German polymer company Covestro (Leverkusen; www.covestro.com) – the former Bayer MaterialScience – in partnership with automotive manufacturers, has developed “Baydur 71IF36”, a PU matrix system for carbon fibre structural components. The carbon-fibre reinforced PU composites have three times the energy absorption of comparable resins, providing an extremely high level of safety for vehicle occupants in the event of a collision, Covestro said. The carbon fibre content is approximately 54% by volume.

“We developed the polyurethane system with high-profile partners in the automotive industry and optimised it for the latest requirements,” said Detlef Mies, Covestro’s RTM composites expert. He added that prototypes made by Covestro’s partner ThyssenKrupp had performed extremely well in testing.

Covestro said car makers and direct suppliers also benefit from the high productivity rate which is achieved by the high-pressure resin transfer moulding (HP-RTM) process. In the HP-RTM process, wovens or fabric with oriented carbon fibres are laid in the mould. Then, the low-viscosity PU system is injected into the closed mould under high pressure. Because of the system’s high reactivity, the composite cures rapidly and fully. Covestro said cycle times are just a few minutes – ranging from one to five depending on the size of the final product – with consistently high quality.