FIELD: chemistry.
SUBSTANCE: invention relates to a polyethylene composition for making pipes, which contains a polymer base comprising two polyethylene fractions with different molecular weight, to a pipe containing said composition and to use of said composition to make articles, preferably pipes. The polymer base accounts for not less than 90 wt % of the overall composition and has density of 932-938 kg/m3.The fraction of ethylene homo- or copolymer (A) has lower average molecular weight than the fraction of ethylene homo- or copolymer. The polyethylene composition has melt flow rate MFR5 between 0.1 and 0.6 g/10 min and shearing stress η2.7 kPa between 85 and 230 kPa. The polyethylene composition has improved combination of properties, particularly high flexibility, high mechanical strength and good long-term stability.
EFFECT: pipes obtained from the disclosed polyethylene composition have good operational characteristics, long-term stability and good resistance to rapid propagation of cracks, which facilitates their use in conveying liquids under pressure.
16 cl, 1 tbl, 3 ex
