As active fillers, silica have become an integral part of tire production and the manufacture of technical rubber items. They are a key component of treads in green tires, which differ from conventional tires by their low rolling resistance and a significantly improved “grip” (vehicle traction). This reduces CO2 emissions and lowers fuel consumption by up to eight percent. Better road grip makes an important contribution to enhanced safety – especially in wet conditions – due to much shorter braking distances.
The successful advance of precipitated silica would not have been feasible in tire applications without sulfur silanes. Since hydrophilic silica does not mix well with hydrophobic rubber, the addition of sulfur silane ensures that the incompatible components of rubber and silica can achieve a chemical bond. This became a reality with the introduction of Evonik’s Silica/Silane technology, in which ULTRASIL® VN 3 and Si 69® played a key role. Evonik is the only company worldwide to manufacture both silica and silanes.
ULTRASIL® 7800 GR - the next generation of silica
As tires are becoming larger and wider, the challenge for tire manufacturers is to give tires sufficient stiffness in spite of their size. This has a direct impact on improved and direct steering. Evonik made it a top priority to immediately respond to this market trend and developed a new product that meets these requirements. “With the custom-tailored silica ULTRASIL® 7800 GR, we managed to find the right mix to give SUV tires sufficient stiffness in spite of their size,” explains Dr. Hark-Oluf Asbahr, Rubber Silica Marketing. The researchers at Evonik refined the structure of the silica particles to enable optimal performance in the right location. This innovation at the microscopic level has led to major improvements. “It's an advantage we can also use for the production of all-season tires,” Asbahr reports.
Sporty driving and long service life
“The use of the new ULTRASIL® 7800 GR considerably strengthens the tread compound, which creates direct feedback between the tire and the steering system,” Asbahr explains further. This improves steering performance and enables a sporty yet safe driving style in SUVs and with all-season tires. Because ULTRASIL® 7800 GR increases the abrasion resistance of the tire tread, the driving pleasure is also long-lived. As a result, the tire profile and road grip are maintained longer and the tire can be driven safely for a longer time. That’s an advantage that not only benefits consumer wallets, but also the environmental footprint.
Easy to process
Despite its increased specific surface, the new ULTRASIL® 7800 GR remains easy to process. As a result, ULTRASIL® 7800 GR can be integrated into existing production processes without any problems.
“The demand for SUVs is steadily increasing worldwide, along with the demand for custom-tailored silica. The largest sales market is currently in the United States,” explains Dr. Bernhard Schäfer, head of Rubber Silica. This prompted Evonik to build a production facility in South Carolina in the southeastern United States, which will manufacture the new ULTRASIL® 7800 GR along with other ULTRASIL® types starting from mid-2018. ULTRASIL® 7800 GR is already available from other American production facilities.