Anti-Graffiti Properties of Polyurethane Powder Coatings

Graffiti in street furniture and architectural facades is an increasingly important issue. For metallic structures, anti-graffiti coatings have to guarantee excellent corrosion protection, as well as have an easy-To-remove capability. In addition, color and gloss should not be changed because of natural weathering. In this work, two anti-graffiti polyurethane powder coatings applied were studied. In particular, these layers were deposited on aluminum substrate used in architectural application. Two different surface finishes, smooth and wrinkled, were considered. The efficiency of four different removers was investigated. For this purpose graffiti were drawn on the coatings by means of blue felt-Tip marker and a red acrylic spray paint. Gloss and color changes were collected. Methyl-ethyl-ketone and a remover, based on aliphatic and aromatic compounds, resulted in the most effective means, producing a limited change in the appearance. On the contrary, the wrinkled surface result was less resistant. To simulate the weathering effect, UV-B cyclic tests and the Taber abrasion test were carried out.