The use of the colour orange to identify live, plastic-sheathed components is becoming well-established in electric vehicles, but it is a challenge to develop orange compounds that exhibit high colour stability over the long term. LANXESS has now succeeded in doing just this.
The specialty chemicals company offers a wide range of orange-coloured polyamide and polybutylene terephthalate (PBT) compounds for precisely these kinds of high-voltage applications. The products will be coloured in the highly vivid RAL 2003 (LANXESS colour code 200849) tone. Another colour variant is almost ready to be introduced. The compounds will be available both in a standard formulation and with thermal stabilisation, which will help to improve colour stability when the component is exposed to heat.
Julian Haspel, Manager of the e-Powertrain Team, which has recently been established in the LANXESS High Performance Materials (HPM) business unit, said: “We want to provide a Yellow Card listing from the US testing organisation Underwriters Laboratories for all the compounds we offer, which means that the molders will not have to colour the product themselves nor to undergo the time-consuming UL certification process. They can deploy the compounds instantly, which helps to cut costs.
“The standard versions of the compounds still exhibit sufficiently high colour stability after 1,000 ageing hours at 130°C. “The thermally stabilised material settings even have the potential to withstand 1,000 hours at 150°C without the orange colour changing significantly.”
Among the first product types to feature the new colour are the glass-fibre-reinforced, halogen-free flame-retardant polyamide 6 compounds Durethan BKV20FN01, BKV30FN04 and BKV45FN04. A special feature here is the Durethan BKV45FN04, which is 45% glass-fibre-reinforced yet still easy-flowing. It passes the UL 94 flammability test with the top classification V-0 with a test specimen thickness of 0.4mm.
Haspel added: “Its high stiffness and strength make the material ideal for not only structural components in the battery such as cell frames and end plates, but also large, high-voltage connectors requiring high mechanical stability.”
The compound is also characterised by high tracking resistance at high electrical voltages. This also applies to the two other polyamide variants. For example, orange-coloured Durethan BKV30FN04 has a CTI value (comparative tracking index, IEC 60112) of 600.
Durethan BG30XH3.0 remains the perfect choice for exceptionally low-warpage structural plastic. It has been reinforced with a mixture of glass fibres and glass microbeads. The H3.0 thermal stabilisation is copper- and halide-free, which prevents electrical corrosion in the vicinity of live metal parts.
The hydrolysis-stabilised, glass-fibre-reinforced PBT compound Pocan BF4232HR is also part of the new product series. In the colour orange, it also achieves V-0 classification in the UL 94 flammability test with a test specimen thickness of as little as 0.4mm.
The high hydrolysis resistance is demonstrated in the long-term test SAE/USCAR-2 Rev. 5 of the American Society of Automotive Engineers (SAE), which was designed specially for plug connectors. Haspel: “Our PBT fulfilled requirements up to Class 5, the strictest variant of this test.”
LANXESS will continue to expand its range of orange-coloured compounds. “We develop application-specific, customised material variants in accordance with market requirements,” said Haspel.
At HPM, the new compounds form part of a development focus on new forms of mobility. In addition to halogen-free flame-retardant polyamides, whose additive packages are specially designed for electromobility applications, HPM also offers, for example, highly heat-conductive polyamide six versions and electromagnetically shielding compounds.