The Next Million Kilometers: Use of PE-RT for Industrial Pipe Applications

Session 4A
9:30

Detlef Schramm, Dow Europe GmbH

The application of PE-RT (Polyethylene of Raised Temperature resistance) industrial pipe applications is discussed. This type of material has been established in hot and cold water (domestic) applications. Due to its unique molecular structure and crystalline microstructure, which provides excellent Long Term Hydrostatic Strength at high temperatures without crosslinking the material, PE-RT is now also used for large diameter pipe for industrial applications.

PE-RT type resins are successfully used in domestic hot and cold water piping systems for most applications. The easy processing and outstanding material properties made these resins also attractive for use in larger dimensions, where regular Polyethylene cannot be used or has temperature limitations. They also compete with high end engineering plastics, offering significant cost savings.

A recently developed PE-RT type material offers still higher long-term strength at high temperature and further improved processability. This combination makes this resin particularly suitable for high temperature applications. An example of the latter is in larger diameter cooling water pipes in power plants. Pipes based on these materials can be connected via heat welding or by the use of mechanical fittings. Furthermore, this material can be used in industrial applications, were the use of traditional Polyethylene is limited due to the temperature resistance and metallic materials suffer from corrosion. The excellent weldability of these materials provides various opportunities to connect also larger dimension pipe – made from other materials, for example regular PE100. Another example of this is the use in multi-layer structured oil pipelines on-shore and off-shore.

This paper presents the material science and product design concepts that govern the high long-term hydrostatic strength at high temperatures. By controlling the molecular structure, the melt rheology and solid state properties can be influenced. This results in a unique balance of processability and hydrostatic strength.

Further discussed are the product features and benefits of PE-RT materials. The paper shows examples of the application range for this type of products, provides details about the testing for chemical resistance and the quality performance of the welding.