German chemicals conglomerate Lanxess supplies raw materials to just about every major automotive manufacturer, and your car is likely to contain a host of Lanxess products, from the tyres to the dashboard plastics and possibly even the tanned leather seats. The company is also the world’s largest producer of synthetic rubber (with around a fifth of the market).
Synthetic rubber, as its name implies, doesn’t contain any natural rubber. It’s a polymer, which makes it a kind of plastic, which is derived from petroleum, a popular target of eco warriors and tree huggers.
Biomass (or plants in plain English) holds the key to making rubber that is kinder to the environment. Lanxess, for example, has in the past year introduced industrial quantities of Keltan Eco to the market. A type of bio-based rubber that contains 70 percent of the organic base material (to be increased to 90 percent in the coming years), Keltan Eco is derived from sugarcane grown in Brazil.
Not quite the sweet green drink enjoyed in hawker centres, but it can quench manufacturers’ thirst for eco-friendly ethylene propylene rubber, with automotive applications that include door/window/boot seals, coolant hoses, drive belts and tyre inner tubes.
Another source of biomass with commercial potential is isobutene made using renewable resources. Isobutene is an important raw material in the manufacture of butyl rubber for the tyre industry, and it is made from petroleum derivatives in petrochemical plants. The green alternative to isobutene is isobutanol, an organic compound “fermented” from corn. Isobutanol is already a basic building block for the production of bio-fuel for jet aircraft as well as a variety of plastics, fibres and rubber elements.
GREEN REALITY CHECK
According to Christoph Kalla, a two-decade Lanxess veteran in the company’s performance butadiene rubber division, 87.5 percent of a tyre’s CO2 footprint isn’t generated from the manufacture of said tyre, but through actual use – producing the tyre only counts for around 10 percent. If this 10 percent were to be cut to eight percent, the CO2 reduction would be insignificant, whereas a 10 percent improvement in the rolling resistance of petroleum-based rubber would have a far greater impact on the tyre’s overall carbon footprint.
Kalla also believes that using biomass-based rubber simply for the sake of grabbing headlines or satisfying environmentalists could be counter-productive, because manufacturing such green rubber typically requires more raw material than usual and a higher level of energy. There is also the issue of fuel crops competing with food crops for limited arable land, which would open up a whole new can of worms.
“In the end, you need to strike a positive balance. The consumer is also very interested in seeing more done with renewables or the extraction of usable materials from waste, but it must all make sense,” Kalla concludes.
Sensible, indeed, is the introduction of compulsory tyre labelling in the European Union by the end of this year.
ROLLING IN GREENERY
The tyres of today are clearly superior to those of the 1970s. On average, they deliver over 70 percent better mileage and require a 35 percent shorter braking distance in the wet. Their rolling resistance is also nearly 40 percent lower than that of tyres from three decades ago.
Today’s energy-efficient tyres conserve fuel, too. With the four “rubber rollers” at each corner of the vehicle responsible for 20 to 30 percent of a car’s total fuel consumption, they can really help the cost-conscious driver trim his petrol bill. Just by keeping the tyre pressure correct, he can go further on every tank – a mere 1 bar below the recommended pressure can increase the car’s fuel consumption by a few millilitres per kilometre. Tests have proven that if a vehicle rolls down a ramp with its engine off, green tyres alone can stretch the “freewheeling” by up to 60 percent compared to conventional tyres.
Green tyres are more expensive than their regular equivalents, but tyremakers estimate that the extra cost can be recouped after two years – based on an annual mileage of 15,000km, average fuel economy of over 15km per litre and a driving pattern of 40 percent city, 20 percent country and 40 percent highway.
Tyres with more than a tinge of “green” in them have rolled into the motoring mainstream and will become increasingly prominent in the years to come. Indeed, green tyres are on a roll.
This story was first published in the October 2012 issue of Torque.