In two years Pirelli & Cie SpA went from researching guayule as a rubber substitute to testing an ultra-high performance tire made from the guayule plant on a track.
Pirelli says the timeline of the project is a record for the company. In 2013 Pirelli signed an agreement with Versalis (Eni) for an exclusive supply of guayule natural rubber. Since then, Pirelli researchers have studied the characteristics of the new primary material in laboratory conditions in order to assess how it would best translate to road use.
The guayule plant typically grows in arid climates, and can grow with little water and no pesticides, making it a viable alternative to the Hevea Brasiliensis rubber plant.
The program has been made possible thanks also to a research project that Versalis has carried out on technologies used for the extraction of rubber, as well as the particularly resinous nature of the plant, which has allowed Pirelli to obtain material that is capable of satisfying the requirement for performance alongside compatibility with the non-elastomeric parts that make up a tire.
The research carried out by Versalis is part of the development program for a wide technological platform to incorporate guayale usage throughout industry, starting with experimental crop growing in southern Europe and expanding into various technologies aimed at extracting the natural rubber with the aim of using it to make tires.
On the track in Italy, the tires were subjected to extreme usage simulations, including wet conditions, and demonstrated the same performance as the equivalent tires made with synthetic polymers from oil-derived products, Pirelli said.
The choice of a Maserati to test the new tires on their track debut was not a random one: it is a high performance car capable of generating demanding loads on the tires.
Substituting petrochemical polymers with alternative and renewable primary materials is a key objective for Pirelli’s research division. Alongside development of these new biopolymers as a key ingredient in compounds, Pirelli already produces tires that use renewable primary materials, such as silica obtained from rice husks, the non-edible part of rice that is usually destined to be burned.
Sergio Lombardini, research and development and technology innovation director of Versalis, said: “For Versalis, guayale is the perfect bio matter on which to develop a genuinely integrated bio refinery. Using a technological platform aimed at integral use of guayale, it’s going to be possible to produce tires and resins that have an application both in the automotive and construction industries, as well as making use of other constituents of this bio matter 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.”
Fabrizio Sanvito, project management and technical benchmark at Pirelli, added: “The track testing phase of our guayale rubber tires has been more than positive. 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 tires and extract the most meaningful results.
"After the success of this first phase, we are now assessing the possibility of trying out these prototype tires in winter conditions.”
