Pipe made of ethylene polymer

摘要

The pipe of the present invention comprises an ethylene base polymer comprising ethylene and an alpha-olefin having 3 to 20 carbon atoms, wherein (A) a maximum value of the residual stress is 0.13 MPa or less; (B) the crystallinity is 0.630 to 0.850; (C) a gradient of the crystallinity against a thickness of the pipe is 0.465 or less; and (D) the pipe has a thickness of 5 to 50 mm. It is excellent in a durability, a rigidity and an impact resistance and suited to uses for large diameter pipes receiving a high internal pressure.