Sustainability and high performance are the most significant drivers of fundamental change in the tire industry today. And judging by the cross-section of experts at 5th Annual Innovative All-Season & Winter Tire Development Forum held earlier this month, the idea that these trends are incompatible is actually proving to be quite the opposite.
Chief Technology Officer at CarbonX Daniela Sordi talks about which trends are compelling tire makers to accelerate innovation in an industry that is often characterized as “slow to change,” why innovative fillers like CarbonX must be part of the solution, and the impact CarbonX has had in tire formulations for PCR, truck, and bicycle racing tires.
Better fuel efficiency needed to meet EU emission targets
Improving fuel efficiency to reduce CO2 emissions from road transport is crucial for achieving the EU’s GHG emissions reduction target by 2030. Tires account for 20-30% of fuel consumption, and that is mostly due to rolling resistance, so that reducing the rolling resistance in tires could make a significant impact on reducing CO2 emissions.
Rolling resistance is the biggest factor in tire fuel consumption, but conventional additives are limited in how much they can improve the rolling resistance, and even more so without compromising safety or durability.
Higher durability needed to reduce CO2 and TRWP emissions
Tire makers are facing almost as much pressure to increase durability as they are fuel efficiency. For one thing, making tires more lightweight increases increase fuel efficiency. Making them last longer also lowers the lifetime CO2 emissions.
And increasing the abrasion resistance could also reduce another increasing environmental concern, tire and road wear particles (TRWP). Tire & Road Wear Particles (TRWP) have also been identified as a major contributor to the microplastic problem – linked not only to polluted oceans, but also to the melting of arctic ice caps and global warming.
There are still no standards for wear in the EU’s new tire energy labelling scheme because there is still no good method for correlating tire abrasion to particle emissions and the declining performance of worn tires.
“It’s very important to find a way measure these emissions and come to an agreement on a standard which can be applied to tire development in order to minimize tire particle emissions,” says Sordi.
Nevertheless, the EU has already mandated the development of a suitable methodology and tire makers must prepare for this certain eventuality.
Demand for an “All-in-One” tire increases
According to Nokian Tyres, global sales for all-season tires have increased by a staggering 425 percent since 2012, and they were the only tires to increase in sales during the pandemic.
Given their growing popularity, many tire makers are putting more effort into designing an all-in-one tire that truly excels in all seasons and driving conditions at the same time, rather than optimizing parameters without excessive compromise on the others.
Circularity: cradle-to-grave sustainability
In addition to reducing the environmental impact of the products in the use phase, tire makers have also been working to lower their own environmental footprint and incorporate sustainability in the production and end-of-life phases.
“The aim here is to simplify processing, minimize or eliminate waste, improve resource efficiency, and use sustainable and/or waste materials to produce all the raw materials you need to make new tires,” says Sordi.
More manufacturers are rethinking the materials they use from a sustainability perspective, looking to improve the recyclability of their products, simplify and reduce the energy intensity of processing, and reduce their reliance on virgin raw materials.
Changing the game with disruptive fillers
Up until now, tiremakers were limited to how much they could improve one performance parameter without significantly compromising another. But In order to achieve the sustainability we need with the performance we want, innovative additives and fillers that can “break the magic triangle” must be part of the solution.
“Tiremakers need to consider new additives which allow you to tailor specific performance metrics without affecting others,” says Sordi.
Defying convention with CarbonX
CarbonX has yielded promising results when used to replace various carbon blacks used in tire formulations for PCR, truck, and bicycle tires. Daniela Sordi explains what makes CarbonX a unique alternative to conventional additives, and how it can help tiremakers meet higher demands in performance and sustainability.
“In every case, CarbonX was able to improve one or more parameters without compromising performance in the others,” says Sordi.
In PCR tires, silica is typically used to maximize fuel efficiency, but this compromises wear. Carbon black can improve wear further, but it comes at the cost of fuel efficiency and grip. Using CarbonX to replace N375 in a sSBR/BR formulation improved both rolling resistance and wear without compromising grip.
Bicycle Racing Tires
In bicycle racing tires, CarbonX was used to substitute N200/N300 in an NR/BR recipe. Several carbons are generally required to maintain grip while maximizing speed. But the use of a single CarbonX grade was able to significantly improve rolling resistance by 44% without compromising grip or abrasion resistance. This case shows how CarbonX can reduce processing complexity, requiring only one filler where often two are required.
In truck tires, tire makers use a high-surface, high-structure carbon like N115 to meet high wear resistance targets. CarbonX was used to substitute N115, improving the heat build-up and the rolling resistance by a factor of 24% and 12%, respectively. Moreover, we were able to maintain high wear resistance and grip.
CarbonX can maintain wear properties because it adheres better and distributes more evenly within the polymer than carbon blacks, which improves the durability and the abrasion resistance in a tire. Another advantage to CarbonX is that all grades also have very low levels of PAHs, which are considered carcinogenic and are often found in tire and wear particles.
How it works
CarbonX is a relatively new carbon structure that is best described as a three-dimensional network structure of connected carbon filaments. The filaments are highly crystalline, and the crystallites within the filaments are highly aligned.
CarbonX improves rolling resistance by reducing heat build-up and hysteresis. The high polymer-filament interaction means CarbonX compounds are strong enough to deform and still maintain grip and road adhesion without breaking. Meanwhile, the high crystallinity within the filaments dissipate the forces and heat generated from road contact more effectively, thereby reducing hysteresis. It is these same structural properties which also improve abrasion resistance, allowing tire makers to improve wear and fuel efficiency concurrently.
In terms of processability, CarbonX compounds all exhibit lower viscosity when compared to analogous carbon blacks, which means that manufacturers can increase throughput with the same energy invested.
The time to change is now
“With 1.6 billion tires sold around the world every year,” says Sordi, “car makers have a great opportunity to make a positive impact by acting quickly to meet regulatory and market demands in performance as well as sustainability. CarbonX can help tire makers accelerate their transition.”
For more information on CarbonX business cases in tires, please contact Sophie Dik at email@example.com