Polymer compositions and pressure-resistant pipes made thereof

• Main Authors: BAECKMAN, MATS, EK, CARL-GUSTAF, PAKKANEN, ANNELI, PALMLOEF, MAGNUS
• Format: Patent
• Language: English; French; German
• Published: 09.12.2009
• Subjects: CHEMISTRY; COMPOSITIONS BASED THEREON; COMPOSITIONS OF MACROMOLECULAR COMPOUNDS; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP

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/m 3 , a melt index MFR 5 of from 0.5 to 6.0 g/10 min, a melt index MFR 2 of from 0.1 to 2.0 g/10 min and a shear thinning index SHI 2.7/210 of from 2 to 50. In addition the multimodal copolymer comprises. (A) from 30 to 70 % by weight, based on the combined amount of components (A) and (B), of a low molecular weight ethylene polymer selected from ethylene homopolymer and a copolymer of ethylene and one or more alpha-olefins having from 4 to 10 carbon atoms and having a weight average molecular weight of from 5000 to 100000 g/mol and a density of from 945 to 975 kg/m 3 ; and (B) from 30 to 70 % by weight, based on the combined amount of components (A) and (B), of a high molecular weight copolymer of ethylene and one or more alpha-olefins having from 4 to 10 carbon atoms and having a weight average molecular weight of from 100000 to 1000000 g/mol and a density of from 890 to 929 kg/m3.