided. An example of an improved catalyst composition is a supported catalyst system that includes at least one titanium compound, at least one magnesium compound, at least one electron donor compound, at least one activator compound, and at least one silica support material, the at least one silica support material having a median particle size in the range of from 20 to 50 microns with no more than 10% of the particles having a size less than 10 microns and no more than 10% of the particles having a size greater than 50 microns.

Abstract: Blends of very low density polyethylene produced using metallocene catalysts (mVLDPE) and linear low density polyethylene (LLDPE) are disclosed. The polymer blends include a metallocene-catalyzed VLDPE polymer having a density of less than 0.916 g/cm3, the VLDPE polymer preferably being linear and without long chain branching, and a LLDPE polymer having a density of from 0.916 to 0.940 g/cm3. The polymer blends are particularly suitable in blown and cast film applications.