Pirelli to launch car tires with lignin reinforcing filler

Nuremberg, Germany – Pirelli is to introduce passenger car tires incorporating wood-derived lignin fillers produced via an innovative process technology later this year.

The industrial process has been optimised for "scale-up and utilisation in car tire products,” Luciano Tadielli, innovative materials researcher, Pirelli Tyre SpA, said at the DKT IRC conference.

Employing novel chemical treatment and co-precipitation techniques, Pirelli's development follows years of R&D to overcome the challenges of successfully mixing lignin into rubber compounds.

“You will find the lignin filler in the tire from the end of this year,”  Tadielli told ERJ in an interview following a 28 June presentation* about the technology at the Nuremberg Messe.

As a bio-based material, lignin – a by-product of the paper pulping process in the paper industry – offers a sustainable alternative to carbon black as a reinforcing filler in tires and rubber products.

Pirelli will start with one application in one tire size, as the lignin-based compounds for each application can be very different, according to the Milan-based researcher.

"It is not like [adding] a new grade of carbon black, which is already a norm and can be swapped in one-to-one in different tire compounds," he explained.

Tadielli went on to say that the tire compound being developed will have a lignin filler content of around 15%, which means substituting half of the carbon black.

And, while Pirelli is very much OE-oriented, he indicated that its first lignin-filled tire would likely be for the replacement segment, “to see what happens from a market point-of-view.”

Automotive OEs, explained the materials scientist, are currently focused on the incorporation of renewables from the perspective of the entire vehicle.

"So, if they want to make an action only about recyclable materials... then lignin is off the table because it is not in that area.

But, Tadielli concluded, if they ask for sustainable, bio-sourced materials, then here we are."

*The DKT presentation was delivered jointly with co-presenter Francesco Romani, innovative materials and compounding manager, Pirelli Tyres GmbH. We will report further on this development in European Rubber Journal magazine.