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Complete Recycling of Composite Material Comprising Polybutylene Terephthalate and Copper

Fraunhofer Institute for Process Engineering and Packaging IVV, Process Development for Polymer Recycling, Giggenhauser Straße 35, 85354 Freising, Germany
Technical University of Munich, TUM School of Life Sciences Weihenstephan , Alte Akademie 8, 85354 Freising, Germany
Author to whom correspondence should be addressed.
Academic Editor: Michele Rosano
Recycling 2017, 2(2), 9;
Received: 3 April 2017 / Revised: 22 May 2017 / Accepted: 2 June 2017 / Published: 8 June 2017
Composite materials comprising plastic and metal parts generate a large amount of waste containing valuable components that are difficult to separate and recycle. We therefore developed an economical solvent-based process for the recovery of costly manufactured composite materials comprising several copper panels over-moulded with a polymeric matrix of polybutylene terephthalate (PBT). We applied the CreaSolv® Process, which uses proprietary formulations with a low risk to user and environment, in order to dissolve the polymer and retain the inert copper. After separating the metal from the solution, solvent recovery was achieved by means of vacuum distillation and melt degassing extrusion. The recovered solvent was collected and recycled while maintaining its original properties. We tested two candidate solvents with PBT, measuring their impact on the molecular weight (Mw) and polydispersity of the polymer at different residence times and dissolution temperatures. We found that increasing the temperature-time-load had a negative effect on the Mw. Both solvents we tested were able to dissolve the polymeric matrix within 30 min and with moderate energy consumption. Furthermore, we found that the exclusion of oxygen during dissolution significantly increases the quality of the recovered polymer and metal. We transferred the process from the laboratory scale to the small-technical scale and produced material for large analytical and mechanical quality evaluation, revealing no decline in the polymer quality by blending with new plastic. The recovered copper met virgin material properties. Therefore, both components of the original composite material have been recovered in a form suitable for reuse. View Full-Text
Keywords: polymer; recovery; solvent-based; automotive; WEEE; PBT; CreaSolv® Process polymer; recovery; solvent-based; automotive; WEEE; PBT; CreaSolv® Process
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MDPI and ACS Style

Knappich, F.; Hartl, F.; Schlummer, M.; Mäurer, A. Complete Recycling of Composite Material Comprising Polybutylene Terephthalate and Copper. Recycling 2017, 2, 9.

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