The project partners CFK-Valley Stade Recycling GmbH & Co. KG, Wischhafen, and the Lüdenscheid Plastics Institute developed a process by which the carbon fiber contained in composite materials waste, production waste or “end- of-life” products can be recycled and transferred to new, high-quality carbon fiber products.
For a wide range of applications – some of which involve the aviation-, wind power- and leisure industries, but the automobile manufacturing industry as well – carbon fiber composites (CFK) are being increasingly used. When traditional fiberglass is replaced by carbon, product weight savings of up to 25 % can be achieved. However, the manufacture of carbon fiber is highly energy-intensive and expensive, and in the manufacture of CFK components 10–30 % waste loss is generally unavoidable. Therefore it is desirable to recover the recyclable carbon fiber contained in the waste material.
This has been done by CFK-Valley Stade Recycling GmbH & Co. KG, Wischhafen, in cooperation with the Lüdenscheid Plastics Institute (Kunststoff-Institut Lüdenscheid): the project partners developed a process by which the carbon fiber contained in composite materials waste, production waste or “end- of-life” products can be recycled and transferred to new, high-quality carbon fiber products. The CFK waste is first treated in such a manner that it can be processed in a pyrolysis installation. Through special process control the polymer matrix is pyrolized and the carbon fiber is recovered in the form of loosely intertwined, two-dimensional bundles.
The subsequent associated challenge was to put the recycled fiber into a form suitable for further processing. The solution was found to be grinding the fiber to a fine consistency and compacting it into small fiber balls. These fiber balls are free-flowing and can be introduced into new compounds dust-free and, therefore, used in fiber-reinforced plastics. The compounds manufactured thus can be further processed in injection molding- and extrusion procedures.
This project was funded by the Deutsche Bundesstiftung Umwelt (DBU). Read more: https://www.dbu.de/123artikel36938_2430.html
Foto: CFK Valley, Stade