Abstract: Catalysts for the polymerization of olefins are disclosed, comprising the product obtainable by contacting: (A) a bridged and/or substituted cyclopentadienyl compound of Ti, Zr or Hf; (B) one or more organometallic aluminium compounds of formula (II): AlR43−zHz wherein the substituents R4, same or different from each other, are linear or branched, saturated or unsaturated C1-C20 alkyl or alkylaryl radicals, optionally containing Si or Ge atoms, wherein at least one of the substituents R4 is different from a straight alkyl group; z is 0 or 1; and (C) water, the molar ratio between the organometallic aluminium compound and water being comprised between 1:1 and 100:1; said catalyst being obtainable by a process comprising the following steps: (i) contacting component (A) with part of component (B) in the absence of component (C); (ii) contacting part of component (B) with component (C) in the absence of component (A) and successively (iii) contacting the products obtained in steps (i) and (ii).

Abstract: Ethylene based copolymers having high molecular weights, narrow molecular weight distributions, and a very good homogeneous distribution of the comonomer units can be obtained in high yields at temperatures of industrial interest, by carrying out the polymerization reaction in the presence of metallocene catalysts comprising particular bridged bis-indenyl compounds substituted in the 3-position on the indenyl groups.

Abstract: Ethylene based copolymers having high molecular weights, narrow molecular weight distributions, and a very good homogeneous distribution of the comonomer units can be obtained in high yields at temperatures of industrial interest, by carrying out the polymerization reaction in the presence of metallocene catalysts comprising particular bridged bis-indenyl compounds substituted in the 3-position on the indenyl groups.

Abstract: Supported catalysts for the polymerization of olefins comprise the following components: (A) a porous organic support functionalised with groups having active hydrogen atoms; (B) an organo-metallic compound of aluminium containing heteroatoms selected from oxygen, nitrogen and sulphur; and (C) a compound of a transition metal selected from those of groups IVb, Vb or VIb of the Periodic Table of the Elements, containing ligands of the cyclopentadienyl type. These supported catalysts, obtainable in the form of spherical particles, can be used in the polymerization reaction of olefins either in liquid or in gas phase, thus producing polymers endowed with a controlled morphology and with a high bulk density.

Abstract: Metallocene compounds having the general formula (I): R1 are hydrocarbon groups, R2 are hydrogen or hydrocarbon groups; M is a transition metal of group 3, 4, 5, 6 or to the lanthanide or actinide groups in the Periodic Table; M′ is a transition metal selected from those belonging to group 3 or to the lanthanide or actinide groups in the Periodic Table; X is a monoanionic ligand; p is an integer of from 0 to 3, being equal to the oxidation state of M minus two; q is an integer from 3 to 5; and n is an integer from 1 to 4, when the six-membered rings of formula (Ia) are not perhydrated, and is an integer of from 0 to 4, when the six-membered rings of formula (Ia) are perhydrated as well as in the compound of formula (Ib).

Abstract: Supported catalysts for the polymerization of olefins comprise the following components: (A) a porous organic support functionalised with groups having active hydrogen atoms; (B) an organo-metallic compound of aluminium containing heteroatoms selected from oxygen, nitrogen and sulphur; and (C) a compound of a transition metal selected from those of groups IVb, Vb or VIb of the Periodic Table of the Elements, containing ligands of the cyclopentadienyl type. These supported catalysts, obtainable in the form of spherical particles, can be used in the polymerization reaction of olefins either in liquid or in gas phase, thus producing polymers endowed with a controlled morphology and with a high bulk density.

Abstract: It is disclosed a new catalyst system for the polymerization of olefins comprising the product obtainable by contacting the following components: (A) one or more compounds of a late transition metal belonging to Group 8-11 of the Periodic Table; and (B) the reaction product of water with one or more organometallic aluminum compounds of formula (IV): Al(CH2—CR3R4R5)xR6yHz, wherein R3 is a C1-C20 alkyl, C3-C20 cycloalkyl or C7-C20 alkylaryl radical; R4 is different from a straight alkyl and is a C3-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, C7-C20 alkylaryl or C7-C20 arylalkyl radical; or R3 and R4 form together a C4-C6 ring; R5 is hydrogen or a C1-C20 alkyl, C6-C20 aryl, C7-C20 alkylaryl or arylalkyl radical; R6 is a C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, C7-C20 alkylaryl or C7-C20 arylalkyl radical; x is 1-3; z is 0-1; and y is 3−x−z; the molar ratio between said organometallic aluminum compound and water being comprised between 0.5:1 and 100:1.

Abstract: Zirconocene compounds with two indenyl ligands linked in the 2 position by means of a two-carbon-atoms divalent bridging group can be suitably used as components of catalysts for the polymerization of olefins. Particularly it is possible to prepare, with high yields, ethylene (co)polymers having low molecular weights and narrow molecular weight distributions, without the need of using considerable amounts of molecular weight regulators, such as hydrogen.

Abstract: Processes for the polymerization of olefins in which late transition metal complexes, such as nickel, iron, cobalt and palladium complexes, are used as a polymerization catalyst have improved polymer productivity when oxidizing agents are present during at least a portion of the polymerization. The polymers produced are useful as elastomers, for packaging films, and molding resins.

Abstract: Zirconocene compounds with two indenyl ligands linked in the 2 position by means of a two-carbon-atoms divalent bridging group can be suitably used as components of catalysts for the polymerization of olefins. Particularly it is possible to prepare, with high yields, ethylene (co)polymers having low molecular weights and narrow molecular weight distributions, without the need of using considerable amounts of molecular weight regulators, such as hydrogen.

Abstract: Zirconocene compounds with two indenyl ligands linked in the 2 position by means of a two-carbon-atoms divalent bridging group can be suitably used as components of catalysts for the polymerization of olefins. Particularly it is possible to prepare, with high yields, ethylene (co)polymers having low molecular weights and narrow molecular weight distributions, without the need of using considerable amounts of molecular weight regulators, such as hydrogen.

Abstract: A class of bridged or unbridged metallocene compounds is disclosed, wherein the cyclopentadienyl ligands have two or four adjacent substituents forming one or two alkylenic cycles of from 4 to 8 carbon atoms.

Abstract: A multi-stage process for preparing ethylene (co)polymers having broad molecular weight distributions is disclosed, said process comprising: (A) a first polymerization stage in which, in the presence of a Ti or V catalyst, a first ethylene polymer is prepared; (B) a treatment stage in which the catalyst used in the first stage is deactivated and in which a bridged bis-2-indenyl zirconocene is supported on the ethylene polymer produced in stage (A), optionally in the presence of a suitable cocatalyst; and (C) a second polymerization stage in which ethylene is polymerized in the presence of the product obtained from stage (B). Furthermore, polyethylene obtainable by the above process is disclosed, having intrinsic viscosity ranging from 0.5 to 6 dl/g, Mw/Mn>8 and cold xylene solubility<1.2% wt.

Abstract: Zirconocene compounds with two indenyl ligands linked in the 2 position by means of a two-carbon-atoms divalent bridging group can be suitably used as components of catalysts for the polymerization of olefins. Particularly it is possible to prepare, with high yields, ethylene (co)polymers having low molecular weights and narrow molecular weight distributions, without the need of using considerable amounts of molecular weight regulators, such as hydrogen.

Abstract: A class of bridged or unbridged metallocene compounds is disclosed, wherein the cyclopentadienyl ligands have two or four adjacent substituents forming one or two alkylenic cycles of from 4 to 8 carbon atoms. These metallocenes are useful as catalyst components for the polymerization of olefins, particularly for the (co)polymerization of ethylene and for the polymerization of propylene.

Abstract: Catalysts for the polymerization of olefins which comprise the reaction product of (a) a bridged and/or substituted cyclopentadienyl compound of titanium, zirconium, or hafnium; (b) an organometallic aluminum compound of formula Al(CH.sub.2 --CR.sup.4 R.sup.5 R.sup.6).sub.w R.sup.7.sub.y H.sub.z, wherein in the (CH.sub.2 --CR.sup.4 R.sup.5 R.sup.6) groups, which are the same or different, R.sup.4 is an alkyl, alkenyl or arylalkyl group having from 1 to 10 carbon atoms, R.sup.5 is an alkyl, alkenyl, aryl, arylalkyl or alkylaryl group having from 3 to 50 carbon atoms and, optionally, R.sup.4 and R.sup.5 can be fused together to form a ring having from 4-6 carbon atoms, R.sup.6 is hydrogen or an alkyl alkenyl or arylalkyl group having from 1 to 10 carbon atoms, the R.sup.7 substituents, the same or different, are alkyl, alkenyl, aryl, arylalkyl or alkylaryl radicals having from 1 to 10 carbon atoms and, optionally, can contain Si or Ge atoms, w is 1, 2 or 3, z is 0 or 1, and y=3-w-z; and (c) water.

Abstract: Ethylene copolymers are prepared with comonomers selected from:(a) .alpha.-olefins,(b) cycloolefins and(c) polyenes,with a content of ethylene units of between 80 and 99 mol %, a content of units derived from .alpha.-olefin, cycloolefin and/or polyene comonomers of between 1 and 20 mol %, characterized in that:(a) in TREF (Temperature Rising Elution Fractionation) analysis, a quantity equal to at least 90% by weight of the copolymer is eluted within a temperature interval of less than 50.degree. C., and(b) M.sub.w /M.sub.n >3, where M.sub.w is the weight-average molecular weight and M.sub.n is the number-average molecular weight, both determined by means of GPC.

Abstract: Copolymers of ethylene with comonomers selected from (a) alpha-olefins, (b) cycloolefins and/or (c) dienes, characterized by the fact that:the molar percentage of the comonomer (% .alpha.) and the density of the copolymer (D) satisfy the relation % .alpha.+150D.ltoreq.141.

Abstract: Homopolymers or copolymers obtained by a multistage process of olefins having the formula CH.sub.2 .dbd.CHR, in which R is hydrogen or R has from 1 to 10 carbon atoms and is an alkyl, cycloalkyl or aryl group, the process comprising:(A) a first stage of polymerization in which one or more of the olefins are polymerized in the presence of a titanium or vanadium catalyst;(B) a treatment stage in which the product obtained in the first stage of polymerization (A) is brought into contact with a compound capable of deactivating the catalyst present in the stage (A); and also brought into contact with a compound of a transition metal M selected from the group consisting of Ti, Zr, V, or Hf containing at least one M-.pi. bond and optionally with an alkyl-Al compound; and(C) a second stage of polymerization in which one or more of the olefins are polymerized, in one or more reactors, in the presence of the product obtained in treatment stage (B).

Abstract: Catalysts component of the (co)polymerization of alpha-olefins CH.sub.2 .dbd.CHR, wherein R is hydrogen or an alkyl radical having from 1 to 8 carbon atoms, comprising a product of the composition:VCL.sub.y.z(b)wherein (b) represents an organic compound selected from alkyl, aryl and acyl halides, y is a number higher than 2 and lower than 4, and preferably comprised between 2.5 and 3.5 and z is a number higher than zero and lower than or equal to 2, and preferably between 0.002 and 1. Components can be obtained as products of the reaction, carried out at temperatures higher than 10.degree. C., between VCl.sub.4 and the compound (b). Particularly preferred among compounds (b) are benzoyl chloride, p-methoxybenzoyl chloride and p-chloro benzoyl chloride. From the components of the invention, either supported or not, catalysts having high activity particularly useful for the production of ethylene polymers showing broad molecular weight distribution can be prepared.