French automotive plastics component producer Mecaplast says it can make significant weight reductions in injection moulded TPO parts by partially replacing talc filler with Hyperform® HPR-803i high performance reinforcing agent from Milliken. As proof, Mecaplast has used a TPO compound containing a mix of talc and Hyperform HPR-803i (total additive content around 10% by weight) to mould prototype B-pillar covers that it normally supplies in a conventional 20% talc-filled TPO (elastomer-modified polypropylene). The prototype parts weighed 524 g, 7% less than the commercial parts. The compound has a density of 0.98 g/cm3, which compares with 1.04 g/cm3 for a 20% talc-filled TPO with similar mechanical properties.
The final product costs are exactly the same: Hyperform HPR-803i costs more than talc, but this is cancelled out by the reduced total material requirement. Car drivers will benefit because they will use less fuel. The savings achievable by using Hyperform HPR-803i in B-pillar covers will be relatively small, but Samson-Maguet says Hyperform HPR-803i can also be used to reduce weight in larger parts such as C-pillars and sill panels. Mecaplast plans to use compounds containing Hyperform HPR-803i for this kind of parts. Nathalie Samson-Maguet says that for a typical C-segment car, use of compounds containing Hyperform HPR-803i in these parts alone could yield a total weight saving of at least 225 g, leading to a potential reduction in carbon dioxide emissions of 0.022 g/km. The EU recently set new standards for CO2 emissions for cars. It has set a maximum of 120g/km on average by the end of this year, with a further reduction to 95g/km on average by 2020. Lightweighting will be an important weapon for auto makers in helping them achieve these targets. In addition to reducing part weight, it improves scratch resistance. This is important as the B-pillar covers are normally installed in the car unpainted, and get their colour from masterbatch.