Si 291® makes e-cars even more environmentally friendly

In line with the e-mobility trend, Evonik Silanes has a new sulphur silane in its portfolio. Si 291® is particularly suitable for use in the green tires of electric cars and is now available from Evonik Silanes.

More and more electric cars are on the roads worldwide. Since they often emit less CO2 over their life cycle than combustion engines, they are a particularly climate-friendly way for people to get from A to B. Modern high-performance tires with a Silica/Silane system in the tire tread, known as "green tires", ensure low rolling resistance. This increases the range of electric cars and makes them even more resource-efficient and sustainable.

Vehicles with combustion engines also become more environmentally friendly through the use of green tires, as they reduce fuel consumption and thus contribute to lower CO2 emissions.

The magic triangle of tyre performance  

In addition to rolling resistance, good wet grip on the road plays an important role in safe driving so that the car does not leave the road even in poor weather conditions, under heavy braking or on tight bends. In turn, high abrasion resistance of the tire extends its mileage. These three factors form the three corners of the so-called magic triangle of tire performance - the better the tires perform in these properties, the better the performance.

This is where the Silica/Silane system comes into play: the tread of a tire consists of a rubber compound that is optimized by reinforcing fillers or filler systems - precipitated silica in combination with silanes.

As the polar silicas are not compatible with the non-polar rubber, they are combined with bifunctional organosilanes, which chemically bind the silica to the rubber. The result: compared to systems with carbon black, the rolling resistance is significantly reduced, and wet grip is also improved, while the abrasion properties remain the same. This makes the tires more efficient, safer and more sustainable.

With the trend towards e-mobility, tire manufacturers are demanding ever higher levels of silica in the tire tread, which goes hand in hand with correspondingly higher quantities of silane. "The reason for this is that the higher weight of electric cars places greater demands on the tires than combustion engines, which in turn requires a different tire design," says Michael Kempf, Head of the Tires and Mechanical Rubber Goods market segment at Evonik Silanes. "High silica fill levels also improve the wet skid properties of the tire tread."

Si 291® significantly reduces the rolling resistance of green tires  

Evonik Silanes has added a new silane to its portfolio that perfectly supports this trend. Si 291® is a sulphur silane with outstanding dynamic and rubber-technological properties: Tensile and abrasion resistance is increased compared to Si 69®, while rolling resistance is significantly reduced. Thanks to its low viscosity, the formulation is also particularly easy to process when Si 291® is used.

"Evonik's silica ULTRASIL® product portfolio in conjunction with the new Si 291 offers numerous possibilities for controlling and optimizing rubber performance in a wide range of areas," adds Anna Kunze, Global Marketing Head of Rubber Silica.

Si 291® thus complements the product range of high-performance silanes for green tires and is positioned between the standard silane Si 69®, which revolutionized the tire industry several decades ago, and the best-performance silane Si 363®, which achieves the very highest performance in terms of the magic triangle. Si 291® is now commercially available. "By offering our customers the perfect silane for tire treads with high filling levels - ideal for e-cars - we are going one step further and making green tires even greener," summarizes Kempf.