| abstract |
Polymeric materials, particularly polyethylene (PE) are crosslinked by using a new continuous method based on photo-initiated crosslinking with UV-light. In the method of processing, the polymer, after mixing with suitable crosslinker, photo-initiator, and possible stabilizers, is extruded into a suitable shape whereupon the still warm, soft melt, directly after extrusion ("on line") is crosslinked to a high gel content. New photo-initiators with high solubility in the polymer melt and with low vapor pressure in the melting range of the polymer have been manufactured and are used in the process. The polymer melt is taken through an irradiation unit containing one or more UV-lamps. The method is fast and can be used for crosslinking of e g tape, hot water pipes and electric cable insulation. |