Abstract: Process and apparatus for discharging polyolefin particles from a gas-phase polymerization reactor of a pressure from 1.0 MPa to 10 MPa to a discharge vessel of a pressure from 0.1 MPa to 1.0 MPa wherein the discharging is carried out discontinuously through at least two discharge lines in which the polyolefin particles are transported horizontally or upwards.

Abstract: Embodiments of the present disclosure relate to a method of preparing polyethylene compositions comprising polymerizing ethylene in a first gas-phase reactor and polymerizing ethylene in a second gas-phase reactor in the presence of hydrogen; wherein at least one of the first or second gas-phase reactors comprises a first and second polymerization zone; wherein a hydrogen pressure of the first and second polymerization zones are different such that at least a portion of the second ethylene cycles through the first and second polymerization zones and a gas mixture of each polymerization zone is partially or totally prevented from entering the other zone.

Abstract: A novel polymer composition is described comprising ethylene homopolymers and/or copolymers of ethylene with C3-C8-alpha-olefins which polymer composition has a density of from 0.940 to 0.949 g/cm3, a melt index (HLMI) according to DIN EN ISO 1133:2005, condition G at 190° C. and 21.6 kg, of from 3 to 7 g/10 min. and a Hostalen Long Chain Branching Index (HLCBI) of from 3 to 8, and which polymer composition is produced by polymerisation with one or more Ziegler catalysts in a series of at least two polymerization reactors. The new polymer composition can in particular be used for blow moulding of intermediate bulk containers.

Abstract: A novel polyethylene is devised which polyethylene is particularly advantageous for manufacturing rotomoulded articles.

Abstract: Process for the preparation of a polyolefin polymer by continuously polymerizing one or more olefin monomers in suspension at temperatures of from 40° C. to 120° C. and pressures of from 0.1 to 10 MPa in the presence of a polymerization catalyst in at least one polymerization reactor, comprising a) withdrawing a suspension of solid polyolefin particles in a suspension medium from the polymerization reactor, wherein the suspension has a temperature of from 65° C. to 120° C.; b) feeding the suspension withdrawn from the polymerization reactor to a moderating vessel; c) keeping the suspension in the moderating vessel at a temperature of from 60° C. to 85° C. for a time sufficiently long that the mean residence time of the suspension in the moderating vessel is at least 5 min; d) withdrawing suspension from the moderating vessel; e) cooling the suspension withdrawn from the moderating vessel to a temperature of from 20° C. to 55° C.

Abstract: A polymerization process comprising contacting under polymerization conditions ethylene and at least propylene to obtain a copolymer containing from 96% by mol to 71% by mol of ethylene derived units, in the presence of a catalyst system obtainable by contacting: b) at least a metallocene compound of formula (I), b) alumoxane or a compound capable of forming an alkyl metallocene cation; and optionally c) an organo aluminum compound; wherein the groups R1-R4, L, M and W are described in the text.

Abstract: A polymerization process comprising contacting under polymerization conditions ethylene and at least one alpha olefin of formula CH2=CHA wherein A is a C2-C20 alkyl radical to obtain a copolymer containing from 95% by mol to 50% by mol of ethylene derived units in the presence of a catalyst system obtainable by contacting: b) at least a metallocene compound of formula (I) b) alumoxane or a compound capable of forming an alkyl metallocene cation; and optionally c) an organo aluminum compound; wherein the groups R1-R4, L, M and W are described in the text.

Abstract: A process for homogenizing and pelletizing a polyethylene composition comprising the steps of a) providing a polyethylene composition having a density of from 0.90 g/cm3 to 0.97 g/cm3 and a melt flow rate MFR21.6 at 190° C. under a load of 21.6 kg of from 1 g/10 min to 80 g/10 min, b) melting the polyethylene composition; c) passing the melt through a combination of screens consisting of screens having a mesh opening of at least 205 ?m and comprising at least two screens having a mesh opening of from 205 ?m to 350 ?m; and e) pelletizing the molten polyethylene composition, the use of a polyethylene composition obtained by such a process for the preparation of films, fibers, pipes, blow-molded articles, injection-molded articles, compression-molded articles or rotomolded articles and films, fibers, pipes, blow-molded articles, injection-molded articles, compression-molded articles or rotomolded articles prepared from a polyethylene composition obtained by such a process.

Abstract: A method for feeding an antistatic compound to a polymerization reactor, the method comprising the steps of: a) dispersing, under mixing conditions, a catalyst powder and an antistatic compound in a liquid medium, so as to form a suspension of the catalyst powder and of the antistatic compound in the liquid medium; b) transferring the obtained suspension to a polymerization reactor.

Abstract: A solid catalyst component comprising the product of a process comprising (a) reacting a magnesium alcoholate of formula Mg(OR1)(OR2) compound, in which R1 and R2 are identical or different and are each an alkyl radical having 1 to 10 carbon atoms, with titanium tetrachloride carried out in a hydrocarbon at a temperature of 50-100° C., (b) subjecting the reaction mixture obtained in (a) to a heat treatment at a temperature of 110° C. to 200° C. for a time ranging from 3 to 25 hours (c) isolating and washing with a hydrocarbon the solid obtained in (b), said solid catalyst component having a Cl/Ti molar ratio higher than 2.5.

Abstract: A molding composition is suitable for the production of pipes having improved resistance to thermooxidative degradation when these pipes are in long-term contact with liquids comprising disinfectants having an oxidizing effect. Such molding composition comprises, in addition to thermoplastic polyolefins, a polyoxy compound and/or a polyhydroxy compound as additive in an amount of from 0.01 to 1.0% by weight. In addition, the molding composition can further comprise an unsaturated aliphatic hydrocarbon in an amount of up to 5% by weight. The invention also relates to a process for improving the long-term resistance of water pipes to damage caused by oxidizing disinfectants from the water by use of this molding composition.

Abstract: A novel polyethylene composition is described. The composition is suitable for manufacturing especially stretched bands or tapes, also coined raffia in the art.

Abstract: A copolymer of ethylene, a catalyst system suitable to prepare the copolymer, and a process to prepare such copolymer are described. The copolymer comprises from 60 to 80% by weight of ethylene and from 20 to 40% by weight of at least one first ?-olefin comonomer having n carbon atoms and at least one second ?-olefin comonomer having (n?1) carbon atoms, n being from 4 to 13, has a polydispersity Mw/Mn equal to or lower than 3.5, and a density from 0.855 to 0.880 g/cm3. The copolymer is obtained by subjecting ethylene and said at least one first ?-olefin comonomer to a polymerization stage in the presence of a catalyst system capable of forming a copolymer of ethylene and said at least one first ?-olefin comonomer having n carbon atoms, while forming the second ?-olefin comonomer having (n?1) carbon atoms.

Abstract: A multimodal polyethylene composition comprising at least three ethylene polymer fractions having distinct molecular weights or comonomer contents, the at least three ethylene polymer fractions comprising at least one first ethylene polymer fraction having a first molecular weight, at least one second ethylene polymer fraction having a second molecular weight higher than the first molecular weight, and at least one third ethylene polymer fraction having a third molecular weight higher than the first molecular weight, wherein the at least one first ethylene polymer fraction and the at least third ethylene polymer fraction are prepared by the use of a first and, respectively, third catalyst of the single site type.

Abstract: A novel polyethylene is devised which polyethylene is particularly advantageous for manufacturing rotomoulded articles.

Abstract: A novel process for the manufacture of a mixed catalyst system by combining a Ziegler catalyst and a tridentate iron complex is described, which is characterized in that the reaction of a tridentate ligand with an iron compound is performed in an organic solvent containing less than 10 percent by weight, based on the total amount of the organic solvent, of electron donor compounds selected from the group consisting of ethers, aliphatic esters, aromatic esters, tertiary amines, amides, silanes, silazanes or orthoesters.

Abstract: The present invention relates to a process for preparing a catalyst solid for olefin polymerization, comprising a finely divided support, an aluminoxane and a metallocene compound, which comprises: a) firstly combining the finely divided support with the aluminoxane and subsequently b) adding the reaction product of a metallocene compound with at least one organometallic compound to the modified support, catalyst solids obtainable by this process, catalyst systems comprising these catalyst solids, their use for the polymerization of olefins and a process for the polymerization of olefins.

Abstract: A blown film having a thickness from 8 to 200 ?m and dart drop impact DDI of more than 400 g, comprising a polyethylene molding composition having a multimodal molar mass distribution; a density from 0.940 to 0.948 g/cm3; an MFR190/5, from 0.10 to 0.50 dg/min; comprising: 40 to 60% of an ethylene homopolymer A having a molecular weight; 25 to 45% of a copolymer B of ethylene and at least one comonomer selected from the group of olefins having from 4 to 8 carbon atoms, said copolymer B having a molecular weight higher than said molecular weight of homopolymer A; and 10 to 30% of a copolymer C of ethylene and at least one comonomer, said copolymer C having a molecular weight higher than said molecular weight of copolymer B, all percentages being based on the total weight of the molding composition.

Abstract: The invention relates to a polyethylene molding composition having a multimodal molecular mass distribution and comprising a first ethylene homopolymer fraction (I), a second ethylene copolymer fraction (II) and a third ethylene copolymer fraction (III). The molding composition has a density at a temperature of 23° C. in the range from 0.945 to 0.953 g/cm3, an MFR (190° C./5 kg) in the range from 2 to 7 g/10 min and a viscosity number VN3 of the total mix of ethylene homopolymer fraction (I), copolymer fraction (II) and ethylene copolymer fraction (III), measured in accordance with ISO/R 1191 in decalin at a temperature of 135° C., in the range from 200 to 250 cm3/g. The invention further relates to the use of such a molding composition for producing high-strength injection-molded screw cap closures for bottles comprising beverages, especially carbonated beverages.

Abstract: Process for supportation of a catalyst system comprising at least two different active catalyst components on a support wherein in an earlier supportation step a first active catalyst component is applied to the support at a first predetermined temperature and in a later supportation step a second active catalyst component is applied to the support at a temperature which is at least 20° C. lower than the first predetermined temperature.