Development of cross-linked polymer material recycling technology by supercritical water

Abstract

Because of its excellent insulating characteristics cross-linked polyethylene has been used widely as an insulating material for electric wires and cables. However, from the viewpoint of recycling, a thermal recycling process such as liquefaction becomes the main technique, because cross-linking makes it difficult to plasticize although cross-linked polyethylene is a high quality material with quite a small amount of foreign material and impurities. We developed a material recycling technique that cuts cross-linking parts of cross-linked polyethylene by using super-critical water technology and makes it possible to reuse them as a thermoplastic resin. As a result, it was possible to re-cross-link the thermoplastic polyethylene that was obtained by super-critical water processing, and the resulting characteristics were confirmed to be nearly equivalent to those before processing.