Patent ID: 6684910
Filing Date: 2004-02-03
Classification: B32B,F16L,Y10T

Abstract:
A pipe of layers of thermoplastic polyolefins of a similar type, however, with different properties, which are joined inseparably to one another, an outer first layer and a second layer, adjoining the inside of the first layer, consisting of a material, which is not cross-linked, the second layer having approximately the FNCT value or the NPT value of a single-layer standard pressure pipe and the first layer having an FNCT value, which is higher by a factor of at least 3 than that of the second layer and an NPT value, which is higher than that of the second layer, wherein a third layer, adjoining the inside of the second layer, is provided and also consists of a material, which has not been cross-linked, and has an FNCT value, which is higher by at least a factor of 3 and an NPT value, which is higher by a factor of at least 2 than the corresponding values of the second layer.