Solving “magic triangle” of tread rubber composites with phosphonium-modified petroleum resin

Abstract

The wet traction, rolling resistance and abrasion resistance have rarely been improved simultaneously in tread rubbers, which is regarded as “magic triangle” in tire industry. Recently, we have demonstrated that phosphoniums are effective in lowering rolling resistance of tread via catalyzing the interfacial silanization. In addition, incorporating the C5/C9-based petroleum resin into tread formulation is a well-established technology toward high wet traction. Accordingly, we aim to solve the “magic triangle” dilemma by using phosphonium-modified petroleum resin (PSR), which is prepared through a two-step reaction. PSR is incorporated into the silica-filled styrene-butadiene rubber (SBR) composites with bis [3-(triethoxysilyl)propyl] tetrasulfide (TESPT). Due to the electrostatic interaction between PSR and silica, the dispersion of silica is improved. Moreover, PSR exhibits catalytic effect on the interfacial silanization, leading to the improvement of interfacial interactions. With incorporation of 2 phr of PSR, the tan δ at 0 °C and abrasion loss of the rubber composite are increased by 19% and decreased by 28%, respectively, which suggests that the wet traction and abrasion resistance are increased. The tan δ at 60 °C of the rubber composite is decreased by 14%, indicating that the rolling resistance is decreased. In addition, the overall excellent “magic triangle” performance of a typical tread rubber is also demonstrated by incorporating PSR, indicating that PSR has great potential in practical applications. We envisage that this study provides a new solution for high-performance tread rubber for green tires.