RECYCLING CONCEPTS FOR POLYURETHANES AND POLYCARBONATE

The opinion is that all thermoplastics are infinitely recyclable, while crosslinked polyurethanes (PUR) and thermosets are not recyclable. The present paper uses comparative data to show that the waste management problem associated with crosslinked PUR materials has been largely overcome on a pilot-plant scale. Direct and indirect material recycling as well as thermal recycling are discussed. A direct recycling method in which granulated PUR-RIM scrap is made to "flow" under heat and pressure to re-mould it, is quoted as evidence that crosslinked polyurethane elastomers can be reclaimed and reused in a similar manner to thermoplastics. This process is called "compression molding". Recycling methods for thermoplastics under consideration from an early stage, as well as entirely new possibilities that are emerging, are demonstrated, using polycarbonate Makrolon(R) as an example.