摘要:
Methods for improving heat transfer in polymerization processes are described herein. The methods generally include contacting olefin monomer with a catalyst system within a reaction zone to form particles having a first average particle size and altering the reaction zone to improve heat transfer and form polymer particles having a second average particle size. For example, the second average particle size may be larger than the first average particle size and the second particle size results in improved heat transfer over the first particle size.
摘要:
Disclosed is a bimodal Ziegler-Natta catalyzed polyethylene, having a density of from 0.930 g/cc to 0.960 g/cc, and a molecular weight distribution of from 10 to 25, wherein an article formed therefrom has a PENT of at least 1500. Also disclosed is a method of preparing a tubular article including obtaining a bimodal polyethylene having a density of from 0.930 g/cc to 0.960 g/cc and a molecular weight distribution of from 10 to 25, and processing the polyethylene under conditions where a specific energy input (SEI) is less than 300 kW·h/ton, and wherein the article has a PENT of at least 1500. Further disclosed is a method for controlling the degradation of polyethylene including polymerizing ethylene monomer, recovering polyethylene, extruding the polyethylene, and controlling the degradation of polyethylene by measuring the SEI to the extruder and adjusting throughput and/or gear suction pressure keep SEI less than 300 kW·h/ton, and forming an article.
摘要:
Polyolefins may be prepared using a cocatalyst conforming to the formula: AIRz(Xz)nLzm wherein Rz is a linear or branched organic moiety having at least 5 carbons and Xz is a linear or branched organic moiety having at least 5 carbons or a heterocyclic moiety having at least 4 atoms and can be anionic or di-anionic. The aluminum complex may also be in the form of an adduct complex where Lz is a Lewis base and m=1-3. The cocatalyst Rz components are selected such that they do not react with water under polymerization conditions to form a species that is highly soluble in the polymerization diluent. Use of the specified cocatalyst reduces fouling during metallocene-catalyzed runs and “post-metallocene hangover” when the same production equipment is transitioned to non-metallocene catalyst runs using catalysts such as chromium.
摘要:
Methods of forming polyolefins and catalysts are described herein. Such methods generally include forming Ziegler-Natta catalyst compounds in the absence of one or more blended compounds typically used to form such catalyst.
摘要:
Disclosed is a bimodal Ziegler-Natta catalyzed polyethylene, having a density of from 0.930 g/cc to 0.960 g/cc, and a molecular weight distribution of from 10 to 25, wherein an article formed therefrom has a PENT of at least 1500. Also disclosed is a method of preparing a tubular article including obtaining a bimodal polyethylene having a density of from 0.930 g/cc to 0.960 g/cc and a molecular weight distribution of from 10 to 25, and processing the polyethylene under conditions where a specific energy input (SEI) is less than 300 kW·h/ton, and wherein the article has a PENT of at least 1500. Further disclosed is a method for controlling the degradation of polyethylene including polymerizing ethylene monomer, recovering polyethylene, extruding the polyethylene, and controlling the degradation of polyethylene by measuring the SEI to the extruder and adjusting throughput and/or gear suction pressure keep SEI less than 300 kW·h/ton, and forming an article.
摘要:
Disclosed is a bimodal Ziegler-Natta catalyzed polyethylene, having a density of from 0.930 g/cc to 0.960 g/cc, and a molecular weight distribution of from 10 to 25, wherein an article formed therefrom has a PENT of at least 1500. Also disclosed is a method of preparing a tubular article including obtaining a bimodal polyethylene having a density of from 0.930 g/cc to 0.960 g/cc and a molecular weight distribution of from 10 to 25, and processing the polyethylene under conditions where a specific energy input (SEI) is less than 300 kW·h/ton, and wherein the article has a PENT of at least 1500. Further disclosed is a method for controlling the degradation of polyethylene including polymerizing ethylene monomer, recovering polyethylene, extruding the polyethylene, and controlling the degradation of polyethylene by measuring the SEI to the extruder and adjusting throughput and/or gear suction pressure keep SEI less than 300 kW·h/ton, and forming an article.
摘要:
Methods of forming polyolefins and catalysts are described herein. Such methods generally include forming Ziegler-Natta catalyst compounds in the absence of one or more blended compounds typically used to form such catalyst.
摘要:
Polyolefins may be prepared using a cocatalyst conforming to the formula: AIRz(Xz)nLzm wherein Rz is a linear or branched organic moiety having at least 5 carbons and Xz is a linear or branched organic moiety having at least 5 carbons or a heterocyclic moiety having at least 4 atoms and can be anionic or di-anionic. The aluminum complex may also be in the form of an adduct complex where Lz is a Lewis base and m=1-3. The cocatalyst Rz components are selected such that they do not react with water under polymerization conditions to form a species that is highly soluble in the polymerization diluent. Use of the specified cocatalyst reduces fouling during metallocene-catalyzed runs and “post-metallocene hangover” when the same production equipment is transitioned to non-metallocene catalyst runs using catalysts such as chromium.
摘要:
A Ziegler-Natta type catalyst component can be produced by a process comprising contacting a magnesium dialkoxide compound with a halogenating agent to form a reaction product A, and contacting reaction product A with a first, second and third halogenating/titanating agents. Catalyst components, catalysts, catalyst systems, polyolefin, products made therewith, and methods of forming each are disclosed. The reaction products can be washed with a hydrocarbon solvent to reduce titanium species [Ti] content to less than about 100 mmol/L.
摘要:
Polymerization processes and polymers formed therefrom are described herein. The polymerization processes generally include contacting ethylene and propylene with a multi-component catalyst composition including a first catalyst component including a chromium oxide based catalyst and a second catalyst component selected from metallocene and Ziegler-Natta catalysts within a polymerization reaction vessel to form a random copolymer, wherein the second catalyst component exhibits a higher comonomer response than the first catalyst component.