What counts is the blend: innovative new tyre composites help to save fuel and the environment

More than 40 percent of the truck tires are retreaded. Researchers at the Fraunhofer PAZ they want to make more durable and more fuel-efficient. Photo: Fraunhofer PAZ

Longer useful life, lower costs: these are the objectives that research scientists at the Fraunhofer Pilot Plant Centre in Schkopau are aiming to achieve in the work they are doing to improve reprocessed lorry tyres. They are focussing in this context on innovative new composites containing recyclate, the purpose of which is to help to minimise the consumption of natural rubber resources and to lower fuel consumption.

Rubber is in short supply and competition on the tyre market is fierce – two factors that are clear indications of the need for action in the commercial vehicle tyre field. To tackle this challenge, the research scientists from the Fraunhofer Pilot Plant Centre, a joint venture between the Fraunhofer Institute for Applied Polymer Research in Potsdam and the Fraunhofer Institute for Mechanics of Materials in Halle, are developing sustainable and economic solutions in a number of different projects.

One major approach is the retreading of lorry tyres using improved new tread materials that contain recycled rubber powder. In the “Ekorund” research project, which is about to be completed, the Fraunhofer Pilot Plant Centre is liaising with industrial partners to determine how the properties of retreaded tyres can be optimised to such an extent that as much rubber as possible can be saved, on the one hand, while the running properties of the tyre tread can be improved, on the other hand, in order to save fuel and to lengthen the useful life of the tyres.

“The project has economic benefits for the industry, since tread can be produced that minimises resource input and is more energy-efficient. ‘Ekorund’ also helps to achieve the CO2 savings specified in the German government’s climate targets, because reprocessed tyres save both fuel and emissions”: this is how Project Manager Professor Mario Beiner summarises the results of the project that has been funded by the German Ministry of Education and Research and that has been in progress for more than two years now.

The Fraunhofer Pilot Plant Centre has been concentrating in particular on the composition of the rubber composites that are needed for the reprocessed tread. The consumption of fuel that is attributable to tyres is due primarily to the tyre tread – the goal is to reduce rolling friction while maintaining tyre grip in wet conditions.

Retreaded tyres already account for 40 per cent of lorry tyres nowadays. When tyres are recycled, the tread is removed and is then reapplied to the tyre casing via cold / hot processes. In this context, the ‘Ekorund” syndicate made up of members of the scientific and local / national business communities is investigating the incorporation of rubber powders (recyclates) in the tyre tread. The aim is to choose optimum rubber powders and to determine the maximum amount of recyclate that can be used in the reprocessing of tyres.

Tremendous progress has already been made in this work, says Beiner. The expert reports that they have been successful in incorporating significant proportions of special rubber powders and in improving the performance of the tyre at the same time. It has been possible to reduce the rolling friction of the tyre tread without any noticeable loss of wet grip and abrasion properties. GD

Fraunhofer Institute for Applied Polymer Research