Abstract: A bimodal polymer composition comprising a lower molecular weight homopolymer and a higher molecular weight copolymer wherein the bimodal polymer composition has a density of from about 0.930 gram per cubic centimeter (g/cc) to about 0.970 g/cc, a ratio of high load melt index:melt index of from about 10 to about 150 and an Environmental Stress Crack Resistance (ESCR) of from about 25 hours to about 300 hours when measured in accordance with ASTM D1693 or ASTM D2561. A chromium-catalyzed polymer composition comprising (i) a lower molecular weight homopolymer and (ii) a higher molecular weight copolymer, wherein the bimodal polymer composition has an Environmental Stress Crack Resistance (ESCR) of from about 25 hours to about 300 hours when measured in accordance with ASTM D1693 or ASTM D2561.

Abstract: Disclosed are to metallocyclopropene complexes, methods of making same, methods for ring expansion metathesis polymerization, and polymers prepared by the methods for ring expansion metathesis polymerization.

Abstract: The invention relates to a process for transitioning from a first continuous polymerization reaction in a gas phase reactor conducted in the presence of a first catalyst to a second polymerization reaction conducted in the presence of a second catalyst in the gas phase reactor wherein the first and second catalysts are incompatible, the process comprising: (a) discontinuing the introduction of the first catalyst into the gas phase reactor; (b) introducing an effective amount of cyclohexylamine into the reactor to at least partially deactivate the first catalyst; (c) introducing an organometallic compound into the reactor and reacting the organometallic compound with cyclohexylamine; (d) introducing a gas composition into the reactor for the second polymerization reaction and (e) introducing the second catalyst into the reactor.

Abstract: A process for recycling solvent used in an ethylene-based polymerization comprising: passing a solvent stream which has been used in a first ethylene-based solvent polymerization reactor through an online purification bed to produce a recycle solvent stream, wherein the solvent stream prior to being passed through the online purification bed comprises solvent, ethylene, hydrogen, polymerization by-products and optionally comonomer; and passing the recycle solvent stream from the online purification bed to a second ethylene-based solvent polymerization reactor; wherein the second ethylene-based solvent polymerization reactor exhibits a catalyst efficiency dip of less than or equal to 20% for no longer than a forty-eight hour period following a swap of the online purification bed to a regenerated purification bed which contains an adsorbent having low reactivity to alkenes is provided.

Abstract: Process for introducing a fresh feed of fresh comonomer and/or fresh inert hydrocarbon to a polymerization reactor which is part of a polymerization process having high and low pressure recovery systems, the high pressure recovery system being at a pressure of 0.5 MPa (5 bar) or above and the low pressure recovery system being at a pressure of less than 0.5 MPa (5 bar). The process includes passing the fresh feed and a process stream containing a first component of hydrogen, nitrogen and/or methane and a second component of a monomer to a separator which is part of the low pressure recovery system and is at a pressure of 0.4 MPa or less to produce a first stream containing a majority of the first component and a second stream containing the second component and a majority of the fresh feed, and passing the second stream to the polymerization reactor.

Abstract: A method for producing polymer particles includes a preparation step for preparing a first oily liquid containing an oily olefin monomer, a radical polymerization initiator, and an iodine molecule; a synthesis step for obtaining a second oily liquid containing at least an iodine compound produced by a reaction between a radical generated by cleavage of the radical polymerization initiator and the iodine molecule in the first oily liquid; a suspension step for obtaining an oil droplet of the second oily liquid by suspending the second oily liquid in an aqueous solution containing an oxidizing agent, an acid, and a dispersant; and a polymerization step for polymerizing the oily olefin monomer in the oil droplet.

Abstract: A method comprising contacting an olefin in the presence of a catalyst and a melt index modifier (MIM) under conditions suitable to form a polyolefin and recovering the polyolefin, wherein the polyolefin melt index is increased by at least about 25%, wherein the normalized catalyst activity is decreased by less than about 10%, and wherein the MIM is characterized by the general formula R1—HC?CH—R2 or R3R4C?CH2 where R1, R2, R3, R4 are each selected from the group consisting of a non-aromatic organyl group.

Abstract: The invention relates to a catalyst metering device with a valve formed of an iron-based alloy steel hardened to a Rockwell hardness C of at least 60. The device can be used for metering of a catalyst for an ethylene polymerization reaction. The invention further relates to ethylene polymerization wherein the catalyst is metered in a catalyst metering device with a iron-based alloy steel hardened valve, as well as to a ethylene polymerization reactor comprising such a catalyst metering device.

Abstract: This invention relates to processes for increasing the viscosity of an oligomer composition including contacting the oligomer composition comprising one or more vinyl terminated oligomer with a supported mixed metal oxide catalyst; wherein the contacting causes the reaction of the vinyl terminated oligomers; and producing a product oligomer composition having a higher viscosity than the oligomer composition.

Abstract: A method for transitioning from a Ziegler-Natta to a Phillips catalyst system for the olefin polymerization reaction in one reactor, preferably a gas phase reactor, is described. The method comprises the steps of a) discontinuing a first olefin polymerization reaction performed in the presence of the Ziegler-Natta catalyst system; b) performing a second olefin polymerization reaction in the presence of a further catalyst system comprising catalyst components (A) and (B) producing, respectively, a first and a second polyolefin fraction, wherein the Mw of the first polyolefin fraction is less than the Mw of the second polyolefin fraction and the initial activity of catalyst component (A) exceeds the initial activity of catalyst component (B); and c) performing a third olefin polymerization reaction the presence of the Phillips catalyst system.

Abstract: Process for producing homopolymers or copolymers of conjugated dienes by contacting monomeric material having at least one conjugated diene with a catalyst system including two or more different transition metal compounds and optionally one or more activators. Preferred transition metal compounds are based on cobalt and chromium, especially complexes thereof having benzimidazole ligands.

Abstract: A method for treating at least one interior surface (for example, a bed wall) of a fluidized bed polymerization reactor system, including by applying a solution catalyst (preferably at least substantially uniformly and in liquid form) to each surface, and optionally (where a catalyst component of the solution catalyst comprises at least one chromium containing compound) oxidizing at least some of the applied chromium containing compound in a controlled manner.

Abstract: This invention relates to a catalyst system comprising: an activator, such as an aluminum alkyl, alumoxane or combinations thereof; a first catalyst precursor prepared by contacting compound (I) represented by the formula: with an optionally substituted alkyl or optionally substituted aryl alcohol; wherein Z—O is a support material, where O is oxygen and Z is Si, Ti, Al, Sn, Fe, Ga, Zr, B, Mg or Cr; each X is, independently, nitrogen, oxygen phosphorous, or sulfur, provided that both X's are not each oxygen; each n is, independently, 1 or 2, provided the total of n=3; each R is, independently, an alkyl group, a substituted alkyl group, an aryl group, or a substituted aryl group, provided at least one R group is an aryl or substituted aryl group; and a second catalyst precursor, wherein the second catalyst precursor is a metallocene compound. This invention also relates to the use of the above catalyst system to polymerize olefins and other monomers.

Abstract: A method comprising (a) providing a catalyst comprising chromium and a support having a pore volume of from about 1.7 ml/g to about 3.5 ml/g and a surface area of from about 450 m2/g to about 700 m2/g, (b) oxidizing the catalyst to form an oxidized catalyst, (c) reducing the oxidized catalyst to form an oxidized reduced catalyst, (d) oxidizing the oxidized reduced catalyst to form an activated catalyst, (e) contacting the activated catalyst with an olefin under conditions suitable to form a polyolefin, and (f) recovering the polyolefin, wherein the polyolefin has a density of greater than about 0.960 g/cc and a melt index of from about 1.3 g/10 min. to about 2.8 g/10 min.

Abstract: Disclosed herein are various processes, including continuous fluidized-bed gas-phase polymerization processes for making a high strength, high density polyethylene copolymer, comprising (including): contacting monomers that include ethylene and optionally at least one non-ethylene monomer with fluidized catalyst particles in a gas phase in the presence of hydrogen gas at an ethylene partial pressure of 100 psi or more and a polymerization temperature of 105° C. or less to produce a polyethylene copolymer having a density of 0.945 g/cc or more and an ESCR Index of 1.0 or more wherein the catalyst particles are prepared at an activation temperature of 700° C. or less, and include silica, chromium, and titanium.

Abstract: A method comprising (a) contacting a support and a chromium-containing compound to form chromium-containing support, (b) heat treating the chromium-containing support in an oxidizing atmosphere to form a treated support, (c) contacting the treated support with carbon monoxide to form a CO-contacted support, and (d) contacting the CO-contacted support with hydrogen to form a catalyst. A method comprising oxidizing a chromium-treated support to form a polymerization catalyst, contacting the polymerization catalyst with carbon monoxide to form a reduced polymerization catalyst, contacting the reduced polymerization catalyst with hydrogen to form an activated polymerization catalyst, and contacting the activated polymerization catalyst with ethylene in a reaction zone under suitable reaction conditions to form a random copolymer.

Abstract: The present invention concerns a catalyst for the production of high density polyethylene, by homopolymerising ethylene or copolymerising ethylene and an alpha-olefinic comonomer comprising 3 to 10 carbon atoms, prepared by the steps of: a) selecting a silica support with a specific surface area larger than 300 m2/g; b) treating the silica support with a titanium compound, in order to introduce titanium into the support, or with an aluminium compound, in order to introduce aluminum into the support; c) either treating the titanated silica support with an aluminum compound, in order to introduce aluminum into the titanated silica support, or treating the aluminated silica support with a titanium compound, in order to introduce titanium into the aluminated silica support; d) depositing a chromium compound on the titanated and aluminated silica support to form a catalyst; e) activating the catalyst of step d) under air in a fluidised bed at a temperature of from 600 to 800° C.

Abstract: This invention is directed to processes of making polymer in the presence of a hydrofluorocarbon or perfluorocarbon and recovering the polymer. The processes provided enable polymerization processes to be practiced with minimal fouling in the reaction system, and provide polymer products that can be manufactured to relatively low densities. The invention is particularly beneficial in the production of ethylene based polymers using chromium catalyst systems.

Abstract: This invention relates to a method of preparing a supported catalyst comprising the steps of contacting a solid titanium with a supported catalyst compound, and heating the combination to at least 150° C.

Abstract: A method for polymerizing ethylene is provided. The method can include preparing a supported catalyst composition comprising the steps of: (a) dehydrating a chromium impregnated support; (b) at least partially dissolving a titanium-containing compound in one or more inert solvents to provide a solution comprising the titanium-containing compound; (c) contacting the dehydrated chromium impregnated support with the titanium-containing solution to provide a mixture comprising the solvent, titanium-containing compound and chromium impregnated support; (d) removing the solvent from the mixture; and (e) activating the product of step (d) at a temperature of at least 800° F. (427° C.) to provide a supported titanated chrome catalyst composition. The supported titanated chrome catalyst composition can be feed to a slurry reactor, and contacted with an optional co-catalyst, under polymerization conditions, with ethylene.

Abstract: A catalyst used for trimerization of ethylene into 1-hexene is descrobed, which comprises (i) a specific organometallic complex having a neutral multidentate ligand having a tripod structure, (ii) an alkylaluminoxane, and an optional ingredient selected from: (iii) a halogenated inorganic compound, (iv) a specific alkyl group-containing compound, (v) a combination of a halogenated inorganic compound with a specific alkyl group-containing compound, (vi) an amine compound and/or an amide compound, and (vii) a combination of an amine compound and/or an amide compound with a specific alkyl group-containing compound.

Abstract: The present invention concerns a catalyst for the production of high density polyethylene, by homopolymerising ethylene or copolymerising ethylene and an alpha-olefinic comonomer comprising 3 to 10 carbon atoms, prepared by the steps of: a) selecting a silica support with a specific surface area larger than 300 m2/g; b) treating the silica support with a titanium compound, in order to introduce titanium into the support, or with an aluminium compound, in order to introduce aluminium into the support; c) either treating the titanated silica support with an aluminum compound, in order to introduce aluminum into the titanated silica support, or treating the aluminated silica support with a titanium compound, in order to introduce titanium into the aluminated silica support; d) depositing a chromium compound on the titanated and aluminated silica support to form a catalyst; e) activating the catalyst of step d) under air in a fluidised bed at a temperature of from 600 to 800° C.

Abstract: A process to produce ethylene polymers is provided.

Abstract: This invention relates to a method to polymerize olefins comprising contacting a solid aluminum or solid titanium compound with a supported catalyst compound, heating the solid aluminum or solid titanium compound to cause the solid compound to vaporize, optionally activating the support by oxidation, thereafter contacting the activated support with one or more olefin monomers.

Abstract: This invention discloses a process for the preparation of polyethylene resins having a narrow molecular weight distribution that comprises the steps of: (i) providing a first high molecular weight metallocene-produced linear low density polyethylene (mLLDPE) resin having a density of from 0.920 to 0.940 g/cm3 and a MI2 of from 0.05 to 2 g/10 min; (ii) providing a second high density polyethylene (HDPE) prepared either with a Ziegler-Natta or with a metallocene catalyst, said polyethylene having a density ranging from 0.950 to 0.970 g/cm3 and a MI2 of from 0.5 to 10 g/10 min; (iii) physically blending together the first and second polyethylenes to form a polyethylene resin having a narrow molecular weight distribution, a density ranging from 0.940 to 0.955 g/cm3 and a MI2 of from 1 to 2 g/10 min.

Abstract: A method for the treatment of catalysts or catalyst carriers by: a) introducing and distributing a gas in the lower section of a reactor containing a catalyst or catalyst carrier bulk material; b) forming a fluidized bed in the reactor; c) treating the particles in the fluidized bed while removing the fine particles an/or retaining the course particles by means of a separating organ and d) discharging the reactor. To this end, a reactor bottom which tapers downwards is used.

Abstract: Methods of preparing a polymerization catalyst are provided that include contacting a support comprising alumina with a sulfating agent and with chromium. In an embodiment in which the chromium is provided from a chromium compound such as chromium oxide, the support may be calcined after loading the sulfating agent and the chromium on the support. Alternatively, the sulfating agent can be loaded on the support while calcining it. In another embodiment in which the chromium is provided from an organochromium compound, the support may be calcined after contacting it with the sulfating agent and before contacting it with the organochromium compound. Catalysts compositions formed by the foregoing method are provided. In an embodiment, catalyst compositions comprise chromium and a sulfate treated alumina support. The catalyst compositions have an activity for ethylene polymerization that is at least about 25% greater than an activity of the same catalyst without sulfate.

Abstract: A process for polymerizing polyethylene with chromium-based catalysts wherein one or more supported chromium-based catalysts is mixed with mineral oil to form a slurry and the slurry is then introduced into a polymerization reactor, especially a gas-phase polymerization reactor.

Abstract: The present invention is directed to the use of aluminum alkyl activators and co-catalysts to improve the performance of chromium-based catalysts. The aluminum alkyls allow for the variable control of polymer molecular weight, control of side branching while possessing desirable productivities, and may be applied to the catalyst directly or separately to the reactor. Adding the alkyl aluminum compound directly to the reactor (in-situ) eliminates induction times.

Abstract: The invention provides a supported chromium catalyst system comprising a chromium catalyst precursor bound via at least one heteroatom to a functionalised support, said heteroatom being connected to said support via an organic group.

Abstract: A process to produce ethylene polymers is provided. Particularly, a process to produce ethylene polymers having a broad molecular weight distribution is provided. More particularly, a process to produce ethylene polymers that have low formation of smoke and odor during blow molding is provided.

Abstract: A method of transitioning catalysts for polyolefin polymerization is provided. In one aspect, the process includes providing a polymerization reactor that includes a first catalyst system, contacting olefin monomers with the first catalyst system to form polyolefin in a first polymerization reaction and introducing a catalyst killer to the polymerization reactor in an amount sufficient to terminate the first polymerization reaction. The method further includes introducing a second catalyst system to the polymerization reactor in the presence of at least a portion of the catalyst killer, wherein the at least a portion of the catalyst killer is an amount sufficient to activate the second catalyst system and contacting olefin monomers with the second catalyst system to form polyolefin in a second polymerization reaction.

Abstract: An improved polymerization process includes withdrawing a portion of a fluid slurry through a plurality of active continuous take off mechanisms, monitoring the pressure of feed material fed to the reactor, and adjusting the continuous take off mechanisms in response to the monitored feed line pressure.

Abstract: An olefin polymerization process wherein monomer, diluent and catalyst are circulated in a continuous loop reactor and product slurry is recovered by means of a continuous product take off. The product slurry is exposed to a pressure drop in a flash zone, producing a second slurry and vaporized diluent. The vaporized diluent produced in said flash chamber is condensed by heat exchange, without compression.

Abstract: Polymerization processes for ethylene and at least one mono-1-olefin comonomer having from about three to eight carbon atoms per molecule in the presence of a twice-aged catalyst system comprising chromium supported on a silica-titania support and a trialkylboron compound is provided. Novel ethylene copolymers also are produced.

Abstract: A conjugated diene polymer is produced by continuously polymerizing a conjugated diene monomer with a catalyst consisting essentially of specified components (a) to (c) and reacting with at least one of specified components (d) and (e) and has a content of cis-1,4-bond of not less than 85%, a content of 1,2-vinyl bond of not more than 2.0% and a ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) of not more than 5, and contains at least one functional group selected from epoxy group and hydroxyl group in its molecule. And also, a rubber composition comprises 10-200 parts by weight of silica based on 100 parts by weight of rubber ingredient consisting of 10-100% by weight of the above conjugated diene polymer and 90-0% by weight of the other diene polymer or natural rubber.

Abstract: An olefin polymerization process wherein monomer, at least one olefin comonomer different from the olefin monomer, diluent and catalyst are circulated in a continuous loop reactor and product slurry is recovered by means of a continuous product take off. The continuous product allows operating the reaction at significantly higher solids content in the circulating slurry.

Abstract: A chromium containing catalyst wherein the chromium atom is in one of its higher valence states and is immobilized to a support-agglomerate composed of at least one inorganic oxide component and at least one ion-containing layered component.

Abstract: A copolymer of ethylene and a higher alpha-olefin having broadened melt processing windows and reduced melt fracture can be produced using a chromium-containing catalyst system and a trialkyl boron cocatalyst. The polymerization process must be carefully controlled to produce a copolymer resin that easily can be made into articles of manufacture.

Abstract: Use of metallocene catalyst component for the preparation of a syndiotactic polyolefin having a monomer length of up to C10, which component has the general formula: R″(CpR1R2)(Cp′R1′R2′)MQ2 wherein Cp is a cyclopentadienyl ring; Cp′ is a 3,6 disubstituted fluorenyl ring; R1 and R2 are each independently H or a substituent on the cyclopentadienyl ring which is proximal to the bridge, which proximal substituent is linear hydrocarbyl of from 1 to 20 carbon atoms or a group of the formula XR*3 containing up to 7 carbon atoms in which X is chosen from Group IVA, and R* is the same or different and chosen from hydrogen or alkyl; R1′ and R2′ are each independently substituent groups on the fluorenyl ring, each of which is a group of the formula AR′″3, in which A is chosen from Group IVA, and each R′″ is independently hydrogen or a hydrocarbyl having 1 to 20 carbon atoms; M is a Group IVB transition metal or vanadium; each Q is hydrocarbyl having 1 to

Abstract: Hydroxyalkylamines can, in addition to imparting antistatic properties, significantly improve the color, i.e., the whiteness, of polyolefin resins produced with chromium-based catalysts and metallocene catalysts. Additionally, such compounds can impart improved whiteness at a loading significantly lower than that required to impart antistatic properties. Surprisingly, the discovered improvement in whiteness is not, however, observed in resins produced using other types of catalysts.

Abstract: High melt index polyolefins have been obtained with chromium silica catalysts under conventional polymerization conditions without the use of titanium or other additives. The useful chromium silica catalysts have a pore volume in the range of 1.9-2.9 cc/g and a narrow pore size distribution. The silica is a silica gel preferably obtained from a low solids, rapid gelation process.

Abstract: A polymerization loop reactor including a loop reaction zone, a continuous takeoff, and a fluid slurry disposed in the reaction zone. A generally cylindrical wall defines the loop reaction zone. The length of the loop reaction zone and the nominal outside diameter of the generally cylindrical wall define a length/diameter ratio greater than 250. The reactor can be charged with a fluid slurry including an olefin monomer reactant, solid olefin polymer particles, and a liquid diluent. The concentration of the solid olefin polymer particles in the slurry can be greater than 40 weight percent based on the weight of polymer particles and the weight of liquid diluent. Also disclosed is a polymerization process carried out by polymerizing, in the loop reaction zone of a reactor as defined above, at least one olefin monomer in a liquid diluent to produce a fluid slurry as defined above.

Abstract: Polymerization processes for ethylene and at least one mono-1-olefin comonomer having from about three to eight carbon atoms per molecule in the presence of a twice-aged catalyst system comprising chromium supported on a silica-titania support and a trialkylboron compound is provided. Novel ethylene copolymers also are produced.

Abstract: A process comprising polymerizing ethylene, or polymerizing ethylene and at least one other olefin, to produce a polymer is provided.

Abstract: Described is the use of nanoscale metal oxide particles as catalysts for the thermal and/or photochemical polymerization of species having at least one polymerizable carbon-carbon multiple bond and/or at least one carbon containing ring capable of undergoing a ring opening polymerization.

Abstract: Hydroxyalkylamines can, in addition to imparting antistatic properties, significantly improve the color, i.e., the whiteness, of polyolefin resins produced with chromium-based catalysts and metallocene catalysts. Additionally, such compounds can impart improved whiteness at a loading significantly lower than that required to impart antistatic properties. Surprisingly, the discovered improvement in whiteness is not, however, observed in resins produced using other types of catalysts.

Abstract: This invention relates to a method for purifying and drying a polymer hydrogel. This invention is based in part upon the discovery that rapid drying of polymer hydrogels can eliminate the problem of unacceptable levels of soluble oligomers caused by prolonged thermal treatment. Rapid drying techniques allow drying hydrogels containing more water than was previously considered possible without a loss in product quality. Furthermore, it was discovered that slurries comprising polymer hydrogels and large quantities of water can be spray dried and that spray drying can be conducted with only minimal oligomer formation.

Abstract: The present invention is directed to producing a resin which, when formed into a film, has excellent gas barrier and/or moisture barrier (low MVTR) properties. Further, the resin has a relatively high molecular weight distribution, preferably above 6, and has excellent processability/extrudability. The resin is produced using a cyclopentadienyl chromium compound, preferably a mono CpCr compound, on a support, preferably a silica support. A particularly preferred catalyst for use in the present invention comprises pentamethylcyclopentadienyidimethylchromiumpyridine. Preferably, the catalyst is used in a slurry polymerization process.

Abstract: A process is disclosed for producing polyethylene resin of broad molecular weight distribution, when formed into a film, high barrier to moisture (low MVTR (Moisture Vapor Transmission Rate) for the film). The resin is formed by polymerizing ethylene, preferably in a gas phase process or in a slurry process, using a post-titanated catalyst, that is, a catalyst wherein after initial formation of a catalyst comprising Cr—Ti-inorganic refractory support, further titanium is added to the catalyst in a post-titanation step, preferably to increase the titanium content of the catalyst to a final level preferably between 7 and 9.5 wt. %.