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Recycling of coated and painted textile and plastic materials

Periodic Reporting for period 1 - DECOAT (Recycling of coated and painted textile and plastic materials)

Reporting period: 2019-01-01 to 2020-07-31

“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, leaving incineration as the only end-of-life option.

The DECOAT project tries 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 CreaSolv® process, developed by DECOAT partner Fraunhofer IVV, coatings are dissolved, 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 developed 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 (CreaSolv®, oven, microwave, steam generator etc.).
Within this first reporting period, the focus was on the development of the triggerable materials. Several types of triggers have been realised, eg thermo-responsive core-shell structures and Super Absorbing Polymer or SAPs triggers. Their testing and integration in coatings systems is on-going. Further, the basic coating formulations that will be used have been further defined, both for application on plastics and on textile substrates.
Reprocessing and recycling studies on the plastic substrates were started, coating formulations with triggerable materials have been checked and promising first tests with the Creasolv process on coated textiles was performed. Both a microwave test rig (to define the microwave processing parameters for debonding) and an optical monitoring test rig (to identify fluorescent particles for use as optical markers) have been setup. First materials were screened and tested to see which ones are the most appropriate to be incorporated into coatings for monitoring purposes.
Safety assessment related to DECOAT work is in good progress, based on contribution and consultation from partners. A safety walkthrough & on-site exposure measurement campaign has been performed at the premises of partner NTUA on CVD manufacturing of CNTs. A series of safety recommendations were provided, while a Safety-by-Design strategy for inherently safer CNT materials has been identified. Data collection workshops on LCA have been carried out to provide data for the screening LCA studies. Also, initial in-vitro cytotoxicity tests have been performed assessing the viability of the cell cultures in the presence of triggerable materials.
The dissemination and exploitation activities are on-going: a press release was issued at project start, the website is operational, newsletters were published and DECOAT organised a first public workshop at the ECOMONDO fair in Italy.
Within the textile sector, mechanical recycling of end-of-life textile is most advanced and commercially viable. Chemical recycling is emerging but so far only limitedly available, a nice example is the production of polyamide 6 from for example EoL fish nets or carpets scrap. In the plastics sector melt reprocessing of used plastics is more common. In all mentioned recycling methods, coatings and paints are seen as impurities, making recycling much more difficult or even impossible. So, currently coated and painted textiles and plastics are excluded from the corresponding recycling streams.

A contribution to augment the recycling rates is the inclusion of coated and painted textiles and plastics in the recycling processes (which are now being incinerated or landfilled).
DECOAT focusses on closing this gap in the recycling loop. After shredding and sorting the discarded good, a new step in the recycling process is introduced, allowing to remove the coatings/paints from the bulk material. Separation techniques, known to the recycling industry, will be used to separate the debonded coating/paint from the bulk material, allowing standard reprocessing of the bulk material e.g. via extrusion processes which are generating regained plastic pellets, which can be used to produce novel goods.