Textination Newsline

In collaboration with industrial partners, researchers at the Fraunhofer WKI have developed a vehicle underbody made from natural fibers and recycled plastics for automotive construction. The focus at the Fraunhofer WKI was directed at the development of the materials for injection molding as well as the hydrophobization of flax and hemp fibers for natural-fiber-reinforced mixed-fiber non-wovens.

The component fulfills the stringent technical requirements in the underbody area and could replace conventional lightweight vehicle underbodies in the future. With this development, the climate and environmental balance is optimized throughout the entire product life cycle.

The project partners Fraunhofer WKI, Thuringian Institute for Textile and Plastics Research (TITK), Röchling Automotive SE & Co. KG, BBP Kunststoffwerk Marbach Baier GmbH and Audi AG have succeeded in developing a sustainable overall concept for vehicle underbodies. The researchers have thereby taken a challenging component group with a high plastic content and made it accessible for the utilization of natural materials. Until now, natural-fiber-reinforced plastics have predominantly been used in cars for trim parts without significant mechanical functions. Structural components such as vehicle underbodies are, however, exposed to enormous loads and place high demands on the bending and crash behavior of the material. In modern lightweight vehicle concepts, high-performance materials made from glass-fiber-reinforced plastics are therefore utilized.

The project team was able to replace the glass fibers with natural materials such as flax, hemp and cellulose fibers and to produce underbody components with a natural-fiber content of up to 45%. In the area of polymers, virgin polypropylene was completely dispensed with and solely recyclates were utilized. All the challenges associated with this material changeover – both the lower initial mechanical properties of the materials and the temporally restricted processing windows – were solved by means of skillful compound combinations.

At the Fraunhofer WKI, materials for injection molding were developed. “Natural-fiber injection-molded compounds have so far been known primarily for their increased strength and stiffness compared to non-reinforced polymers. In the development of the vehicle underbody, we have furthermore succeeded in fulfilling the stringent requirements for low-temperature impact strength through an innovative combination of selected post-consumer recyclates (PCR) as a matrix and natural fibers of varying degrees of purity - without forfeiting the required stiffness and strength,” explained Moritz Micke-Camuz, Project Manager at the Fraunhofer WKI.

Within the framework of the development, fiber-composite components made from natural-fiber-reinforced mixed-fiber non-wovens (lightweight-reinforced thermoplastic, LWRT) were realized for the first time at the TITK and at Röchling. The developed product not only fulfills the mechanical requirements: It also withstands in particular the challenges posed by the humid environment in which it is used. For the hydrophobization of flax and hemp fibers for LWRT components, a continuous furfurylation process was developed at the Fraunhofer WKI. Through furfurylation, moisture absorption can be reduced by up to 35 percent without impairment of the bending strength of the subsequent components. The furfurylated fiber material can also be easily processed on a non-woven production line.

The prototype components produced were subsequently extensively tested both at component level and in road tests. Amongst others, the vehicles from the VW Group’s new “Premium Platform Electric” (PPE) were used for this purpose. Long-term experience has already been gathered within the framework of the series testing. The gratifying result of these tests: The newly developed biocomposites fulfill all standard requirements for underbody components and have proven to be suitable for series production. Neither the use of natural fibers nor of (post-consumer) recyclates leads to a significant impairment of the properties.

One major advantage of the innovation is the significantly improved carbon footprint: Compared to series production, 10.5 kilograms of virgin material (PP/glass fiber) can be replaced by 4.2 kilograms of natural fibers and 6.3 kilograms of post-consumer recyclate. As a result, CO2 emissions during production, use and product life have been reduced by up to 40 percent.

Within the scope of the development project, an innovative, holistic overall concept for vehicle underbodies, including recycling with cascading re-use of the components, was developed. From a technical point of view, vehicle underbodies can be manufactured entirely from the new, high-performance lightweight bio construction material in the future.

The project was funded by the German Federal Ministry for Economic Affairs and Climate Action (BMWK) via the project management organization TÜV Rheinland.

• Bcomp wins BMW Group Supplier Innovation Award in the category “Newcomer of the Year”

The sixth BMW Group Supplier Innovation Awards were presented at the BMW Welt in Munich on 17 November 2022. The coveted award was presented in a total of six categories: powertrain & e-mobility, sustainability, digitalisation, customer experience, newcomer of the year and exceptional team performance.

Bcomp won the BMW Group Supplier Innovation Award in the Newcomer of the Year category. Following a successful collaboration with BMW M Motorsport for the new BMW M4 GT4 that extensively uses Bcomp’s powerRibs™ and ampliTex™ natural fibre solutions and BMW iVentures recently taking a stake in Bcomp as lead investor in the Series B round, this award is another major step and recognition on the path to decarbonizing mobility.

“Innovations are key to the success of our transformation towards electromobility, digitalisation and sustainability. Our award ceremony recognises innovation and cooperative partnership with our suppliers – especially in challenging times,” said Joachim Post, member of the Board of Management of BMW AG responsible for Purchasing and Supplier Network at the ceremony held at BMW Welt in Munich.

BMW first started to work with Bcomp’s materials in 2019 when they used high-performance natural fibre composites in the BMW iFE.20 Formula E car. From this flax fibre reinforced cooling shaft, the collaboration evolved and soon after, the proprietary ampliTex™ and powerRibs™ natural fibre solutions were found successfully substituting selected carbon fibre components in DTM touring cars from BMW M Motorsport. By trickling down and expanding into other vehicle programs, such developments highlight the vital role that BMW M Motorsports plays as a technology lab for the entire BMW Group. This continues in the form of the latest collaboration with Bcomp to include a higher proportion of renewable raw materials in the successor of the BMW M4 GT4.

With the launch of the new BMW M4 GT4, it will be the serial GT car with the highest proportion of natural fibre components. Bcomp’s ampliTex™ and powerRibs™ flax fibre solutions can be found throughout the interior on the dashboard and centre console, as well as on bodywork components such as the hood, front splitter, doors, trunk, and rear wing. Aside from the roof, there are almost no carbon fibre reinforced plastic (CFRP) components that were not replaced by the renewable high-performance flax materials. “Product sustainability is increasing in importance in the world of motorsport too,” says Franciscus van Meel, Chairman of the Board of Management at BMW M GmbH.

Bcomp is a leading solutions provider for natural fibre reinforcements in high performance applications from race to space.

The company started as a garage project in 2011 with a mission to create lightweight yet high performance skis. The bCores™ were launched and successfully adopted by some of the biggest names in freeride skiing. The founders, material science PhDs from École Polytechnique Fédérale de Lausanne (EPFL), used flax fibres to reinforce the balsa cores and improve shear stiffness. Impressed by the excellent mechanical properties of flax fibres, the development to create sustainable lightweighting solutions for the wider mobility markets started.

Flax is an indigenous plant that grows naturally in Europe and has been part of the agricultural history for centuries. It requires very little water and nutrients to grow successfully. In addition, it acts as a rotational crop, thus enhancing harvests on existing farmland. Neither cultivation nor processing of the flax plants requires any chemicals that could contaminate ground water and harvesting is a completely mechanical process. After harvesting the entire flax plant can be used for feed, to make oil and its fibres are especially used for home textiles and clothing. The long fibre that comes from the flax plant possesses very good mechanical properties and outstanding damping properties in relation to its density, making it especially suited as a natural fibre reinforcement for all kinds of polymers.

The harvesting and processing of flax takes place locally in the rural areas it was grown in. Using European flax sourced through a well-established and transparent supply chain it allows to support the economic and social structure in rural areas thanks to the large and skilled workforce required to sustain the flax production. When it comes to the production of technical products like the powerRibs™ reinforcement grid, Bcomp is investing in local production capacities close to its headquarters in the city of Fribourg, Switzerland, thus creating new jobs and maintaining technical know-how in the area. The production is built to be as efficient as possible and with minimal environmental impact and waste.

Further strengthening the local economy, Bcomp aims to hire local companies for missions and with the headquarters being located in Fribourg’s “Blue Factory” district, Bcomp can both benefit from and contribute to the development of this sustainable and diverse quarter.