Abstract:
A process to perform the finishing of polyolefins produced by gas-phase catalytic polymerization of one or more a-olefms in the presence of a polymerization diluent selected from a C 3 -C 5 alkane, wherein the polyolefm granules discharged from the gas-phase reactor are subjected to: (1) a first degassing step in which said polyolefm is counter-currently contacted with a gaseous stream containing at least 85% by mol of a stripping agent selected from a C 3 -C 5 alkane, said gaseous stream being continuously derived from the monomer recovery section of the polymerization plant; (2) a second degassing step in which said polyolefm is counter-currently contacted with steam, the amount of steam being from 10 to 200 Kg per 1000 kg of polyolefin.
Abstract:
Method for continuously removing the unreacted butene-1, and optionally other volatile components, from a polymeric solution obtained by liquid phase (co)polymerization of butene-1, the method comprising the steps of: subjecting the polymeric solution to heating and mixing conditions such that a mixture is formed consisting substantially of: (1) a polybutene melt containing entrapped butene-1 and (2) supercritical gaseous butene-1; subjecting the above mixture to a sequence of devolatilization steps operating at decreasing pressures.
Abstract:
A process for the gas-phase polymerization of α-olefÊns CH 2 =CHR, where R is hydrogen or a hydrocarbon radical having 1-12 carbon atoms, carried out in a first and a second interconnected polymerization zones, wherein the growing polymer particles flow through the first of said polymerization zones (riser) under fast fluidization conditions, leave said riser and enter the second of said polymerization zones (downcomer) through which they flow downward in a densified form, leave said downcomer and are reintroduced into said riser, in which process: (a) the gas mixture present in the riser is totally or partially prevented from entering the downcomer, and (b) the gaseous composition inside a portion of the downcomer is maintained substantially similar to the gaseous composition reacting in the riser.
Abstract translation:其中R是氢或具有1-12个碳原子的烃基的α-烯烃CH 2 R 2 = CHR的气相聚合方法是在第一和第二互连聚合区 ,其中生长的聚合物颗粒在快速流化条件下流过第一个所述聚合区(提升管),离开所述提升管并进入其中以致密化形式向下流动的所述聚合区(降液管)中的第二个,离开所述降液管和 重新引入所述提升管中,在该过程中:(a)存在于提升管中的气体混合物完全或部分地被阻止进入降液管,并且(b)降液管的一部分内的气态组合物保持基本上类似于气体 组合物在提升管中反应。
Abstract:
A process for preparing a broad molecular weight polyethylene carried out in the presence of a catalyst system comprising (i) a solid catalyst component comprising Mg, Ti, halogen, and optionally an internal electron donor compound, and (ii) an Al-alkyl cocatalyst said process comprising at least two step of polymerization (a) and (b), in which, - in a first step (a) ethylene is polymerized in the presence of a molecular weight regulator in order to produce a ethylene (co)polymer, and in a further step (b), which is carried out in the presence of an external electron donor compound added to this polymerization step as a fresh reactant, ethylene is copolymerized with an alpha olefin of formula CH2=CHR, in which R is a C1-C20 hydrocarbon group, to produce an ethylene copolymer having a molecular weight higher than that of the copolymer produced in step (b).
Abstract:
Extruded articles, particularly films, comprising an ethylene polymer obtained by a polymerization process carried out in the presence the products obtained by contacting the following components: (a) a solid catalyst component comprising a magnesium halide, a titanium compound having at least a Ti-halogen bond and optionally one or more internal electron donor compounds, (b) an aluminum hydrocarbyl compound, (c) optionally an external electron donor compound, and (d) a polyalcohol partially esterified with carboxylic acids with alkyl groups having at least 10 carbon atoms.
Abstract:
A process for introducing a catalyst powder based on a titanium compound supported on magnesium halide into a gas-phase olefin polymerization reactor, characterized in that it comprises: (a) storing the catalyst powder under an atmosphere of a liquid C 3 -C 12 alkane; (b) withdrawing from step (a) a measured amount of said catalyst powder by means of a rotary valve; (c) transferring said metered amount of catalyst powder to a catalyst activation section by a continuous pick-up flow of a liquid C 3 -C 12 alkane; (d) contacting the catalyst powder with a liquid phase comprising an organo-aluminum compound and optionally an external donor compound, at a temperature ranging from -20 °C to 60 °C; (e) introducing the activated catalyst powder in one or more gas-phase olefin polymerization reactors, where a gaseous mixture comprising at least one alpha-olefin is subjected to polymerization.
Abstract:
A solution process for polymerizing one or more α-olefins of the formula CH 2 =CHR, where R is H or an alkyl radical C 1 -C 18 , to produce a polymer that is soluble in the reaction medium, comprising the steps of: - continuously polymerizing in a liquid phase the α-olefin in the presence of a catalyst system based on a transition metal compound to obtain a solution of polymer in the reaction medium; - the polymeric solution obtained from step a) is then mixed in one or more mixing stages with an aqueous mixture comprising one or more organic compounds having at least a hydroxy or epoxy group, said aqueous mixture having a dynamic viscosity at 30°C higher than 50 cP (centiPoise).
Abstract:
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.
Abstract:
A process to perform the finishing of polyolefins produced by gas-phase catalytic polymerization of one or more α-olefms in the presence of a polymerization diluent selected from a C 3 -C 5 alkane, wherein the polyolefm granules discharged from the gas-phase reactor are subjected to: (1) a first degassing step in which said polyolefm is counter-currently contacted with a gaseous stream containing at least 85% by mol of a stripping agent selected from a C 3 -C 5 alkane, said gaseous stream being continuously derived from the monomer recovery section of the polymerization plant; (2) a second degassing step in which said polyolefm is counter-currently contacted with steam, the amount of steam being from 10 to 200 Kg per 1000 kg of polyolefin.
Abstract:
Process for preparing a broad molecular weight polyethylene by polymerizing ethylene in the presence of a polymerization catalyst, the process comprising the following steps, in any mutual order: a) polymerizing ethylene, optionally together with one or more a-olefinic comonomers having from 3 to 12 carbon atoms, in a gas-phase reactor in the presence of hydrogen, b) copolymerizing ethylene with one or more a-olefinic comonomers having from 3 to 12 carbon atoms in another gas-phase reactor in the presence of an amount of hydrogen less than step a), where in at least one of said gas-phase reactors the growing polymer particles flow upward through a first polymerization zone under fast fluidization or transport conditions, leave said first polymerization zone and enter a second polymerization zone through which they flow downward under the action of gravity.