At Fraunhofer ICT in Pfinztal, Germany, a continuous lab-scale process (4 – 11 kg/h) for the removal of phthalate-based plasticizers (DEHP) from soft PVC was installed successfully (Figure 1). The main outcome of these trials was a stable extrusion and extraction process and the reproducibility of the conducted trials. The extraction efficiencies however remained below 1 % for DEHP removal.
Although the extraction of phthalate plasticizer showed promising results in semi-continuous batch extraction, the transfer of extraction conditions towards a continuous extractive extrusion proved to be very challenging.
Figure 1: Continuous extraction process for removing plasticizers from PVC with scCO2 and co-solvent
The further procedure is to continue the extraction trials according to a semi-continuous batch-process as carried out in WP 2 in larger batch extraction vessels. To optimize the extraction yield and to be able to supply project partners with large volumes of legacy free PVC, bigger batch reactors will be used (up to 5 liters) at Fraunhofer ICT.