Differences In Polymer Coatings For Metal Tiles

2023 Author: Douglas Hoggarth | [email protected]. Last modified: 2023-05-24 11:23

The appearance and durability of steel building materials largely depend on the protective coating that protects it from aggressive environmental influences. The correct choice of metal roofing (taking into account climatic and geographical conditions) can significantly increase its service life.

Finnish manufacturers have developed several coatings for metal tiles, which have their own characteristics and areas of application. Let's take a closer look at each of them:

PURAL (PU) - Coating based on polyamide modified polyurethane. Developed in 1999 by specialists of the Finnish concern Rautaruukki exclusively for use on the roof, it is recognized as the best coating offered today. The Pural coating has a silky matte surface.

Why is pural considered optimal coverage?

• Pural is highly resistant to corrosion, fading and mechanical damage. The thickness of the pural coating is 0.05 mm, of which 0.02 mm falls on the primer. Its thickness is much higher than the thickness of primer paints applied under other polymer coatings, which means that it contains more anti-corrosion component.

  Pural coated steel is used for the production of both metal and seam roofing. Pural coated sheets are easy to process (cut and do not give microcracks on the folds) at temperatures down to -15 degrees Celsius, which is lower than sheets with other coatings. Roofers and tinsmiths appreciate this coating very highly.

  Manufacturer's warranty - 15 years.

The combination of all these qualities gives us reason to assert that pural is the optimal coating for metal tiles.

PUR coated metal tiles are also presented on the Russian market. Some sellers mislead buyers, claiming that this is the same pural, only not Finnish, but Swedish. However, it is not. Pural-coated steel is produced by the Finnish concern Ruukki (this is the name of the Rautaruukki concern since September 1, 2004). The above-mentioned coatings differ substantially, primarily in the coating material. Pural is a polyurethane-based coating that is significantly stronger than PUR coating. PUR is a polyester-based coating (also known as P-50, produced by the Swedish concern SSAB). In addition, the pural has a thicker primer coat, therefore better protection against corrosion. PUR-coated metal tiles are more difficult to install at sub-zero temperatures - the minimum processing temperature is only -5 degrees Celsius, compared to -15 for pural. Laboratory tests show that pural has a higher color fastness. Finally, the PUR coating has an unstable coating thickness (42-48 microns versus 50 microns for pural).

POLYESTER (PE) - polyester based coating. It is the most inexpensive of the Finnish coating manufacturers. It is suitable for those who do not have any increased requirements for reliability. Metal tiles with this coating can withstand high air temperatures, are resistant to corrosion, and their resistance to mechanical damage is lower than that of Pural and PVF2 coatings.

MATT POLYESTER (PEMA) - This polyester coating has good color fastness, corrosion and mechanical resistance and good weather resistance. Most often, this coating is chosen by people who care about the lack of gloss on the roof.

PVF2 (PVDF) - near industrial plants, the air is polluted by compounds of various chemical elements (sulfur, chlorine, nitrogen), as well as dirt and soot. For such aggressive conditions the PVDF coating is best suited, consisting of 80% polyvinyl fluoride and 20% acrylic. This coating was originally developed for facades and is mainly used on façade structures. The strongest, most UV-resistant coating practically does not fade, has a beautiful gloss. In terms of its performance characteristics, PVF2 coating is comparable to pural coating, however, metal tiles with this coating are more expensive.

PLASTIZOL (PVC) is a decorative polymer consisting of polyvinyl chloride and plasticizers. Due to the large thickness of plastisol (0.2 mm), this coating is one of the most resistant to mechanical damage, but it has a relatively low temperature resistance and resistance to UV radiation. Finnish manufacturers do not provide a guarantee for this coating and are gradually reducing its production.

As they say, trust, but verify. If you are choosing a metal tile, you have already bypassed several roofing companies, where you have taken samples of coated metal, and you still doubt its quality, come to us, we will conduct comparative tests with you and choose the most suitable coating.