Abstract: A process, particularly a gas phase fluidised bed process, for the production of polymers avoids formation of sheets or chunks within the reactor, without the need to use antistatic agents, which can reduce the activity of the catalyst or alter the characteristics of the yielded product. According to the invention, a device generates a corona discharge in the polymerisation reactor during the polymerisation process; an AC voltage difference is applied between the elements which constitute the discharging pair of the device.

Abstract: The thermal oxidative stability of acrylic grafted polymers is improved by (a) graft polymerizing monomers selected from the group consisting of (i) an ester or salt of an unsubstituted or 1-3 C alkyl-substituted acrylic acid and (ii) an ester or salt of an unsubstituted or 1-3 C alkyl-substituted acrylic acid and about 1 to about 10 mole %, based on the total monomers added, of an unsubstituted or 1-3 C alkyl-substituted acrylic acid, to a backbone of a propylene polymer material in the presence of a 4-vinyl-substituted 5-12 C cyclic 1-alkene, wherein the total amount of polymerized monomer is about 20 to about 200 parts per hundred parts of the propylene polymer material and the vinyl-substituted cyclic alkene is present in an amount of about 1 mole % to about 30 mole %, based on the total moles of monomer added, and (b) removing any unreacted grafting monomer from the resulting grafted propylene polymer material, decomposing any unreacted initiator, and deactivating any residual free radicals in the materi

Abstract: A process for polymerizing addition polymerizable monomers using hafnocenes catalysts/catalyst precursors having a selected symmetry condition under condensed polymerization conditions where the symmetry condition is such that the resulting polymer has varying degrees of tactioselectivity or copolymers having regions of varying degrees of tactioselectivity. Preferred classes of the haflocenes are capable of generating near pure isospecific and syndiospecific polymers in solution or in bulk polymerization conditions.

Abstract: The invention relates to solid catalyst components for the polymerization of olefins CH2═CHR, in which R is hydrogen or a hydrocarbyl radical with 1-12 carbon atoms, comprising Ti, Mg, halogen and an electron donor compound selected from cyanoesters of formula (I): wherein R1 is a C1-C20 linear or branched alkyl, alkenyl, cycloalkyl, cycloalkylalkyl, alkylcycloalkyl, aryl, arylalkyl or alkylaryl group; n is 0, 1, 2 or 3; R2, R3, R4 and R5 are independently selected from hydrogen or C1-C20 linear or branched alkyl, alkenyl, cycloalkyl, cycloalkylalkyl, alkylcycloalkyl, aryl, arylalkyl or alkylaryl groups; two or more of R2 and R3, and R4 and R5, can be joined to form a cycle. Said catalyst components when used in the polymerization of olefins are characterized by an excellent response to hydrogen and capability to produce polymers with broad Molecular Weight Distribution.

Abstract: Process for the gas-phase polymerization of olefins of the formula CH2═CHR where R is hydrogen or an alkyl or aryl radical with 1 to 8 carbon atoms carried out in one or more reactors having a fluidized or mechanically agitated bed, using a catalyst obtained by reaction of a titanium halide or haloalcoholate and optionally an electron-donor compound supported on an active Mg-dihalide with an Al-trialkyl compound and optionally an electron-donor compound, comprising the steps of: a) contacting the catalyst components in the absence of polymerizable olefin or optionally in the presence of said olefin in an amount to from up to 3 g per g of solid catalyst component; b) prepolymerizing propylene or mixtures of propylene with ethylene or an alpha-olefin to form a propylene polymer having an insolubility in xylene of at least 60% by weight, in an amount of from 5 g of polymer per g of solid catalyst component to 10% by weight of the final catalyst yield; and c) polymerizing one or more CH2═CHR olefins

Abstract: A polymer blend having a high melt strength and a low Young's modulus after irradiation of the polymers contains (1) a propylene homopolymer or copolymer having an isotactic index of greater than 90 and (2) a propylene homopolymer or copolymer having a crystallinity of <24% made using a metallocene catalyst. The blend can be used for extrusion coating (including fabric coating), foam extrusion, blow molding, and thermoforming applications.

Abstract: Amorphous copolymers of ethylene with propylene, and optionally with minor amounts of polyenes, have the following characteristics: (A) the % content by mole of propylene in the copolymer (%P) and the triads ratio EPE/(EPE+PPE+PPP) satisfy the following relationship: 0.01%P+EPE/(EPE+PPE+PPP)≧1 (B) less than 2% of the CH2 groups in the chain are in sequences (CH2)n, wherein n is an even number. These copolymers are obtainable by operating in the presence of particular metallocene catalysts having two fluorenyl groups joined together through a bridging group.

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: Polyolefin compositions comprising: A) a heterogeneous polyolefin composition itself comprising a fraction (A1) which is insoluble in xylene at room temperature and a fraction (A2) which is soluble in xylene at room temperature; and B) a branched propylene polymer. The said compositions are particularly processable when used in the process for the preparation of blown films. The films obtained by the said process are moreover characterized by excellent mechanical properties.

Abstract: The present invention relates to supported catalysts for the polymerization of alpha-olefins which comprise the reaction product of: (a) an Al-alkyl compound; (b) a silicon compound containing at least one Si—OR or Si—OCOR or Si—NR2 bond, R being a hydrocarbyl radical; (c) a solid comprising, as essential support, a Mg dihalide in active form and, supported thereon, a Ti halide or a halo-Ti-alcoholate and a particular type of electron donor compound. The present invention also relates to supported catalyst components.

Abstract: Injection-moulded refrigerator liners of a thermoplastic polymer characterized by the presence of means for mechanical bonding on the insulating foam.

Abstract: Catalysts for the polymerization of olefins comprise the product of the reaction between: (A) a titanium, zirconium or hafnium product with substituted cyclopentadiene ligands, (B) a mixture of two organometallic aluminium compounds, with at least one of the groups bound to the aluminium being other than a linear alkyl, and (C) water. When used in the polymerization of olefins, these catalysts show higher activities, at short residence times, than corresponding catalysts obtained from the individual components of the above-mentioned mixtures of aluminium compounds.

Abstract: A new process is disclosed, particularly simple, convenient and practical, for the direct synthesis of metallocenes of formula (I): (CP)(ZR1m)n(A)rMLpL′q wherein (ZR1m)n is a divalent group bridging Cp and A; Cp is a substituted or unsubstituted cyclopentadieryl group; A is —O—, —S—, —N(R2)—, wherein R2 is hydrogen, alkyl, cycloalkyl aryl, alkylaryl or arylalkyl, or A has the same meaning of Cp; M is a transition metal belonging to group 3, 4, 5, 6 or to the lanthanide or actinide groups; L is a monoanionic sigma ligand, such as alkyl, cycloalkyl, aryl, alkylaryl or arylalkyl, optionally containing Si or Ge; L′ is halogen or —OR5, R5 being a hydrocarbon radical; m is 1 or 2; n is 0-4; r is 0 or 1; p is 1-3; q is 0-2.

Abstract: Metallocene compounds having two fluorenyl ligands bridged with a single silicon or germanium atom, said atom having two substituent groups containing a total of at least four carbon atoms, are useful as catalyst components for the polymerization of olefins. Particularly, it is possible to prepare high molecular weight atactic polypropylene with improved yields with respect to the known catalysts.

Abstract: A polymer composition with improved scratch and mar resistance contains (1) a graft copolymer comprising a backbone of a propylene polymer material having graft polymerized thereto at least one vinyl monomer capable of being polymerized by free radicals, and (2) an additive selected from the group consisting of (a) about 0.5% to about 10% of at least one low molecular weight ethylene polymer or a functionalized derivative thereof, and (b) a combination of (i) about 0.5% to about 10% of at least one of the low molecular weight ethylene polymers in (a) and (ii) about 0.5% to about 10% of inorganic microspheres, based on the total weight of the composition. Optionally the composition can also contain a compatibilizing agent such as an unsaturated carboxylic acid-functionalized propylene polymer material.

Abstract: Polyolefin compositions obtained by mixing: (A) A heterogeneous polyolefin composition itself comprising a fraction (A1) which is insoluble in xylene and a fraction (A2) which is soluble in xylene; (B) a polyolefin composition comprising a low density ethylene copolymer (B1) and a propylene copolymer (B2) of relatively high insolubility in xylene; and, optionally, (C) a branched propylene polymer. The films obtained with the said compositions show improved mechanical properties and impact strength when compared with polyethylene-based films.

Abstract: A process for preparing bis-cyclopentadienyl compounds bridged by a methylene group is reported, said process comprising reacting formaldehyde with a cyclopentadienyl compound in the presence of a base and of a solvent having a dielectric constant (.epsilon.), measured at 25.degree. C., higher than 7. The bridged compounds, obtainable in high yields with this simple single-step process, can be used to prepare ansa-metallocenes, active as catalyst components in the polymerization of olefins.

Abstract: Stretchable multilayer films in which at least one outer layer (A) comprises a linear low density polyethylene (LLDPE), at least one intermediate layer (B) comprises a polyolefin composition containing LLDPE and a propylene polymer having an insolubility in xylene higher than 70%, and at least another layer (C) comprises a very low density polyethylene (VLDPE). bSaid films show an excellent balance between mechanical properties, represented as tear resistance and strength at break, and optical properties represented as gloss and haze.

Abstract: Amorphous copolymers of ethylene with .alpha.-olefins and optionally minor amounts of polyenes are disclosed, having the following characteristics:(A) the % by mole content of .alpha.-olefin in the copolymer (%.alpha.) and the ratio between the molar amount of .alpha.-olefin diads and the molar content of .alpha.-olefin in the copolymer (.alpha..alpha./.alpha.) satisfy the following relationship:(%.alpha.)-250(.alpha..alpha./.alpha.).gtoreq.10(B) less than 2% of the CH.sub.2 groups in the polymeric chain are in sequences (CH.sub.2).sub.n, wherein n is an even number.These copolymers are obtainable by operating in the presence of particular metallocene-based catalysts having two fluorenyl groups joined together through a bridging group.

Abstract: Blends can be obtained from polymers in particle form and powdery additives of higher melting point by heating the polymer particles so as to create a molten layer on their surface and forcing the powdery particles into said layer. After cooling, components of even very different density and morphology result inseparable. The process can be performed in a gas-loop, wherein the polymer and the additives are dragged by a hot gas flow.