A solution polymerization process uses a reactor system in which a first stage is operated in a non adiabatic (cooled) manner and is connected to a second stage containing a downstream reactor that is operated adiabatically. In an embodiment, the first reactor stage includes at least one loop reactor and the second stage includes a tubular reactor. In an embodiment, the first stage is operated with a single site catalyst and at least one downstream reactor uses a Ziegler Natta catalyst.

A system and method of producing polyethylene, including: polymerizing ethylene in presence of a catalyst system in a reactor to form polyethylene, wherein the catalyst system includes a first catalyst and a second catalyst; and adjusting reactor conditions and an amount of the second catalyst fed to the reactor to control melt index (MI), density, and melt flow ratio (MFR) of the polyethylene.

Catalyst systems and methods for making and using the same are described. A method includes selecting a catalyst blend using a blend polydispersity index (bPDI) map. The polydispersity map is generated by generating a number of polymers for at least two catalysts. Each polymer is generated at a different hydrogen to ethylene ratio. At least one catalyst generates a higher molecular weight polymer and another catalyst generates a lower molecular weight polymer. A molecular weight for each polymer is measured. The relationship between the molecular weight of the polymers generated by each of the catalysts and the ratio of hydrogen to ethylene is determined. A family of bPDI curves for polymers that would be made using a number of ratios of a blend of the at least two catalysts for each of a number of ratios of hydrogen to ethylene. A ratio for the catalyst blend of the catalysts that generates a polymer having a bPDI that matches a polymer fabrication process is selected, and the product specific polyolefin is made using the catalyst blend.

A method for feeding an antistatic compound to a polymerization reactor comprising the steps of: a) dispersing, under mixing conditions, a catalyst powder and an antistatic compound in an oil, so as to form a suspension of catalyst powder and antistatic compound in said oil; b) successively adding, under mixing conditions, a molten thickening agent to said suspension from step a), while maintaining said suspension at a temperature such that said thickening agent solidifies on contact with said suspension; c) transferring the product obtained from b) to a polymerization reactor.

Processes for transitioning from a first catalyst to a second catalyst in a gas phase polymerization reactor. In some embodiments, the processes relate to transitioning from a metallocene catalyst to a Ziegler-Natta catalyst. In other embodiments, the processes relate to transitioning from a first Ziegler-Natta catalyst to a second Ziegler-Natta catalyst.

There are provided a polyethylene capable of improving tensile strength while maintaining excellent processability and Mooney viscosity characteristics when preparing a chlorinated polyethylene compound by implementing a molecular structure having a low content of low molecular weight and a high content of high molecular weight, and a chlorinated polyethylene prepared using the same.

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.

A system and method of producing polyethylene, including: polymerizing ethylene in presence of a catalyst system in a reactor to form polyethylene, wherein the catalyst system includes a first catalyst and a second catalyst; and adjusting reactor conditions and an amount of the second catalyst fed to the reactor to control melt index (MI), density, and melt flow ratio (MFR) of the polyethylene.

Catalyst systems and methods for making and using the same are described. A method includes selecting a catalyst blend using a blend polydispersity index (bPDI) map. The polydispersity map is generated by generating a number of polymers for at least two catalysts. Each polymer is generated at a different hydrogen to ethylene ratio. At least one catalyst generates a higher molecular weight polymer and another catalyst generates a lower molecular weight polymer. A molecular weight for each polymer is measured. The relationship between the molecular weight of the polymers generated by each of the catalysts and the ratio of hydrogen to ethylene is determined. A family of bPDI curves for polymers that would be made using a number of ratios of a blend of the at least two catalysts for each of a number of ratios of hydrogen to ethylene. A ratio for the catalyst blend of the catalysts that generates a polymer having a bPDI that matches a polymer fabrication process is selected, and the product specific polyolefin is made using the catalyst blend.

Disclosed is an antistatic agent for a metallocene olefin polymerization process and a polymerization method using the same, by which discontinuity event due to sheeting or drooling occurring in the olefin polymerization process can be effectively reduced, enabling continuous operation for a long time, and the obtained final product can be applied to various applications including food contact use. The present disclosure includes an olefin polymerization method, which comprises forming a mixture in which an antistatic agent containing diglycerol oleate is mixed with a low molecular weight hydrocarbon, supplying the antistatic agent mixture and a metallocene-based catalyst composition comprising a metallocene catalyst and aluminoxane to two or more polymerization reactors, and polymerizing one or more alpha-olefins in the presence of the antistatic agent mixture and catalyst composition.