All in the green zone

Next fall, purchasers of new tires or a new car will be able to view tire characteristics at a glance from the accompanying label: This indicates the energy efficiency of the tires in terms of reduced fuel consumption and lower CO2 emissions, their safety when braking on wet roads, and their noise emission levels. An EU regulation requires all tire manufacturers to provide labeling of this kind from November 2012.

This marks a step further toward the 20 percent saving of energy throughout the EU by the year 2020. The classification of tires, as prescribed from November 2012, extends from the lowest standard (the red G category) to the highest (the green A category). Cars with category A (green) tires consume about 7.5 percent less fuel than those with category G and have a stopping distance about 18 m shorter on a wet road, from a speed of 80 km/h. Noise emission as the vehicle drives past is specified in decibels (dB). Tires emitting less than 69 dB are regarded as particularly quiet; this corresponds to the A category.

More transparency in tire purchase

In the future, consumers will see at a glance how the tires affect fuel consumption, wet grip, and noise emission, and can decide more independently and reliably on what is important to them. The German Automobile Club (ADAC), Germany‘s largest automobile association, regards the label as a useful supplement to its own tests. Consumers will have access to information on at least the three tire properties shown on the label, and be able to take this into account in their purchasing decisions. The label is not intended as a substitute for a comprehensive tire test, however: Information on mileage and driving characteristics, for example, is lacking, as are data for driving properties on snow and ice. “The label will lead to greater transparency,” says Christian Buric of ADAC.

Into the green category with the silica-silane system “We hold the key to the future promotion of as many tires as possible into the green category for wet grip performance and gas consumption,” says Hans-Detlef Luginsland, head of the Tire & Rubber market segment of Evonik Industries. Evonik is the only supplier worldwide to offer the tire industry the silica-organosilane reinforcing system, which crucially determines tire tread performance. “Without this component, rolling resistance cannot be reduced,” says Luginsland. And everything depends on that: Reduced rolling resistance reduces fuel requirements and thus also emissions of carbon dioxide and other climate changing gases generated during fuel combustion. It is also important to adjust the formulation of the rubber compound so that abrasion is as low as possible without affecting dry and wet grip. In the rubber compound, the rubber and silica components are linked together. Because of their different chemical character, no direct link is possible. This is where bifunctional organic silicon compounds, organosilanes for short, come into the picture: They serve as coupling agents, binding the two substances. For continuous improvement of the silica-silane system, Evonik‘s chemists, physicists, and engineers are working on refining the silica particles and finetuning the chemistry of the silanes for improved adhesion promotion.

Getting truck tires rolling

The silica-silane technology is now standard throughout Europe, at least in passenger cars, for optimizing tire treads for rolling resistance. “And it‘s state of the art outside Germany as well,” as Luginsland says, because tires imported into Europe must also carry a label. Evonik‘s scientists are also working intensively on making the silica-silane system usable specifically for truck tires; this would significantly reduce fuel costs also for truck tires.

Investments and collaborations for innovation

To be able to offer consumers tires with A and B labels, tire manufacturers must invest in materials development and innovative products, and rely for this on intensive collaboration with suppliers of raw materials and subsuppliers, including Evonik. If countries like China and Korea want to sell tires to Europe in the future, they will need to systematically come to grips with silica-silane technology and the corresponding materials. Evonik is excellently prepared for this development. The company plans to invest further and expand the worldwide production network. Existing development collaboration and product innovations will be intensified and pick up speed.

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