Abstract: A catalyst system comprising a half-sandwich chromium complex, an activator support and an optional cocatalyst. A compound of formula Cp?Cr(Cl)2(Ln), where Cp? is ?5-C5H4CH2CH2CH?CH2 and Ln is pyridine, THF or diethylether. A compound of formula Cp?Cr(Cl)2(Ln), where Cp? is ?5-C5H4C(Me)2CH2CH2CH?CH2 and Ln is pyridine, THF or diethylether.

Abstract: The present invention discloses catalyst compositions employing silicon-bridged metallocene compounds with bulky substituents. Methods for making these silicon-bridged metallocene compounds and for using such compounds in catalyst compositions for the polymerization of olefins also are provided.

Abstract: A polymerization reactor system includes features for operating two or more reactors in series or parallel. The system includes a discharge line coupled to an outlet of a first polymerization reactor, a first conduit connecting the first polymerization reactor to a second polymerization reactor via the discharge line, a second conduit connecting the first polymerization reactor to a flashline apparatus via the discharge line, and a diverter valve coupling the first and second conduits to the discharge line. The diverter valve is configured to selectively open the discharge line to the first conduit and close the discharge line to the second conduit in a first valve state and to selectively open the discharge line to the second conduit and close the discharge line to the first conduit in a second valve state. The diverter valve is capable of switching between the first and second valve states.

Abstract: The present invention provides a polymerization process utilizing a dual ansa-metallocene catalyst system. Polymers produced from the polymerization process are also provided, and these polymers have a reverse comonomer distribution, a non-bimodal molecular weight distribution, a ratio of Mw/Mn from about 3 to about 8, and a ratio of Mz/Mw from about 3 to about 6.

Abstract: Systems and methods for the maintenance of active chromium-based catalysts and their use in polymerization processes are described. In one embodiment, a system for the introduction of multiple polymerization components to activate a chromium based catalyst within a mix tank is described. Other described features may include materials and methods to purify the liquid medium of a catalyst slurry so that the catalyst slurry maintains a high level of activity. The active chromium-based catalyst may provide polyolefins with a number of desirable properties in a reliable, consistent, and predictable manner.

Abstract: A composition comprising a low density polyethylene (LDPE) and a metallocene-catalyzed linear low density polyethylene (mLLDPE) wherein the composition when extruded as a molten resin displays a neck-in value that is about equal to or increased by less than about 10% of the neck-in value observed when using the LDPE alone. A method comprising blending a LDPE and a mLLDPE of this disclosure to form a polymer blend having a miscibility factor of 1; extruding the polymer blend onto a substrate wherein the extruded polymer blend has a neck-in that is about equal to or increased by less than about 10% of the neck-in value observed when using the LDPE alone and wherein an amount of trim waste produced is equal to or about 10% less trim waste than the amount of trim waste produced when utilizing an extrusion coating using LDPE alone.

Abstract: A method comprising forming a polymeric composition by adding zinc oxide to a polymer wherein a pipe formed from the polymeric composition displays a time to failure as determined in accordance with ASTM F2263-07(E1) that is increased by greater than about 25% when compared to an otherwise similar pipe formed from a polymeric composition lacking zinc oxide. A pipe comprising polyethylene and greater than about 0.5 wt. % zinc oxide having a time to failure as determined in accordance with ASTM F2263-07(E1) that is at least about 25% greater than an otherwise similar pipe prepared in the absence of zinc oxide. A method comprising forming a composition comprising a polymer and zinc oxide into an article, and testing the structural integrity of the article when exposed to chlorinated water wherein the zinc oxide is present in an amount of from about 500 ppm to about 10000 ppm.

Abstract: Methods and systems for preparing catalyst, such as chromium catalysts, are provided. The valence of at least a portion of the catalyst sent to an activator is changed from Cr(III) to Cr(VI). The catalyst is prepared or activated continuously using a fluidization bed catalyst activator.

Abstract: An olefin polymerization process and apparatus wherein a fluid slurry comprising monomer, diluent and catalyst is circulated in a continuous loop reactor by two or more pumps. The process and apparatus allow operating the reaction at significantly higher solids content in the circulating fluid slurry. In a preferred embodiment, the fluid slurry is circulated by two impellers arranged so that the downstream impeller benefits from the rotational energy imparted by the upstream impeller. An olefin polymerization process operating at higher reactor solids by virtue of more aggressive circulation has improved efficiencies, particularly in larger-volume reactors.

Abstract: A process is provided to inhibit or limit the decomposition of a halide-containing olefin oligomerization catalyst system during recovery of an oligomerization product. The process includes deactivation of an olefin oligomerization catalyst system present in an olefin oligomerization reactor effluent stream by contact with an alcohol under conditions that minimize potential for deactivated catalyst system decomposition. Such conditions include minimization of the water content of the deactivation agent and concentration of the deactivation agent.

Abstract: A method of treating a polymerization reactor effluent stream comprising recovering the reactor effluent stream from the polymerization reactor, flashing the reactor effluent stream to form a flash gas stream, separating the flash gas stream into a first top stream, a first bottom stream, and a side stream, wherein the side stream substantially comprises hexane, separating the first top stream into a second top stream and a second bottom stream, wherein the second bottom stream substantially comprises isobutane, and separating the second top stream into a third top stream and a third bottom stream; wherein the third top stream substantially comprises ethylene, and wherein the third bottom stream is substantially free of olefins.

Abstract: The present invention provides polymerization catalyst compositions employing half-metallocene compounds with a heteroatom-containing ligand bound to the transition metal. Methods for making these hybrid metallocene compounds and for using such compounds in catalyst compositions for the polymerization of olefins also are provided.

Abstract: We disclose a monovinylarene-conjugated diene block copolymer containing a plurality of monovinylarene-conjugated diene mixed blocks, wherein each mixed block contains conjugated diene units and monovinylarene units in a weight ratio of about 0.05 to about 0.33. We also disclose a composition containing (a) from about 50 parts by weight to about 95 parts by weight of the monovinylarene-conjugated diene block copolymer and (b) from about 5 parts by weight to about 50 parts by weight of polystyrene; wherein the monovinylarene-conjugated diene block copolymer and the polystyrene total 100 parts by weight.

Abstract: The present invention provides dual catalyst systems and polymerization processes employing these dual catalyst systems. The disclosed polymerization processes can produce olefin polymers at higher production rates, and these olefin polymers may have a higher molecular weight and/or a lower melt index.

Abstract: A manufacturing system for producing polyolefin includes a polymerization reactor, a flash chamber, and a purge column. In certain embodiments, the purge column may receive a solids stream directly from the flash chamber. Further, the purge column may function as a feed tank for an extruder within an extrusion/loadout system. According to certain embodiments, the manufacturing system may be configured to consume less than 445 kilowatt-hours of energy per metric ton of polyolefin produced based on consumption of electricity, steam, and fuel gas.

Abstract: Catalyst compositions comprising a first metallocene compound, a second metallocene compound, an activator-support, and an organoaluminum compound are provided. An improved method for preparing cyclopentadienyl complexes used to produce polyolefins is also provided.

Abstract: The present invention provides metal-containing sulfated activator-supports, and polymerization catalyst compositions employing these activator-supports. Methods for making these metal-containing sulfated activator-supports and for using such components in catalyst compositions for the polymerization of olefins are also provided.