While composites, in general, offer a number of characteristics that make them the go-to choice of material across various industries, they have one considerable drawback: the lack of easy recyclability. They consist of different materials, which are difficult to separate at the end of life. Covestro’s Maezio brand of continuous fiber-reinforced polycarbonate composites is no exception.
These composites combine carbon fiber with a thermoplastic — polycarbonate — as the substrate material, yielding composite uni-directional tapes that can be laminated at different angles to form sheets tuned to provide a specific mechanical performance. The tapes are lightweight, offer high strength and exceptional design flexibility and versatile processing options for production at scale.
To date, however, Covestro has been unable to recycle the waste generated during the production of the tapes. This waste, however, is also a valuable raw material - the reason the company has now sought out recycling specialist carboNXT as a new partner.
CarboNXT, which last year was acquired by Mitsubishi Chemical Advanced Materials, has developed a process that allows the waste to be processed on an industrial scale. Its pyrolytic technology allows the carbon fiber to be recycled while maximally retaining its mechanical properties and without damaging the surface structure. The process yields recycled carbon fiber with a high degree of purity that can be customized to specification and recompounded into new products.
At carboNXT, the composite production waste produced at Covestro is recycled back into its constituent parts, which can then be reprocessed into virgin-like materials and reused in other products, said Lisa Ketelsen, Head of Thermoplastic Composites at Covestro.
"Our company has many years of experience in recycling carbon fiber-reinforced thermoplastics and has the necessary plant technologies to process such waste,” noted Tim Rademacker, general manager at Mitsubishi Chemical Advanced Materials and responsible for the carbon fiber recycling business. "From the processed waste, we produce high-quality new compounds of carbon fiber-reinforced polycarbonate for Covestro at CarboNXT."
Demand for recycled products is high, not just because they are valuable raw materials, but also because more and more industrial customers and consumers are looking for more sustainable products. The project will now be further developed to market maturity by Covestro, Mitsubishi Chemical Advanced Materials and possibly other partners.