Abstract: Gas-phase fluidized-bed reactor for polymerizing ethylenically unsaturated monomers, comprising a reactor chamber (1) in the form of a vertical tube, if desired a calming zone (2) following the upper section of the reactor chamber, a circulation gas line (3), a circulation gas compressor (4) and a cooling device (5), where, in the region of transition of the reaction gas from the circulation gas line into the reactor chamber and in the lower section of the reactor chamber itself, there is either no gas distributor plate at all or only a gas distributor plate the total surface area of whose gas orifices is more than 20% of the total surface area of said gas distributor plate.

Abstract: Method of polymerizing ethylene with C3-C20-olefine-comonomer, comprising the step of carrying out the olymerization in a single gas phase reactor with a mixed catalyst system herein the catalyst system has a catalyst mileage of higher than 6000 g polymer product/g catalyst.

Abstract: Process for preparation of ethylene homopolymers or copolymers, comprising the steps of a) polymerization of ethylene or of ethylene with one or more other 1-olefins in the presence of a chromium catalyst at temperatures of from 20 to 200° C. and at pressures of from 0.1 to 20 MPa, where the chromium catalyst can be prepared via application of one or more chromium compounds to a silicate support and subsequent thermal activation under oxidative conditions at temperatures of from 620 to 900° C.; b) mixing of the polyethylene in the melt in the presence of from 1000 to 2000 ppm of an antioxidant comprising at least one sterically hindered phenol and comprising at least one phosphite in a mixing ratio of from 1:5 to 5:1, with specific energy input of at least 0.17 kWh/kg.

Abstract: A polyethylene for IM having excellent processing properties in terms of spiral flow testing is devised.

Abstract: A polyethylene which comprises ethylene homopolymers and/or copolymers of ethylene with 1-alkenes and has a molar mass distribution width Mw/Mn of from 5 to 30, a density of from 0.92 to 0.955 g/cm3, a weight average molar mass Mw of from 50000 g/mol to 500 000 g/mol and has from 0.01 to 20 branches/1000 carbon atoms and a z-average molar mass Mz of less than 1 million g/mol, a process for its preparation, catalysts suitable for its preparation and also films in which this polyethylene is present.

Abstract: Method of preparing olefin polymers, which comprises the polymerization of at least one ?-olefin in the presence of a hybrid catalyst to produce a polymer comprising at least a higher molecular weight polymer component and a lower molecular weight polymer component in the presence of water in an amount of from 2 to 100 mol ppm and/or carbon dioxide in an amount of from 2 to 100 mol ppm, in each case based on the total reaction mixture, in order to alter the ratio of the higher molecular weight polymer component to the lower molecular weight polymer component. This enables the ratio of the higher molecular weight component to the lower molecular weight component to be controlled selectively.

Abstract: Ethylene copolymers composed of ethylene units and units composed of at least one other 1-olefin whose density is from 0.940 to 0.955 g/cm3, whose vinyl end group content is at least 0.5 end groups, based on 1000 carbon atoms, whose tensile impact strength atn, measured to ISO 8256 (1997)/1A at ?30° C., is greater than or equal to 145 kJ/m2, and whose content of comonomer side chains per 1000 carbon atoms Cx is above a value defined via equation I, Cx=128.7?134.62 d? (I), where d? is the density d of the copolymer in g/cm3, and a process for their preparation, and their use as blow-molded products.

Abstract: Method of changing from a polymerization using a first catalyst to a polymerization using a second catalyst which is incompatible with the first catalyst in a gas-phase reactor, which comprises the steps a) stopping of the polymerization reaction using the first catalyst, b) flushing of the reactor under polymerization conditions with at least one deactivating agent comprising a volatile constituent and a nonvolatile constituent in a weight ratio of from 0.1 to 1000, c) introduction of the second catalyst into the reactor and d) continuation of the polymerization using the second catalyst.

Abstract: Polyethylene which comprises ethylene homopolymers and/or copolymers of ethylene with 1-alkenes and has a molar mass distribution width Mw/Mn of from 3 to 30, a density of from 0.945 to 0.965 g/cm3, a weight average molar mass Mw of from 50 000 g/mol to 200 000 g/mol, a HLMI of from 10 to 300 g/10 min and has from 0.1 to 15 branches/1000 carbon atoms, wherein the 1 to 15% by weight of the polyethylene having the highest molar masses have a degree of branching of more than 1 branch of side chains larger than CH3/1000 carbon atoms, a process for its preparation, catalysts suitable for its preparation and also injection moldings in which this polyethylene is present.

Abstract: Process for preparation of ethylene homopolymers or copolymers, comprising the steps of a) polymerization of ethylene or of ethylene with one or more other 1-olefins in the presence of a chromium catalyst at temperatures of from 20 to 200° C. and at pressures of from 0.1 to 20 MPa, where the chromium catalyst can be prepared via application of one or more chromium compounds to a silicate support and subsequent thermal activation under oxidative conditions at temperatures of from 620 to 900° C.; b) mixing of the polyethylene in the melt in the presence of from 1000 to 2000 ppm of an antioxidant comprising at least one sterically hindered phenol and comprising at least one phosphite in a mixing ratio of from 1:5 to 5:1, with specific energy input of at least 0.17 kWh/kg.

Abstract: Process for preparing polyolefins having high molecular weights in the presence of a catalyst comprising an organic transition metal compound in a gas-phase fluidized-bed reactor, where the polyolefins prepared have a melt flow rate at 2.16 kg and 190° C. in accordance with ISO 1133 of less than 4 g/10 min. According to the present invention, a start-up phase during which a polyolefin having an increased melt flow rate of above 4 g/10 min is produced for a transitional period is provided. In this way, trouble-free start-up of the reactor is ensured even in the case of polymer products having a high molecular weight and a melt flow rate below 4 g/10 min and even when using catalysts based on organic transition metal compounds, in particular metallocene catalysts.

Abstract: An apparatus for the polymerization of olefins, in particular ethylene, comprising a gas-phase fluidized-bed reactor (1), a recycle gas line (2) connected to the reactor for discharging and recirculating the recycle gas stream comprising the unpolymerized olefin and a cyclone (3) located in the recycle gas line for the reduction and precipitation of the solid particles entrained in the recycle gas from the reactor, with the cyclone comprising an upper section (3a) which has an essentially vertical central axis, whose wall extends along a rotationally symmetric body and which is provided with a cyclone inlet (4) arranged eccentrically relative to the central axis, a middle section (3b) which adjoins the upper section (3a) and whose wall extends along a rotationally symmetric body which tapers in a downward direction, a lower section (3c) for discharging the solid particles precipitated from the recycle gas which adjoins the middle section (3b) and whose wall extends along a rotationally symmetric body and a tu

Abstract: Apparatus for the polymerization of olefins, in particular ethylene, comprising a gas-phase fluidized-bed reactor (1), a product offtake line (15) for taking polymer particles either continuously or discontinuously from the reactor (1), which line (15) is connected to a depressurization vessel (2) for separating polymer particles and gas, a recycle gas filter (3) for freeing the gas of entrained fine particles connected to the depressurization vessel (2), a compressor which compresses the gas which has been freed of fine particles and recirculates it into the reactor (1), with the recycle gas filter (3) having an inlet chamber (4) provided with a gas inlet (6), an outlet chamber (5) provided with a gas outlet (7), an essentially vertical sheet-like filter medium (9) for retaining the fine particles which separates the inlet chamber (4) from the outlet chamber (5) and a particle outlet (8).

Abstract: Monomodal copolymers of ethylene and molding compositions comprising such copolymers, wherein the copolymers have a density determined according to DIN EN ISO 1183-1, variant A in the range from 0.938 to 0.944 g/cm3, a melt index MFR21 determined according to ISO 1133 at 190° C. under a load of 21.6 kg in the range from 12 to 17 g/10 min, a weight average molar mass Mw, in the range from 140 000 g/mol to 330 000 g/mol, a polydispersity Mw/Mn in the range from 9 to 17, and a content of comonomer side chains per 1000 carbon atoms C x equal to or above a value defined via equation (I) Cx=128.7?134.62×d?, wherein d? is the numerical value of the density of the copolymer in g/cm3, the use of the copolymers for producing injection-molded articles, as well as injection-molded articles comprising the copolymers, and process for the preparation of such monomodal copolymers.

Abstract: Method of preparing olefin polymers, which comprises the polymerization of at least one ?-olefin in the presence of a hybrid catalyst to produce a polymer comprising at least a higher molecular weight polymer component and a lower molecular weight polymer component in the presence of water in an amount of from 2 to 100 mol ppm and/or carbon dioxide in an amount of from 2 to 100 mol ppm, in each case based on the total reaction mixture, in order to alter the ratio of the higher molecular weight polymer component to the lower molecular weight polymer component. This enables the ratio of the higher molecular weight component to the lower molecular weight component to be controlled selectively.

Abstract: Gas-phase fluidized-bed reactor for polymerizing ethylenically unsaturated monomers, comprising a reactor chamber (1) in the form of a vertical tube, if desired a calming zone (2) following the upper section of the reactor chamber, a circulation gas line (3), a circulation gas compressor (4) and a cooling device (5), where, in the region of transition of the reaction gas from the circulation gas line into the reactor chamber and in the lower section of the reactor chamber itself, there is either no gas distributor plate at all or only a gas distributor plate the total surface area of whose gas orifices is more than 20% of the total surface area of said gas distributor plate.

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: Molding composition comprising polyethylene and having a density in the range from 0.915 to 0.955 g/cm, an MI in the range from 0 to 3.5 g/10 min, an MFR in the range from 5 to 50, a polydispersity Mw/Mn in the range from 5 to 20, and a z-average moiar mass Mz of less than 1 million g/mol, a process for preparing such a composition, a catalyst suitable for the preparation of the same, as well as films comprising this molding composition.

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.