Abstract: A process for preparing ethylene homopolymers and copolymers in a tubular reactor having two or more polymerization zones at temperatures of between 150° C. and 350° C. and pressures in the range from 500 to 5000 bar, using oxygen as initiator, which comprises using, as molar mass regulator, one or more aliphatic ketones of the formula I, where the variable R1 is a C1-C6-alkyl or C3-C12-cycloalkyl, ethylene homopolymers and copolymers obtainable therefrom and their user for producing injection-molded products in the cosmetics, medical and food sectors are described.

Abstract: Process for preparing a supported catalyst for the polymerization and/or copolymerization of olefins which has a chromium content of from 0.01 to 5% by weight, based on the element, which comprises (a) preparing a homogeneous solution comprising an organic or inorganic chromium compound and at least one further organic or inorganic compound of elements selected from among Mg, Ca, Sr, B, Al, Si, P, Bi, Sc, V, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, Ru, Rh, Pd, Hf, Ta, W in a protic or aprotic polar solvent, (b) bringing the solution from a) into contact with a finely divided inorganic support to form a catalyst precursor, (c) if appropriate, removing the solvent from the catalyst precursor and (d) calcining the catalyst precursor at temperatures of from 350 to 950° C., preferably 400 to 900° C., under oxidative conditions.

Abstract: Use for packaging items sensitive to light of a polymer composition in the form of film or moulded articles comprising a polymeric resin and one or more photochromic additive.

Abstract: A multimodal polyethylene having an inverse comonomer distribution, as well as a process carried out in a single reactor in the presence of a mixed catalyst composition comprising two different polymerization catalysts, are described. The multimodal polyethylene has a density of 0 915-0 970 g/cm3, a weight average molar mass Mw of 100 000-900 000 g/mol, and a polydispersity Mw/Mn, of at least 15. The at least one homopolymer has a density of 0 950-0 975 g/cm3, a weight average molar mass Mw of 10 000-90 000 g/mol and a polydispersity Mw/Mn, higher than 3 and lower than 10, and the at least one copolymer has a polydispersity Mw/Mn between 8 and 80.

Abstract: Specific iron complexes (A), a catalyst system for polymerization of olefins comprising at least one metal complex (A) and/or (A?), a prepolymerized catalyst system, the use of these catalyst systems for the polymerization of olefins, and a process for the preparation of polyolefins by polymerization or copolymerization of olefins in the presence of one of the described catalyst systems.

Abstract: The present invention relates to pulverulent solids obtainable by reaction of a metal alkyl compound of a divalent or higher-valent metal and a finely divided support which on its surface bears functional groups which can form a chemical bond between the metal atom of the metal alkyl compound and the surface of the support, wherein the particles of the finely divided support have particle diameters of less than 1000 nm and less than 5% by weight of the metal alkyl compound is extractable in a single extraction of the pulverulent solid with 20 ml of heptane per gram of solid at 50° C. In addition, the invention relates to a process for preparing the pulverulent solids, a catalyst composition for the polymerization of olefins which comprises the pulverulent solids and polymerization processes using the catalyst composition.

Abstract: A process for preparing a broad molecular weight polyethylene carried out in the presence of a catalyst system comprising (i) a solid catalyst component comprising Mg, Ti, halogen, and optionally an internal electron donor compound, and (ii) an Al-alkyl cocatalyst said process comprising at least two step of polymerization (a) and (b), in which: in a first step (a) ethylene is polymerized in the presence of a molecular weight regulator in order to produce a ethylene (co)polymer, and in a further step (b), which is carried out in the presence of an external electron donor compound added to this polymerization step as a fresh reactant, ethylene is copolymerized with an alpha olefin of formula CH2?CHR, in which R is a C1-C20 hydrocarbon group, to produce an ethylene copolymer having a molecular weight higher than that of the copolymer produced in step (b).

Abstract: Process for preparing diimine compounds, in which a discarbonyl compound is reacted with primary amines in the presence of phosphorus pentoxide.

Abstract: Process for producing a catalyst system, which comprises the following steps: A) provision of a mixture of at least two different organic transition metal compounds, at least one hydrolyzed organoaluminum compound and a solvent and impregnation of a dry porous support component with the mixture from step A), with the total volume of the mixture being from 0.6 to 1.5 times the total pore volume of the support component, and also catalyst systems obtainable in this way and their use for olefin polymerization.

Abstract: The present invention relates to a process for the racemoselective preparation of ansa-metallocene complexes of the formula (I) which comprises reacting a ligand starting compound of the formula (II) with a transition metal compound of the formula (III) (LB)yM1(NR3R4)Xx-1??(III) where R1, R1? are identical or different and are each hydrogen or an organic radical having from 1 to 40 carbon atoms, R2, R2? are identical or different and are each hydrogen or an organic radical having from 1 to 40 carbon atoms, R3 is an organic radical having from 1 to 40 carbon atoms, R4 is hydrogen or an organic radical having from 1 to 40 carbon atoms, T, T? are identical or different and are each a divalent organic group which has from 1 to 40 carbon atoms and together with the cyclopentadienyl ring forms at least one further saturated or unsaturated, substituted or unsubstituted ring system which has a ring size of from 5 to 12 atoms, where T and T? may contain the heteroatoms Si, Ge, N, P, As, Sb, O, S, Se or Te

Abstract: The invention relates to a process for preparing a poly-1-olefin by polymerization of a 1-olefin of the formula R4CH?CH2, where R4 is hydrogen or an alkyl radical having from 1 to 10 carbon atoms, in suspension, in solution or in the gas phase, at a temperature of from 20 to 200° C. and a pressure of from 0.

Abstract: Pulverulent solid which consists essentially of at least one metal alkyl compound bound chemically and/or physically to a finely divided, porous, mechanically stable and chemically inert support, has a proportion by weight of metal alkyl compound of at least 5% by weight, based on the support, and has an angle of repose, determined in accordance with ISO 4324, of up to 48°. The solid allows trouble-free metering as active component into a reactor.

Abstract: The invention relates to a polyethylene molding composition which has a multimodal molecular mass distribution and comprises a low molecular weight ethylene homopolymer A, a high molecular weight ethylene copolymer B and an ultrahigh molecular weight ethylene copolymer C. The molding composition has a density at a temperature of 23° C. in the range from 0.940 to 0.957 g/cm3, an MFR (190° C./2.16 kg) in the range from 0.5 to 4 dg/min and a viscosity number VN3 of the mixture of ethylene homopolymer A, copolymer B and ethylene copolymer C, measured in accordance with ISO/R 1191 in decalin at a temperature of 135° C., in the range from 150 to 300 cm3/g. The invention further relates to the use of such a molding composition for producing injection-molded finished parts, and to finished parts produced by injection molding.

Abstract: A compound of formula (X): wherein R1, R2, equal to or different from each other are hydrogen or a linear or branched saturated or unsaturated C1-C20-alkyl, C3-C20-cycloalkyl, C6-C20-aryl, C7-C20-alkylaryl or C7-C20-arylalkyl radical, optionally containing heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements; or they can form a C4-C7 ring optionally containing O, S, N, P or Si atoms that can bear substituents; R3 is hydrogen or a linear or branched saturated or unsaturated C1-C20-alkyl, C3-C20-cycloalkyl, C6-C20-aryl, C7-C20-alkylaryl or C7-C20-arylalkyl radical, optionally containing heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements; or two adjacent R3 groups can form a C4-C7 ring optionally containing O, S, N, P or Si atoms, wherein said ring can bear substituents; and at least one of R1, R2 or R3 is different from hydrogen.

Abstract: The present invention relates to a process for the meso-selective preparation of ansa-metallocene complexes of the formula (I), which comprises reacting a ligand starting compound of the formula (II) with a transition metal compound of the formula III, where R1, R1 are identical or different and are each hydrogen or an organic radical having from 1 to 40 carbon atoms, R2, R2 are identical or different and are each hydrogen or an organic radical having from 1 to 40 carbon atoms, R3 is a bulky organic radical which has at least 3 carbon atoms, is bound to the oxygen atom via a nonaromatic carbon or silicon atom and may be substituted by halogen atoms or further organic radicals having from 1 to 20 carbon atoms and may also contain heteroatoms selected from the group consisting of Si, N, P, O and S, T, T? are identical or different and are each a divalent organic group which has from 1 to 40 carbon atoms and together with the cyclopentadienyl ring forms at least one further saturated or unsaturated, substituted

Abstract: A multimodal polyethylene composition, in particular suitable for the preparation of films, but also textile articles, blow molded articles and injection molded articles is described.

Abstract: Monomodal molding compositions based on polymers of ethylene, wherein the density of the molding compositions is in the range from 0.940 to 0.96 g/cm3, the Mi is in the range from 0.5 to 10.0 g/10 min. the polydispersity Mw/Mn is in the range from 3 to 20, the branches/1000 carbon atoms is in the range from 0.1 to 10 and the weight average molar mass Mw is in the range from 50000 g/mol to 150000 g/mol, and also injection-molded shaped bodies as well as screw closures comprising the molding compositions.

Abstract: Monocyclopentadienyl complexes in which the cyclopentadienyl system is substituted by at least one bridged donor, where the bridge contains at least one atom of group 14 of the Periodic Table and at least one atom of group 15 or 16 of the Periodic Table, and a catalyst system comprising at least one of the monocyclopentadienyl complexes, and also methods of preparing them, the use of the catalyst system for the polymerization or copolymerization of olefins and a process for preparing polyolefins by polymerization or copolymerization of olefins in the presence of the catalyst system and the preparation of the associated cyclopentadienyl system.

Abstract: The invention relates to a process for preparing an essentially spherical support for olefin polymerization catalysts, which comprises the steps: preparation of a hydrogel comprising a cogel of silicon oxide and at least one further metal oxide, if appropriate, washing of the hydrogel until the content of alkali metal ions is less than 0.1% by weight, based on the weight of solids, extraction of the water from the hydrogel until the water content is less than 5% by weight, based on the total content of liquid, and drying of the hydrogel to form a xerogel. According to the invention, the extraction step comprises at least one batchwise extraction with an organic solvent which is at least partially miscible with water down to a water content of less than 50% by weight, followed by at least one continuous extraction with an organic solvent which is at least partially miscible with water.

Abstract: The invention relates to a process for preparing hydrogenated or partially hydrogenated, racemic ansa-metallocene complexes by reacting bridged or unbridged transition metal complexes with alkali metal compounds or alkaline earth metal compounds, heating the resulting reaction mixture to a temperature in the range from ?78 to 250° C. and at least partially hydrogenating the reaction products in the presence of a suitable catalyst, to the corresponding hydrogenated or partially hydrogenated metallocenes and to their use as catalysts or as a constituent of catalysts for the polymerization of olefinically unsaturated compounds or as reagents or catalysts in stereoselective synthesis.