Green Rubber: Green measures to recalibrate the impact of tyres

The use of green rubber and recycling of end-of-life tyres (ELTs) can mitigate the carbon impact of the tyre industry, says Angelica Buan in this report.

Carbon emissions from tyres

The evolution of vehicles has taught us lessons on how transportation has contributed to the economic advancement and, on the one hand, the rising pollution levels. The transport industry is touted to account for nearly a quarter of global carbon emissions. Pivoting to lightweight, fuel-efficient models and electric vehicles (EVs) may deliver the needed change towards a decarbonised automotive sector, but their utmost adoption will not happen overnight.

Looking past EVs and lightweight cars, pollution guardians have spotted the quintessential part of a vehicle as a pollution contributor – the tyres.

Recent findings by Emissions Analytics indicate that pollution from worn tyres is a thousand-fold worse than vehicle exhaust emissions. It reported that harmful particle matter from tyres, as well as brakes, is a growing environmental problem. The increasing demand for EVs, its batteries make them heavier than standard cars, and large, heavy vehicles such as SUVs, worsen the situation.

The report added that vehicle tyre wear pollution is completely unregulated, unlike exhaust emissions, which have been rapidly reduced by car makers in light of the stringent emissions regulations. New cars now emit very little in the way of particulate matter but there is growing concern around non-exhaust emissions (NEE), which impact air quality.

NEEs are particles released into the air from brake wear, tyre wear, road surface wear and resuspension of road dust during on-road vehicle usage. Currently there is no legislation on the limit or reduction of NEEs. These emissions are believed to constitute the majority of primary particulate matter from road transport, 60% of PM 2.5, and 73% of PM10.

Green Rubber: Green measures to recalibrate the impact of tyres

The UK’s Air Quality Expert Group (AQEG) 2019 report, Non-Exhaust Emissions from Road Traffic, recommends recognising NEEs as a source of ambient concentrations of airborne particulate matter, even for vehicles with zero exhaust emissions, such as EVs. As a short-term remedy, the researchers suggest fitting higher quality tyres as a way to reduce NEEs; to have the tyres inflated to the correct level and to effectively reduce vehicle weight.

There are a few other studies that have pointed to tyres as a source of pollution particles. Back in 2019, Swiss Federal Laboratories for Materials Science and Technology (EMPA) launched a study highlighting microrubbers being released by worn out tyres.

Microrubbers are the finest particles from tyre abrasion, mainly from cars and trucks, which enter the soil and air through the road surface or are removed by artificial turf. In the study, it found that tyre abrasions are responsible for 97% of the particles released in the environment; and 3% by artificial turf. From1988 to 2018, around 200,000 tonnes of microrubbers have accumulated in Switzerland’s environment, EMPA stated.

Findings such as the abovementioned bring attention to how tyres, a major component in mobility developments, can actually make or break the green initiatives of the automotive sector.

Tyre makers rally for low-rolling resistance tyres

One of the main focuses of the tyre industry’s innovations is on lowering the rolling resistance of tyres for better fuel economy and greater reduction of carbon emissions.

Low-rolling resistance green tyres have come about because of a growing awareness of making tyres environmentally-friendly and adoption is advancing, with global tyre brands responding to this demand.

The Michelin X

Michelin North America has recently launched its new tyre offering, Michelin X One Line Energy T2 tyre, which it said is its most fuel-efficient trailer tyre to date, for the North American line-haul market. It described the new tyre as delivering improved tread wear while providing fuel and weight savings. The tyre can increase fuel savings through an 11% lower rolling resistance when used in trailers and can increase revenue by carrying up to 130 kg of payload.

It features a tread design that helps prevent irregular wear and incorporates compounds designed to improve resistance to late-life tyre aggression. The dualcompound tread consists of a mileage top layer that controls tread stiffness and stress to reduce irregular wear and a fuel-efficient bottom layer that minimises internal casing temperatures for low rolling resistance. The tread incorporates directional microsipes, resulting in a directional tyre for the first half of tyre life. Located along the centre ribs, matrix siping with zigzag walls interlock for squirm resistance.

Conti EcoRegional truck tyre range

Another global tyre major, Continental, has rolled out its latest green tyre offering, the Conti EcoRegional truck tyre line. The new tyres feature reduced fuel consumption and improved mileage, thus enabling fleet operators to significantly increase the efficiency of vehicles in regional transport, according to the Germandomiciled tyre producer.

The Conti EcoRegional HS3 and HD3 warrant reduced CO2 emissions owing to a new manufacturing process in combination with an innovative tread design for the steering axle and a rubber compound that is optimised for rolling resistance for the drive axle.

The Conti EcoRegional HS3 was produced using the new Conti Diamond Technique production process, and features an optimised tread surface pattern in the ground contact area with a modified tread groove geometry, reduced sipe width, and W-tread groove technology for particularly even abrasion. The tyre runs with the tried-and-tested tread concept of the Conti Hybrid Gen 3 line, but uses a new, innovative tread compound in the form of Conti InterLock Technology. It is said to enable an unprecedented level of low rolling resistance with the same mileage, especially in regional and highway applications.

In both Conti EcoRegional HS3 and HD3, base compounds optimised for rolling resistance are used; and in the casing, compounds optimised for rolling resistance are used.

Shandong Linglong Tyre showcased three new bio-based tyres

Over in China, a major consumer of tyres owing to its huge vehicle demand, the country is served with new biobased rubber tyres from Shandong Linglong Tyre. The new range of biobased rubber tyres were unveiled during an industry event held in mid-September in Shanghai.

Developed in collaboration with Beijing Chemical Industry University over the past three years, the tyres use a host of biobased rubber products. As part of the key bio-rubber R&D project, Linglong says it is able to produce dandelion-rubber snow tyres, radial truck tyre based on eucommia rubber and itaconate biosynthesis steel-belted rubber tyres.

Eucommia ulmoides (EU) gum is a natural polymer material extracted from EU oliver, which can be applied in the tyre industry to reduce the rolling resistance of the tread compound and save the energy, Linglong said. It adds that the solar-source development of a new generation of biobased rubber was part of its strategy to address the unsustainable production of synthetic rubber and natural rubber as well as the shortage of resources. China has no local source of natural rubber, and thus imports 80% of the polymer. The tyres have been evaluated to display performance that is superior to traditional rubber, Linglong quipped.

 Read more…