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: The present invention relates to a slurry process for preparing an ethylene polymer having a melt flow ratio F/P, according to ASTM 1238, of higher than 25, carried out in two or more stages of polymerization at temperatures in the range from 60 to 120° C., in which at least two of the said two or more polymerization stages are carried out under different concentration of a molecular weight regulator, said process being carried out in the presence of a catalyst system comprising the product obtained by contacting (A) a solid catalyst component comprising Ti, Mg, halogen, and having a porosity (PF), measured by the mercury method and due to pores with radius equal to, or lower than, 1 ?m of at least 0.3 cm3/g and a surface area determined by BET method, of lower than 100 m2/g, and (B) of an organoaluminum compound.

Abstract: The present invention refers to a process for overcoming the problem of formation of oligomeric-polymeric complexes during preparation of cyclopentadienyl metallocenes comprising ligands bridged by at least three carbon atoms. According to the invention a process is presented comprising the steps of deprotonating a biscyclopentadienyl ligand bridged by a chain having a backbone of at least three carbon atoms by a base and reacting the deprotonated ligand with at least one alkali or alkaline earth metal alkylating agent and a salt of a transition metal belonging to group 3, 4, 5, 6 or to the lanthanide or actinide groups of the Periodic Table of the Elements.

Abstract: Monocyclopentadienyl complexes in which the cyclopentadienyl system bears at least one unsubstituted, substituted or fused, heteroaromatic ring system bound via a specific bridge, a catalyst system, comprising at least one of these monocyclopentadienyl complexes, 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 polymers obtainable therewith.

Abstract: A method for the treatment of catalyst or catalyst support material in an apparatus in which the treatment is carried out continuously in such a way that the physical and/or chemical conditions change during entry of the catalyst or catalyst support material into the apparatus and/or during exit thereof from the apparatus and/or the catalyst or catalyst support material is transported in the apparatus through zones (5, 6, 7) having different physical and/or chemical conditions.

Abstract: Disclosed are compounds of the following core structure, and their use as polymerization catalysts: wherein M1 is a group lVb transition metal, R5 is a substituted aryl group, and Ra forms a heteroatom-containing ring fused to the cyclopentadienyl ring.

Abstract: Transition metal complexes of the formula (Ia) or (Ib), in which the substituents and indices have the following meanings: M is titanium, zirconium, hafnium, vanadium, niobium or tantalum or an element of the third subgroup of the Periodic Table or of the lanthanoids, X is fluorine, chlorine, bromine, iodine, hydrogen, C1-C10-alkyl, C6-C15-aryl, alkylaryl having 1 to 10 carbon atoms in the alkyl radical and 6 to 20 carbon atoms in the aryl radical, —OR5 or —NR5R6, n is 1, 2 or 3, where n is the valency of M minus the number 2, Z is a three-way bridge and A and A1 are two-way bridges.

Abstract: A process for increasing the flame resistance of polyethylene-containing, single- or multilayer hollowware, in particular plastic fuel tanks, by heat treating the hollowware at 60-135° C.

Abstract: The invention relates to a method for producing rac/meso metallocenes, the rac/meso metallocenes themselves, and their use in the production of polyolefins.

Abstract: Supported catalyst systems are obtainable by A) reaction of an inorganic carrier with a metal compound of the general formula I M1(R1)r(R2)s(R3)t(R4)u  I  where M1 is an alkali metal, an alkaline earth metal or a metal of main group III or IV of the Periodic Table, R1 is hydrogen, Ch1-C10-alkyl, C6-C15-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, R2 to R4 are each hydrogen, halogen, C1-C10-alkyl, C6-C15-aryl, alkylaryl, arylalkyl, alkoxy or dialkylamino each having 1 to 10 carbon atoms in the alkyl radical and 6 to 20 carbon atoms in the aryl radical, r is an integer from 1 to 4 and s, t and u are integers from 0 to 3 the sum r+s+t+u corresponding to the valency of M1, B) reaction of the material obtained according to A) with a metallocene complex in its metal dihalide form and a compound forming metallocenium ions and C) subsequent reaction with a metal compound of the general formula I

Abstract: Polymers of alkenes are prepared by suspension polymerization in the presence of catalyst systems by a process in which the catalyst systems used are supported catalyst systems obtainable by A) reaction of an inorganic carrier with a metal compound of the general formula I M1(R1)r(R2)s(R3 )t(R4 )u  I where M1 is an alkali metal, an alkaline earth metal or a metal of main group III or IV of the Periodic Table, R1 to R7 are variously halogen, alkoxy, dialkylamino, hydrogen, C1-C10-alkyl, C6-C15-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, s, t and u are integers from 1 to 4 the sum r+s+t+u corresponding to the valency of M1, B) reaction of the material obtained according to A) with a metallocene complex in its metal dihalide form and a compound forming metallocenium ions and C) subsequent reaction with a metal compound of the general formula II M2(R5)o(R6)p(R7)q  II.

Abstract: Propylene-ethylene copolymers obtainable by three-step polymerization from the gas phase in an agitated fixed bed by means of a Ziegler-Natta catalyst system which, in addition to a titanium-containing solid component, also contains, as cocatalyst, an aluminum compound, where, in a first polymerization step, propylene is polymerized at from 60 to 90° C. and at from 20 to 40 bar and at a mean residence time of the reaction mixture of from 0.5 to 5 hours, then, in a second polymerization step, a mixture of propylene and ethylene is polymerized onto the polymer obtained from the first polymerization step at from 40 to 110° C. and from 5 to 30 bar, this pressure being at least 7 bar below the pressure in the first polymerization step, and at a mean residence time of the reaction mixture of from 0.2 to 4 hours, and then, in a third polymerization step, ethylene or a mixture of ethylene and propylene is polymerized onto the polymer obtained from the second polymerization step at from 40 to 110° C.

Abstract: Process for the preparation of an olefin polymer using metallocenes containing specifically substituted indenyl ligands A highly effective catalyst system for the polymerization of olefins comprises a cocatalyst, preferably an aluminoxane, and a metallocene of the formula I in which, preferably M1 is Zr or Hf, R1 and R2 are alkyl or halogen, R5 is hydrogen or alkyl, R3 and R4 are alkyl, where R3, R4 and R5 may be halogenated, —(CR7R8)m—R6—(CR7R8)n— is a single- or multi-membered chain in which R6 may also be a (substituted) heteroatom, and m+n is zero or 1.