Fibers represent major processing challenges, especially in recycling operations. Yet there are solutions for a wide range of applications on the horizon, thanks to the FiberXpert feeder and basic research performed by Brabender Technologie.
Take the example of carbon fibers – manufacturing carbon fiber panels often generates a great deal of waste, which needs to be disposed of. Dr. Rudolf Emmerich and Dr. Jan Kuppinger from the Fraunhofer Institute for Chemical Technology (ICT) wrote in a paper published in 2014: “The use of preforms to manufacture CFRP components using the Liquid Composite Moulding (LCM) method generates up to 40 percent waste, which also entails a considerable commercial loss.” Given that carbon-reinforced materials are being used more and more frequently, both environmental and commercial pressures are increasing. The problem is that shredding these panels produces flakes and fibers, the mixed consistency of which makes feeding extremely difficult.
Natural fibers tell a similar story. They too are used as a renewable raw material to reinforce plastics. But here too feeding has to date been very difficult. Just like with carbon fibers, mechanical interference often results in the formation of product bridges when natural fibers are processed, meaning the fibers do not reach the feed screw. “These products do not flow of their own accord but have to be conveyed”, Jochen Keesen, Head of Brabender Technologie’s Technical Center, explains. “Traditional stirring agitators or vibration cannot work with these materials.”
The same applies to PP and PET flakes or other shredded materials like bottle flakes (shredded PET bottles). Here an intermediate recycling step can be removed if the flakes can be fed directly. Previously flakes have had to be processed into regranulate material before they can be reintroduced into the recycling loop.
Brabender Technologie has looked in to this problem and has developed a device, the FiberXpert, whose design, screw profiles, agitator configuration and output provide solutions to these various problems. “We have already received plenty of inquiries from end users, manufacturers of fibers and flakes as well as from extruder manufacturers and compounders. Successful trials have already been conducted,” Bernd Hüppmeier, D /A / CH Sales Manager at Brabender Technologie, states.
A testing line is to be reserved for this feeder in the new Technical Center (you can read more about this on pages 18 to 22). “Feeding the material into the feeder is also an important component of the process. That’s why the FiberXpert will be one of those machines that we will initially have to custom-configure in the Technical Center for practically every application”, Jochen Keesen explains.