New Technologies # 2004 Milan
Silane crosslinking is one of the major methods used commercially today to bring about crosslinking of pipes. However, to achieve reasonable crosslinking rates it is necessary to add a catalyst masterbatch at extrusion. In addition some kind of post extrusion treatment at elevated temperature is necessary. Catalyst systems used in the pipe industry have all been based on tin, usually di-butyl-tin-di-laurate (DBTL). The tin catalyst and the post extrusion treatment enable the pipe to achieve the 65% degree of crosslinking required by the specification within a few hours for a standard plumbing pipe. This should be compared to several months needed to crosslink at ambient conditions. There are however some drawbacks connected with the post treatment of the pipes, e.g. cost for the handling of an extra production step, investment in equipment and space for hosting the equipment. A new catalyst system (Ambicat) for silane PE-X pipe manufacturing was recently launched on the market. By using this novel technology there are possibilities to avoid the previously mentioned drawbacks. This technology allows desired crosslinking to take place within a week at ambient conditions. In combination with new innovative base graft materials very flexible piping can be produced and still meet the ISO/CEN and DIN standards for HDPE-X. It is foreseen that this material/catalyst concept would be particularly attractive for plumbing and heating pipes, a variety of multilayer pipes and novel pipeline renovation solutions. A short overview on new high strength silane materials is also given.