Mecaplast, a global automotive supplier founded in 1955 in Monaco, is pioneering interesting new processes for creating lightweight automotive components.
In a project called PLUME that is partially funded by the French government, the weight of interior and exterior components can be reduced by as much as 50%.
These steps are involved:
- A specially formulated polypropylene with chemical blowing agent are injected into a mold cavity, which then partially opens as the top layer becomes solid; and
- When the movable section of the cavity moves back, pressure drops and the chemical blowing agent then expands, creating a foamed area in the part.
Honda and Toyota use a similar process with a talc-filled polypropylene, which limits surface finish. Talc is also heavy. Mecaplast claims that the surface of its
components are filler-free, allowing further weight reduction, good surface appearance and no decrease in mechanical properties.
The new filler technology is interesting.
The key is a high performance reinforcing agent called Hyperform HPR-803i from Milliken (Spartanburg, SC). Mecaplast has used a TPO compound TPO (elastomer-modified polypropylene) using talc and Hyperform HPR-803i to mold prototype B-pillar covers that it normally supplies in a conventional 20% talc-filled TPO. Total additive content around 10% by weight.
The prototype parts weighed 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.
Nathalie Samson-Maguet, Mecaplast’s research & innovation manager, says final product costs are the same: higher costs for Hyperform HPR-803i are cancelled out by the reduced total material requirement. The compound is produced by Inno-Comp in Hungary.
One critical aspect of the specially developed polypropylene is high melt flow (MFI is greater than 50 g/10 min). The resin supplier is Sumika Polymer Compounds, which is part of Sumitomo Chemical.
Other partners in the $3 million development project are mold maker Cero (Nantes, France); the polymer science research laboratory IMP at the University of Saint-Etienne; and Cemef, a research laboratory.
Tests will be performed on a tailgate interior trim and exterior beltline moldings that will be produced in a grained surface that will require no painting and another version that will be paintable.