Tag Archives: PVDF paint

Kynar paint for Barndominiums

Kynar Paint for Barndominiums

Many potential barndominium owners are looking to get the greatest value for their investment and many see this as their ‘forever’ home. If you fall into this category, I would highly recommend exploring Kynar® painted steel.

I could extol 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, PVDF is a kind of fluoropolymer, 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 resin; higher concentrations do not coat well, since acrylic is important for dispersion during coating processes.

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 an exception of carbon black. Many simple inorganics are metal oxides, such as 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 these paints carry 20- to 30- year warranties which allow for extremely little face, these companies all use ceramics and appropriate inorganic pigments.
One manufacturer we purchase Kynar 500 painted steel from is McElroy Metal. Here is a photo which really shows off performance differences between Kynar and SMP: http://www.mcelroymetal.com/elements/files/Kynar%20500%20VS.%20SP%20Flyer

Sadly, PVDF paints are not available nationwide. Personally – if available where I was planning to build and color choice was other than White, I would make an investment for better paint. I want my building to look as close to new as possible, for as long as I own it!

At NFBA’s (National Frame Building Association) 2019 Expo I cornered Sherwin-William’s representative for further information on Fluropon® (PVDF). Please enjoy this video:


SMP: Silicone-modified Polyester Paint

In today’s marketplace, most pole buildings are roofed and sided with silicon-modified polyester paint or SMP.

SMPs create a middle ground between PVDFs (Polyvinylidene Fluorides) and polyesters. Also known as silicone-protected and siliconized polyesters, SMPs use polymerized silicone to improve polyester’s chalk performance and gloss retention. Companies initially experimented with varying levels of silicone, and marketed high levels as superior to lower levels, but silicone became less important as the polyester resins themselves improved. Most SMPs now contain 30 percent or less silicone.

Steel Paint LayersSilicone-modified polyester systems vary greatly in quality. Polyester quality outweighs silicone content in importance, but SMPs still outperform straight polyesters in chalk resistance. A more important difference is in pigment type and quality. Some formulations use the same ceramic pigments as PVDFs; others rely on simple inorganics or organics. Since the better resin does little to prevent an organic pigment from fading, paying for silicone is no excuse for going cheaper with pigment.

SMPs vary in gloss from 20-60 at 60 degrees (semi-gloss to medium gloss). Realistic warranties for SMPs vary between 10-20 years and can feature impressive chalk, fade, and gloss retention promises. There are companies which do offer unrealistically long SMP warranties – I would encourage the reading of the actual warrantees closely, before paying extra for a product with a drastically high fade rate over time.

Like polyesters, SMPs are harder than PVDF resins, making them more resistant to rough handling. They are also more brittle, and tiny fractures can form on bends during roll forming. Manufacturers have generally considered these microscopic fractures insignificant, however some companies are warming their SMP coil before sending through the roll former.

Most paint decisions are compromises between performance and costs, with SMP being the middle ground in both as compared to polyesters or PVDFs. Color is an important consideration. Light colors reduce the appearance of chalk, and are readily formatted with inorganics. Some companies will offer polyesters in a light color range, but shift customers over to an SMP for darker ones.

With a chalk/fade advantage over polyesters, and a scratch/abrasion resistance advantage over PVDFs, SMPs are the most widely-used paint system in the non-commercial building market. SMP is still a good paint system – it just allows for more chalking and fading over a given time period than PVDFs such as Kynar®.