Abstract: An ethylene/alpha-olefin copolymer that can be synthesized in a fluidized-bed, gas phase polymerization reactor and made into a blown film. The ethylene/alpha-olefin copolymer is characterized by a bubble stability-effective combination of properties comprising density, melt flow ratio (I21/I5), and melt storage modulus G? (G?=3,000 Pa). The synthesis in the FB-GPP reactor is characterized by a property-imparting-effective combination of operating conditions comprising reactor bed temperature and H2/C2 gas molar ratio. An embodiment of the blown film consisting of the ethylene/alpha-olefin copolymer is characterized by enhanced bubble stability. A method of making the ethylene/alpha-olefin copolymer. A film comprising the ethylene/alpha-olefin copolymer. A method of making the film. A manufactured article comprising the film.

Abstract: A system and method for feeding a chromium-based catalyst to a polymerization reactor; adding a reducing agent to the chromium-based catalyst, and polymerizing an olefin into a polyolefin in the polymerization reactor in the presence of the chromium-based catalyst.

Abstract: The present disclosure provides for a system and method for producing a polyethylene polymer (PE) that includes measuring a melt flow index (MFI) of the PE, comparing the measured value of the MFI to a predetermined desired range for the MFI, changing a catalyst feed rate to the polymerization reactor based on the compared values of the MFI, where changes in the catalyst feed rate preemptively compensate for subsequent changes in an oxygen flow rate to the polymerization reactor that maintain a predetermined residence time and bring the MFI of the PE into the predetermined desired range for the MFI; and changing the oxygen flow rate to the polymerization reactor thereby maintaining both the predetermined residence time and bringing the MFI of the PE into the predetermined desired range for the MFI. The measuring and comparing steps are repeated to ensure the measured value of the MFI is within the predetermined desired range of the MFI at the predetermined residence time.

Abstract: Embodiments of the present disclosure are directed towards methods for rating polymerization processes based upon a first cracking index (value and a second cracking index value.

Abstract: A system and method for charging a chromium-based catalyst to a mix vessel; introducing a reducing agent through an entrance arrangement into the mix vessel, and agitating a mixture of the chromium-based catalyst, the reducing agent, and a solvent in the mix vessel to promote contact of the reducing agent with the chromium-based catalyst to give a reduced chromium-based catalyst.

Abstract: Polymerization process control methods for making polyethylene are provided. The process control methods include performing a polymerization reaction in a polymerization reactor to produce the polyethylene, where ethylene, and optionally one or more comonomers, in the polymerization reaction is catalyzed by an electron donor-free Ziegler-Natta catalyst and an alkyl aluminum co-catalyst. A melt flow ratio (I21/I2) of the polyethylene removed from the polymerization reactor is measured and an amount of long chain branching (LCB) of the polyethylene from the polymerization reactor is controlled by adjusting a weight concentration of the alkyl aluminum co-catalyst present in the polymerization reactor.

Abstract: A system and method for charging a chromium-based catalyst to a mix vessel; introducing a reducing agent through an entrance arrangement into the mix vessel, and agitating a mixture of the chromium-based catalyst, the reducing agent, and a solvent in the mix vessel to promote contact of the reducing agent with the chromium-based catalyst to give a reduced chromium-based catalyst.

Abstract: 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 is formed by a trimmed catalyst system including a supported catalyst including bis(n-propylcyclopentadienyl) hafnium (R1)(R2) and a trim catalyst comprising meso-O(SiMe2Ind)2Zr(R1)(R2), wherein R1 and R2 are each, independently, methyl, chloro, fluoro, or a hydrocarbyl group.

Abstract: Disclosed herein are methods of controlling polymer properties in polymerization processes that use a chromium-based catalyst. An embodiment discloses a method of producing a polyolefin comprising: contacting a reaction mixture and a reduced chromium oxide catalyst in a gas-phase reactor to produce the polyolefin, wherein the reaction mixture comprises a monomer and a co-monomer; and changing a reaction temperature in the gas-phase reactor by about 1° C. or more whereby a gas molar ratio of the co-monomer to the monomer is changed by about 2% or more and a co-monomer content of the polyolefin at substantially constant density is changed by about 2% or more. Additional methods and compositions are also provided.

Abstract: Embodiments of the present disclosure are directed towards method for modifying a polymer flow index. As an example, a method for modifying a polymer flow index can include providing monomers to a polymerization reactor, providing a chromium catalyst to the polymerization reactor, and providing an active amount of a flow index modifier to the polymerization reactor, wherein the flow index modifier is selected from carbon dioxide, carbon monoxide, 2,4-hexadiene, and combinations thereof.

Abstract: Modified chromium-based catalyst compositions for olefin polymerization are disclosed. The modifiers prevent or reduce catalyst particle aggregation providing improved catalyst particle dispersion and consistent flow index response of the compositions in olefin polymerization.

Abstract: Catalyst systems and methods for making and using the same. A method for making a catalyst support includes forming a mixture of a support material and a fluoride donor. The mixture is added to a fluidized bed reactor. The mixture is fluidized to form a fluidized bed while maintaining a flow rate of a fluidizing gas of about 0.1 ft./sec at less than about 370° C. and greater than about 0.35 ft./sec at temperatures greater than about 370° C. The mixture is calcined to decompose the fluoride donor, forming a fluorinated support.

Abstract: Disclosed herein are methods of controlling polymer properties in polymerization processes that use a chromium-based catalyst. An embodiment discloses a method of producing a polyolefin comprising: contacting a reaction mixture and a reduced chromium oxide catalyst in a gas-phase reactor to produce the polyolefin, wherein the reaction mixture comprises a monomer and a co-monomer; and changing a reaction temperature in the gas-phase reactor by about 1° C. or more whereby a gas molar ratio of the co-monomer to the monomer is changed by about 2% or more and a co-monomer content of the polyolefin at substantially constant density is changed by about 2% or more. Additional methods and compositions are also provided.

Abstract: A catalyst system for polymerizing olefin-based polymers and interpolymers is disclosed. The catalyst system may include a supported chromium catalyst and a Ziegler-Natta catalyst comprising a bulking agent, Mg, and Ti. The Ziegler-Natta catalysts in catalyst systems disclosed herein run exceptionally well without addition of excessive amounts of co-catalyst, thus allowing for use of chromium based supported catalysts that would otherwise be overwhelmed by aluminum alkyl. Further, embodiments disclosed herein may be run without an internal electron donor, and the lack of an internal electron donor in the system also prevents poisoning of the chromium catalysts by the internal electron donor. By including or co-feeding a chromium based catalyst with these Ziegler-Natta catalysts, it has been found that the molecular architecture of the resulting polyolefins, such as polyethylenes, may provide for resins with excellent processing properties.

Abstract: A system and method for feeding a chromium-based catalyst to a polymerization reactor; adding a reducing agent to the chromium-based catalyst, and polymerizing an olefin into a polyolefin in the polymerization reactor in the presence of the chromium-based catalyst.

Abstract: Catalyst systems and methods for making and using the same. A method for making a catalyst support includes forming a mixture of a support material and a fluoride donor. The mixture is added to a fluidized bed reactor. The mixture is fluidized to form a fluidized bed while maintaining a ratio of a pressure drop across a distributor plate to a pressure drop across the fluidized bed of greater than about 7%. The mixture is calcined to decompose the fluoride donor, forming a fluorinated support.

Abstract: A system and method for feeding a chromium-based catalyst to a polymerization reactor; adding a reducing agent to the chromium-based catalyst, and polymerizing an olefin into a polyolefin in the polymerization reactor in the presence of the chromium-based catalyst.

Abstract: A film formed from a polyethylene copolymer using a reduced chromium oxide catalyst, ethylene monomers and a co-monomer selected from butene monomers or 1-hexene, where the polyethylene copolymer has a density in the range of from about 0.935 to about 0.950 g/cm3 and an I21/I5 in a range of about 18.0 to about 30.0. The film formed from the polyethylene copolymer has a dart drop impact (g/im) that significantly greater as compared to a film of the polyethylene copolymer formed using a silyl chromate catalyst in place of the reduced chromium oxide catalyst. A method of making such films is also provided.

Abstract: Catalyst systems and methods for making and using the same. A method for making a catalyst support includes forming a mixture of a support material and a fluoride donor. The mixture is added to a fluidized bed reactor. The mixture is fluidized to form a fluidized bed with a height to diameter ratio of at least about 2.3. The mixture is calcined to decompose the fluoride donor, forming a fluorinated support.

Abstract: Polymerization process control methods for making polyethylene are provided. The process control methods include performing a polymerization reaction in a polymerization reactor to produce the polyethylene, where ethylene, and optionally one or more comonomers, in the polymerization reaction is catalyzed by an electron donor-free Ziegler-Natta catalyst and an alkyl aluminum co-catalyst. A melt flow ratio (I21/I2) of the polyethylene removed from the polymerization reactor is measured and an amount of long chain branching (LCB) of the polyethylene from the polymerization reactor is controlled by adjusting a weight concentration of the alkyl aluminum co-catalyst present in the polymerization reactor.