Abstract: The present invention relates to a polyolefin composition comprising a polyolefin base resin and an antioxidant, characterized in that said polyolefin composition has a lifetime of at least 200 h in a test measuring the resistance against ClO2-containing water at 90° C. and at a concentration of ClO2 of 4 ppm wherein the equipment used is according to ASTM F2263-03. The present invention further relates to a pipe comprising the polyolefin composition according to the invention, to the use of the polyolefin composition for the production of a pipe, and to the use of a particularly selected antioxidant for increasing the resistance of a polyolefin composition against degradation caused by contact with ClO2-containing water.

Abstract: The application relates to a polyethylene composition having a base resin, the base resin comprising (A) a first polyethylene fraction, and (B) a second polyethylene fraction, wherein the melt flow rate MFR5/190° c. of the first fraction is higher than the melt flow rate MFR5/190° c. of the second fraction, the flow rate ratio FRR21/5 of the polyethylene composition, defined as the ratio of melt flow rate MFR21-6/190° c. to melt flow rate MFR5/190° c., is within the range of 15-28, and 10 the melt flow rate MFR5/190° c. of the polyethylene composition is within the range of 0.5-1.1 g/10 min.

Abstract: The present invention relates to a polyolefin composition comprising a polyolefin base resin and an antioxidant, characterized in that said polyolefin composition has a lifetime of at least 200 h in a test measuring the resistance against ClO2-containing water at 90° C. and at a concentration of ClO2 of 4 ppm wherein the equipment used is according to ASTM F2263-03. The present invention further relates to a pipe comprising the polyolefin composition according to the invention, to the use of the polyolefin composition for the production of a pipe, and to the use of a particularly selected antioxidant for increasing the resistance of a polyolefin composition against degradation caused by contact with ClO2-containing water.

Abstract: The present invention deals with polymer compositions suitable for making pipes. The compositions comprise a multimodal copolymer of ethylene and one or more alpha-olefins having from 4 to 10 carbon atoms wherein the multimodal ethylene copolymer has a density of from 924 to 935 kg/m3, a melt index MFR5 of from 0.5 to 6.0 g/10 min, a melt index MFR2 of from 0.1 to 2.0 g/10 min and a shear thinning index SHI2.7/210 of from 2 to 50.

Abstract: The present invention deals with polymer compositions suitable for making pipes. The compositions comprise a multimodal copolymer of ethylene and one or more alpha-olefins having from 4 to 10 carbon atoms wherein the multimodal ethylene copolymer has a density of from 924 to 960 kg/m3, a melt index MFR5 of from 0.5 to 6.0 g/10 min, a melt index MFR2 of from 0.1 to 2.0 g/10 min and a shear thinning index SHI2.7/210 of from 2 to 50. The compositions further have a level of volatile compounds of at most 100 ppm by weight and/or a homogeneity rating of at most 3.

Abstract: The present invention relates to a pipe or a supplementary pipe article comprising a polyethylene composition comprising a base resin which comprises (A) a first ethylene homo- or copolymer fraction, and (B) a second ethylene homo- or copolymer fraction, wherein fraction (A) has a lower average molecular weight than fraction (B), the base resin has a flexural modulus determined according to ISO 178 of 1000 MPa or higher, and the composition further comprises (C) an inorganic mineral filler, wherein inorganic mineral filler (C) is present in the composition in an amount of 1 to 70 wt. %, and to the use of said composition for the production of a pipe or a supplementary pipe article.

Abstract: The present invention relates to a polyethylene composition comprising a base resin which comprises (a) an ethylene homo- or copolymer fraction (A); and (b) an ethylene homo- or copolymer fraction (B), wherein (i) fraction (A) has a lower average molecular weight than fraction (B); (ii) the base resin has a density of 940 to 947 kg/m3; (iii) the polyethylene composition has an MFR5 of 0.1 to 0.5 g/10 min; and (iv) the polyethylene composition has an SHI(2.7/210) of 10 to 49. Furthermore, the present invention relates to an article, preferably a pipe comprising said composition and to the use of said composition for the production of an article, preferably a pipe.

Abstract: A pipe or a supplementary pipe article comprising a polyethylene composition comprising a base resin which comprises: (A) a first ethylene homo- or copolymer fraction having an MFR2 in the range of 300 to 700 g/10 min, and (B) a second ethylene homo- or copolymer fraction, wherein fraction (A) has a lower average molecular weight than fraction (B), wherein the base resin has a density in the range of 0.945 to 0.949 kg/cm3 and an MFR5 in the range of 0.2 to 0.4 g/10 min and a comonomer content of higher than 2.0 wt.-% and a SHI(2.7/210) in the range of 55 to 100.

Abstract: The present invention deals with coated pipes having a layer of multimodal polyethylene. The multimodal ethylene copolymer is a copolymer of ethylene with one or more alpha-olefin comonomers having from 4 to 10 carbon atoms and has a weight average molecular weight of from 70000 g/mol to 250000 g/mol and a melt index MFR2 of from 0.05 g/10 min to 5 g/10 min, a melt index MFR5 of from 0.5 to 10 g/10 min and a density of from 945 kg/m3 to 958 kg/m3. The coatings have a high stiffness, good properties at elevated temperatures and acceptable stress-cracking properties.

Abstract: The present invention relates to a pipe or a supplementary pipe article comprising a polyethylene composition comprising a base resin which comprises (A) a first ethylene homopolymer fraction, and (B) a second ethylene homo- or copolymer fraction, wherein fraction (A) has a lower average molecular weight than fraction (B), and the composition further comprises (C) an inorganic mineral filler, wherein inorganic mineral filler (C) is present in the composition in an amount of 1 to 70 wt. %, and to the use of said composition for the production of a pipe or a supplementary pipe article.

Abstract: The present invention relates to a polyethylene composition comprising a base resin which comprises (a) an ethylene homo- or copolymer fraction (A); and (b) an ethylene homo- or copolymer fraction (B), wherein (i) fraction (A) has a lower weight average molecular weight than fraction (B); (ii) the base resin has a density of 932 to 938 kg/m3; (iii) the polyethylene composition has an MFR5 of 0.1 to 0.6 g/10 min; and (iv) the polyethylene composition has a shear stress ?2.7 kPa of 85 to 230 kPas. Furthermore, the present invention relates to an article, preferably a pipe comprising said composition and to the use of said composition for the production of an article, preferably a pipe.

Abstract: The present invention deals with coated pipes having a layer of multimodal polyethylene. The multimodal ethylene copolymer is a copolymer of ethylene with one or more alpha-olefin comonomers having from 4 to 10 carbon atoms and has a weight average molecular weight of from 70000 g/mol to 250000 g/mol and a melt index MFR2 of from 0.05 g/10 min to 5 g/10 min, a melt index MFR5 of from 0.5 to 10 g/10 min and a density of from 945 kg/m3 to 958 kg/m3. The coatings have a high stiffness, good properties at elevated temperatures and acceptable stress-cracking properties.

Abstract: The present invention relates to a polyethylene composition comprising a base resin which comprises (a) an ethylene homo- or copolymer fraction (A); and (b) an ethylene homo- or copolymer fraction (B), wherein (i) fraction (A) has a lower average molecular weight than fraction (B); (ii) the base resin has a density of 940 to 947 kg/m3; (iii) the polyethylene composition has an MFR5 of 0.1 to 0.5 g/10 min; and (iv) the polyethylene composition has an SHI(2.7/210) of 10 to 49. Furthermore, the present invention relates to an article, preferably a pipe comprising said composition and to the use of said composition for the production of an article, preferably a pipe.

Abstract: A pressureless pipe and polymer composition for making such a pipe as well as the use of the polymer composition for pressureless pipes and supplementary parts, are disclosed. The polymer composition is characterized in that the polymer comprises a multimodal ethylene polymer including a copolymer of ethylene and a C4-C10 &agr; -olefin comonomer; the ethylene polymer has a total density of 953-958 kg/m3 and a MFR5 of 0.2-2.0 g/10 min; the ethylene polymer has a modulus of elasticity, determined according to ISO 178 of 1300-1700 MPa; the ethylene polymer has a resistance to slow crack growth, determined according to ASTM F 1473 of more than 1.5 hrs.

Abstract: A pipe or a supplementary pipe article comprising a polyethylene composition comprising a base resin which comprises: (A) a first ethylene homo- or copolymer fraction having an MFR2 in the range of 300 to 700 g/10 min, and (B) a second ethylene homo- or copolymer fraction, wherein fraction (A) has a lower average molecular weight than fraction (B), wherein the base resin has a density in the range of 0.945 to 0.949 kg/cm3 and an MFR5 in the range of 0.2 to 0.4 g/10 min and a comonomer content of higher than 2.0 wt.-% and a SHI(2.7/210) in the range of 55 to 100.

Abstract: The present invention relates to a polyolefin composition comprising a polyolefin base resin and an antioxidant, characterized in that said polyolefin composition has a lifetime of at least 200 h in a test measuring the resistance against ClO2-containing water at 90° C., and at a concentration of ClO2 of 4 ppm wherein the equipment used is according to ASTM F2263-03. The present invention further relates to a pipe comprising the polyolefin composition according to the invention, to the use of the polyolefin composition for the production of a pipe, and to the use of a particularly selected antioxidant for increasing the resistance of a polyolefin composition against degradation caused by contact with ClO2-containing water.

Abstract: The present invention concerns a multimodal polyethylene composition comprising a base resin comprising three ethylene homo- or copolymer fractions (A), (B) and (C) with different weight average molecular weight Mw, wherein a) fraction (A) has an MFR21 equal or lower than 20 g/10 min, b) fraction (B) has a lower weight average molecular weight than fraction (C), c) fraction (C) has a lower weight average molecular weight than fraction (A), d) the composition has a viscosity at a shear stress of 747 Pa (eta747) of 350 kPas or higher, and e) the composition has a MFR5 of 0.15 g/10 min or higher and a white spot area of 1% or below. Furthermore, the present invention relates to a process for the production of such a composition as well as to the use of such a composition for the production of a pipe, for moulding applications, and wire and cable applications.

Abstract: The present invention relates to a polyethylene resin comprising A) a first ethylene homo- or copolymer fraction, and B) a second ethylene homo- or copolymer fraction, wherein fraction (A) has a lower molecular weight than fraction (B), characterized in that the polymer resin powder obtained directly after the final polymerisation step has a particle size distribution PSD95/5 equal to or smaller than 12. Furthermore, the invention relates to a process for the production of a polymer composition comprising: (i) a step in which ethylene monomers, and optionally further alpha-olefin-comonomers, are polymerised in liquid phase in the presence of a polymerisation catalyst, (ii) a step in which ethylene monomers, and optionally further alpha-olefin comonomers, are polymerised in the gas phase in the presence of a polymerisation catalyst, and (iii) obtaining a polymer resin powder after the final polymerisation step wherein the powder has a particle size distribution PSD95/5 equal to or smaller than 12.

Abstract: The present invention relates to a multimodal polyethylene composition for pipes which comprises polyethylene composition comprising a base resin which comprises (A) an ethylene homo- or copolymer fraction, and (B) an ethylene copolymer fraction comprising at least one alphaolefin comonomer having at least 4 carbon atoms, wherein (i) fraction (A) has a lower average molecular weight than fraction (B), and (ii) the comonomer content and the density d of the base resin satisfy the following relation: comonomer [mol %]>?0.0612 d [kg/m3] mol %/(kg/m3)+58.6, and (iii) the base resin comprises mom than 0.5 mol % of at least one alpha-olefin comonomer having at leant 4 carbon atoms. Furthermore, the present invention relates to a process for the production or said composition, a pipe comprising said composition and to the use of said composition for the production of a pipe.

Abstract: The present invention in a first embodiment concerns a multimodal, preferably bimodal, polyethylene composition comprising a base resin which comprises (A) a first ethylene homo- or copolymer fraction, and (B) a second ethylene homo- or copolymer fraction, wherein fraction (A) has a lower molecular weight than fraction (B), the ratio of the MFR2 of fraction (A) and the MFR5 of the base resin being from 200 to 1500, and the composition has a white spot area of 1% or below. In a second embodiment, the present invention concerns a polyethylene composition comprising a base resin comprising (A) a first ethylene homo- or copolymer fraction, and (B) a second ethylene homo- or copolymer fraction, wherein fraction (A) has a lower molecular weight than fraction (B), the ratio of the MFR2 of fraction (A) and the MFR5 of the base resin being from 200 to 1500, and the composition has a rating in the ISO 18553 white spot rating test of below 4.5.