Aus der Branche

Auf der diesjährigen JEC World zeigt das STFI Highlights aus dem Carbonfaserrecycling sowie einen neuen Ansatz von hanfbasierten Bastfasern, die als Bewehrung im Leichtbau vielversprechende Eigenschaften mitbringen.

Grünes Snowboard
Auf der JEC World in Paris vom 5. bis 7. März 2024 zeigt das STFI ein Snowboard der Firma silbaerg GmbH mit patentiertem anisotropen Kopplungseffekt aus Hanf und recycelten Carbonfasern mit biobasiertem Epoxidharz. An der Entwicklung des Boards waren neben silbaerg und STFI auch die Partner Circular Saxony - das Innovationscluster für die Kreislaufwirtschaft sowie FUSE Composite und die bto-epoxy GmbH beteiligt. Das grüne Snowboard wurde mit JEC Innovation Award 2024 in der Kategorie „Sport, Freizeit und Erholung“ ausgezeichnet.

VliesComp
Rezyklate in verschiedenen Leichtbaulösungen wieder in den Markt zu bringen, ist das Ziel der im Projekt VliesComp vereinigten Industriepartner Tenowo GmbH (Hof), Siemens AG (Erlangen), Invent GmbH (Braunschweig) und STFI. Beispielhaft wurden dabei unter anderem die Anwendungsfelder „Innovative E-Maschinenkonzepte für die Energiewende“ und „Innovative E-Maschinenkonzepte für die E-Mobilität“ betrachtet. Gezeigt wird auf der JEC World in Paris ein Leichtbaulagerschild für E-Motoren, das auf Basis von Hybridvliesstoffen – einer Mischung aus thermoplastischer Faserkomponenten und recycelter Verstärkungsfasern – sowie auch Vliesstoffen mit 100 % recycelten Verstärkungsfasern hergestellt wurde. Das Lagerschild wurde schlussendlich mit einem Rezyklatanteil von 100 % gefertigt. Die Untersuchungen ergaben, dass im Vergleich zur Variante aus Primärkohlenstofffasern im RTM-Verfahren eine Reduzierung des CO₂-Äquivalents um 14 % bei gleicher Leistung möglich ist. Die Berechnung zur Verwendung des Prepreg-Verfahrens unter Nutzung eines Bioharzsystems zeigt ein Potenzial zur Reduzierung des CO₂-Äquivalents um fast 70 %.

Bastfaserbewehrung
Zur Stabilitätserhöhung im Pflanzenstängel bilden sich im Rindenbereich Bastfasern aus, die den Stengel stützen, aber im Gegensatz zum starren Holz sehr flexibel aufgebaut sind und es ermöglichen, dass schlanke, hohe Pflanzen sich im Wind bewegen können, ohne zu brechen. Ein neues Verfahren gewinnt die Bastrinde des Hanfes durch Schälen. Die daraus erzielten Kennwerte, wie Zug-E-Modul, Bruchkraft und Dehnung, sind vielversprechend im Vergleich mit den am Markt verfügbaren Endlosrovingen aus Flachs. Das Material könnte als Bewehrung im Leichtbau seine Anwendung finden. Das STFI stellt zur JEC World Bewehrungsstäbe aus, die im Pultrusionsverfahren auf Basis biobasierter Bewehrungsfasern aus Hanfbast für mineralische Matrices, zu einem Gewirke verarbeitet wurden.

Increasing energy and resource efficiency in the construction sector will be key to the EU’s ambition of achieving climate neutrality by 2050. By enabling the manufacture of strong, durable and lightweight products, composite materials can help the construction sector improve its environmental sustainability, as well as reduce total lifecycle costs. The latest EPTA industry briefing, Pultruded composites contribute to a more sustainable future for construction, discusses how pultruded composites answer the need for materials offering high performance, faster installation, corrosion resistance and low maintenance.

The report is available to download from the EPTA website.

The future of construction
As one of the largest global users of energy and raw materials, the construction industry is under immense pressure to improve its sustainability. At the same time, it must respond to demands for improved performance and reduced total cost of ownership. New materials will be needed to minimise the use of natural resources, enable a reduction of carbon footprint and facilitate circular economy practices. Choosing the optimum materials required for durability throughout the lifecycle will be increasingly important. A shift to off-site production is also forecast, where factory-controlled environments and automated processes can improve quality control, lower waste, and reduce work on site.

Lightweight pultruded parts can be pre-assembled into modules or complete structures in the factory for faster installation on site. Lightweight profiles lower energy use during transportation and installation, and a longer service life combined with minimal maintenance can deliver a reduced through-life carbon footprint. Pultruded parts such as profiles, gratings, beams, tubes and planks are increasingly found in a range of building, construction and infrastructure applications. Examples include bridge decks, fencing, stairs and handrails, train platforms, cladding, utility poles, modular building concepts, and window frames.

One application offering large growth potential for composites is bridges. Composite bridges are being designed to provide a service life of 100 years and unlike steel bridges do not require regular repainting to protect them from corrosion. Over recent years, pultruded glass fibre composite has become a highly popular choice for pedestrian and cycle bridges. Pre-fabricated ‘easy fit’ bridge decking planks, pre-assembled bridge modules and complete bridge ‘kits’ are now available. Corrosion-resistant composite bridges are ideal for use near water or on the coast, and in remote locations where regular maintenance operations would be difficult. A composite bridge can deliver the same performance as a steel structure with a weight saving of up to 50% or more. This enables more streamlined bridge designs which require less substantial supporting structures and foundations, greatly reducing consumption of materials and energy. Lightweight also results in easier logistics and simplified installation. Pultruded are more easily transported to the construction site, with lower fuel consumption, and easier to move on site, often reducing labour requirements and the capacity of lifting equipment.

A lifecycle approach
As the construction industry looks to the future, the environmental and economic benefits of composite materials linked to easier logistics and installation, durability and low maintenance are becoming increasingly valued. More projects are demonstrating the benefits of composite materials and standards covering the design, fabrication and installation of pultruded profiles are making it easier for the construction industry to use them. With ongoing development and collaboration, pultrusion has the potential to contribute to a more sustainable future for construction and many other industries. EPTA will continue to promote the advancement of pultrusion technology and its applications and foster sustainable practices within the industry.

The European Pultrusion Technology Association (EPTA) has published a report from its latest conference, which focuses on advances in sustainability and recycling.

More than 130 professionals from the global pultrusion community gathered at the 16th World Pultrusion Conference in Paris on 5-6 May 2022. Organised by EPTA in collaboration with the American Composites Manufacturers Association (ACMA), the event featured 25 international speakers sharing insight on market trends, developments in materials, processing and simulation technologies, and innovative pultruded applications in key markets such as building and infrastructure, transportation and wind energy.

‘Bio-pultrusion’:  
Composites based on natural fibres offer a number of benefits, including low density and high specific strength, vibration damping, and heat insulation. The German Institutes for Textile and Fiber Research Denkendorf (DITF) are developing pultrusion processes using bio-based resins and natural fibres. Projects include the BioMat Pavilion at the University of Stuttgart, a lightweight structure which combines ‘bamboo-like’ natural fibre-based pultruded profiles with a tensile membrane.

Applications for recycled carbon fibre (rCF):
The use of rCF in composite components has the potential to reduce their cost and carbon footprint. However, it is currently used to a limited extent since manufacturers are uncertain about the technical performance of available rCF products, how to process them, and the actual benefits achievable. Fraunhofer IGCV is partnering with the Institute for Textile Technology (ITA) in the MAI ÖkoCaP project to investigate the technical, ecological and economic benefits of using rCF in different industrial applications. The results will be made available in a web-based app.

Circularity and recycling:
The European Composites Industry Association (EuCIA) is drafting a circularity roadmap for the composites industry. It has collaborated with the European Cement Association (CEMBUREAU) on a position paper for the EU Commission’s Joint Research Centre (JRC) which outlines the benefits of co-processing end-of-life composites in cement manufacturing, a recycling solution that is compliant with the EU’s Waste Framework Directive and in commercial operation in Germany. Initial studies have indicated that co-processing with composites has the potential to reduce the global warming impact of cement manufacture by up to 16%. Technologies to allow recovery of fibre and/or resin from composites are in development but a better understanding of the life cycle assessment (LCA) impact of these processes is essential. EuCIA’s ‘circularity waterfall,’ a proposed priority system for composites circularity, highlights the continued need for co-processing.

Sustainability along the value chain:
Sustainability is essential for the long-term viability of businesses. Resin manufacturer AOC’s actions to improve sustainability include programmes to reduce energy, waste and greenhouse gas emissions from operations, the development of ‘greener’ and low VOC emission resins, ensuring compliance with chemicals legislation such as REACH, and involvement in EuCIA’s waste management initiatives. Its sustainable resins portfolio includes styrene-free and low-styrene formulations and products manufactured using bio-based raw materials and recycled PET.