BMW has employed Clariant Hydrocerol chemical foaming agents (CFAs) in the dashboards in almost all of their vehicles, including the 3 series and 5 series. The additive not only reduces the weight of the dashboards, but also improves mechanical properties like bending strength -- the ability to withstand shock loading during a collision for instance. The project is a key component in the automaker’s effort to reduce vehicle weight, improve fuel economy and cut the amount of polymer material used.

“Hydrocerol chemical foaming additive masterbatches play a critical role in a Clariant-wide program to support a more sustainable plastics industry,” explains Laura Carrillo, Clariant’s Head of Market Segment Automotive in Europe. “According to published reports, BMW was able to reduce the weight of their vehicle dashboards by 20%, with our Hydrocerol. This weight reduction is important as part of the overall lightweighting strategy that vehicle producers need to have in place to meet the stringent emission reduction targets required by legislation. Every kg reduced has a positive contribution to lower fuel consumption and thus reduces CO2 emissions to the atmosphere”

Added to plastics during processing, Hydrocerol is activated by heat and releases gas. This gas forms a cellular foam structure from inside while the outer skin remains solid so that the foam is not visible from outside. Because the gas displaces the polymer, less plastic is needed to produce an acceptable part. Hydrocerol can be processed on almost any commercially available injection molding unit. In BMW’s case, the density reduction was especially dramatic because CFAs were used in combination with core-back technology – a process that opens the mold slightly to further reduce pressure and allow the foam core to expand.

Hydrocerol offers other processing advantages too. In contrast to conventional molding, it is not necessary to use holding pressure for foaming since pressure would suppress the foam formation. This results in energy savings due to lower cycle times and lower clamping forces needed.