| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a polyethylene pipe useable even under high circumferential stress. <P>SOLUTION: The polyethylene pipe is composed of a polyethylene resin composition composed of (A) a high-density and low-molecular weight ethylene polymer and (B) a low-density and high-molecular weight ethylene copolymer obtained by polymerizing ethylene with≥6Cα-olefin by a metallocene catalyst and having 960-965 kg/m<SP>3</SP>density, 0.15-0.3 g/10 min melt flow rate values (MMI) at 190°C under 5 kg load and≥100 hr breaking time in a constant stress environmental stress cracking test under 5 MPa stress. In the polyethylene pipe, breaking time under≤14 MPa circumferential stress at 20°C is≥50 hr and breaking time under≤5 MPa circumferential stress at 80°C is≥3,000 hr. <P>COPYRIGHT: (C)2004,JPO&NCIPI</p> |
