In applications that require special material properties that cannot be fulfilled by standard plastics, engineering plastics are used. Often, engineering plastics are characterised by better mechanical properties than standard plastics. However, other characteristics can also be decisive for their use instead of a standard plastic. The special properties of engineering plastics are accompanied by a higher material price. This value of engineering plastics is a reason to recycle the materials. Furthermore, recycling avoids plastic waste and the energy-intensive production of virgin material.
In this research project, technical plastics are to be recycled by producing fibre-reinforced compounds from the plastics. The compounds are to achieve almost the same properties as compounds made from virgin material, so that they can also be used in demanding applications.
Compound development takes place on co-rotating twin-screw extruders. These have a high mixing effect and are therefore particularly suitable for incorporating the fibres into the plastic melt.
Due to the fact that the plastics to be reused are mixed with additives that were beneficial in the original application and that no grade purity is guaranteed for plastic waste, two challenges arise that do not exist in compound production from virgin material. Firstly, mixtures of different plastics and additives are more difficult to process than firmly defined formulations of virgin material and known additive mixtures. Secondly, the waste materials used may contain plastics that are incompatible with each other. These difficulties must be taken into account during material development and overcome by using additives.