Schemm, Van de Vliet, Koennecke, Grasmeder
Hot Water & Industrial Applications # 2004 Milan
Polybutene-1 (PB-1) is a relatively unexplored polyolefin which shares many features in common with conventional polyolefins like polypropylene and polyethylene, while at the same time offering versatility, value and opportunity through a range of properties not usually associated with this type of resin. Pipes made from PB-1 have been in the market since the mid 1960’s. Due to the strategic importance of PB-1 to Basell’s busines portfolio, the company developed an innovative process technology using a Ziegler-Natta catalyst system to produce PB-1. Since 2003 a 45 KT plant using this technology has been in operation at Moerdijk, The Netherlands. The new technology has allowed Basell to improve on PB-1 properties and has resulted in a new generation of PB-1 resins for pipe applications. When applying the MRS classification used for conventional polyolefins (20°C, 50 yrs), the new generation PB-1 could be classified as PB 140. For a plastic pipe producer, a stronger resin can result in a substantial material saving, hence a lower production cost; for the installer, a stronger resin can result in a lighter pipe combined with a comparable creep performance and even greater flexibility. The flexural modulus of the old and new generation materials is similar, allowing for fast installation speed and a limited requirement for fittings. For small diameter pipe, flexibility is an important installation advantage (e.g. wall heating application); for larger diameter pipe applications, a “flexible” pipe can offer specific advantages. Together with our customers we have evaluated the weldability of the different PB-1 products and found them to be similar. With PB-1 being used by our customers in both extrusion and injection moulding, fittings from PB-1 can also be produced, resulting in a wide variety of available jointing techniques. These go from the classical compression or crimp fittings, over push-fit systems, to socket- and electrofusion fittings. Local traditions and specific installation requirements appear to define the jointing technique used. As PB-1 piping systems developed by our customers can be made out of a single material it makes them potentially easily recyclable. PB-1 can be viewed as an environmental friendly material for other reasons too; less weight per meter; the molecular architecture of the polymer remains essentially unchanged through extrusion and injection moulding to final transport of water in an installation, just the form is different; and let us not forget its mechanical performance, an indicator of its durability in service. As we are just about to start to explore the boundaries of our new technology, we consider the properties of the “next generation” PB-1 materials as a starting point. We continue to work on improving the material’s performance to meet specific customer and market requirements in a multitude of pipe applications developed by our customers, focused on promoting the replacement of traditional materials and ensuring sustainable growth .
