# 2010 Vancouver
Developments in catalyst and process technology have resulted in a new, highly differentiated product family based on ethylene-a-olefin copolymers. This paper reports the key attributes of those materials. These polymers form the basis for a new class of Polyethylene materials: PE-RT (Polyethylene of Raised Temperature resistance) for hot water pipe applications. PE-RT is suitable for use in all hot water pipe applications — and has a track record of more than 28 years‘'*), The uniqueness of these materials is that they do not need to be cross-linked to deliver good Long Term Hydrostatic Strength (LTHS) at high temperatures.
This results in significant processing advantages over cross-linked PE (PEX) systems and allows therefore the use in larger diameter industrial applications.
The hot and cold water pipe market has traditionally been dominated by copper and galvanized steel pipe. Over the last 25-30 years plastics have made significant inroads in this application. Although copper is still the dominant material in most parts of the world, consumption of plastics in hot water pipe applications is estimated at 180,000 mt globally, of which half is used in Europe (50% market share).
The advantages of polyolefin plastics are that they exhibit no corrosion and are resistant to many chemicals. They are flexible and easy to install (as "endless" pipe), are leak-tight by fusion welding and are light in weight which makes them easy to transport and handle on site.
Plastics suitable for domestic pipes are PE (polyethylene), PP-R (random PP copolymers) and PB (polybutene). Due to concerns over service temperature limitations, PE was originally not considered suitable for this application, compared to PP-R and PB, which have inherently better high temperature performance.
However, cross-linking of polyethylene allows an improved upper service limitation. Hence cross-linked PE pipes (PEX) meets the desired long term hydrostatic strength requirements at elevated temperature. The better flexibility, high thermal conductivity, good economics and inert behavior provided by PE, resulted in the fast growth of PEX, among other material options. Cross-linked PE is currently the leading plastic material used in the hot and cold water market.