“Plastics are fundamental to our everyday life. Yet they are one of the most wasteful examples of our existing linear, take-make-dispose economy. With 8 million tonnes of plastic entering the ocean each year, we urgently need to rethink the way we make, use, and reuse plastics. Catalysing change through collaboration in this global material flow will not only create a more effective plastics system, but will also demonstrate the potential for a wider shift from a linear to a circular economy - an economy in which plastics never become waste” quote from the Ellen MacArthur Foundation.
One ‘easy’ way to boost recycling is designing consumer goods out of one material, which facilitates recycling at end-of-life. This approach contributes to the shift from a linear to a circular economy. Unfortunately, it is not always technically feasible to produce goods out of one material, without compromising their desired functional performance. In many cases coatings, paints or laminates (referred to within this article as ‘coatings’) are indispensable to ensure good performance. Unfortunately, these coatings hinder recycling, or even render it completely impossible, leading to incineration or landfill as end-of-life option.
The DECOAT project tried to work out a new recycling principle that can contribute to the overall goal of recycling these coated materials, and so to the circular economy. The bulk material itself is often made of a monomaterial. So, if the coating can be removed from the bulk material, the latter can be further recycled.
DECOAT stands for ‘Recycling of coated and painted textile and plastic materials’ and is funded by the European Commission via the Horizon 2020 programme.
DECOAT focusses on ‘design for recycling’: by adding special newly developed additives between the bulk material and the coating, for example in a primer or in an adhesive layer, the coating can be removed on demand. These additives will respond to a specific trigger, which enables debonding. The trigger can be heat, steam, microwaves, … depending on the used additive.
Another approach used in the project is dissolution, and hence removal, of the coating by green solvents. In the solvent based process, developed by DECOAT partner Fraunhofer IVV, coatings are dissolved or delaminated, and impurities are filtered off, leaving a pure stream of polymers, which can be reprocessed. In this approach no debonding additives need to be added, which is the main difference with the approach explained above.
To envision a realistic recycling line, the disassembled material needs to follow the correct flow in the recycling plant, ending up in the correct triggering device. Besides the actual debonding additives, specific dyes will be investigated allowing optical sorting. This optical sorting step ensures that the materials are separated based on their debonding additives, or the absence of them. The coated parts are consequently directed to the correct processing device (solvent based, oven, microwave, steam generator etc.).
