Enhancing performance of silica-reinforced natural rubber tire tread compounds byapplying organoclayas secondary filler

Silica-reinforced natural rubber (NR) tire tread compounds are investigated using organoclay (OC) as secondary filler. Byvarying mixer temperature settings at a silica/OC ratio of 45/10 phr, dumptemperatures are reached of approximately 120, 140, 150, and 160 °C. The increased dump temperature leads to a better silanization reaction resulting in lower mixing torque, Mooney viscosity, and Payne effect. The optimum mixing dump temperature was found to be around 150 °C. By varying the loadings of OC in the silica-filled NR compounds from 0 to 36 wt% relative to total filler amount, the increased OC loadings decreased the Payne effect and compound viscosities, significantly shortened scorch and cure times, and raised the tan delta at -20 and 0 °Cas indications for ice traction and wet skid resistance of tire treads made therefrom. The optimum loading ofOC of 9 wt% relative to total filler content shows better Payne effect, cure rate index, tan delta at-20 and 60 °C indicative for rolling resistance, and DIN (German Institute of Standardization) abrasion resistance index. The results indicate that the use of this hybrid filler may provide tires with better wet traction and lower rolling resistance and wear resistance compared with the pure silica-filled system.