Improving recyclate quality with stabilisers

Improving recyclate quality with stabilisers – a cooperation between industry and Fraunhofer shows how it can be realised

Newsletter 01/2021

© Fraunhofer LBF
Recyclate stabilisers, a piece of the puzzle in the compounding of plastics

Processing difficulties, quality problems and insufficient ageing stability are frequent complaints when recyclates are used instead of new plastics. On the other hand, the circular plastics economy needs a significant increase in recycling rates, which also makes ecological sense. What needs to be done to successfully place recyclates on the market? Together with L. Brüggemann GmbH & Co. KG, CCPE researchers are developing new additive systems.

A plastic recyclate often behaves differently from comparable new material: this is caused by ageing processes at the molecular level during the first application, mixtures of different manufacturers even in the case of unmixed collections, contamination by foreign polymers, but also residues from contact media. These factors mean that a recyclate can rarely be used in the same form as it comes from the sorting process. What can be done in such a case?

The addition of additives is the method of choice. As with new goods, small quantities have a big effect. Stabilisers lead to consistent processing, fewer failed batches, improved mechanical characteristics, less discolouration, etc. With stabilisers, it is even possible to use recyclates from

short-term applications such as packaging in long-term applications with appropriate ageing stability.

The new stabiliser systems developed by the Fraunhofer Institute for Structural Durability and System Reliability LBF, Plastics Division, are being made ready for the market together with an industrial partner, L. Brüggemann GmbH & Co. KG, are being made ready for the market. Samples are already available for polypropylene recyclates. The effects of damage are specifically and significantly reduced so that the recyclates produced with them are again suitable for processing into sophisticated products. The new stabiliser systems for polyolefins are groundbreaking when it comes to making these plastics circular.

Material recycling and quality enhancement of recyclates through analytical expertise and formulation development with additives are essential elements in the Fraunhofer Cluster Circular Plastics Economy CCPE here system services for a functioning circular plastics economy are created.

Contact person:
Prof. Dr. Rudolf Pfaendner (, Tel. +49 6151 705-8605)