Synthetic Rubber: Rubbers go the extra mile for green tyres

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Advancements in synthetic rubbers contribute to the tyres’ potential to enhance fuel economy of vehicles, says Angelica Buan.

Tyre sales continue to multiply year after year alongside robust vehicles sales. A report from Expert Market Research predicted that the global tyre market is set to cross a volume of nearly 4 billion units by 2022. The numbers favour synthetic rubber, which makes up 60% of a modern tyre. Hence, over that period, the synthetic market rubber will be worth more than US$37 billion growing at a CAGR of 5.5% from 2017-2022, referencing to a Markets and Markets report. Add on another year and the global synthetic rubber market would have achieved close to US$36 billion, Transparency Market Research highlighted in its 2015-2023 report.

Synthetic rubber gives passenger car and motorcycle tyres good grip performance; makes tyres last longer; and provides rolling resistance. For the latter, the lower rolling resistance, the better the fuel economy of the vehicle.


Synthetic rubber may have been, to say the least, a saving grace for many rubber-dependent industries, especially during the time of fluctuating natural rubber (NR) prices. Factors that affect price volatility of NR range from inconsistent supply of raw material or supply glut to high demand. On the other hand, synthetic rubber’s supply is more stable and thus enables cost benefit and increased profit margins for industrial consumers of rubber.

Of the industries consuming synthetic rubber, including footwear, sports and leisure goods, building and construction and automotive, to name a few, the tyre sector is the largest end-user segment of the synthetic rubber market.

Lower rolling resistance, less carbon footprint

The tyre industry is rebutting rising energy costs, rigorous government regulations, especially in Europe where tyre labelling has already been enforced; and growing environmental awareness among consumers with fuel efficient tyres. Of particular interest in this segment are the green tyres.

Green tyres feature lower rolling resistance, or the energy spent by a tyre per unit of distance covered, and thus are more fuel efficient. Low rolling resistant-tyres play a vital role in promoting fuel economy of vehicles. A 10% reduction in tyre rolling resistance will translate to 1-2% improvement in vehicle fuel economy.

German speciality chemicals company Lanxess’s subsidiary Arlanxeo, a producer of synthetic rubbers for green tyres, claims in an 18 month-test it conducted in 2015 with German energy provider, Rhein Energy, that low rolling resistant-green tyres enable fuel savings of up to 7% in urban traffic.


The synthetic rubber producer also attributed the growing demand for this segment to the megatrend mobility. The company is a key supplier of Nd-PBR (neodymium polybutadiene) and SSBR (solution styrene-butadiene rubber) to global tyre manufacturers serving countries and regions where vehicle demand is high. Both products are essential to the production of green tyres that are more fuel efficient, safer and durable, than standard tyres, according to Lanxess, which also owns the world’s largest plant for Nd-PBR sited in Singapore.

Development strides for SBR

SBR (styrene-butadiene rubber), formed by a 1:3 ratio copolymerisation of styrene and butadiene, respectively, offers the value-added features of reduced rolling resistance and better grip, thus, it has a wide following among tyre manufacturers seeking to produce tyres that has lower carbon footprint and increased fuel efficiency.

SBR is one of oldest synthetic rubbers, developed in the 1930s; and it has evolved since then using advanced processes.

Today, SBR is the largest product segment of the synthetic rubber market, accounting for more than 30% share in 2014.

SBR, which delivers better processability, heat ageing, and abrasion resistance, is primarily used in the manufacture of car tyres. Other applications of SBR include conveyor belts, gaskets, hoses, floor tiles, footwear, and adhesives.

The emulsion-SBR and solution-SBR formulations are widely used for green tyres; and to meet the tyre labelling standards.

The global SBR market is expected to grow at a CAGR of 7.36% from 2014-2019, according to Sandler Research in its report on the global SBR market.

Meanwhile butadiene rubbers, synthetic and biobased, are predicted to top US$24 billion by 2024, owing to the expanding tyre industry size, according to Global Market Insights. Biobased butadiene is likely to reach a 13% CAGR from 2017-2024.

Versalis (Eni), an Italy-based company, has a technology for green tyres that it had developed with Ecombine and EVE Rubber Institute, and is based on proprietary SSBR and Nd-HCBR technologies. The technology platform enables the development of new materials with enhanced mechanical performances and environment-friendly features, according to Versalis.


In 2013, it can be recalled that Versalis formed partnership with tyre maker Pirelli in developing guayule rubber, and can be considered to be among the pioneers that took keen interest in biobased rubbers.

Versalis also formed a partnership with US-based biotechnology company Genomatica to develop the sugar-derived bio-butadiene (bio-BDE) technology and for which they had been recognised last year with an Environmental Achievement of the Year award at the European Tire Technology International Awards for Excellence and Innovation.

Growing market for biobased EPDM

The EPDM (ethylene propylene diene monomer) market has huge demand from the automotive industry, accounting for a larger share of its market. EPDM offers high heat resistance, weather resistance, and vibration absorption, making it suitable for different applications. These include hoses, mechanical goods for under-the-hood applications, body sealing, weather-stripping, belts, engine mounts, brake parts, windshield wipers, and more, according to Markets and Markets in its report covering the US$7.2 billion EPDM market to 2020.


For green tyres, biobased EPDM is opted amid the pressure on the industry to manufacture more vehicle tyres made from renewable raw materials.

Arlanxeo also helps boost green tyre manufacturing with its range of Keltan EPDM products such as Keltan Eco EPDM rubber derived from biobased ethylene, supplied by Brazil’s Braskem. It was introduced as an alternative to conventional synthetic rubber from fossil raw materials. Accordingly, Arlanxeo has examined the combination of plasticiser oils and fillers for this bio-based rubber, to reduce the carbon footprint of the resulting compounds still further.

Arlanxeo’s recent offering is a semi-crystalline EPDM grade with a very high Mooney viscosity for demanding rubber applications, particularly in the automotive industry. The first Keltan grade with five digits, Keltan 13561C DE, has a high product viscosity of 130 Mooney Unit (MU) – higher than any other current Keltan EPDM grade, Arlanxeo said.

The new EPDM grade delivers improved mixing and fast extrusion behaviour with high elasticity and collapse resistance in high filled compounds, supporting the reduction of overall compound volume costs.

When replacing existing EPDM polymers, Keltan 13561C DE can significantly improve the mechanical properties in EPDM compounds with the same compound loading. The new Keltan grade has been launched in China and South America.

Sustainable tyres with isoprene

The growing rubber industry and demand for rubber products is the major driving factor of global biobased isoprene market. Isoprene is a key molecule in car tyres and can be obtained from plants, trees, grasses, or corn.

The rising awareness for environmental friendly products is also expected to boost demand for biobased isoprene for a host of applications.

Reducing the rolling resistance of tyres helps in reducing the energy expended by the vehicle while moving forward.

Isoprene, a colourless volatile liquid produced by various plants such as oaks, legumes, eucalyptus mint, poplars and others, is gaining traction as a bio-based synthetic rubber. Isoprene is also known as 2-methyl-1, 3-butadiene is used as a chemical raw material; it is also used as a starting material for synthetic rubbers.


A very small proportion of bio-based isoprene is used in the production of fragrance intermediates and flavours. Isoprene, along with other unsaturated compounds, is used to manufacture polymeric materials, Transparency Market Research stated in its isoprene market report.

It added that there is rising interest in the production of GMO isoprene. Tyres are the major application for bio-based isoprene. Moreover, it is also suited for other applications such as in footwear, medical appliances, mechanical instruments and sporting goods. Surgical gloves such as nitrile, vinyl and latex gloves are also manufactured using biobased isoprene. As well, transportation jets and jet fuels also make use of bio-based isoprene for its production.

Meanwhile, in a recent development on isoprene, a team of researchers, led by the University of Minnesota, has invented a new technology to produce tyres from trees and grasses. The researchers claimed that the tyre from the biomass produced as a result of their study would be identical to existing car tyres with the same chemical make-up, colour, shape, and performance. The new study is published by the American Chemical Society’s ACS Catalysis journal.

The new three-step chemical process is a patent-pending technology that is viable for commercialisation. “This research could have a major impact on the multi-billion dollar automobile tyres industry,” said Paul Dauenhauer, a University of Minnesota Associate Professor of chemical engineering and materials science and Lead Researcher of the study.

The researchers explained that currently isoprene is produced by thermally breaking apart molecules in petroleum that are similar to gasoline in a process called “cracking.” The isoprene is then separated from hundreds of products and purified. In the final step, the isoprene reacts with itself into long chains to make a solid polymer that is the major component in car tyres.

They said that biomass-derived isoprene has been a major initiative of tyre companies for the past decade, with most of the effort focused on fermentation technology (similar to ethanol production). However, renewable isoprene has proven a difficult molecule to generate from microbes, and efforts to make it by an entirely biological process have not been successful.

“Economically bio-sourced isoprene has the potential to expand domestic production of car tyres by using renewable, readily available resources instead of fossil fuels,” said Frank Bates, Professor of Chemical Engineering and Materials Science, of the University of Minnesota Regents.

Existing and upcoming technology breakthroughs for bio-based synthetic rubbers are expected to make significant impact to the tyre and other rubberdependent industries to deliver their environmental friendly commitment to consumers.