One word says it all – Kynar®. I could extol the aesthetic reasons to use Kynar® painted steel for longer than anyone would be willing to listen.
Polyvinylidene fluoride is acknowledged as the premium resin for coil coatings. Popularly known by its original trade name Kynar®, is a PVDF resin-based coating or finish, a family which includes Teflon and Halar. Key to these chemicals’ toughness is the bond between carbon and fluoride, the strongest possible polymeric connection.
PVDF resin has superior chalk resistance and gloss retention, as well as stain and chemical resistance. It is softer than SMPs and polyesters, however, making it highly formable without risk of cracking, but also relatively easy to scratch during transport or installation. PVDF is most durable when it makes up 70 percent of the resin; higher concentrations do not coat well, since the acrylic is important for dispersion during the coating process.
There are two general classes of pigments. Organic, or carbon-based, pigments are generally synthetic and relatively inexpensive to make. However, organics have fairly weak molecular bonds which are easily broken down by moisture, UV and pollutants, and so are prone to fading. Inorganic pigments are those which do not contain carbon, and may be naturally occurring or manufactured. They generally offer good fade resistance, with the exception of carbon black. Many simple inorganics are metal oxides, such as the widely used iron oxide and titanium dioxide.
Kynar® 500/Hylar 5000 systems, which are required to contain 70 percent PVDF, do not vary greatly between manufacturers. Since the paints carry 20- to 30- year warranties which allow for extremely little face, the companies all use ceramics and appropriate inorganic pigments.
One of the manufacturers we purchase Kynar® 500 painted steel from is McElroy Metal. Here is a photo which really shows the performance difference between Kynar® and SMP: https://www.mcelroymetal.com/elements/files/Kynar%20500%20VS.%20SP%20Flyer.pdf
Sadly, PVDF paints are not available nationwide. Personally – if available where I was planning to build and the color choice was other than White, I would spend the money for the better paint. I want my investment to look as close to new as possible, for as long as I own the building!
Kynar 500® is a registered trademark belonging to Arkema Inc