Polymers, and systems and methods for making and using the same are described herein. A polymer includes ethylene and at least one alpha olefin having from 4 to 20 carbon atoms. The polymer has a melt index ratio (MIR) greater than about 40. The polymer also has a value for Mw1/Mw2 of at least about 2.0, wherein Mw1/Mw2 is a ratio of a weight average molecular weight (Mw) for a first half of a temperature rising elution (TREF) curve from a cross-fractionation (CFC) analysis to an Mw for a second half of the TREF curve. The polymer also has a value for Tw1Tw2 of less than about 15 C., wherein Tw1Tw2 is a difference of a weight average elution temperature (Tw) for the first half of the TREF curve to a Tw for the second half of the TREF curve.

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: 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.

An olefin resin having requirements (I) to (VI) is provided: (I) a grafted olefin polymer containing a main chain with an ethylene/-olefin copolymer and a side chain with a propylene polymer; (II) the ratio P wt % of propylene polymer is from 5 to 60 wt %; (III) when the ratio of the amount of a component(s) having a peak temperature of a differential elution curve as measured by CFC using o-dichlorobenzene of less that 65 C., to the amount of () taken as E wt %, the value a represented by an equation (Eq-1), is 1.4 or more; (IV) the melting point (Tm) is 120 to 165 C. and the glass transition temperature (Tg) is 80 to 30 C., as measured by DSC; (V) the hot xylene-insoluble content is less than 3 wt %; and, (VI) the limiting viscosity as measured in decalin at 135 C. is 0.5 to 5.0 dl/g.

Silica-coated alumina activator-supports, and catalyst compositions containing these activator-supports, are disclosed. Methods also are provided for preparing silica-coated alumina activator-supports, for preparing catalyst compositions, and for using the catalyst compositions to polymerize olefins.

Provided are a novel transition metal compound, a transition metal catalyst composition for preparing an ethylene homopolymer or a copolymer of ethylene and -olefin, containing the same, a method for preparing an ethylene homopolymer or a copolymer of ethylene and -olefin using the same, and an ethylene homopolymer or a copolymer of ethylene and -olefin prepared using the same.

This disclosure relates to rotomolded articles, having a wall structure, where the wall structure contains at least one layer containing an ethylene interpolymer product, or a blend containing an ethylene interpolymer product, where the ethylene interpolymer product has: a Dilution Index (Y.sub.d) greater than 1.0; total catalytic metal 3.0 ppm; 0.03 terminal vinyl unsaturations per 100 carbon atoms. The ethylene interpolymer products have a melt index from about 0.5 to about 15 dg/minute, a density from about 0.930 to about 0.955 g/cm.sup.3, a polydispersity (M.sub.w/M.sub.n) from about 2 to about 6 and a CDBI.sub.50 from about 50% to about 98%. Further, the ethylene interpolymer products are a blend of at least two ethylene interpolymers; where one ethylene interpolymer is produced with a single-site catalyst formulation and at least one ethylene interpolymer is produced with a heterogeneous catalyst formulation.

This disclosure relates to rotomolded articles, having a wall structure, where the wall structure contains at least one layer containing an ethylene interpolymer product, or a blend containing an ethylene interpolymer product, where the ethylene interpolymer product has: a Dilution Index (Y.sub.d) greater than 1.0; total catalytic metal 3.0 ppm; 0.03 terminal vinyl unsaturations per 100 carbon atoms. The ethylene interpolymer products have a melt index from about 0.5 to about 15 dg/minute, a density from about 0.930 to about 0.955 g/cm.sup.3, a polydispersity (M.sub.w/M.sub.n) from about 2 to about 6 and a CDBI.sub.50 from about 50% to about 98%. Further, the ethylene interpolymer products are a blend of at least two ethylene interpolymers; where one ethylene interpolymer is produced with a single-site catalyst formulation and at least one ethylene interpolymer is produced with a heterogeneous catalyst formulation.

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.

Silica-coated alumina activator-supports, and catalyst compositions containing these activator-supports, are disclosed. Methods also are provided for preparing silica-coated alumina activator-supports, for preparing catalyst compositions, and for using the catalyst compositions to polymerize olefins.

Disclosed herein are ethylene-based polymers produced using dual metallocene catalyst systems. These polymers have low densities, high molecular weights, and broad molecular weight distributions, as well as having the majority of the long chain branches in the lower molecular weight component of the polymer, and the majority of the short chain branches in the higher molecular weight component of the polymer. Films produced from these polymers have improved impact and puncture resistance.