| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a synthetic resinous double pipe which is free from wrinkles in an inside of its inner pipe, and has good durability and molding performance. <P>SOLUTION: This synthetic resinous double pipe H is composed of an outer pipe 1 alternately provided with spiral crest portions 1a and trough portions 2a in an axial direction on an outer surface, and the cylindrical inner pipe 2 integrally joined with the outer pipe on an inner surface of each crest portion 2a of the outer pipe. The outer pipe 1 is formed by a high-density polyethylene resin, and the inner pipe 2 is formed by a low-density polyethylene resin. <P>COPYRIGHT: (C)2003,JPO</p> |
