In a joint project, BASF and STR Automotive were able to use premium components in mass production for the first time thanks to the new Elastolit R 8819 Lightweight material. Compared to conventional production with PU-RRIM materials, this new process offers a significant weight reduction. The usual thickness of the 3 mm component can be reduced to less than 2.5 mm without affecting its treatment, quality or even mechanical properties.
A high-module PU material
The front and rear bumpers of small-series cars are usually made with short fibre-reinforced polyurethane (PU-RRIM) systems with a thickness of 3 mm. Attempts to lighten by reducing the thickness of the component or using a special filling associated with a reduction in material density failed because their mechanical properties (solidity, rigidity, hold and impact resistance) proved insufficient. This procedure also failed during the climate test.
The exchanges between BASF and STR Automotive resulted in a technical solution based on a classic high module PU material that is resistant to high temperatures, rigid and with very good impact resistance.
"Improving the performance of the material matrix allows the designer to create a much thinner component, without compromising on quality," explains Jurgen Schneider of the Technical Development Department of BASF Polyurethanes GmbH in Lemf-rde. Depending on the requirements and applications, Elastolit R 8819 Lightweight can be associated with a variety of loads: standard mineral fiber for components such as rear bumpers, a combination of carbon fiber and mineral fiber for vertical elements with low thermal expansion (e.g. side panels), or a combination of carbon fibers and light hollow glass spheres for the elements for which lightening is a priority.
"Close cooperation with STR Automotive was one of the decisive factors in the successful launch of this new product. Thanks to this innovation specialist, we benefit from a partner who supports the development of materials at an advanced stage for existing components and has brought his expertise in manufacturing and production of these components," says Giuseppe Monaco, Key Account Manager of the Performance Materials division of BASF Italia S.p.A.
For the first set of elements made from Elastolit R 8819 Lightweight, the weight has already been reduced by 600 g per sq m. For the rear panels, this translates into a lightening of up to 1.5 kg. Massimo Cecchini, CEO of STR Automotive, founded in 2002, is pleased with these results. "With this new material and compatible load options, we have a good range of tools that allow us to meet different requirements. For our customers, it is important to obtain high quality components. The relief must not be at the expense of quality and the price-performance ratio must also be balanced," he says.