HIGH DENSITY POLYMER COMPOSITIONS, A METHOD FOR THEIR PREPARATION AND PRESSURE-RESISTANT PIPES MADE THEREFROM

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 937 to 950 kg/m 3 , a melt inde...

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Bibliographische Detailangaben
Hauptverfasser: TURPEINEN TARJA TUULIKKI, BACKMAN MATS, SEVERN JOHN, EK CARL GUSTAF, PALMLOF MAGNUS, PAKKANEN ANNELI
Format: Patent
Sprache:eng ; kor
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Zusammenfassung: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 937 to 950 kg/m 3 , a melt index MFR 5 of from 0.3 to 3.0 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 30. 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 960 to 977 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/m 3 .