The present disclosure relates to dual catalyst systems and processes for use thereof. The present disclosure further provides a catalyst system that is a combination of at least two hafnium metallocene catalyst compounds. The catalyst systems may be used for olefin polymerization processes. The present disclosure further provides for polymers, which can be formed by processes and catalyst systems of the present disclosure.

The present disclosure provides bridged metallocene catalyst compounds comprising SiSi bridges, catalyst systems comprising such compounds, and uses thereof. Catalyst compounds of the present disclosure can be hafnium-containing compounds having one or more cyclopentadiene ligand(s) substituted with one or more silyl neopentyl groups and linked with an SiSi-containing bridge. In another class of embodiments, the present disclosure is directed to polymerization processes to produce polyolefin polymers from catalyst systems comprising one or more olefin polymerization catalysts, at least one activator, and an optional support.

Catalyst systems and methods for making and using the same. A method of polymerizing olefins to produce a polyolefin polymer with a multimodal composition distribution, includes contacting ethylene and a comonomer with a catalyst system. The catalyst system includes a first catalyst compound and a second catalyst compound that are co-supported to form a commonly supported catalyst system. The first catalyst compound includes a compound with the general formula (C.sub.5H.sub.aR.sup.1.sub.b)(C.sub.5H.sub.cR.sup.2.sub.d)HfX.sub.2. The second catalyst compound includes at least one of the following general formulas:

##STR00001##

In both catalyst systems, the R groups can be independently selected from any number of substituents, including, for example, H, a hydrocarbyl group, a substituted hydrocarbyl group, or a heteroatom group, among others.

Catalyst systems and methods for making and using the same. A method of methylating a catalyst composition while substantially normalizing the entiomeric distribution is provided. The method includes slurrying the organometallic compound in dimethoxyethane (DME), and adding a solution of RMgBr in DME, wherein R is a methyl group or a benzyl group, and wherein the RMgBr is greater than about 2.3 equivalents relative to the organometallic compound. After the addition of the RMgBr, the slurry is mixed for at least about four hours. An alkylated organometallic is isolated, wherein the methylated species has a meso/rac ratio that is between about 0.9 and about 1.2.

Disclosed herein is a catalyst compound represented by Formula (I) or Formula (II):

##STR00001##

M is a group 4 metal. Each of R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.8, and R.sup.9 is independently hydrogen, or a C1-C50 substituted or unsubstituted hydrocarbyl, halocarbyl, silylcarbyl, alkoxyl, siloxyl, or one or more of R.sup.1 and R.sup.2, R.sup.2 and R.sup.3, R.sup.3 and R.sup.4, R.sup.5 and R.sup.6, R.sup.6 and R.sup.7, and R.sup.7 and R.sup.8 are joined to form cyclic a saturated or unsaturated ring. Each X is independently a halide or C1-C50 substituted or unsubstituted hydrocarbyl, hydride, amide, alkoxide, sulfide, phosphide, halide, or a combination thereof, or two Xs are joined together to form a metallocycle ring, or two Xs are joined to form a chelating ligand, a diene ligand, or an alkylidene. Also disclosed is a method for using the catalyst compound in a catalyst system to produce polyolefin polymers.

This invention relates to a polyethylene composition, and films therefrom, comprising at least 65 wt % ethylene derived units and from 0.1 to 35 wt % of C3-C12 olefin comonomer derived units, where the polyethylene composition has: a) an RCI,m of less than 85 kg/mol; b) a Tw.sub.1-Tw.sub.2 value of from 15 to 40 C.; and c) an Mw.sub.1/Mw.sub.2 value of less than 1.5 where the film has a) a heat seal initiation temperature of X C. or less at 5 N of force, where X=0.0015Y(psi)+62.6 (where Y is the average 1% Secant modulus ((MD+TD)/2)) of the film; b) a dart drop impact of 300 g/mil or more; c) an MD Elmendorf tear of 230 g or more; and d) average 1% Secant modulus ((MD+TD)/2) of 20,000 psi or more.

Catalyst systems and methods for making and using the same. A method of methylating a catalyst composition while substantially normalizing the entiomeric distribution is provided. The method includes slurrying the organometallic compound in dimethoxyethane (DME), and adding a solution of RMgBr in DME, wherein R is a methyl group or a benzyl group, and wherein the RMgBr is greater than about 2.3 equivalents relative to the organometallic compound. After the addition of the RMgBr, the slurry is mixed for at least about four hours. An alkylated organometallic is isolated, wherein the methylated species has a meso/rac ratio that is between about 0.9 and about 1.2.

A system and method of producing polyethylene, including: polymerizing ethylene in presence of a catalyst system in a reactor to form polyethylene, wherein the catalyst system includes a first catalyst and a second catalyst; and adjusting reactor conditions and an amount of the second catalyst fed to the reactor to control melt index (MI), density, and melt flow ratio (MFR) of the polyethylene.

Catalyst systems and methods for making and using the same are described. A method includes selecting a catalyst blend using a blend polydispersity index (bPDI) map. The polydispersity map is generated by generating a number of polymers for at least two catalysts. Each polymer is generated at a different hydrogen to ethylene ratio. At least one catalyst generates a higher molecular weight polymer and another catalyst generates a lower molecular weight polymer. A molecular weight for each polymer is measured. The relationship between the molecular weight of the polymers generated by each of the catalysts and the ratio of hydrogen to ethylene is determined. A family of bPDI curves for polymers that would be made using a number of ratios of a blend of the at least two catalysts for each of a number of ratios of hydrogen to ethylene. A ratio for the catalyst blend of the catalysts that generates a polymer having a bPDI that matches a polymer fabrication process is selected, and the product specific polyolefin is made using the catalyst blend.

The present disclosure relates to asymmetric ansa-metallocene catalyst compounds that include at least one indenyl ligand substituted at the 3-position with a C.sub.3-C.sub.40 -branched alkyl, such as 1-methylethyl, 1-methylpropyl, 1-methylbutyl, 1-ethylbutyl, 1,3-dimethylbutyl, 1-methyl-1-ethylbutyl, 1,1-diethylbutyl, 1-propylpentyl, and the like. Catalyst systems prepared with the catalyst compounds, polymerization methods using such catalyst systems, and polyolefins made using the polymerization methods are also described.