2026 年 99 巻 6 号 p. 136-141
Petroleum resins are widely used in applications such as paints, adhesives, and rubber compounds due to their miscibility with various solvents and polymers. Particularly within the automotive industry, extensive research is being conducted to achieve further improvements in fuel efficiency. It is known that incorporating petroleum resins into rubber compounds modifies the rubber, notably enhancing its wet grip properties. This study focused on a newly developed modified petroleum resin (MPR), which possesses reactive groups for interaction with rubber and has been confirmed to provide a balanced improvement in wet grip, fuel efficiency, and abrasion resistance. Using nano-palpation atomic force microscopy, the morphology and physical properties of SBR compounded with MPR and silica were examined. In well-balanced tire compounds, the miscibility between MPR and SBR is crucial. However, the introduction of a third component, silica, was found to cause MPR to selectively distribute and localize at the silica interface. This localization could be eliminated by doubling the kneading time or by adding MPR later. Stress-strain curves suggested that stress chains connecting silica particles appear within the matrix, leading to a stress upturn. The fine dispersion of MPR within the matrix mitigates stress concentration at the silica interface, thereby enhancing tensile properties.
