| 摘要 |
<p>The invention relates to a pipe comprising layers of thermoplastic polyolefins of the same type, but of different properties, which are inseparably connected to each other. An outer layer and a second layer adjacent to the inner surface thereof comprise an uncross-linked material. The second layer has approximately the FNCT value or the NPT value of a single-layered standard pressure pipe and the first layer has an FNCT value at least a factor of three higher, or an NPT value greater than the second layer. Furthermore a third layer, adjacent to the inner surface of the second layer, which also comprises an uncross-linked material and has an FNCT value higher than the second layer by a factor of at least three or an NPT value higher than the second layer by a factor of at least two.</p> |
