| 摘要 |
PROBLEM TO BE SOLVED: To provide a piping material (pipe and joint) including a polyethylene resin composition which is classified into PE100 by the ISO 9080 standard, assured in 100-year warranty, has an excellent long-term characteristic, and has excellent molding processability and a pipe surface property.SOLUTION: The piping material includes the polyethylene resin composition including an ethylene homopolymer and/or a copolymer of ethylene andα-olefin whose carbon number is 3 to 20, and satisfying the followings of (1) to (4). (1) Density is 948 to 952 kg/m. (2) A melt flow rate (cord T) is 0.30 to 0.50 g/10 min. (3) A molecular distribution is not smaller than 15 and smaller than 25. (4) In a hot rolling inner pressure creep test at a temperature of 20°C regulated by ISO 9080, a ratio of an inclination of a plot line of a logarithm of hoop pressure with respect to a logarithm of a break time has the following relationship. Inclination before 1,000 hours/inclination after 1,000 hours>1.5. |
