Plastic additives make a significant contribution to improving the quality of recycled materials

The use of plastics from recyclates is largely determined by their quality. With the exception of production waste with little damage, a used plastic cannot be used in the form in which it is produced or collected. Usually, if necessary, it is sorted, cleaned and reprocessed, for example into granules. For a sufficient recyclate quality with adequate processing and long-term stability for the intended application, post-stabilization with suitable additives is often required. With appropriate additives such as stabilizers, compatibilizers and reactive additives, recyclates achieve comparable properties to virgin material.

Additives ensure recyclate quality

Post-stabilization of recyclates with suitable additives is an essential lever for improving recyclate quality. The stabilizers used protect the recyclate from further oxidative (and/or photooxidative) damage analogous to virgin material. Although stabilizer residues from the initial application make a contribution during recycling and further recyclate stabilization, they are generally not sufficient, especially if the old plastic originates from a short-term initial application (e.g. packaging) and its further use is intended for a long-term application. Suitable additives for post-stabilization of recyclates for process or long-term heat stability are mainly phosphites/phosphonites as well as phenolic antioxidants in combination with co-stabilizers e.g. acid scavengers. Low or high molecular weight sterically hindered amines and/or UV absorbers such as benzophenone or benzotriazole can be used to improve light stability.

Additive formulation improves films from film recyclate

As an example, successful post-stabilization could be demonstrated on polyethylene films, which can nowadays be produced from film recyclates. In order for these to be reliable and durable, no defects must occur during production. By adding a suitable additive formulation, the film quality was significantly improved. The manufacturing process becomes more efficient and cost-effective

The EU Plastics Strategy aims to change the way plastic products are designed, manufactured, used and recycled in the EU. A key message is also to make recycling more profitable for industry. Improved recyclate quality offers the chance to increase their demand. Researchers at Fraunhofer LBF work with you to develop the best technical and cost solution for the desired property profile.