Flat transparent top coat for retroreflective sheeting

Abstract From the Canadian patent

The novel retroreflective sheeting has a flat transparent top coat which is as tough and as resistant to solvents and abrasion as are alkyl resins and as weather, resistant as are acrylic polyesters. That top coat is made from a mixture of hydroxy-functional acrylic polyol and a curing agent which is an aliphatic polyfunctional isocyanate such as the biuret of 1,6-hexamethylene diisocyanate. The retroreflective sheeting may have a dual-layer top coat, the outer layer being relatively hard to provide good resistance to solvents abrasion and, weathering, and the inner layer being softer to make the sheeting more conformable.