POLYETHYLENE RESIN COMPOSITION, PIPE, AND JOINT

摘要

PROBLEM TO BE SOLVED: To provide a polyethylene resin composition having excellent long-term characteristics classified into PE100 of ISO 9080 with 100 years of guarantee and having excellent moldability, and to provide a pipe and a joint comprising the composition.SOLUTION: The polyethylene resin composition comprises an ethylene single polymer and/or a copolymer of ethylene and α-olefin having 3 to 20 carbon atoms, and satisfies the following conditions (1) to (4). The composition has (1) a density of 946 to 953 kg/m, (2) a melt flow rate (code T) of 0.15 to 0.50 g/10 min, (3) a molecular weight distribution of 15 to 40; and (4) in a hot internal pressure creep test at 20°C specified by ISO 9080, a ratio of gradients in a plotted line of a logarithm of a hoop pressure with respect to a logarithm of a fracture time satisfies (gradient in a period of less than 1000 hours)/(gradient in a period of from 1000 hours and beyond)>1.5.