© Fraunhofer-Institut für Bautechnik IBP
Author profile picture

Carpets are not recyclable after the end of their service life, as they belong to the group of composite materials whereby purely mechanical recycling is scarcely an option. Carpets are largely made up of petroleum-based polypropylene. They are generally burned or end up in landfills. In the European Union alone, 1.6 million metric tons of old carpets are disposed of in this way each year.

Good quality

A team of researchers, among them the Technical University of Graz (Switzerland) the British Axion Recycling (UK) and Fraunhofer IBP (Germany), has developed a new recycling process as part of the EU-led ‘Isoprep’ project. “With this process, polypropylene can be recovered from carpet waste for the first time,” said scientist Maike Illner in a Fraunhofer press release. The recovered polypropylene is of such good quality that it can be reused like newly manufactured polypropylene. Of course, the recycled material can also be used for lower quality products (‘down-cycling’).

An economic analysis shows that the recycling process is cost-competitive. The recycling process can therefore be applied on an industrial scale.

The process developed by the Fraunhofer Institute for Building Physics IBP and its partners is also fairly competitive from a cost point of view. A preliminary economic analysis shows that the rate of loss from recycling is less than one percent, which means that the process is cost-competitive. This is good news, as it enables the recycling process to be applied on an industrial scale.. 

Commonly used polymer base

About a quarter of the carpet waste processed in the project comprises the petroleum-based plastic polypropylene. The recycling process consequently also achieves significant environmental savings.

Polypropylene is a petroleum-derived polymer and the second most widely used base polymer after polyethylene. It is widely used in a substantial number of products, including food and beverage packaging, carpets, electronics, automotive interiors, pipes, home furnishings and even banknotes. However, polypropylene is an unsustainable raw material and a major contributor to non-biodegradable plastics, which habitually pollute both land and sea. Currently, only one percent of products containing polypropylene are recycled.