Berthold, Boehm, Enderele, Groebel, Lueker, Lecht, Schulte
# 1995 Edinburgh
Recently Business Unit Polyethylene of Hoechst AG developed a Ziegler-catalyst-system providing very high catalyst activity even in presence of high hydrogen concentrations. The catalyst is applied to an appropriaie Z-stage-polymerization process. This technology is carried out in a modern, fully automated production plant resulting in products with outstanding quality consistency. By this it is possible to tailor-make high molecular PE-HD pipe resins with excellent perjormance in PE 80 and PE 100 class. Those bimodal pipe resins allow the manufacturing ofpipes with a very high lifetime expectancy. The resins are characterized by a remarkably improved stiffness to toughness relationship. The resistance to Rapid Crack Propagation is as outstanding as the Environmental Stress Crack Resistance. As an advantagefor the manufacture of large diameter pipes a reduction of waN thickness is possible. On the other hand higher safety factors or higher pressure levels can be achieved by maintaining common dimensions. m t h a raw material of these characteristics the pipe manufacterer is able to produce pipes with enhanced inherent safety.
