Recyclate Upgrading Thanks to Specific Additives Leads to a Full Second Life in Various Applications

It is more and more urgent to treat end-of-life plastics wastes exceeding hundred thousand tonnes a day. That is an economic and environmental requirement that must be solved to perpetuate the life and the economic activity of our Earth. Our attitude must evolve toward the "Cradle to Cradle" concept leading to zero wastes and the re-manufacturing of new goods with the same level of quality as that of the original goods. Mechanical waste plastic recycling combined with a suitable upgrading of properties is one of the ways with several advantages such as cost savings, the reduction of wastes near zero, the preservation of non-renewable fossil fuels and raw materials, the decrease of energy consumption, and of CO₂ and other GHG emissions. Recycling and reuse of commodity such as polyethylene, PVC, styrenics, and engineering plastics from polypropylene and thermoplastic polyester up to polyamide can lead to an average CO₂ saving of 50%. Considering recycled and upgraded plastics as a valuable plastics mine, some best practices must be met to improve the chances of success, for example:
- Compatibilize the various polymers with compatibilizers
- Adapt the rheology to get closer to virgin polymers with chain extenders or conversely with chain scissors
- Enhance mechanical properties to get closer to the original ones or to reach suitable levels for the targeted application. Impact strength, tensile strength can be controlled with organic ingredients, fillers or fibres. Nanofillers generate new possibilities without density damages.
- Adjust the durability with antioxidant, stabilizers, anti-UV. Packages of two or three additives are often the most efficient.
- If shade adjustment cannot be obtained with an addition of colorants and pigments, the colour can be totally hidden with black additives.
- Fire behaviour, electrical and other special properties can be achieved with conventional formulations.
The upgrading formula depends on the main and secondary polymers, the feedstock residual additive levels, the purity, and the degradation scenario and level. Required additive loadings can be substantially higher for recycling than for virgin polymers.