Top coats for building and construction

In cases where the coating itself does not provide all the desired properties - mostly with PVC and also with silicones - top coats or top finishes are applied to form a final barrier to the environment, providing UV stability, hardness, durability, inertness and self-cleaning attributes. Top finish systems apply a thin barrier layer of material to the exterior surface. This barrier layer minimises plasticiser migration and provides a hard surface which sheds dirt. The effectiveness and longevity of the top finish depends on its chemical make-up and on the thickness of the barrier layer applied to the surface. 

Top finishes are formulated using clear acrylic, acrylic/vinyl or acrylic/ polyurethane resins and are applied at a thickness ranging from 0.1 mm to 0.4 mm. Other top finishes on a base of fluorocarbonpolymers, e.g. PVDF, PVF or FEP, are applied within a range of 1.0-1.5 mm. If the top layer is applied as a foil, e.g. 0.03 mm PVF foil, it will give better protection than would a top coat applied in liquid form, because the surface will be more effectively sealed against environmental impact. If weldable textiles or foils are welded together, the non-weldable top coats have to be removed from the welding area. If not done properly, this already critical zone is left partly unprotected. 

---