Pirelli tests guayule rubber UHP tyres

Tests of Pirelli ultra high performance tyres containing natural rubber sourced from guayule plants have taken place at the Circuito di Balocco track in Italy and at Pirelli’s own circuit in Vizzola, near Milan. The manufacturer says that extreme usage simulations showed comparable performance between these tyres and equivalent tyres produced using oil-derived synthetic polymers. The success of these initial tests at Vizzola and Balocco is now being followed up by an evaluation of how the prototype tyres will perform in the cold.

The on-track “extreme usage simulations” involve evaluations in both wet and dry conditions and were carried out using a Maserati test vehicle, a car chosen for its ability to generate “demanding loads” on the tyres. “The track testing phase of our guayule rubber tyres has been more than positive,” comments Fabrizio Sanvito, project management and technical benchmark at Pirelli. “The choice of a high-performance car to carry out these tests was dictated by the need to place the biggest possible demands on the tyres and extract the most meaningful results. After the success of this first phase, we are now assessing the possibility of trying out these prototype tyres in winter conditions.”

Progression from the very first primary research project to the recent physical tyre test took only two years. Pirelli signed an agreement with Versalis (Eni) in 2013 to secure exclusive supply of guayule-sourced natural rubber for use in tyre manufacture. Since this time, Pirelli’s researchers have closely studied the characteristics of the raw material in laboratory conditions in order to assess how it would best translate to road use.

The programme was in part made possible by a research project Versalis carried out on technologies used to extract rubber, as well as the particularly resinous nature of the plant; the findings of this work has allowed Pirelli to obtain a material that satisfies the requirements for performance and compatibility with the non-elastomeric parts that make up a tyre.

Substituting petrochemical polymers with alternative, renewable primary materials is a stated key objective for Pirelli’s research division. Alongside developing these new biopolymers as a key compound ingredient, Pirelli already produces tyres that use renewable primary materials, such a silica obtained from rice husks.

“For Versalis, guayule is the perfect biomatter on which to develop a genuinely integrated biorefinery,” notes Sergio Lombardini, Versalis’ R&D and technology innovation director. “Using a technological platform aimed at integral use of guayule, it’s going to be possible to produce tyres and resins that have an application both in the automotive and construction industries, as well as making use of other constituents of this biomatter that can be used in the pharmaceutical and health care sectors. The collaboration with Pirelli can only increase the chances of success in this innovative project with massive potential.”