There are two types of powder coating; thermosetting powders and thermoplastic powders. Thermosetting powders are talked about a lot and used by everyone from OEMs to job shops. When thermosetting powders are cured in the oven they crosslink and essentially create a whole new chemistry that can’t be changed. There are a range of chemistries — think polyester, epoxy, urethane etc. — and they are generally available in a huge range of colors and special effects.
Thermoplastic powders are perhaps less well known but just as interesting! Thermoplastic powders utilize longer chain molecules, and they do not crosslink. There are also different chemistries available with thermoplastic powders — for example, nylon and polyethylene — and while they are available in many different colors for very beautiful coatings, they are often used for their functional properties rather than wide-ranging aesthetics. Unlike thermosetting powders that crosslink and don’t melt again after cure, thermoplastics do melt again when exposed to high heat after cure.
Q: Have there been any breakthroughs in thermoplastic powder coatings recently?
When talking about the pros and cons of thermoplastic powder coatings, traditionally the outstanding impact resistance, corrosion resistance and UV performance were a tradeoff for lower scratch resistance. Thermoplastic powder coatings were always a great option in applications where the impact resistance was more important than the scratch resistance. Well, there have been some drastic breakthroughs in this department. Thermoplastic powder coatings can now provide scratch resistance performance much closer to conventional thermoset coatings. In extreme applications such as inground parts that are in contact with dirt and rocks, the scratch resistance of thermoplastic powders can be well past conventional thermoset. And this is opening up thermoplastic powders to new applications where scratch resistance is every bit as important as impact resistance. Trailers are an excellent example.
Q: What are good examples of thermoplastic powder coatings applications?
Thermoplastic powders are known for their excellent adhesion to metal substrates, outstanding mechanical and chemical performance, and they also deliver excellent weathering, so are used in a wide range of industries and applications. The most famous — or at least one of the most fun applications — are football helmet masks! If you have a 250-pound football player coming at you, you want tough protection — and, of course, team colors are also important.
A particularly unique technical advantage is that thermoplastic powder will flex and actually bend with the metal substrate. In fact, the metal will usually break well before the thermoplastic powder film. A great example of this is welded wire parts. You may think of it as impact resistance — and there is an element of that — however, welded wire parts have to flex and almost move. Take, for example, the coating on a shopping cart when a case of bottled water is tossed in. If it doesn’t flex, then it will crack and allow rust in — and there begins a whole host of other problems. A recent field study demonstrated this with some very interesting results.
Read more: Cleveland Ohio Powder Coating: On Thermoplastic Powder Coatings
