The consistent further development of synthetic rubber has resulted in a significant improvement in the overall performance of vehicle tires. German specialty chemicals group LANXESS offers a number of interesting and innovative highlights for the tire segment.
Specifically, LANXESS’s new solution styrene-butadiene rubbers (S-SBR) have become accessible through intelligent, newly developed production processes. Trials performed at LANXESS test laboratories and with customers have shown that, with these new tire tread elastomers, it is possible to simultaneously raise the wet grip and the rolling resistance of the tires to a completely new level. Previously, these properties were contradictory.
"Current debate on intelligent tires is focused primarily on the progress being made in the field of sensor technology," says Christoph Kalla, Global Head of Marketing at LANXESS’s Performance Butadiene Rubbers business unit. "We are delighted with this latest development, because it shows just how much modern tire production can profit from the use of state-of-the-art special-purpose rubbers from LANXESS."
For example, the latest tire pressure monitoring systems (TPMS) directly point out the potential of modern butyl and halobutyl rubber grades from LANXESS.
The difference between standard and high-end products often involves making difficult modifications to the elastomer molecules – a field that is nowadays only mastered by research-intensive premium providers in the rubber sector.
LANXESS is working on the further development of styrene-butadiene rubber grades that are produced by the solution process via so-called "anionic polymerization". This technology results in particularly low-branched rubber molecules, noted for their comparatively narrow molecular weight distribution – which rubber experts associate with good abrasion resistance and rolling resistance. It has already been possible to modify these molecules in many ways via their chemically active terminal groups. They can, for example, be joined to one another to improve their processing properties or be provided with special chemical "anchor points" at the ends to allow the rubber to interact better with fillers, thereby improving the rolling resistance of the tire without impairing the grip on wet roads.
LANXESS has now taken this concept a step further by introducing "intelligent" solution SBR rubber grades that have "anchor points" not just at the ends of the molecules but along their entire length. These enable the elastomer to interact with other constituents of the rubber.
Laboratory trials showed that such S-SBR rubbers have precisely the desired properties that are associated in practice with improved wet grip (high tan ä value at 0 °C) and, simultaneously, reduced rolling resistance (low tan ä at 60 °C). With "conventional" rubber types, it was impossible to increase one value without lowering the other. The abrasion level is also very low with these new rubber grades. Furthermore, the positive effect is seen even when the microstructure of the rubber is varied by making normal changes to the polymerization conditions. Initial practical trials at some of our customers have also yielded improved tire performance.
LANXESS’s "intelligent" rubber solution has given tire developers a completely new tool to work with: Now, for the first time, rolling resistance and wet grip can both be significantly optimized at the same time.
"Our ongoing research shows what can still be achieved with modern tire raw materials," says Kalla. "It also demonstrates just how much innovation potential there still is in the material, even nearly a hundred years after the discovery of the first synthetic rubber in the laboratories of our predecessors in Leverkusen."
The latest development follows on seamlessly from the many other innovations that have come from LANXESS in the past and provided a major stimulus to the global trend towards high-tech tires.
The Performance Butadiene Rubbers business unit belongs to the Performance Polymers segment, which achieved total sales in fiscal 2007 of EUR 2.68 billion.
LANXESS (lanxess.com) is a leader in specialty chemicals with sales in 2007 of EUR 6.61 billion and currently around 15,000 employees in 21 countries. The company is represented at 44 production sites worldwide. The core business of LANXESS is the development, manufacture and sale of plastics, rubber, intermediates and specialty chemicals.