Themal Demands

The foil-shielded cable with a conductive core for connecting shows specific electrical properties and fulfils increased thermal demands. The core and jacket materials must conform to the thermal requirements of temperature class D pursuant to the ISO 6722 automotive standard, which equates to a continuous use temperature of 150 °C across its service life (3,000 hrs). This is why we use the high-performance material ETFE (a fluoropolymer) for the core insulation. It boasts excellent thermal, mechanical and chemical durability.

Electron-beam crosslinking

An integrated conductive core contacts the aluminium foil, which serves as shielding with 100% coverage. A special feature is that the material of the conductive core, polypropylene (PP), also withstands the continuous use temperature of 150 °C – a LEONI unique selling point: Up to now, temperatures of 105 °C to a maximum of 125 °C were the norm. The flame-retardant jacket material consists of (electron-beam) irradiation cross-linked polyethylene (PE) where we did without DecaBDE-based flame retardants. The advantages of this separate crosslinking process are maximum extrusion speed (regardless of the required crosslinking speed) as well as the recycling of the waste material not crosslinked. Moreover, and in contrast to silane crosslinking, this does not require an activator, meaning that no ‘foreign substance’ is added to the material. Electron-beam crosslinking is therefore a method by which certain polymers can be given the properties of comparatively expensive, usually difficult-to-process high-performance polymers. The approval that LEONI recently received from VW for this special cable is a milestone. We are able to tailor further solutions to individual customer requirements in the > 150 °C temperature range.

  • Physical crosslinking (vulcanisation): Reaction occurs ina steam tube under defined conditions in terms of temperature, pressure and humidity
  • Silane crosslinking: on standard extrusion lines, compound with added activator for crosslinking in a climatechamber under defined conditions
  • Electron-beam crosslinking: a very sophisticated process, requires special equipment. Here, standard extrusion is followed by a process that provides the energy for three-dimensional linking of the molecular chains. High-energy beta rays, which are electrically generated in electron-beam accelerators, trigger chemical reactions in the polymer. Outcome: an increase in the molecular bonds.