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Removal of Legacy Substances from polyvinylchloride (PVC) via a continuous and sustainable extrusion process

Periodic Reporting for period 2 - REMADYL (Removal of Legacy Substances from polyvinylchloride (PVC) via a continuous and sustainable extrusion process)

Reporting period: 2020-12-01 to 2022-05-31

Polyvinyl chloride, also called PVC or simply vinyl, is one of the most widely used polymers in the world. It can be found in products such as piping, shower curtains, window frames, cable insulation, flooring and even medical equipment. Due to the long useful life of many PVC products, old PVC products can contain hazardous additives that are no longer allowed in new PVC products, therefore recycling is challenging. The EU-funded REMADYL project is tackling this important problem with a single-step continuous process to remove the additives and deliver high-quality REACH-compliant PVC.

The presence of legacy substances (LS) is a persistent barrier for PVC recycling as there are currently no economically viable solutions for their removal. This seriously hampers the recycling of PVC. Indeed, although the material itself is intrinsically very well suited for recycling (almost 800.000 tons of PVC were recyled in 2019 within VinylPlus), the situation is as follows:
* No viable methods exist to remove lead and plasticizers from PVC
* Mechanical recycling does not remove any of the hazardous substances from PVC
* Lead content in the PVC remains and is transferred into the new product

To reach our ambitious overall project goal, REMADYL has the following key objectives:
* A lab-scale process for rejuvenating PVC
* Detection and sorting process for PVC containing legacy substances
* Pilot line development for a continuous extractive extrusion process for rejuvenating PVC
* Demonstration of the re-use of rejuvenated PVC materials streams
* Safe handing and re-use of the by-products
* Policy contribution at European, national and regional level
The Legacy Substances of main concern are lead and DEHP. Both legacy substances pose a serious issue towards the future recycling of PVC products. Therefore, in order to remove these legacy substances (LS), REMADYL investigates 3 different extraction technologies: (i) extractive extrusion cleaning technologies for phthalate removal from plasticized PVC; (ii) use of Layered double hydroxides (LDH) as scavengers for lead in the PVC melt; (iii) extraction and improving accessibility of the LS in the PVC matrix via Natural Deep Eutectic Solvents ((NA)DES).

The technical R&D work focusses on developing batch extraction processes and transferring them to (semi-) continuous lab and pilot scale:
• In WP1 monitoring systems for LS were developed: a novel spectroscopic technique for lead with sufficient high resolution and a NIR spectroscopy combined with chemometric analysis in reflectance mode for plasticizers.
• In WP2 batch extractions process were developed leading to high extraction rates (>70%) for DEHP in P-PVC, the use of pure extraction solvents for Pb in uPVC with extraction rates of 88 % and a filtering capacity of the LDH for lead of 40%.
• In WP3 the time, pressure, and temperature boundaries for continuous removal of DEHP using scCO2 extractive extrusion were determined. Regarding Pb removal, in-line continuous extractive extrusion was performed, achieving a reduction of lead content of 67%.
• In WP4 the main advances have been made in the cleaning procedure of residual PVC from the scavenger material, as well as in the updated evaluation of contaminants and guidelines and methodology for the safe handling of by-products.

In WP6 data collection to develop mass and energy balances on REMADYL technologies lead to the first LCA results showing the importance of green solvents and solvent re-use. Regarding the dissemination and communication (WP7), our digital presence on social media was strengthened. REMADYL has been presented at eleven international conferences and established further synergies with ongoing projects and initiatives.
To tackle this major challenge, REMADYL will develop a breakthrough continuous process based on extractive extrusion technology in combination with novel solvents and melt filtration, which has the potential of rejuvenating ‘old PVC’ into high purity PVC tuned towards the demands of various soft and hard PVC products at market competitive cost. The process also has potential for other plastics applications, e.g. removal of (halogenated) flame retardants. Using this process, REMADYL will support the circular use of PVC for window profiles and waterproofing sheets, providing a flagship example for the circular economy. The extracted phthalate plasticizers will be safely disposed (with energy valorisation) and the lead will be re-used in batteries.

Two different pilots are planned:
*Demonstration of the re-use of rejuvenated PVC for soft applications, eg PVC sheets
*Demonstration of the re-use of rejuvenated PVC for rigid applications, eg window frames

In order to establish these demonstrations, we intend to combine a continuous lab-scale and pilot extraction processes with the recycling/re-use of the byproducts. A further attention point is the safe handling of these byproducts.
Furthermore, the sustainability of the entire process will be demonstrated. Further, we will also focus on the regulatory framework and take into account the relevant health, safety and environmental aspects linked to the REMADYL activities.

REMADYL will deliver a breakthrough support to the Circular Economy Package and resource efficiency targets for Europe as recovered PVC will reduce incineration and landfilling. The expected developments are expected to bring the following impacts:
*Increased purity and/or desirable quality of Secondary Raw Materials
*Increased recycling rate for, and reduced landfill and incineration of, Secondary Raw Materials
*Reduced risk of retaining hazardous substances in recycled materials
*The implementation of the European Commission Strategy on Plastics in a Circular Economy and of the SPIRE PPP Roadmap
*Improving industries innovation capacity and creating market opportunities
*Contribution to climate protection: recycling generates lower CO2 emission than producing virgin PVC.