Abstract: The invention relates to a process for the preparation of an olefin polymer comprising at least two polymerization stage in the presence of an olefin polymerization catalyst material, an olefin polymer produced by such process, and the use of such polymers for the production of fibres, pipes, films, moulded products and products for wire and cable applications.

Abstract: The present invention relates to a stabilizing agent for polymers or copolymers which is a copolymer of ethylene or propylene (A) and a vinyl compound (B) having the formula: wherein X is O, NH or NR5; R1, R2 and R3 are each independently H, C1-C8 alkyl, C1-C8 substituted aryl; R4 is H, C1-C8 alkyl, C6-C12 cycloalkyl, C1-C10 acyl, C1-C10 acyloxy or C1-C8 alkyl ether; R5 is C1-C8 alkyl and wherein the copolymer has at least 1 mol % (B) and has an MFR2 of 1-1000 g/10 min.

Abstract: The present invention concerns a high melt strength propylene polymer or copolymer suitable for manufacturing foams and thermoformed product exhibiting a melt strength of at least 3 g and comprising a high molar mass portion and a low or medium molar mass portion. The polymers are produced by subjecting propylene and optionally other olefins to polymerization in a plurality of polymerization reactors connected in series, employing different amounts of hydrogen as a molar mass modifier in at least two of the reactors, and carrying out the polymerization reaction in the presence of a catalyst system capable of catalyzing the formation of a high molar mass polymerization product having a MFR2 of less than 0.1 g/l0 min and a low or medium molar mass polymerization product having a MFR2 of more than 0.5 g/10 min.

Abstract: Olefin polymerization may be catalysed by a wide range of catalytic materials. Described herein is a heterogeneous olefin polymerization catalyst comprising a porous paniculate support material having impregnated therein a metallocene catalyst the metal atom whereof is bound to an amide group which is not bound to an &eegr;-ligand of the metallocene, or the reaction product of a said metallocene catalyst and a co-catalyst.

Abstract: The present invention concerns polymer compositions and a process for the preparation thereof. The compositions comprise a propylene polymer nucleated with a polymeric nucleating agent containing vinyl compound units, and 0.1 to 10% talc, calculated from the weight of the composition, to reduce shrinkage and to improve stiffness of the composition.

Abstract: A process for homo or copolymerizing propylene, wherein propylene is polymerized in the presence of a catalyst at an elevated temperature in a reaction medium in which a major part of the reaction medium is propylene and the polymerization is carried in at least one CSTR or loop reactor, where the polymerization is carried out at a temperature and a pressure which are above the corresponding critical temperature and the pressure of the reaction medium and were the residence time is at least 15 minutes. The process can also have a subcritical loop polymerization before the supercritical stage polymerization or gas phase polymerization after the supercritical stage polymerization.

Abstract: A process for the preparation of a catalyst material and the resultant catalyst material. The process comprises the steps of: (a) treating a particulate support material with an alkylating agent; (b) contacting the alkylating agent treated support material with a procatalyst; optionally (c) contacting the support material with an ionic catalyst activator, and optionally (d) recovering the catalyst-carrying support material. The process allows the simple and effective alkylation of procatalysts, such as metallocene procatalysts. The procatalyst comprises at least one triaza containing ligand.

Abstract: An apparatus for the polymerization of olefin monomers comprising means for forming a fluid stream containing catalyst, means for continuously feeding the fluid stream into an elongated polymerization reactor having at least two successive chambers separated by dividing plates having a diameter slightly smaller than that of the polymerization rector, means for feeding monomers, and an optional catalyst and donor into the polymerization reactor under temperature conditions to polymerize the olefin while maintaining a mixed flow in the chambers to polymerize the monomers and optional comonomer in the fluid, and means for removing the resultant polymer slurry from the polymerization reactor.

Abstract: A semiconducting composition for the inner semiconducting layer of an electric cable, an electric cable incorporating the composition, and a method of producing a cross-linked inner semiconducting layer of an electric cable are disclosed. The semiconducting composition comprises, based on the total weight of the composition, (a) 30-90% by weight of an ethylene copolymer, (b) carbon black in an amount at least sufficient to make the composition semiconducting, (c) 0-8% by weight of a peroxide cross-linking agent, (d) 0-8% by weight of conventional additives, characterized in that said ethylene copolymer (a) is an ethylene-methyl (meth)acrylate copolymer, preferably comprising 5-25% by weight of methyl(meth)acrylate, based on the weight of the copolymer.

Abstract: The invention relates to metallocen compounds having &eegr;5 ligands comprising at least four fused rings and having a sum of fused rings in all of its &eegr;5 ligands being at least 6. Such compounds are for example {[1-(7,9-diphenylcyclopent[a]acenaphthadienyle)-1-phenyle-2-(7,9-diphenylcyclopent[a]acenaphthadienyl)]ethane} zirconium dichloride, {[1-(7,9-diphenycyclopent[a]acenaphthadienyl)-1-phenyl-2-flourenyl]ethane} zirconium dichloride, [bis(7,9-diphenylcyclopent[a]acenaphthadienyl)] zirconium dichloride and [bis(7,9-diphenylcyclopent[a]acenaphthadienyl)]hafnium dichloride. The invention also relates to a catalyst composition comprising such as an aluminoxane. The metallocene compound and the catalyst composition can successfully be used to produce high molecular weight polyethene and long-chain branch polypropene.

Abstract: A process for homo or copolymerizing propylene, wherein propylene is polymerized in the presence of a catalyst at an elevated temperature in a reaction medium, in which a major part is formed by propylene. The polymerization is carried in at least one slurry reactor in the presence of liquid propylene at a temperature between 80° C. and the critical temperature of the reaction medium and a catalyst system producing within said temperature range a high productivity and essentially constant isotacticity within wide melt index range.

Abstract: Use of at least partly cross-linked polyolefin plastic, which is oriented biaxially, as material for pressure pipes, is described. The pressure pipe is produced by extrusion with subsequent axial and peripheral orientation of the pipe, the pipe being at least partly cross-linked before the biaxial orientation. Preferably, the pipe is cross-linked to about 20-50% before orientation. By the at least partial cross-linking before orientation, this can be carried out at temperatures above the crystalline melting point of the plastic material.

Abstract: The invention relates to a copolymer composition prepared from copolymers of propene and &agr;-olefin having 2 to 12 carbon atoms, having high molecular weight, a broad molecular weight distribution and an improved comonomer distribution. The invention relates also to a process for producing the composition and the use of the composition in pipes, fittings, profiles, films and foams. The composition is a so-called reactor mixture of copolymers of said monomers comprising a first copolymer having a higher molecular weight, an &agr;-olefin content of 3 to 10 wt. % and a melt flow rate MFR2 of 0,005 to 0,8, and a second copolymer having a lower molecular weight, thus the final composition has a comonomer content of 2 to 10 wt. %, a melt flow rate MFR2 of 0,05 to 2,5 wt. %, a melt flow ratio MFR10/MFR2 of 6 to 15, and the split of the copolymers in the composition between the higher molecular weight copolymer and the lower molecular weight copolymer is from 40/60 to 70/30.

Abstract: A method for transitioning between two different catalysts in olefin polymerizations, a first catalyst and a second catalyst, comprising the steps of: discontinuing the feed of the first catalyst into the polymerization reactor, and introducing the second catalyst into the reactor, wherein the transition is performed between a chromium-based catalyst and a metallocene catalyst.

Abstract: According to the invention a new catalyst precursor is obtained, in which alkoxy or siloxy substitution in the 2-position of 5-membered ring of indenyl compound has been carried out. Thereby a metallocene compound is achieved, in which an oxygen atom is directly bonded to the 2-position of a pentahapto indenyl moiety. The catalyst precursors can be used as components for olefin polymerization catalysts.

Abstract: A process for the reduction of reactor fouling at radical initiated high pressure polymerisation of ethylene (co)polymers is described. The process is characterised in that an adhesion reducing silicon containing compound is added to the polymerisation reactor, preferably in an amount of 0.001-3% by weight, based on the amount of polymer produced. Preferably the silicon containing compound is hexadecyl trimethoxy silane.

Abstract: A process for the polymerization of ethylene and optionally &agr;-olefins to form ethylene homopolymer or copolymers having a broad molecular weight distribution, comprising polymerization of 100-80 wt. % of ethylene and 0-20 wt. % of comonomer in the presence of two independent, simultaneously present catalysts A and B, wherein catalyst A, deposited on an inorganic support, comprises chromium in a predominantly oxidant state of 2 and catalyst B comprises a bis-cyclopentadienyl chromium compound reacted with an inorganic support.

Abstract: Disclosed is the homogenous reaction at 40-200° C. of MgX12−nR1OH (where n=2.0-6.4) with TiX24 and a higher (C6-C20) alkyl ester of a carboxylic acid, optionally in the presence of a solvent. In such a completely homogenous reaction, no carrier appears. In order to obtain a product in the liquid stage, the molar ratio between the ester and the MgX12.nR1OH should be at least 0.8/j wherein j is the number of carboxyl groups in the ester. If the ester has two carboxyl groups, for instance, j is 2 and the molar ratio should be at least 0.8/2, that is, 0.4.

Abstract: A process for polymerization of olefin monomers by forming a fluid stream containing catalyst, continuously feeding the fluid stream into an elongated polymerization reactor having at least two successive chambers separated by dividing plates having a diameter slightly smaller than that of the polymerization rector, feeding monomers, and an optional catalyst and donor into the polymerization reactor under temperature conditions to polymerize the olefin while maintaining a mixed flow in the chambers to polymerize the monomers and optional comonomer in the fluid, and removing the resultant polymer slurry from the polymerization reactor.

Abstract: A multilayer pipe having improved resistance to rapid crack propagation is described.; The pipe consists of at least two layers of different propylene plastic materials, which are so selected and combined that the pipe has a resistance to rapid crack propagation, measured as the critical temperature, which is equal to or lower than 0° C. The pipe is made of polypropylene plastic, and at least one of the layers of the pipe comprises a polypropylene plastic, which is selected from a propylene contanig from 1.0 to 10.0% by weight of ethylene or C4-C10-&agr;-olefin repeating units and having an MFR2 value of between 0.05 and 0.40 g/10 min or an elastromer-modified polypropylene containing from 1.0 to 30% by weight of ethylene or C4-C10-&agr; olefin repeating units and having an MFR2 value of between 0.05 and 50 g/10 min.