POLYETHYLENE FOR PIPE AND COUPLING JOINT, AND MOLDED ARTICLE OF SAME

摘要

This polyethylene for a pipe and coupling joint satisfies characteristics (1)-(5). Characteristic (1): a melt flow rate (HLMFR) of 5-20 g/10 minutes at a temperature of 190°C and a load of 21.6 kg. Characteristic (2): a density (D) of 0.954-0.960 g/cm3. Characteristic (3): a ratio (Mw/Mn) of 15-27 of the weight-average molecular weight (Mw) and number-average molecular weight (Mn) as measured by gel permeation chromatography (GPC). Characteristic (4): a breaking time (FNCT) of 150 hours or greater at 80°C and 5 MPa by full notch creep test. Characteristic (5): a Charpy impact strength (CIS) of 8.5 kJ/m2 or greater measured at -20°C.