A method for predicting physical properties of a polyethylene resin is provided, which can reliably predict a proper charging ratio of a crosslinking agent in the production process of a low density crosslinked polyethylene resin, and the physical properties of the polyethylene resin achieved therefrom. A method for producing a polyethylene resin by applying the same method is also provided.

A method for predicting physical properties of a polyethylene resin is provided, which can reliably predict a proper charging ratio of a crosslinking agent in the production process of a low density crosslinked polyethylene resin, and the physical properties of the polyethylene resin achieved therefrom. A method for producing a polyethylene resin by applying the same method is also provided.

The present invention relates to a method for preparing ethylene vinylacetate copolymer that can improve the mechanical strength of copolymer by controlling the polymerization conditions using an autoclave reactor.

Provided herein are methods of polymerizing α-olefin monomer with a catalyst and hydrogen in a slurry to produce low molecular weight polyolefins. Hydrogen is vented from the low molecular weight polyolefins and then the low molecular weight polyolefins are further polymerized in a gas phase to produce a polyolefin having a molecular weight distribution of between 4.0 and 30 and a flexural modulus between 1500 mPa and 2500 mPa.

A process of preparing a solid catalyst component for the production of polypropylene includes a) dissolving a halide-containing magnesium compound in a mixture, the mixture including an epoxy compound, an organic phosphorus compound, and a hydrocarbon solvent to form a homogenous solution; b) treating the homogenous solution with an organosilicon compound during or after the dissolving step; c) treating the homogenous solution with a first titanium compound in the presence of a first non-phthalate electron donor, and an organosilicon compound, to form a solid precipitate; and d) treating the solid precipitate with a second titanium compound in the presence of a second non-phthalate electron donor to form the solid catalyst component, where the process is free of carboxylic acids and anhydrides.

A process of preparing a solid catalyst component for the production of polypropylene includes a) dissolving a halide-containing magnesium compound in a mixture, the mixture including an epoxy compound, an organic phosphorus compound, and a hydrocarbon solvent to form a homogenous solution; b) treating the homogenous solution with an organosilicon compound during or after the dissolving step; c) treating the homogenous solution with a first titanium compound in the presence of a first non-phthalate electron donor, and an organosilicon compound, to form a solid precipitate; and d) treating the solid precipitate with a second titanium compound in the presence of a second non-phthalate electron donor to form the solid catalyst component, where the process is free of carboxylic acids and anhydrides.

A method for minimizing the amount of catalyst inactivating agent that is present in a liquid fraction recovered from a slurry-based polymer production process, the liquid fraction comprising diluent used in the polymer production process, is disclosed. The method includes steps for controlling the pressure over the liquid fraction collected during diluent recovery so as to minimize the concentration of catalyst inactivating agent that is retained in the recovered liquid fraction. Embodiments of apparatus suitable for conducting the disclosed method are also provided.

Methods for operating a high pressure olefin polymerization reactor include the steps of introducing an initiator stream containing ethylene and an initiator compound through an initiator nozzle into the reactor, introducing an olefin stream containing ethylene and an optional comonomer through an olefin nozzle into the reactor, and polymerizing ethylene and optionally the comonomer in the presence of the initiator stream in the reactor under high pressure polymerization conditions to produce an ethylene polymer. The amount of ethylene in the initiator stream is from 0.01 to 2 wt. % of the amount of ethylene in the olefin stream. An injection nozzle that can be used in conjunction with the high pressure reactor also is described.

Methods for operating a high pressure olefin polymerization reactor include the steps of introducing an initiator stream containing ethylene and an initiator compound through an initiator nozzle into the reactor, introducing an olefin stream containing ethylene and an optional comonomer through an olefin nozzle into the reactor, and polymerizing ethylene and optionally the comonomer in the presence of the initiator stream in the reactor under high pressure polymerization conditions to produce an ethylene polymer. The amount of ethylene in the initiator stream is from 0.01 to 2 wt. % of the amount of ethylene in the olefin stream. An injection nozzle that can be used in conjunction with the high pressure reactor also is described.

A process or apparatus for producing polyethylene with improved film thinning and handleability involves polymerizing high-pressure ethylene using an autoclave-type reactor in the presence of a polymerization initiator. The reaction zone of the reactor has at least two different temperature sections; the polymerization initiator and the ethylene are supplied to the upstream temperature section in the reaction zone and the ethylene is polymerized to generate polyethylene; unreacted ethylene and the polyethylene generated at the upstream temperature section in the reactor flow into the downstream temperature section in communication with the upstream temperature section, so that additional polyethylene is generated at the downstream temperature section. A difference (ΔT [° C.]) between a temperature (T1 [° C.]) of the temperature section positioned upstream and a temperature (T2 [° C.]) of the temperature section positioned downstream in the reaction zone that receives the polymerization initiator and is in the autoclave-type reactor is 2.1° C. to 8.4° C.