Q: I have just started a powder coating operation in Bangladesh and could use your advice. What type of weatherability can I expect out of powder coating technology? Many of my customers are in the architectural business.
A: Congratulations on your new business venture. Powder coating is a great technology in many ways and is a good fit for industries in your developing nation.
A variety of powder coating technologies are commercially available to meet the demands of the architectural industry. Most people differentiate weatherable coatings by their performance in South Florida exposure. The primary criteria are retention of gloss and resistance to color change. Powder coatings generally have excellent corrosion resistance when applied to properly prepared substrates.
Polyester-TGIC, polyester-Primid®, and polyester-urethane powders, if suitably formulated, will endure 18-24 months in Florida before displaying cosmetic signs of degradation. “Superdurable” forms of these three powders have maintained appearance and coating integrity after being subjected to five years of exposure in South Florida.
Acrylic-diacid powders are considered automotive quality. Tests have demonstrated that these products withstand up to nine years of Florida exposure before showing signs of deterioration. Silicone-containing powder technologies have emerged in the past few years. These are almost exclusively targeted at the high-heat market, which includes substrates such as gas grills and exhaust parts. Further development effort is needed before silicone-modified powders can be introduced for the architectural market.
Fluoropolymer-based powder coatings have been developed by several major powder coating suppliers. These materials have been proven to perform admirably after 10+ years of Florida exposure. This technology is great and comes with a significantly higher cost than the more conventional products mentioned previously.
Bangladesh gets a lot of sunlight, and UV durability is an important coating feature. By using a judicious coating selection process, you should be able to satisfy the architectural coating requirements of your customers.