摘要:
Pipes having a design stress of at least 9.0 MPa are produced by using a new bimodal polyethylene composition of particular properties compounded with carbon black.
摘要:
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 6 to 10 carbon atoms and has a weight average molecular weight of from 70000 g/mol to 250000 g/mol, a melt index MFR 2 of from 0.05 g/10 min to 5 g/10 min, a melt index MFR 5 of from 0.5 to 10 g/10 min and a density of from 930 kg/m 3 to 950 kg/m 3 . It has good mechanical properties in a wide range of service temperature and especially a high resistance against stress cracking.
摘要:
The present invention provides a method for tailoring the molecular weight distribution of a multimodal (e.g. bimodal) ethylene polymer having a lower molecular weight component and a higher molecular weight component comprising polymerising ethylene and optionally at least one further alpha olefin in at least two stages, wherein at least one stage is carried out in a slurry phase in the presence of a Ziegler Natta catalyst comprising an electron donor which is an ether.
摘要:
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), and the composition further comprises (C) an inorganic filler, and to the use of said composition for the production of a pipe or a supplementary pipe article.
摘要:
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 MFR 5/190°C of the first fraction is higher than the melt flow rate MFR 5/190°C of the second fraction, the flow rate ratio FRR 21/5 of the polyethylene composition, defined as the ratio of melt flow rate MFR 21.6/190°C to melt flow rate MFR 5/190°C , is within the range of 15-28, and the melt flow rate MFR 5/190°C of the polyethylene composition is within the range of 0.5-1.1 g/10 min.