Anti-Graffiti Clearcoat

Graffiti markings are everywhere. Several types of "anti-graffiti" coatings have been developed over the years to address this ever-increasing problem. Some are one-time-use only; others are semi-permanent. Most are highly durable, crosslinked coating systems. Most can be made graffiti-resistant by the incorporation of surface additives such as fluoro/silane compounds, which orient themselves at the surface providing the marking repellency. All of these encounter some limitations. A new anti-graffiti coating that addresses some of those limitations has been developed. Being a one-pack moisture-cure, this organosiloxane coating eliminates the inconvenience of mixing multiple components typical of the crosslinked systems such as polyurethanes and epoxies the two most common types of high-durability anti-graffiti coatings. In addition, unlike the more traditional, economical single-pack coatings such as alkyds and latexes, this coating provides excellent resistance to weathering and moisture penetration. Moreover, it offers some advantages in cleanability. Pressurized water is typically sufficient to wash off the graffiti markings from this coating. However, stronger cleaning agents may also be used for persistent markings due to the coating's excellent solvent (MEK) resistance. Because of its outstanding adhesion, it can be applied over properly prepared fresh or previously coated concrete or masonry. The preparation, property evaluation, and application of this coating are discussed in this article.