A polyurethane foam system from BASF has reportedly enabled for the first time mass-production of an exterior car part featuring a honeycomb sandwich structure with a class-A film.
The roof module in the standard model of the new smart fortwo consists of a paper honeycomb and two surrounding glass fiber mats. These are sprayed in an impregnation process with the low-density, thermally activable Elastoflex E 3532 and pressed together with a solid-colored class-A film. A single operation thus produces a roof module which is around 30 percent lighter than the standard roof on the previous model - but retains the same strength and flexural rigidity. The lightweight roof was developed by Fehrer Composite Components (Großlangheim, Germany).