Cable harnesses are among the most complex assemblies in electric vehicles. Their numerous connectors must be marked in a wide variety of colors for better differentiation during assembly and maintenance. At the same time, they have to be very flame-retardant and mechanically robust. With the PA-6 compound Durethan BKV30FN04, Lanxess, Cologne, has developed a material for these connectors that has already proven itself in numerous series applications – such as in cable harnesses for various electric models of a European-American automobile manufacturer. “In contrast to polyamides, where flame protection is achieved by means of red phosphorus, our halogen-free flame-retardant compound can also be colored in brilliant light colors such as orange (RAL 2003) or yellow,” explains Bernhard Stoll, an expert in plastics in electrical and electronic parts at Lanxess. “Compound and color show a high level of thermal stability. The connectors can therefore be reliably differentiated by color throughout the life of the car. ”The connector is manufactured by Amphenol-Tuchel Electronics GmbH in Heilbronn, a subsidiary of the American Amphenol Group.
Yellow card entry for all colors
The PA-6 compound from Lanxess is characterized by its high level of flame resistance. In the UL 94 fire test carried out by the US testing company Underwriters Laboratories Inc., it achieved the V-0 classification with a test specimen thickness of 0.75 mm. “We have listed the compounds at UL on the Yellow Card in ‘All Colors’, which also includes yellow, orange and blue colors. This saves the processor from having to color them himself and the time-consuming UL certification. He can use our compounds directly and thus reduce his costs, ”says Stoll.
Cable harnesses run throughout the vehicle and bundle the numerous lines of the on-board network for electrical and electronic functions such as power converters, battery charging systems, electric drives or infotainment. Taken together, the cables can quickly reach a length of several kilometers, which is one reason for the heavy weight of cable harnesses. Their complexity makes wiring harnesses very expensive components. This is why your connectors must not break during assembly. “Our compound has high strength and toughness. The connectors can therefore cope with bumps and falls, ”says Stoll. The thermoplastic has good chemical resistance, so that its strength and rigidity hardly decrease when it comes into contact with electrolytes or cooling media. In addition, it is very resistant to leakage currents at high electrical voltages. In orange, for example, it achieves a CTI value (Comparative Tracking Index, IEC 60112) of 600.
Broad processing window
Durethan BKV30FN04 is also used in connectors beyond electromobility – for example in signal transmission and industrial technology. “Here, too, it can be seen that our compound can be injection molded in a stable process within a wide processing window. In addition, the flame retardant additives of the material hardly form any deposits in the tool, which promotes long tool life and efficient production, ”explains Stoll. In addition, in terms of occupational hygiene, PA 6 is easier to handle than corresponding compounds that are flame-retardant with red phosphorus.
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