Abstract:
A process for the polymerisation of olefins in the presence of a solid catalyst component and a catalyst activator, the process being performed in a gas-phase reactor having interconnected polymerization zones, where the growing polymer particles flow upward through a first polymerization zone (riser) under fast fluidization conditions, leave said riser and enter a second polymerization zone (downcomer) through which they flow downward under the action of gravity, leave said downcomer and are reintroduced into the riser, thus establishing a polymer circulation between said riser and said downcomer, the process being characterized in that said solid catalyst component has an average size P50 ranging from 20 μm to 65 μm and the gas flows upward in said first polymerization zone at a velocity ranging from 0.8 to 2.0 m/s.
Abstract:
Prepolymerized catalyst component for the polymerization of olefins CH 2 =CHR in which R is hydrogen or a hydrocarbyl radical with 1-12 carbon atoms, having average particle size equal to or lower than 30 μm comprising a solid catalyst component comprising magnesium halide, a titanium compound having at least a Ti-halogen bond and at least two electron donor compounds one of which being selected from 1,3-diethers and the other one being selected from esters of aromatic mono or dicarboxylic acids, said solid catalyst component being prepolymerized with an olefin, having from 2 to 10 carbon atoms, to such an extent that the amount of the olefin prepolymer is equal to or lower than 5Og per g of solid catalyst component.
Abstract:
Spherical adducts comprising a MgCl 2 , an alcohol ROH in which R is a Cl-ClO hydrocarbon group, present in a molar ratio with MgCl 2 ranging from 0.5 to 5 and less than 5% wt, based on the total weight of the adduct, of a solid inorganic compound selected from oxides or hydroxides of Si, Al, Mg, Ti and mixtures thereof. The catalyst components obtained from the said adducts generate during polymerization a reduced content of broken polymer particles in comparison with the catalyst obtained from adducts not containing the inorganic solid compound.
Abstract:
The present invention relates to catalysts component for the polymerization of ethylene and its mixtures with olefins CH 2 =CHR, wherein R is an alkyl, cycloalkyl or aryl radical having 1-12 carbon atoms, comprising Ti, Mg, halogen, and 1,2- dimethoxyethane as internal electron donor compound. The catalyst of the invention is suitably used in (co)polymerization processes of ethylene to prepare (co)polymers having narrow Molecular Weight Distribution (MWD) and high bulk density.
Abstract:
The present invention relates to a process for preparing spherical support particles used in the preparation of catalytic components for the polymerization of olefins. The process comprises, (a) forming a mixture of an MgCl2-alcohol adduct in molten form and a liquid which is immiscible with the said adduct in a ratio such that the molten adduct forms the disperse phase, (b) suitably treating the mixture in order to obtain an emulsion, and (c) rapidly cooling the emulsion to solidify the disperse phase and collecting the solid adduct particles, said process being characterized by the fact that at least one of the steps (a) to (c) is carried out in the presence of an applied magnetic or electromagnetic field.
Abstract:
An olefin polymer composition comprising (by weight, unless otherwise specified): A) 60-85% of a crystalline propylene homopolymer or a crystalline copolymer of propylene containing 3% or less of ethylene or C 4 -C 10 α-olefin(s) or of combinations thereof, said homopolymer or copolymer having a Polydispersity Index (P.I.) value of from 4.5-6 and a content of isotactic pentads (mmmm), measured by 13 C NMR on the fraction insoluble in xylene at 25 °C, higher than 96%; B) 15-40% of a partially amorphous copolymer of ethylene containing from 35% to 70% of propylene or C 4 -C 10 α-olefin(s) or of combinations thereof, and optionally minor proportions of a diene. The said olefin polymer composition exhibits a value of elongation at break ranging from 150 to 600% according to ISO method 527.
Abstract:
Process for the preparation of solid particles of a magnesium-chloride alcohol adduct comprising (a) forming an emulsion between a MgCl2 .alcohol adduct in molten form and a liquid phase which is immiscible with the said adduct in the presence of a polyalkyl-methacrylate used as a solution having viscosity ranging from 100 to 5000 mm2/s and (b) rapidly cooling the emulsion to solidify the disperse phase and collecting the solid adduct particles.
Abstract:
A terpolymer containing propylene, ethylene and 1-hexene obtainable by the step of copolymerizing propylene, ethylene and 1-hexene in the presence of a catalyst system comprising the product 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 at least two electron donor compounds one of which being present in an amount from 40 to 90% by mol with respect to the total amount of donors and selected from succinates and the other being selected from 1,3 diethers, (b) an aluminum hydrocarbyl compound, and (c) optionally an external electron donor compound. wherein in the terpolymer (i) the content of 1-hexene derived units ranges from 0.5 to 5.0 wt%; (ii) the content of ethylene derived units is higher than 1.4 t% and fulfils the following relation (1): C �¢ 2