Interaction of Silica Types With Other Compounding Ingredients for Modifying Viscoelastic Properties in Tread Compound Design

The changes in dynamic and physical properties of a fuel efficient, high performance, SSBR compound are evaluated in a partial factorial DOE experiment.  This is done to develop a priority for the factors that influence key viscoelastic and physical properties (responses).  The responses this work investigates are the laboratory test properties generally considered to relate to the tire performance triangle: rolling resistance, wet traction, and abrasion resistance.  This work studies varying three types of highly dispersible (HD) reinforcing silicas: ULTRASIL^® 5000 GR silica, ULTRASIL^® 7000 GR silica and ULTRASIL^® 9000 GR silica having CTAB surface areas of 110, 160, and 200 meters squared per gram, respectively.  These three silicas will be varied along with five other compounding factors.  These “other” compounding factors were selected as key to dynamic-mechanically interacting with the HD silica types being studied.  The expected interactions would allow for greater manipulation of the viscoelastic responses associated with tire performance characteristics.  These “other” compounding factors in this study are: silica loading level, plasticizer loading level, elastomer blend (average glass transition temperature), elastomer microstructure ratio (styrene to vinyl ratio), and silane crosslinking characteristics.  The analysis will summarize the relative strength of each of these factors for the reported rubber viscoelastic and physical properties.