LANXESS offers secure connections in numerous colours

Cable harnesses are among the most complex assemblies found in electric vehicles. Their numerous connectors not only all have to be marked in different colours to indicate a whole range of functions and support assembly and maintenance, but they also have to be highly flame-retardant and mechanically robust.

With the polyamide 6 compound Durethan BKV30FN04, LANXESS has developed a material for these connectors that has already been tried and tested in numerous series applications – including cable harnesses for electric models produced by a European-US automotive manufacturer.

Bernhard Stoll, an expert in the use of plastics in electrical and electronic components at LANXESS, said: “In contrast to polyamides that are flame-protected with red phosphorous, our halogen-free flame-retardant compound can also be dyed with bright, vivid colours like orange (RAL 2003) and yellow. The compound and colour exhibit a high level of heat stability, which means that the different connectors can be easily and reliably distinguished throughout the vehicle’s entire service life.”

The connectors are manufactured by Amphenol-Tuchel Electronics GmbH in Heilbronn, Germany, a subsidiary of the US-based Amphenol Group.  

The polyamide 6 compound from LANXESS is characterised by its outstanding flame-retardant properties. In the UL 94 flammability test of the US testing institute Underwriters Laboratories Inc., it achieved the V-0 classification (test body thickness: 0.75 mm). 

Stoll added: “We have the compounds listed by UL on the Yellow Card under ‘All Colors,’ which also includes colours like yellow, orange and blue. This means that processors will not have to color the product themselves or have the product undergo the time-consuming UL certification process.”  

The total length of the cables can reach several kilometers. The complexity of cable harnesses makes them extremely expensive components, which is why the connectors must not break during installation.

The thermoplastic is highly resistant to chemicals, which means that its strength and stiffness are barely compromised upon contact with electrolytes or coolants. It also exhibits excellent tracking resistance, achieving a CTI (Comparative Tracking Index, IEC 60112) value of 600 in orange. 

Durethan BKV30FN04 is also used in signal transmission technology and industrial engineering. The compound has proved suitable for injection moulding in a stable process within a wide processing window. Its flame-retardant additives leave hardly any deposit in the mould, which helps to ensure a long tool service life.