Sweden's Plastal Group AB helped convince Mercedes-Benz to switch to polypropylene for the body panels on its latest Smart ForTwo car, and has taken home an award for its efforts.
The Society of Plastics Engineers Central Europe on Oct. 22 awarded the first prize for body exterior applications to KungÃ¤lv-based Plastal for use of a Borealis Daplen ED230HP compound for molded-in-color body panels of the latest Smart ForTwo model.
Mercedes introduced the electric Smart ForTwo to the market in January with the first-ever molded-in-color automotive exterior panel in polypropylene with a one-layer protective clear lacquer coating.
The 20 percent mineral-filled, elastomer-modified polypropylene compound has replaced the traditional clear-coated Smart polycarbonate/polybutylene terephthalate body panel that had been used on the Smart ForTwo.
When presenting the award, Rudolf Fernengel, chairman of SPE's Central Europe division, said the Borealis material performs better than PC/PBT in the application due to its lower specific gravity and a 0.1-millimeter thinner wall section, resulting in 20 percent weight savings. Also, the new material's flow enables shorter flow paths and a less-complex hot-runner system. Fernengel added that color streaking - which occurs with PC/PBT and requires some molded-in-color panels to be painted - has been eliminated, together with some blister development, Fernengel said.
Schneider Form, Karl Krumpholz GmbH & Co. KG and R.S. Mecanica made the tools for the PP panels. As with the PC/PBT panels, Plastal (formerly Dynamit Nobel Kunststoff) injection molds the parts on Krauss-Maffei machines at the Smart site in Hambach, France.