Comparative Study of Silica, Carbon Black and Novel Fillers In Tread Compounds

In response to increasing demands for improved fuel economy and performance, companies are seeking advancements in tire technologies ranging from novel constructions to new material systems. Innovations and technology development of tire tread provide exciting opportunities to make strides in low rolling resistance tires.

 The chemical formulation of tread compounds can significantly impact tire performance for key attributes including rolling resistance, traction and wear. In particular, fillers in elastomer compounds significantly affect the behavior of tread compounds. Historically, carbon black was the primary filler in tread compounds and provided enhancement of the tread's wear resistance. Now, with the focus on low rolling resistance tires, emerging commercial options for fillers include new silicas as well as non commercial, unique fillers with varied chemistries and surface geometries.

 In this study, a variety of fillers were evaluated in a model tread compound for low rolling resistance tires. Material properties were compared for tread formulations using a range of filler types including carbon black, silica with varied surface areas, dual phase carbon black-silica, POSS, and aramid-based filler. Key findings include effect of fillers on cure kinetics, tensile properties, durometer and tear resistance. Dynamic mechanical thermal analysis results are correlated to on-vehicle performance predictors for rolling resistance and traction by assessing tangent delta in various temperature regions. This study shows that selection of specialty silicas and unique fillers provide a promising alternative to standard carbon black and silica reinforcements, as indicated by reduction of tangent delta at 60^oC. The primary technical challenges and potential future opportunities for using novel fillers in tread compounds are also discussed.