Covestro: On the path to industrialisation of the pultrusion process
According to Covestro, the manufacture of vehicle parts made of composite materials instead of steel is a lightweight and therefore sustainable solution that reduces fuel consumption and CO2 emissions. This also applies to commercial vehicles such as trucks, which are used heavily on a daily basis. Carbon Truck & Trailer GmbH (CarbonTT) designs truck chassis from carbon fibre-reinforced composites and has the know-how and various IP rights to manufacture and assemble them.
“The lightweight components also enable commercial vehicle manufacturers to meet the increasingly rigorous European Union limit values,” explained Gerret Kalkoffen, Chairman of the Board of CarbonTT. “Logistics companies can use the vehicle to transport larger loads and thus operate more efficiently. In electric mobility, the lightweight chassis compensates for the weight of the battery and at the same time features simpler assembly and superior crash performance.”
Covestro showcased such a composite component at K 2019. According to the company, it can be produced continuously by pultrusion with a Baydur PUL polyurethane matrix system. “With this system, we are pushing boundaries by providing a number of advantages over conventional materials,” said Benedikt Kilian, Project Manager for Process Development in the Polyurethanes segment at Covestro. “The material properties of the end part also meet stringent OEM specifications while enabling a lighter structure. Within seconds, the Baydur PUL low-viscosity system penetrates millions of carbon fibres perfectly and enables CarbonTT to achieve significant productivity gains.”
The profile design of the composite part was developed and optimised by CarbonTT to meet the mechanical requirements, achieve maximum weight reduction and minimise costs. Covestro said that it supports CarbonTT with its Baydur PUL system and with its expertise in optimal pultrusion processing. Pultrusion runs have been successfully performed to demonstrate the benefits of the PU system and are being expanded. The pultrusion process is a continuous process that can be automated to a high degree and is currently in the process of achieving industrial application. This makes it possible to produce differentiated and complex composite parts extremely efficiently, especially if a suitable polyurethane resin is used, said Covestro.
Compared with other resin systems used for pultrusion, Baydur PUL is said to offer superior component and processing qualities. The mechanical properties of parts with a PU matrix enable customers to develop thin profiles and, where possible, use less complex fibre reinforcement. The viscosity of the system is also very low with high reactivity, which allows customers to produce very efficiently at high throughput rates, said the company.