Abstract: 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 in the finished catalyst, is supported on a finely divided inorganic support and is obtainable by concluding calcination at temperatures of from 350 to 1050° C. and has a zinc content of from 0.01 to 10% by weight, based on the element in the finished catalyst.

Abstract: Novel supported, titanized chromium catalysts for the homopolymerization of ethylene and the copolymerization of ethylene with ?-olefins, a process for preparing them and to their use for the polymerization of olefins.

Abstract: Novel supported, titanized chromium catalysts for the homopolymerization of ethylene and the copolymerization of ethylene with ?-olefins, a process for preparing them and to their use for the polymerization of olefins.

Abstract: Novel supported, titanized chromium catalysts for the homopolymerization of ethylene and the copolymerization of ethylene with ?-olefins, a process for preparing them and to their use for the polymerization of olefins.

Abstract: Novel supported, titanized chromium catalysts can be used for the homopolymerization of ethylene and the copolymerization of ethylene with ?-olefins.

Abstract: The invention relates to a process for preparing a catalyst for the polymerization of olefins, which comprises: a) preparation of a finely divided silica xerogel, b) loading of the xerogel with chromium from a solution of chromium trioxide or a chromium compound which is converted into chromium trioxide under the conditions of step c), and c) activation of the resulting product at from 400 to 1100° C. in a water-free gas stream comprising oxygen in a concentration of above 10% by volume, wherein a fluoride doping with a fluorinating agent is carried out in step b) or in step c). Furthermore, the invention relates to a catalyst for the polymerization of olefins which is obtainable by the process of the invention and to a process for the polymerization of olefins in which an olefin or an olefin mixture is polymerized in the presence of a catalyst according to the invention.

Abstract: The invention relates to a process for preparing a catalyst for the polymerization of olefins, which comprises:

Abstract: Novel supported, titanized chromium catalysts can be used for the homopolymerization of ethylene and the copolymerization of ethylene with &agr;-olefins.

Abstract: Bimodal polyethylene blends are made from a high-molecular-weight ethylene copolymer and a low-molecular-weight ethylene homo- or copolymer and have a melt flow rate MFR 190/21.6 of from 6 to 14 g/10 min, a density of from 0.94 to 0.97 g/cm3, an environmental-stress-cracking resistance ESCR>150 h and a value of less than 3 when the quality of blending in the blend is measured to ISO 13949. A process prepares polyethylene blends of this type by melting and homogenization in a mixing apparatus and discharge via a gear pump. The blends are used to produce moldings, in particular hollow articles and pressure pipes.

Abstract: In a low-odor polyethylene blend made from a high-molecular-weight ethylene copolymer obtainable by polymerization in the presence of a Ziegler catalyst and from a low-molecular-weight ethylene homopolymer or ethylene copolymer obtainable by polymerization in the presence of a chromocene catalyst on an oxidic support, the Al content of the high-molecular-weight component is from 5 to 60 mg/kg, the Al content of the low-molecular-weight component is from 0 to 5 mg/kg and the Al content of the blend is from 1 to 55 mg/kg. Processes are described for preparing blends of this type. Their use is described for producing moldings, in particular hollow articles and pipes. Moldings, in particular hollow articles and pipes, are produced from low-odor polyethylene blends.

Abstract: A polymer mixture comprises at least 40 but less than 85% by weight of an ethylene copolymer (A) which has a density of from 0.91 to 0.93 g/cm3, an HLMFR (190° C./21.6 kg) of from 5 to 60 g/10 min and a molar mass distribution Mw/Mn≦3, and more than 15 but at most 60% by weight of an ethylene copolymer (B) which has a density of from 0.93 to 0.945 g/cm3, an HLMFR (190° C./21.6 kg) of from 8 to 20 g/10 min and a molar mass distribution Mw/Mn≧7, where the percentages by weight are in each case based on the total mass of the components (A) and (B).

Abstract: Polymer blends contain at least 85% by weight of ethylene/&agr;-olefin copolymers (A) prepared by metallocene catalysis and from 1 to 15% by weight of essentially linear ethylene/&agr;-olefin copolymers (B) prepared using another catalyst, the percentages in each case being based on the total weight of the polymer blend.

Abstract: Catalyst systems which are suitable for the polymerization of olefinically unsaturated hydrocarbons contain, as active components, A) an amidinato metal complex of the general formula A  where M is a metal from group IIIb, IVb, Vb or VIb of the Periodic Table of Elements or a metal from the lanthanide group, X is a negative leaving atom or a negative leaving group, and the radicals X may be identical or different if (n−m)>1, R1, R2 and R3 are each a C-organic or Si-organic radical, n is the valency of M in the metal complex A and m is from 1 to 5, with the proviso that n−m≧0, and, if required, B) an acceptor compound for the substituent X of the component A as an activator.

Abstract: Polymers of ethylene are obtainable by polymerization of ethylene and, if desired, further comonomers in the presence of a catalyst system comprising as active constituents I) a Phillips catalyst, II) a solid which is different from I) and comprises a component which is derived from the metallocene complexes of the formula (A) in which the substituents and indices have the following meanings:  R1 to R10 are hydrogen, C1-C10-alkyl, 5-to 7-membered cycloalkyl which may in turn bear C1-C6-alkyl groups as substituents, C6-C15-aryl or aryalkyl, where two adjacent radicals may also together form a cyclic group having from 4 to 15 carbon atoms, or Si(R11)3, where R11 is C1-C10-alkyl, C6-C15-aryl or C3-C10-cycloalkyl, or the radicals R4 and R9 together form a group —[Y(R12R13)]m—, where Y is silicon, germanium, tin or carbon, and R12, R13 are hydrogen C1-C10-alky, C3-C10-cycloalyl or C6-C15-aryl, M is a metal of transition groups IV to VIII or a metal of the lanthanide

Abstract: Polymers of C.sub.2 -C.sub.12 -alk-1-enes are prepared at from -50 to 300.degree. C. and from 0.5 to 3000 bar in the presence of a catalyst system by a process in which the catalyst system used is one which containsA) an inorganic or organic carrier,B) a metallocene complex,C) a compound forming metallocenium ions andD) if required, a metal compound of the general formula IM.sup.1 (R.sup.1).sub.r (R.sup.2).sub.s (R.sup.3).sub.t IwhereM.sup.1 is an alkali metal, an alkaline earth metal or a metal of main group III of the Periodic Table,R.sup.1 is hydrogen, C.sub.1 -C.sub.10 -alkyl, C.sub.6 -C.sub.15 -aryl, alkylaryl or arylalkyl, each having 1 to 10 carbon atoms in the alkyl radical and 6 to 20 carbon atoms in the aryl radical,R.sup.2 and R.sup.3 are each hydrogen, halogen, C.sub.1 -C.sub.10 -alkyl, C.sub.6 -C.sub.

Abstract: Polymers of vinylaromatic compounds are prepared at from 0 to 150.degree. C. in the presence of catalyst systems which comprise as active constituentsA) compounds of the formula IXM(Z.sup.1).sub.z.sbsb.1 (Z.sup.2).sub.z.sbsb.2 (Z.sup.3).sub.z.sbsb.3 (I)where the substituents and indices have the following meanings:X is C.sub.1 -C.sub.10 -alkyl, 5- to 7-membered cycloalky,C.sub.1 -C.sub.10 -alkoxy, C.sub.6 -C.sub.15 -aryl or a cyctopentadienyl group,M is a metal of transition groups II to VIII of the periodic Table of the Elements,Z.sup.1 to Z.sup.3are polymers of vinylaromatic compounds, dienes, acrylates or mixtures thereofandZ.sup.1 to Z.sup.3are 0, 1, 2 or 3, where 1.ltoreq.Z.sub.1 +Z.sub.2 +Z.sub.3 .ltoreq.3,andB) linear or cyclic aluminoxane compoundorcompounds which form metallocenium ions and are selected from the group consisting of strong, uncharged Lewis acids, ionic compounds having a Lewis-acid cation and ionic compounds having a Bronsted acid as cation.

Abstract: Homopolymers of ethylene or copolymers of ethylene with other olefins or mixtures thereof are prepared by suspension polymerization in the presence of catalyst systems by a process in which the catalyst systems used are those which contain, as active components,A) a finely divided carrier treated with trialkylaluminum,B) a metallocene complex,C) an open-chain or cyclic alumoxane compound andD) an alkali metal alkyl or alkaline earth metal alkyl or a mixture thereof.

Abstract: Catalyst systems which are suitable for the polymerization of olefinically unsaturated hydrocarbons contain, as active components,A) an amidinato metal complex of the formula A ##STR1## where M is a metal from group IIIb, IVb, Vb or VIb of the Periodic Table of Elements or a metal from the lanthanide group,X is a negative leaving atom or a negative leaving group, and the radicals X may be identical or different if (n-m)>1,R.sup.1, R.sup.2 and R.sup.3 are each a C-organic or Si-organic radical,n is the valency of M in the metal complex A andm is from 1 to 5, with the proviso that n-m.gtoreq.0,and,B) an activator in a molar ratio of activator B to metal complex A of from 0.5:1 to 10,000:1.

Abstract: A process for the preparation of a supported catalyst for the polymerization of .alpha.-olefins, in which(1) a silicon dioxide-containing support gel is prepared by(1.1) introducing a sodium water glass or potassium water glass solution into a swirling stream of an aqueous mineral acid longitudinally and tangentially to the stream, spraying the resultant silica hydrosol in drop form into a gaseous medium and allowing it to solidify to form a hydrogel, and freeing the resultant hydrogel from salts by washing without prior ageing,(1.2) drying the hydrogel resulting from (1.1) to form the support gel,(2) the support gel (1) is charged with chromium trioxide or a chromium compound which can be converted into chromium trioxide under the conditions of process step (3), giving a chromium-containing support gel, and(3) the chromium-containing support gel (2) is heated at from 400.degree. to 1100.degree. C.

Abstract: The invention relates to a process for preparing a catalyst for the polymerization of olefins, which comprises: a) preparation of a finely divided silica xerogel, b) loading of the xerogel with chromium from a solution of chromium trioxide or a chromium compound which is converted into chromium trioxide under the conditions of step c), and c) activation of the resulting product at from 400 to 1100° C. in a water-free gas stream comprising oxygen in a concentration of above 10% by volume, wherein a fluoride doping with a fluorinating agent is carried out in step b) or in step c). Furthermore, the invention relates to a catalyst for the polymerization of olefins which is obtainable by the process of the invention and to a process for the polymerization of olefins in which an olefin or an olefin mixture is polymerized in the presence of a catalyst according to the invention.