Abstract: This invention provides catalyst compositions that are useful for polymerizing at least one monomer to produce a polymer. This invention also provides catalyst compositions that are useful for polymerizing at least one monomer to produce a polymer, wherein said catalyst composition comprises contacting an organometal compound, an organoaluminum compound, and a treated solid oxide compound.

Abstract: Disclosed is a method of producing a polyolefin composition comprising contacting a metallocene pre-catalyst with a substoichiometric amount of a co-catalyst; adding a first olefin monomer; and polymerizing the first monomer for a time sufficient to form the polyolefin. The method allows for the use of a minimum amount of activating co-catalyst, and allows for the production of stereoregular and non-stereoregular polyolefins. The use of configurationally stable metallocene pre-catalysts allows for the production of monomodal isotactic polyolefins having narrow polydispersity. The use of configurationally unstable metallocene pre-catalysts allows for the production of monomodal atactic polyolefins having narrow polydispersity. The method of the present invention optionally further comprises contacting the polyolefin with a second amount of said co-catalyst; adding a second olefin monomer; polymerizing said second olefin monomer to form a block-polyolefin composition.

Abstract: Process for preparing a broad molecular weight polyethylene by polymerizing ethylene in the presence of a polymerization catalyst, the process comprising the following steps, in any mutual order: a) polymerizing ethylene, optionally together with one or more ?-olefinic comonomers having from 3 to 12 carbon atoms, in a gas-phase reactor in the presence of hydrogen, b) copolymerizing ethylene with one or more ?-olefinic comonomers having from 3 to 12 carbon atoms in another gas-phase reactor in the presence of an amount of hydrogen less than step a), where in at least one of said gas-phase reactors the growing polymer particles flow upward through a first polymerization zone under fast fluidization or transport conditions, leave said first polymerization zone and enter a second polymerization zone through which they flow downward under the action of gravity.

Abstract: A method for producing rotomoulding polyethylene by fluidized bed gas phase polymerisation of ethylene and the improved rotomoulding polyethylene obtainable by the process.

Abstract: A shrink film comprising a polyethylene film, characterized in that said polyethylene is an ethylene copolymer mixture having a molecular weight distribution in the range 10 to 35, a density of 915 to 940 kg/m3, a weight average molecular weight of at least 100000 D and an MFR2.16 (190° C.) of 0.1 to 0.9 kg/m3, which copolymer mixture is produced by a two or more stage copolymerization of ethylene and 2 to 10% mole (relative to ethylene) of a C3-12 alpha-olefin comonomer in a series of reactors including at least one slurry loop reactor and at least one gas phase reactor using a heterogeneous Ziegler-Natta catalyst.

Abstract: A catalyst system suitable for the polymerisation of olefins, said system comprising (a) a transition metal compound or lanthanide metal compound (b) a cocatalyst and (c) at least one porous support material characterised in that the porous support material has been pretreated with a halogen-containing organometallic compound, in particularly with a fluorine-containing organometallic compound. The catalyst system is particularly suitable for the preparation of polymers having broad molecular weight distributions from the polymerisation of olefins in the presence of a single site catalyst.

Abstract: Propylene homopolymers or copolymers containing up to 5.0 wt % of alpha-olefin units having from 2 to 8 carbon atoms other than propylene, characterized in that said propylene homopolymers or copolymers have Polydispersity Index value higher than 15, Melt Strength higher than 1.50 cN at 230° C. and Melt Flow Rate (ISO1133, 230° C./2.16 Kg) from 0.01 to 20 g/10 min.

Abstract: Improved thermoplastic polymer blend compositions comprising an isotactic polypropylene component and an alpha-olefin and propylene copolymer component, said copolymer comprising crystallizable alpha-olefin sequences. In a preferred embodiment, improved thermoplastic polymer blends are provided comprising from about 35% to about 85% isotactic polypropylene and from about 30% to about 70% of an ethylene and propylene copolymer, wherein said copolymer comprises isotactically crystallizable propylene sequences and is predominately propylene. The resultant blends manifest unexpected compatibility characteristics, increased tensile strength, and improved process characteristics, e.g., a single melting point.

Abstract: The invention provides a comprising one or more ethylene interpolymers, and wherein the interpolymers, or the composition, has a melt viscosity from 1 to 30,000 cP at 177° C., and wherein at least one ethylene interpolymer has an Rv from 0.3 to 0.99. The invention further provides a composition comprising at least one low molecular weight (LMW) ethylene interpolymer, and at least one high molecular weight (HMW) ethylene interpolymer, and wherein the composition has a melt viscosity from 1 to 30,000 cP at 177° C., and wherein the sum of the Rv from the low molecular weight interpolymer and the high molecular weight interpolymer is from 0.3 to 2. The invention further provides for processes of making such compositions, processes for functionalizing the interpolymer(s) of such compositions, and articles comprising at least one component prepared from an inventive composition.

Abstract: The instant invention is a high-density polyethylene composition, and method of making the same. The high-density polyethylene composition of the instant invention includes an ethylene alpha-olefin copolymer having a density in the range of 0.935 to 0.952 g/cm3, a melt index (I2) in the range of 30 to 75 g/10 minutes, an I21/I2 ratio in the range of 13-35, a Mw/Mn ratio in the range of 3.5-8. The high-density polyethylene composition has a brittleness temperature of at least less than ?20° C. The process for producing a high-density polyethylene composition according to instant invention includes the following steps: (1) introducing ethylene, and an alpha-olefin comonomer into a reactor; (2) copolymerizing the ethylene with the alpha-olefin comonomer in the reactor; and (3) thereby producing the high-density polyethylene composition, wherein the high-density polyethylene composition having a density in the range of 0.935 to 0.

Abstract: The present invention pertains to a heterogeneous ethylene/?olefin copolymer having a relatively high melt index range (I2 from 1.1 to 1.6 dg/min.), low density (0.915 to 0.919 g/cc) and narrow molecular weight distribution (I10/I2 from 7.0 to 7.7), and highly separated composition distribution as determined by SCBD; a process for making such a copolymer; blends thereof with additional polymers; and fabricated articles, especially films, made there from.

Abstract: An improved method for the preparation of a supported polymerisation catalyst system comprises the combination of (i) a porous support (ii) a polymerisable monomer, (iii) a polymerisation catalyst, and (iv) a cocatalyst, characterised in that the polymerisable monomer is added to the porous support before addition of one or both of the polymerisation catalyst and the cocatalyst. The preferred polymerisation catalyst is a metallocene complex and the preferred porous support is silica. The resultant supported catalysts are stable over long periods of time. The supported catalyst are particularly suitable for use in the gas phase.

Abstract: Disclosed is a method of preparing an ultra-high molecular weight, linear low density polyethylene with a catalyst system that comprises a bridged indenoindolyl transition metal complex, a non-bridged indenoindolyl transition metal complex, an alumoxane activator and a boron-containing activator. The ultra-high molecular weight, linear low density polyethylene has a weight average molecular weight greater than 1,000,000 and a density less than 0.940 g/cm3.

Abstract: This invention is directed to a polymerization process that is carried out at relatively high productivity levels and with relatively low fouling. The process includes mixing together a catalyst system, at least one monomer and a hydrofluorocarbon to produce the polymer. The reaction is carried out such that little to no chlorine containing hydrocarbons are present.

Abstract: Multimodal polyolefin polymers may be prepared in series-connected polymerization reactors where a prior reactor is a slurry reactor employing light solvent as the slurry medium and hydrogen to limit polymer molecular weight, the polymer product from the prior reactor being substantially freed of hydrogen prior to entry into a subsequent polymerization reactor operating at low hydrogen pressure to produce a high molecular weight olefin. The economics and operating performance of such a series slurry reactor polyethylene process can be significantly improved through the use of an intermediate slurry transfer system and hydrogen removal apparatus that employs flash drums in series in conjunction with a warm recycle solvent slurry diluent.

Abstract: An ethylene-?-olefin copolymer comprising repeating units derived from ethylene and repeating units derived from an ?-olefin having 3 to 20 carbon atoms and having a melt flow rate (MFR) of from 0.01 to 100 g/10 min, a density (d) of from 890 to 970 kg/m3, a flow activation energy (Ea) of 50 kJ/mol or more, a molecular weight distribution (Mw/Mn) of 3 or more measured by gel permeation chromatography, and a hexane extraction rate (C) of 2.8% or less.

Abstract: A novel process for the polymerization of olefins is provided. The process involves contacting at least one olefin with a Ziegler-Natta type catalyst in the presence of a specified compound that results in the production of polymeric products having a narrower molecular weight distribution. Also provide is a process for narrowing the molecular weight distribution of a polyolefin comprising contacting an olefin, a Ziegler-Natta catalyst and a compound specified herein. Further provided are novel polyethylenes, and films and articles produced therefrom.

Abstract: A copolymer having monomer units derived from ethylene and monomer units derived from an ?-olefin of 3 to 20 carbon atoms, a density of 906 to 970 kg/m3 and an activation energy of flow of 50 kJ/mol or more, and satisfying specific relations among a melt complex viscosity, a melt flow rate and a characteristic relaxation time.

Abstract: An ethylene-?-olefin copolymer having monomer units derived from ethylene and monomer units derived from an ?-olefin of 3 to 20 carbon atoms, a density of 906 to 970 kg/m3, an activation energy of flow of 50 kJ/mol or more and a heat quantity of fusion of a cold xylene soluble part of 30 J/g or more, and satisfying specific relations among a rate of the cold xylene soluble part in the copolymer, the density, a melt flow rate and a characteristic relaxation time.

Abstract: An ethylene (co)polymer of the present invention is a (co)polymer with excellent moldability and mechanical properties and either an ethylene homopolymer or a copolymer of ethylene and an ?-olefin of 4 to 20 carbon atoms. The (co)polymer has methyl branches measured by 13C-NMR less than 0.1 in number per 1,000 carbon atoms and Mw/Mn measured by GPC not lower than 1.8 and lower than 4.5. The (co)polymer is either an ethylene homopolymer or a copolymer of ethylene and an ?-olefin of 3 to 20 carbon atoms. The melt tension (MT) and the swell ratio (SR) satisfy the relation; log(MT)>12.9?7.15×SR; and the intrinsic viscosity ([?]) and the melt flow rate (MFR) satisfy the relation; [?]>1.85×MFR?0.192 in the case of MFR?1 and the relation; [?]>1.85×MFR?0.213 in the case of MFR?1. Such an ethylene (co)polymer can be usable for various molding applications and especially suitable for pipes.

Abstract: Provided are a propylene polymer compositions comprising a propylene copolymer and a propylene homopolymer polymerized in the presence of the propylene copolymer. The propylene polymer compositions exhibit properties such as broad molecular weight distribution, low crystallinity, high solubles and superior crystallization kinetics and are useful in fast cycle-time processing methods such as injection molding, sheet extrusion, thermoforming, and oriented film fabrication. Also provided is a process for preparing the propylene polymer compositions in the presence of a catalyst and at least two electron donors using sequential or parallel polymerization reaction zones. Finally, articles made from the propylene polymer composition are provided, particularly articles requiring high stiffness, high heat deflection temperature, good fatigue resistance and low temperature impact resistance such as appliance parts.

Abstract: A polyethylene film comprising a polymer composition having the characteristics of a total energy dart drop, measured in accordance with ASTM D4272, of greater than a bout 0.45 ft.lbf, a dart drop impact strength, measured in accordance with ASTM D1709 Method A, of greater than about 135 g, and a moisture vapor transmission rate, measured in accordance with ASTM F1249 at 100° F. and 90% relative. humnidity, of less tha about 0.85 g-mil/100 square inch/24 hr, wherein said ASTM tests are performed on a test specimen having a 0.8 mil thickness.

Abstract: The present invention provides method of preparing alkene-acrylate-norbornene terpolymer by polymerization of a monomer mixture consisting of alkene, acrylate and norbornene by a radical initiator under the presence of a Lewis acid. In the method of preparing the alkene-acrylate-norbornene terpolymer of the present invention, the terpolymer may be prepared in the mild condition of low temperature and low pressure by using the Lewis acid so that the process is simple and the property of the terpolymer may be easily controlled. In addition, the terpolymer prepared by the method includes the ethylene and the norbornene simultaneously so that it has high glass transition temperature, and the brittle property in forming of film is improved.

Abstract: Provided are a novel transition metal complex where a monocyclopentadienyl ligand to which an amido group is introduced is coordinated, a catalyst composition including the same, and an olefin polymer using the catalyst composition. The transition metal complex has a pentagon ring structure having an amido group connected by a phenylene bridge in which a stable bond is formed in the vicinity of a metal site, and thus, a sterically hindered monomer can easily approach the transition metal complex. By using a catalyst composition including the transition metal complex, a linear low density polyolefin copolymer having a high molecular weight and a very low density polyolefin copolymer having a density of 0.910 g/cc or less can be produced in a polymerization of monomers having large steric hindrance. Further, the reactivity for the olefin monomer having large steric hindrance is excellent.

Abstract: Embodiments of the invention provide a class of propylene/?-olefin block interpolymers. The propylene/?-olefin interpolymers are characterized by an average block index, ABI, which is greater than zero and up to about 1.0 and a molecular weight distribution, Mw/Mn, greater than about 1.3. Preferably, the block index is from about 0.2 to about 1. In addition or alternatively, the block propylene/?-olefin interpolymer is characterized by having at least one fraction obtained by Temperature Rising Elution Fractionation (“TREF”), wherein the fraction has a block index greater than about 0.3 and up to about 1.0 and the propylene/?-olefin interpolymer has a molecular weight distribution, Mw/Mn, greater than about 1.3.

Abstract: Olefin polymers having a melt strength of about 5cN at 190 ° C., and when made into a film have a CD shrink of at least 20%. Some of the polymers have a comb-like structure with at least 0.3 long-chain branches per 1000 carbon atoms are disclosed. Some compositions described herein include a high molecular weight fraction and a low molecular weight fraction wherein the ratio of the molecular weight of the high molecular weight fraction to the molecular weight of the low molecular weight fraction is greater than about 1.3.

Abstract: Provided is catalyst composition including a transition metal complex precatalyst represented by Formula 1; a first cocatalyst represented by Formula 2 which is an alkylaluminum compound; and a second cocatalyst represented by Formula 3 which is a salt compound comprising a Bronsted acid cation and a noncoordinating, compatible anion. Here, R1, R2, R3, R4, E, Q1, Q2 and M are defined in the specification. Al(R6)3 Formula 2 Here, R6 is defined in the specification. [L-H]+[ZA4]? Here, L, [L-H]+, Z and A are defined in the specification. A catalyst composition including binuclear transition metal complexes, an alkylaluminum compound, and a salt compound including a Bronsted acid cation, and a noncoordinating, compatible anion, and a method of preparing the catalyst composition are provided. The activity of the catalyst composition has been improved.

Abstract: A new class of heterocyclic metallocenes, a catalytic system containing them and a process for polymerizing addition polymerizable monomers using said catalytic system are disclosed; the heterocyclic metallocenes correspond to the formula (I): YjR?iZjjMeQkPl wherein Y is a coordinating group containing a six ? electron central radical directly coordinating Me, to which are associated one or more radicals containing at least one non-carbon atom selected from B, N, O, Al, Si, P, S, Ga, Ge, As, Se, In, Sn, Sb and Te; R? is a divalent bridge between the Y and Z groups; Z is a coordinating group, optionally being equal to Y; Me is a transition metal; Q is halogen or hydrocarbon substituents; P is a counterion; i is 0 or 1; j is 1–3; jj is 0–2; k is 1–3; and l is 0–2.

Abstract: High density polyethylene having reduced melt elasticity and a reduced level of highly short-chain branched polymer molecules and wire and cable insulation compositions based thereon having improved strippability and oxidative stability are provided.

Abstract: An ethylene-based polymer which is an ethylene/C4 to C10 ?-olefin copolymer and satisfies the following requirements [k1] to [k3]: [k1] melt flow rate (MFR) under a loading of 2.16 kg at 190° C. is in the range of 1.0 to 50 g/10 minutes; [k2] LNR defined as a scale of neck-in upon film molding is in the range of 0.6 to 1.4; and [k3] take-up speed at break [DS (m/min)] at 160° C. and melt flow rate (MFR) satisfy the following relationship (Eq-1): 12×MFR0.577?DS?165×MFR0.577 (Eq-1), and a thermoplastic resin composition containing the ethylene-based polymer, provide a molded product, preferably a film, excellent in moldability and mechanical strength.

Abstract: Disclosed is a method of producing a polyolefin composition comprising contacting a metallocene pre-catalyst with a substoichiometric amount of a co-catalyst; adding a first olefin monomer; and polymerizing the first monomer for a time sufficient to form the polyolefin. The method allows for the use of a minimum amount of activating co-catalyst, and allows for the production of stereoregular and non-stereoregular polyolefins. The use of configurationally stable metallocene pre-catalysts allows for the production of monomodal isotactic polyolefins having narrow polydispersity. The use of configurationally unstable metallocene pre-catalysts allows for the production of monomodal atactic polyolefins having narrow polydispersity. The method of the present invention optionally further comprises contacting the polyolefin with a second amount of said co-catalyst; adding a second olefin monomer; polymerizing said second olefin monomer to form a block-polyolefin composition.

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: One or more oligomers of an olefin are prepared in the presence of a single-site catalyst. Preferably, the olefin is an ?-olefin, and the oligomers are a poly-alpha-olefin (PAO). The PAO so prepared is completely or substantially free of tertiary hydrogen resulting from isomerization. Consequently, the PAO possesses improved biodegradability, improved oxidation resistance, and/or a relatively higher viscosity index. The PAO has many useful applications, such as a component of a lubricant.

Abstract: The invention provides an ethylene-?-olefin copolymer which is superior in extrusion molding processability. The present invention is to provide a copolymer of ethylene and ?-olefin of from 4 to 20 carbon atoms, having melt flow rate of from 1 to 100 g/10 min, an activation energy for melt flow of 60 kJ/mol or more, melt tension at 190° C. (MT), intrinsic viscosity ([?]) and a chain length A which satisfy the formula (1) to (3), wherein the chain length A is a chain length at peak position of a logarithm normal distribution curve of a component having the highest molecular weight among logarithm normal distribution curves obtained by dividing a chain length distribution curve obtained by gel permeation chromatography measurement into at least two logarithm normal distribution curves.

Abstract: This invention relates to catalyst compositions comprising a first metallocene compound, a second metallocene compound, at least one chemically-treated solid oxide, and at least one organoaluminum compound. This invention also relates to methods to prepare and use the catalyst compositions and new polyolefins. The compositions and methods disclosed herein provide ethylene polymers and copolymers with lower MI, increased melt strength, and good MD tear properties.

Abstract: An ethylene/?-olefin copolymer comprising a component produced by a non-single-site polymerization catalyst and a component produced by a single-site polymerization catalyst, its preparation and use are described. The copolymer has an ?-olefin content of 5 to 20 percent by weight and shows at least two CRYSTAF peak temperatures differing by at least 15° C. and/or at least two DSC melting peak temperatures differing by at least 15° C.

Abstract: This invention relates to the field of metal-catalyzed olefin polymerization methods and the polymers and films prepared therefrom. In one aspect, this invention provides polyethylene and ethylene/?-olefin copolymers formed in the presence of tightly-bridged metallocene catalyst, organoaluminum cocatalyst, and a chemically-treated solid oxide, and optionally in the presence of additional cocatalysts. The resins and films prepared from these polymers exhibit high haze values, low clarity values, and a low coefficient of friction.

Abstract: Blown films and blow molded objects may be prepared using a polyethylene composition comprising a unimodal metallocene catalyzed polyethylene copolymer. The polyethylene copolymer has high melt fow rate and good melt strength allowing it to be useful in both extrusion and injection blow molding. Blown film prepared therewith has a high level of clarity.

Abstract: A method for making a Ziegler-Natta catalyst support includes the steps of contacting a fumed silica with a surface modifying agent such as a compound having the formula RMgX MgR?R? wherein R, R? and R? are each individually a moiety selected from an alkyl group, cycloalkyl, aryl or alkaryl group, and X is a halogen selected from the group consisting of chlorine, bromine and iodine, to provide a pretreated silica seeding agent. The pretreated silica seeding agent is then dispersed in a non-aqueous liquid magnesium halide/alkanol complex, and the magnesium halide is crystallized onto the silica particles to form catalyst support particles especially suitable for Ziegler-Natta catalysts.

Abstract: Films with excellent machine direction (MD) tear properties comprise at least one layer made from a polymer comprising: (A) at least 50 weight percent (wt%) propylene; and (B) at least 5 wt % ethylene and/or one or more unsaturated comonomers. Representative of component (B) unsatuarated comonomers are the C4-20 ?-olefins, C4-20 dienes, styrenic compounds, and the like. Preferably, the film has at least one of a (i) haze value of less than about 10, (ii) 45 degree gloss of greater than about 65, and (iii) dart value of greater than about 100 g/mil. In one preferred embodiment, the layer comprises a compolymer characterized as having at least one of the following properties: (i) 13C NMR peaks corresponding to a regio-error at about 14.6 and about 15.7 ppm, the peaks of about equal intensity, (ii) a B-value greater than about 1.4 when the comonomer content, i.e.

Abstract: A dual olefin polymerization process is disclosed. The process uses a bridged indenoindolyl ligand-containing Group 4 transition metal complex and an activator. It is carried out in multiple stages or in multiple reactors. The same complex and the same activator are used in all stages or reactors. Different polyolefins are made in different stages or reactors by varying the monomer compositions, hydrogen concentrations, or both. The process of the invention produces polyolefins which have broad molecular weight distributions, composition distributions, or both.

Abstract: Apparatus for olefin polymerization includes one or more shell and tube olefin polymerization reactors, each of which has an olefin polymerization reaction mixture inlet connection and a crude polyolefin product outlet connection. Each reactor is equipped with a recirculation system including a pump arranged to circulate a reaction mixture through the tube side of the reactor independently of the introduction of olefin polymerization reaction mixture into the reactor. The apparatus may also include an inlet reaction mixture distribution manifold and an outlet polymerization reaction mixture collection manifold interconnecting the reactors for operation in parallel. The apparatus also includes catalyst composition and catalyst modifier inlets for each reactor arranged such that a catalyst modifier to may be introduced into each reactor at a rate which is independent of the introduction of catalyst composition.

Abstract: The present method is directed to techniques for estimating and periodically controlling the reactor split of alpha-olefin polymerizations using multiple catalysts that selectively incorporate monomers and other reactants into polymer compositions. The method provides for the rapid determination of instantaneous reactor split and cumulative split in polymerization reactors by the use of a novel linear relationship between Incorporation and Reactor Split.

Abstract: The present invention relates to a process for polymerizing monomer and comonomer(s) utilizing a bulky ligand transition metal metallocene-type catalyst or catalyst system, where the process is operated in the absence of or with a low amount of any of the isomers of the comonomer(s). The level of these isomers in the process of the invention are eliminated or maintained below a threshold level. It has been discovered that removal of certain isomers of the comonomer used in a polymerization process using metallocene-type catalysts results in an improved process.

Abstract: A process for polymerizing olefins is disclosed. The process uses an organometallic complex with at least one non-bridged indenoindolyl ligand bonded to M. The substituent on the indole nitrogen contains an atom selected from the group consisting of S, O, P, and N. Polyolefins from the process have unexpectedly high molecular weight compared with polyolefins made using similar supported indenoindolyl complexes.

Abstract: Metallocene catalyzed polyethylenes are found to have improved physical properties, improved processability and improved balance of properties. Surprisingly, there is a direct relationship between MD shrinkage, and MD tear. Additionally, MD tear is greater than TD tear, and MD tear is also greater than intrinsic tear. MD tear to TD tear ratios are above 0.9, and dart drop impact is above 500 g/mil. The polyethylenes have a relatively broad composition distribution and relatively broad molecular weight distribution.

Abstract: The invention provides for polymerization catalyst compositions, and for methods for introducing the catalyst compositions into a polymerization reactor. More particularly, the method combines a catalyst component containing slurry and a catalyst component containing solution to form the completed catalyst composition for introduction into the polymerization reactor. The invention is also directed to methods of preparing the catalyst component slurry, the catalyst component solution and the catalyst compositions, to methods of controlling the properties of polymer products utilizing the catalyst compositions, and to polymers produced therefrom.

Abstract: A method for preparing a supported organometallic complex is disclosed. An organometallic complex is combined with a support material that has been treated with an organozinc compound. The organometallic complex comprises a Group 3 to 10 transition metal and an indenoindolyl ligand that is bonded to the transition metal. Also disclosed is a process for polymerizing an olefin using the supported complex. Organozinc treatment of the support unexpectedly boosts catalyst activity and polyolefin molecular weight.

Abstract: Improved thermoplastic polymer blend compositions comprising an isotactic polypropylene component and an alpha-olefin and propylene copolymer component, said copolymer comprising crystallizable alpha-olefin sequences. In a preferred embodiment, improved thermoplastic polymer blends are provided comprising from about 35% to about 85% isotactic polypropylene and from about 30% to about 70% of an ethylene and propylene copolymer, wherein said copolymer comprises isotactically crystallizable propylene sequences and is predominately propylene. The resultant blends manifest unexpected compatibility characteristics, increased tensile strength, and improved process characteristics, e.g., a single melting point.

Abstract: Polymerization processes are disclosed for producing polyethylene having a target density and improved environmental stress resistance. Ethylene and optionally one or more ?-olefin comonomers, supported chromium catalyst, and metal alkyl cocatalyst are contacted to produce polyethylene. The density of the polyethylene is determined, and the concentration of cocatalyst is adjusted in response to a deviation between the density of the polyethylene and the target density. The catalyst and cocatalyst can be fed separately into the reactor, or can be co-fed, eliminating the need to pre-contact the catalyst and cocatalyst prior to introducing them into the reactor.