Officials of the town of Norwalk, California, in an effort to combat the eyesores created by graffiti vandals, have specified a durable, urethane-based anti-graffiti coating system to protect 12-foot-tall concrete soundwalls that buffer noise pollution along sections of the Santa Ana Freeway. The system consists of a clear heavy-duty polyurethane applied over a pigmented color coat.
Based on an aliphatic polyisocyanate resin, the urethane topcoat is formulated with a release agent that is said to continually migrate to the coating surface to resist adherence of graffiti materials. The coating resists washing off when graffiti is removed. As an aliphatic system, the urethane coating also resists yellowing, chalking or loss of gloss due to ultraviolet radiation from the sun.