Abstract: The present disclosure relates to a process for the preparation of polyethylene by polymerizing in a slurry ethylene and optionally one or more C3 to C10 alpha-olefins. In some embodiments, the polymerization is carried out in a cylindrical polymerization reactor equipped with an agitator for mixing the contents of the reactor and inducing a flow of the slurry, the ethylene is fed into the reactor by an ethylene injection system comprising one or more injection nozzles which project through the bottom reactor head or through the reactor wall and extend from 0.02-0.5 times the inner diameter D into the reactor, and the ethylene exits the injection nozzle with an exit velocity from 10-200 m/s.

Abstract: A two steps polymerization process for obtaining a polyolefin composition comprising: a) from 25 wt % to 70 wt % of a propylene homopolymer or a propylene-ethylene copolymer containing from 0.1 wt % to 10 wt % of ethylene derived units; b) from 27 wt % to 70 wt % of a copolymer of ethylene and at least one C3-C20 alpha olefins, wherein the ethylene derived units content ranges from 15 wt % to 70 wt %; c) from 3 wt % to 20 wt % of polyethylene homopolymer or an ethylene and at least one C3-C20 alpha olefins copolymer; the sum a)+b)+c) being 100, wherein said process comprises: step a) contacting under polymerization conditions propylene, optionally ethylene and the catalyst system in order to obtain component a), step b) contacting under polymerization conditions ethylene and at least one C3-C20 alpha-olefins and the catalyst system in order to obtain components b) and c); wherein the catalyst system comprises a metallocene compound and an iron complex.

Abstract: The present disclosure relates to a process for the preparation of polyethylene by polymerizing in a slurry ethylene and optionally one or more C3 to C10 alpha-olefins. In some embodiments, the polymerization is carried out in a cylindrical polymerization reactor equipped with an agitator for mixing the contents of the reactor and inducing a flow of the slurry, the ethylene is fed into the reactor by an ethylene injection system comprising one or more injection nozzles which project through the bottom reactor head or through the reactor wall and extend from 0.02-0.5 times the inner diameter D into the reactor, and the ethylene exits the injection nozzle with an exit velocity from 10-200 m/s.

Abstract: Polyethylene composition with improved balance of impact resistance at low temperatures and Environmental Stress Cracking Resistance (ESCR), particularly suited for producing protective coatings on metal pipes, said composition having the following features: 1) density from 0.938 to 0.948 g/cm3; 2) ratio MIF/MIP from 15 to 25; 3) MIF from 30 to 45 g/10 min.; 4) Mz equal to or greater than 1000000 g/mol; 5) LCBI equal to or greater than 0.55.

Abstract: The present technology relates to a polyethylene composition suitable for producing small articles such as flexible and collapsible tubes by blow molding comprising: 1) a density from 0.948 to 0.955 g/cm3; 2) a MIF/MIP ratio from 12 to 25; 3) a MIF from 25 to 40 g/10 min; 4) a Mz from 1000000 to 2000000 g/mol; and 5) a long-chain branching index, LCBI, equal to or greater than 0.55.

Abstract: The present disclosure provides a low density polyethylene (LDPE) having (A) a density from 0.910 to 0.924 g/cm3, determined according to ISO 1183 at 23° C.; (B) an elongational hardening of at least 4.2, at 150° C. at an elongational rate of 1 s?1; (C) a ratio Mw/Mn of at least 18, where (i) Mw is the weight average molar mass, measured by a MALLS detector coupled to a GPC, and (ii) Mn is the number average molar mass, measured by GPC (Gel Permeation Chromatography); and (D) a Mw of at least 230,000 g/mol. The present disclosure also provides an article of manufacture made from or containing (A) a substrate and (B) a coating layer made from or containing the disclosed LDPE. The present disclosure further provides a polymerization process occurring (A) in the presence of oxygen as the only radical initiating agent and (B) in the absence of solvents.

Abstract: A method for controlling a slurry polymerization for the preparation of polyethylene, where the polyethylene is formed in a polymerization reactor comprising a vapor section by contacting a Ziegler-type catalyst, ethylene, and either hydrogen or, as comonomer(s), one or more C3 to C10 alpha-olefins or hydrogen and one or more C3 to C10 alpha-olefins, wherein the ethylene partial pressure is maintained by adjusting the flow rate of the catalyst to the polymerization reactor and the hydrogen/ethylene and comonomer/ethylene partial pressure ratios are maintained by adjusting the flow rates of hydrogen and/or of the one or more comonomers to the polymerization reactor.

Abstract: A process for the preparation of polyethylene by polymerizing in a slurry ethylene and optionally one or more C3 to C10 alpha-olefins in a reactor system comprising a polymerization reactor and one or more first heat exchangers located outside the polymerization reactor where the slurry in the polymerization reactor is cooled by withdrawing slurry from the polymerization reactor, cooling the slurry in the one or more first heat exchangers and returning the cooled slurry to the polymerization reactor, wherein the one or more first heat exchangers are cooled by a first coolant having a temperature of 29° C. or higher.

Abstract: Polyethylene composition for injection molding with a beneficial balance of environmental stress cracking resistance and impact resistance in combination with low warpage and beneficial processing behavior, said composition having the following features: 1) density of 0.945 g/cm3 or higher; 2) MIE from 1 to 30 g/10 min.; 3) ratio MIF/MIE from 15 to 30; 4) ER values from 0.40 to 0.52.

Abstract: The present disclosure relates to metallocene catalysts for use in polymerization processes. Such catalysis may be used to generate long chain polymers with low long chain branching and high molecular weights. Additionally, the size of the polymers produced can be controlled by modifying the ratio of MAO or other activator to metallocene catalyst.

Abstract: A method for controlling the temperature in a polymerization reactor equipped with a cycle gas line for withdrawing reactor gas from the reactor, leading the reactor gas through a heat-exchanger, which is cooled by a cooling medium, which is conveyed in a cooling system through the heat-exchanger, and feeding the reactor gas back to the reactor by adjusting the temperature of the cooling medium entering the heat exchanger, wherein the temperature of the cooling medium entering the heat exchanger is controlled by adjusting the flow rate of the cooling medium in a part of the cooling system by a flow control system comprising two continuously operating flow control devices of different size, which are connected in parallel, a process for polymerizing olefins and a process for controlling the flow rate of a fluid medium.

Abstract: The present technology relates to a process for polymerizing or copolymerizing ethylenically unsaturated monomers in the presence of free-radical polymerization initiators, wherein the polymerization is carried out in a continuously operated tubular reactor at temperatures from 100° C. to 350° C. and pressures from 180 MPa to 340 MPa, with a specific reactor surface area Asp of 2 m2/(t/h) to 5.5 m2/(t/h), and the tubular reactor has a specific ratio RDsp of 0.0050 MPa?1 to 0.0069 MPa?1 and an inner surface which has a surface roughness Ra of 2 ?m or less.

Abstract: The present disclosure relates to an ethylene polymer composition having an eta (0.01) equal to or higher than 35,000 Pa·s, comprising: A) 25-75% by weight of an ethylene polymer selected from ethylene homopolymers, copolymers of ethylene with 10% or less of one or more olefin comonomers, and mixtures of the homopolymers and copolymers; B) 25-75% by weight of a copolymer of ethylene and propylene comprising 45-70% by weight of ethylene; wherein eta (0.01) is the complex shear viscosity at an angular frequency of 0.01 rad/s, measured with dynamic oscillatory shear in a plate-plate rotational rheometer at a temperature of 200° C., and the amounts of A) and B) refer to the total weight of A)+B).

Abstract: The present disclosure generally relates to a slurry polymerization process for the preparation of polyethylene in the presence of a Ziegler catalyst and aluminum alkyl co-catalyst in at least one polymerization reactor, in which process suspension medium comprising a concentration of aluminum alkyl co-catalyst is recycled to the polymerization, the concentration of aluminum alkyl co-catalyst in the recycled suspension medium is determined; and the amount of fresh aluminum alkyl co-catalyst fed to the polymerization is adjusted to maintain a targeted aluminum alkyl co-catalyst concentration in the recycled suspension medium.

Abstract: The present disclosure relates to a polyethylene composition of Raised Temperature Resistance, having the following features: 1) a density from 0.935 to 0.945 g/cm3; 2) a melt flow index MIF from 10 to 18 g/10 min; 3) a melt flow index MIP from 1 to 2.5 g/10 min; and 4) a MIF/MIP ratio from 5 to 10.

Abstract: A slurry polymerization process comprising polymerizing monomers in a reactor comprising baffles, a first slurry feed line for returning cooled slurry from a cooler and optionally a second slurry feed line for transferring reactor slurry from a previous reactor of a cascade of polymerization reactors, wherein the baffle top, the first slurry feed line discharge end and the second slurry feed line end are located below the reactor liquid level.

Abstract: The present disclosure relates to a polyethylene composition with improved swell ratio and mechanical properties for use in preparing blow-moulded articles and having the following features: 1) a density from 0.945 to less than 0.952 g/cm3; 2) an MIF/MIP ratio from 15 to 30; 3) a Shear-Induced Crystallization Index (SIC) from 2.5 to 5.5.

Abstract: The present disclosure relates to a vessel for separating, at a pressure of from 10 MPa to 50 MPa, a composition comprising liquid components and gaseous components into a liquid fraction and a gaseous fraction, wherein the separation vessel has a vertically arranged cylindrical shape, has at its top a manhole, which is surrounded by a thickened by a part of the separation vessel wall; and bears at least one bursting disc which is held by a bursting disc holder which is installed pressure-tight within a boring in the thickened part of the separation vessel wall.

Abstract: The present disclosure generally relates to a process for separating polymeric and gaseous components of a reaction mixture obtained by high-pressure polymerization of ethylenically unsaturated monomers in the presence of free-radical polymerization initiators into a gaseous fraction and a liquid fraction in a separation vessel, wherein the filling level of the liquid fraction in the separation vessel is measured by a radiometric level measurement system comprising at least two radioactive sources and at least three radiation detectors, and the filling level is controlled by a product discharge valve which operates based on data coming from the level measurement system.

Abstract: The present disclosure relates to a process for separating polymeric and gaseous components of a reaction mixture obtained by high-pressure polymerization of ethylenically unsaturated monomers in the presence of free-radical polymerization initiators into in a gaseous fraction and a liquid fraction, wherein the separation is carried out at a pressure of from 15 MPa to 50 MPa and a temperature of from 120° C. to 300° C. in a separation vessel which has a vertically arranged cylindrical shape with a ratio of length to diameter L/D of from 4 to 10 and which is equipped with an inlet pipe which extends vertically from the top into the separation vessel; and the ratio of the inner diameter of the inlet pipe at its lower end and the inner diameter of the separating vessel in its cylindrical part is in the range of from 0.2 to 0.4.