Available coatings include polyesters, plastisols, polyurethanes, polyvinylidene fluorides (PVDF), epoxies, primers, backing coats and laminate films. For each product, the coating is built up in a number of layers.
Primer coatings form the essential link between the pretreatment and the finish coating. Essentially, a primer is required to provide inter-coat adhesion between the pretreatment and the finish coat and is also required to promote corrosion resistance in the total system. The composition of the primer will vary depending on the type of finish coat used. Primers require compatibility with various pretreatments and top coat paint systems; therefore, they usually comprise a mixture of resin systems to achieve this end.
Backing coats are applied to the underside of the strip with or without a primer. The coating is generally not as thick as the finish coating used for exterior applications. Backing coats are generally not exposed to corrosive environments and not visible in the end application.