Abstract: The invention provides new prepolymerized catalyst components for the (co)polymerization of olefins CH2═CHR, wherein R is hydrogen or a C1-C12 alkyl group, characterized by comprising a solid catalyst component, comprising Ti, Mg, halogen and an electron donor compound, being capable of yielding, under standard polymerization conditions, a propylene homopolymer having an insolubility in xylene at 25° C. higher than 90%, which is prepolymerized with ethylene to such an extent that the amount of the ethylene prepolymer is up to 100 g per g of said solid catalyst component. These solid catalyst components display to obtain a high catalyst activity, a high isotactic index, and are not affected by aging.

Abstract: Components of catalysts for the polymerization of olefins are obtained by contacting a Ti compound of formula Ti(OR)n−yXy, where n is the valence of titanium and y is a number between 1 and n, with a pre-polymer having a porosity higher than 0.3 cc/g and containing from 0.5 to 100 g of polymer per g of solid catalyst component, the pre-polymer being obtained by (co)polymerizing an olefin or a diolefin in the presence of a catalyst comprising a Ti, V, Zr of Hf compound supported on an Mg dihalide having a mean crystallite dimension lower than 30 nm.

Abstract: The present invention relates to MgCl2.mROH.nH2O adducts, where R is a C1-C10 alkyl, 2≦m≦4.2, 0≦n≦0.7 , characterized by an X-ray diffraction spectrum in which, in the range of 2&thgr; diffraction angles between 5° and 15°, the three main diffraction lines are present at diffraction angles 2&thgr; of 8.8±0.2°, 9.4±0.2° and 9.8±0.2°, the most intense diffraction lines being the one at 2&thgr;=8.8±0.2°, the intensity of the other two diffraction lines being at least 0.2 times the intensity of the most intense diffraction line. Catalyst components obtained from the adducts of the present invention are capable to give catalysts for the polymerization of olefins characterized by enhanced activity and stereospecificity.

Abstract: The present invention relates to MgCl2.mROH.nH2O adducts, where R is a C1-C10 alkyl, 2≦m≦4.2, 0≦n≦0.7 , characterized by an X-ray diffraction spectrum in which, in the range of 2&thgr; diffraction angles between 5° and 15°, the three main diffraction lines are present at diffraction angles 2&thgr; of 8.8±0.2°, 9.4±0.2° and 9.8±0.2°, the most intense diffraction lines being the one at 2&thgr;=8.8±0.2°, the intensity of the other two diffraction lines being at least 0.2 times the intensity of the most intense diffraction line.

Abstract: The present invention relates to MgCl2.mROH.nH2O adducts, where R is a C1-C10 alkyl, 2≦m≦4.2, and 0≦n≦0.7, characterized by a differential scanning calorimetry (DSC) profile in which no peaks are present at temperatures below 90° C. or, if peaks are present below said temperature, the fusion enthalpy associated with said peaks is less than 30% of the total fusion enthalpy. Catalyst components obtained from the adducts of the present invention are capable to give catalysts for the polymerization of olefins characterized by enhanced activity and stereospecificity with respect to the catalysts prepared from the adducts of the prior art.

Abstract: The present invention relates to components of catalysts for the polymerization of olefins comprising a metallocene compound and a magnesium halide which have particular values of porosity and surface area. Group 4 and vanadium metallocenes are useful metallocenes and the components typically include an electron donor such as an ether, ester or ketone. In particular the components of the invention have surface area (BET) greater than about 50 m2/g, porosity (BET) greater than about 0.15 cm3/g and porosity (Hg) greater than 0.3 cm3/g, with the proviso that when the surface area is less than about 150 m2g, the porosity (Hg) is less than about 1.5 cm3/g. The magnesium halide is complexed by an ether, ester, or ketone electro donor. The components of the invention are particularly suitable for the preparation of catalysts for the gas-phase polymerization of &agr;-olefins.

Abstract: The present invention relates to spherical solid catalyst components for the polymerization of olefins, comprising a titanium compound, supported on a magnesium halide, containing more than one Ti-halogen link and optionally containing groups different from halogen in an amount lower than 0.5 mole per mole of Ti. Spherical solid compounds of the invention are characterized by having a surface area, measured by the BET method, of lower than 70 m2/g, a total porosity, measured by the mercurium method, higher than 0.5 cm3/g and a pore radius such that at least 50% have values higher than 800 Å.

Abstract: The present invention relates to a process for the preparation of MgCl2.pROH.qH2O adducts, where R is a C1-C10 alkyl, 1≦p≦6, and 0≦q≦1, comprising the steps of (a) dispersing magnesium dichloride in an inert liquid, (b)adding the alcohol in vapour phase and maintaining the temperature at values allowing the adduct to be melted, (c)emulsifying the molten adduct in a liquid medium immiscible with and chemically inert to said adduct and, (d) contacting the adduct with an inert cooling liquid.

Abstract: The present invention relates to catalysts for the polymerization of ethylene and its mixtures with olefins CH2═CHRVIII, comprising the reaction product of a solid catalyst component containing Ti, Mg and halogen, an alkyl-Al compound and a particular electron donor compound selected from the compounds containing at least two oxygen atoms bonded to different carbon atoms and selected by standard tests of reactivity with triethyl-Al and MgCl2 compounds. The catalyst of the invention are used in processes for the (co)polymerization of ethylene to prepare (co)polymers having narrow molecular weight distribution (MWD).

Abstract: The present invention relates to components of catalysts for the polymerization of olefins comprising a metallocene compound and a magnesium halide which have particular values of porosity and surface area. In particular the components of the invention have surface area (BET) greater than about 50 m2/g, porosity (BET) greater than about 0.15 cm3/g and porosity (Hg) greater than 0.3 cm3/g, with the proviso that when the surface area is less than about 150 m2/g, the porosity (Hg) is less than about 1.5 cm3/g. The components of the invention are particularly suitable for the preparation of catalysts for the gas-phase polymerization of &agr;-olefins.

Abstract: Components of bimetallic catalysts for the polymerization of olefins comprising a compound of a transition metal M selected from Ti, V, Zr and Hf containing at least one M-&pgr; bond, a compound of Ti or V not containing metal-&pgr; bonds and a support comprising a magnesium halide. The catalysts obtained from the components of the invention are particularly suitable for gas-phase polymerization processes.

Abstract: Components of bimetallic catalysts for the polymerization of olefins comprising a compound of a transition metal M selected from Ti, V, Zr and Hf containing at least one M-&pgr;bond, a compound of Ti or V not containing metal-&pgr; bonds and a support comprising a magnesium halide. The catalysts obtained from the components of the invention are particularly suitable for gas-phase polymerization processes.

Abstract: The present invention relates to spherical solid catalyst components for the polymerization of olefins, comprising a titanium compound, supported on a magnesium halide, containing more than one Ti-halogen link and optionally containing groups different from halogen in an amount lower than 0.5 mole per mole of Ti.

Abstract: The present invention relates to MgCl.sub.2.mROH.nH.sub.2 O adducts, where R is a C.sub.1 -C.sub.10 alkyl, 2.ltoreq.m.ltoreq.4.2, 0.ltoreq.n.ltoreq.0.7, characterized by an X-ray diffraction spectrum in which, in the range of 2.theta. diffraction angles between 5.degree. and 15.degree., the three main diffraction lines are present at diffraction angles 2.theta. of 8.8.+-.0.2.degree., 9.4.+-.0.2.degree. and 9.8.+-.0.2.degree., the most intense diffraction lines being the one at 2.theta.=8.8.+-.0.2.degree., the intensity of the other two diffraction lines being at least 0.2 times the intensity of the most intense diffraction line. Catalyst components obtained from the adducts of the present invention are capable to give catalysts for the polymerization of olefins characterized by enhanced activity and stereospecificity with respect to the catalysts prepared from the adducts of the prior art.

Abstract: Components and catalysts for the polymerization of olefins comprising the product obtained by contacting a compound of a transition metal M, containing at least one M-.pi. bond, with an olefinic prepolymer obtained by polymerization of one or more olefins with a coordination catalyst comprising a compound of Ti or V supported on a magnesium halide.

Abstract: The present invention relates to components of catalysts for the polymerization of olefins comprising the product that can be obtained by bringing a compound of a transition metal M, containing at least one M--.pi. bond, into contact with an olefinic prepolymer obtained by polymerization of one or more olefins with a coordination catalyst comprising a compound of Ti or V supported on a magnesium halide.

Abstract: The present invention relates to spherical solid components of catalysts for the polymerization of olefins comprising, supported on a magnesium dihalide in active form, a titanium compound containing at least one Ti-halogen bond and one OR group, said OR group being bonded to Ti in an amount such that the OR/Ti molar ratio is greater than or equal to 0.5; optionally the component also comprises an electron donor compound. The spherical solid components of the invention are characterized by having a porosity comprised between 0.35 and 0.7 cm.sup.3 /g and by a pore size distribution such that at least 50% of the porosity is due to pores having an average radius greater than 800 .ANG..

Abstract: The present invention relates to components of catalysts for the polymerization of olefins comprising a metallocene compound and a magnesium halide which have particular values of porosity and surface area. In particular the components of the invention have surface area (BET) greater than about 50 m.sup.2 /g, porosity (BET) greater than about 0.15 cm.sup.3 /g and porosity (Hg) greater than 0.3 cm.sup.3 /g, with the proviso that when the surface area is less than about 150 m.sup.2 /g, the porosity (Hg) is less than about 1.5 cm.sup.3 /g. The components of the invention are particularly suitable for the preparation of catalysts for the gas-phase polymerization of .alpha.-olefins.

Abstract: Components of bimetallic catalysts for the polymerization of olefins comprising a compound of a transition metal M selected from Ti, V, Zr and Hf containing at least one M-.pi. bond, a compound of Ti or V not containing metal-.pi. bonds and a support comprising a magnesium halide. The catalysts obtained from the components of the invention are particularly suitable for gas-phase polymerization processes.

Abstract: Multistage process for the polymerization of olefins CH.sub.2 .dbd.CHR, where R is hydrogen or an alkyl, cycloalkyl or aryl radical with 1-10 carbon atoms, comprising two stages of polymerization. In a first stage, in the presence of a titanium or a vanadium catalyst and working in one or more reactors, an olefinic polymer with particular values of porosity is prepared; in a second stage, in the presence of the said porous polymer and a metallocene compound and/or their reaction products, one or more olefins, that are equal to or different from those polymerized in the first stage, are polymerized in one or more reactors.