Kraton pioneered refining crude tall oil (CTO) into biobased chemicals, including tall oil rosin, dating back to the 1930s. Refined rosin typically has a color that can vary from pale yellow to dark red, depending on the CTO source and refining effectiveness. The rosin can then be upgraded into rosin ester resin through a stabilization and esterification process. Formulators use rosin ester resins to make products for various applications, including adhesive applications like case sealing or electronics assembly and coatings applications like furniture varnishing or road marking. Formulators often prefer these biobased resins to petroleum-based alternatives due to performance advantages like adhesion and chemical resistance.
Road markings are an essential application in the coatings industry because of their critical role in road safety. Improving road safety has been an increasingly important goal for governments and road owners worldwide for many years due to the expanding world population and rising mobility. According to the World Health Organization (WHO) Global Status Report on Road Safety, road traffic accidents kill more than 1.3 million people each year. Traffic accidents are the number-one cause of death for children and young adults ages 5 through 29. Road safety experts know that road markings are among the most effective and economic countermeasures to reduce accidents. The growing trend toward vehicle automation is making road markings even more critical. Because more than half of all traffic fatalities involve lane-departure events, lane-keeping technologies have the potential to save millions of lives over time. Lane-keeping technologies depend on machine vision systems constantly identifying the center and edge lines on the roadway. Because of this dependence, several leading players in automated vehicle technology have recognized that road markings are the single most crucial piece of infrastructure to enable vehicle automation.
Key attributes that enable both human and machine visibility of road markings include the markings’ retro-reflectivity and luminance. Glass beads on the road-marking surface bounce light from a car’s headlights back to the driver, giving retro-reflectivity. Titanium dioxide and other pigments in the road marking impart luminance and whiteness, giving the marking visual contrast from unmarked pavement. These attributes offer good visibility in the nighttime and daytime. For this visibility to last, there must be good adhesion to both the road surface and the glass beads. Rosin ester resins are the preferred resin technology in high-performance hot-melt thermoplastic road markings because of the excellent adhesion they can enable.