Influence of Oligomeric Resins On Traction and Rolling Resistance of Silica Tire Treads

This paper highlights the relationship between the function of various oligomeric resins in different concentrations (max 6 phr) on the dynamic mechanical behavior of silica reinforced tire tread compounds, three types of resins were tested: a polyterpene, a terpene-phenolic and a hydrocarbon resin. Dynamic mechanical analysis (DMA) was used, in addition to Mooney viscosity, cure meter tensile and hardness tests to assess the behavior of these resins in the rubber and to characterize the processibility of the compounds. The DMA shows that the resins and rubber compounds are compatible. The tan δ loss angle versus temperature was used as an indication for traction and rolling resistance. The shift in the tan δ peak to a higher temperature, due to the contribution of the higher T_g of the resins, is the reason for improved traction performance. A higher tan δ peak appears with increasing resin concentration. A maximum improvement of ca. 35% in the traction region (0-30°C) is found. The improved tan δ at 60°C, representing the rolling resistance, accounts for a better filler dispersion. This is also confirmed by a decrease in Payne effect. A maximum improvement of ca. 15% is found in the rolling resistance temperature range. The overall best results are found for terpene-phenolic and polyterpene resins, because these resin structures show the most chemical similarity with the rubber compound.