What Is PVDF Coating?

PVDF coating (polyvinylidene fluoride) is the best existing organic coating, offering great colour retention and corrosion resistance. It is made of 70% fluorocarbon resin and 30% acrylic resin, with special weather-resistant pigments. With fluorine resin as the main film-forming material, PVDF is a perfect protective coating for metal building panels, such as steel and aluminum. Its service life can reach 25 years under normal conditions. While it is also suitable for highly corrosive environments.

Compared with traditional paintings, PVDF coating has better weather resistance and superior resistance to corrosion, UV, pollution, and scratch. It will maintain its color and luster after 20 years outdoors. Also, it is available in a wide range of colors. Therefore, PVDF coated steel is mainly used in public buildings, such as airports, commercial or office buildings, sports venues, and buildings in harsh environments, like industrial plants, power plants, steel mills, chemical industry, granaries, etc.

Here let’s use PVCF coated galvanized steel sheet for example to review its structure. It uses galvanized steel sheets as the base metal.

Uses of PVDF Coated Steel

1. Road and bridge construction, road signs and billboards, highway guardrails, railings, etc.
2. Roofing or wall for factory buildings, warehouses, hangars, granaries, gas stations and other industrial buildings; civil buildings, commercial and public buildings, such as office buildings, tourist villas, exhibition centres, gymnasiums; airports, supermarkets; mobile and modular prefabricated houses; etc.
3. Steel structures for overhead antennas and TV towers, etc.
4. Auto parts, trains, aeroplanes, ships, tankers, carriages, etc.
5. Home appliance shells, hardware accessories, ventilation ducts, etc.

Advantages of PVDF Coating

1. Excellent Weather Resistance

PVDF coating contains 70% fluorocarbon resin with a large number of F-C bonds, which determines its super stability. So it has superior resistance to weathering by ultraviolet light, moisture, or temperature. Its surface will not powder or fade for more than 20 years outdoors.

2. Super Corrosion Resistance

Thanks to its excellent resistance to chemicals, such as acid, alkali, salt, etc., PVDF coating will provide a protective barrier for the base metal. Besides, PVDF coating is 6-10 times thicker than the ordinary coating. The thick coating offers high surface hardness and good wear resistance.

3. Excellent High and Low Temperature Resistance

PVDF coating is applied to metal at a temperature of 200°C above, and on the lower surface using EP epoxy powder thermosetting resin, which can be used at 150 °C. After 10 times of freezing-thawing experiments, the resin layer did not fall off, heave, crack, peel, damage and other phenomena. The coating can be used in the temperature range of -60 ℃ to 150 ℃ for a long time.

4. Maintenance-free and Self-cleaning Performance

PVDF coating has very low surface energy, and the surface dust can be self-cleaned by rain. Besides, its maximum water absorption rate is less than 5% and its minimal friction coefficient is 0.15 to 0.17. So it will not stick to dust scale and oil.

5. Strong Adhesion

PVDF coating has excellent adhesion on the surfaces of metals, plastics cement, and composite materials.

Although PVDF coating is more expensive than other coatings, PDVF coated metal is still widely used in buildings. Its resistance to corrosion acid and alkali is 3 times better than common colour coated steel. After 20-30 years of outdoor use, there is no cracking, powdering, or fading on the surface. That’s why PVDF coated steel is getting popular for high-grade buildings (such as airport stadiums, etc.) or buildings in areas of severe corrosion (such as seaside areas, heavy pollution areas, etc.).

What to Know Before Using PVDF Coating?

1. To avoid substrate pollution and chemical conversion coating damage before painting. The pre-treatment process includes cleaning, degreasing, and removing rust from the metal surface first. Also, the paint should be placed in a dry, waterproof, leak-proof, sun-proof, high-temperature-proof, and fire-proof environment;
2. Strictly control the cleanliness of the coating room;
3. Keep the viscosity of the machine stable;
4. The primer coating can be polyurethane primer or epoxy primer;
5. The prepared PVDF paint must be used up within 5 hours in the activation period;
6. Can adopt two-layer and twice-coating method;
7. PMT should be higher than 249 °C, and the curing time should be longer than 23 seconds;
8. After baking, it can be cooled by air cooling or water cooling.

Conclusion

PVDF-coated steel is a versatile product in construction, like wall cladding, roofing sheets, etc. It is also commonly used in shipbuilding,  billboards, highway guardrails, etc. There are various colors, including white, red, blue, silver-grey, etc. You can also choose different colors according to the RAL color card. Also, the finish can be gloss or matte. At Wanzhi Steel, we offer a wide range of color-coated steel coils and sheets with different base metals, coatings (PE, SMP, HDP, PVDF), specifications, colors, finishes, etc. Of course, their price will be different with these factors. As a color-coated steel factory in China, we will provide you with a competitive price as well. Welcome to talk with us for more information.