The coating is applied to metal in several layers:
1. PRIME COATING
2. TOP COAT
3. BACKSIDE COATING.

Primer is applied between the chemical composition layer and the top coat to increase the adhesion of the top layer and anti-corrosion properties. Primer is rich of chrome and provides excellent corrosion protection.

Primer is applied in a thin layer of 5 - 7 m thickness of the dry coating. Primer gets totally dry at °C. Until quite recently, the most common type of primer coating was epoxy primer. The coating typically contains 35-40% solids. However, primer based on polyester is now very popular because of the low cost, the increased adhesion and anti-corrosion properties. Water-based primers are also used, but they are compatible only with water-based topcoats.

In general, water-based coatings are not very popular, since in most cases they are more expensive and more difficult-to-apply. However, these coatings have excellent adhesion.

Special coatings with a high content of particles (often polyurethanes) are also used where a more serious corrosion protection in a corrosive environment is required.

Several types of coating are currently used. The most popular type is polyester-based coating, commonly used for construction purposes (wall panels, metal tile roofing). Other coatings are based on acrylic resins, polyurethane, polyvinyl chloride, water-soluble coatings, with the addition of silicon, based on vinyls and alkyd resins. Each coating has its advantages, it is important that top and primer coatings match. Top coat can also be applied without primer. Particularly durable coatings such as fluorocarbon paints are more and more used nowadays. It’s an excellent coating for aggressive weather conditions, but is also the most expensive so far. Decorative coatings are also rapidly developing. Such coatings may have any image should the customer so wish. The applying process is basically applying of ink to the substrate (with or without prime coating, depending on the further use) by rotogravure or flexographic methods. A thin layer (5um) of transparent lacquer is also applied for excellent coating stability performance.

1) PVDF is the most resistant polymer coating of steel to any non-mechanical effects of the environment. It is recommended to use PVDF products for walls, as PVDF coating acquits itself well in wall panels and provides the longest working lifespan. PVDF ensures long-lasting integrity of the roof and wall covering. PVDF is the most eco-friendly coating which does not fade with time and provides increased resistance to corrosive effects of water, snow, acids and alkalis. The maximum operating temperature is 120 degrees above zero, the minimum operating temperature is 500 C below zero. Color of the covering or the roof of your house, if it is made of PVDF-coated steel, does not fade with time and does not fade in the sun. If your premises are located in an industrial part of the city, near the road, lakes or on the coast, if you are building or cover the chemical production premises, the walls of which will be often washed with water or disinfectant solutions, PVDF-coated steel will be the best material for you. Corus PVDF-coated galvanized steel is available in standard colors, as per RAL catalog, and in colors imitating natural metals - aluminum, copper, gold.

2) POLYESTER (PE) is polyester-based coating. PE-coated products withstand high air temperature and have a greater resistance to corrosion. The material is strong and durable enough: roofs made of PE-coated steel sheets can properly serve for 20-30 years. The warranty period is 10 years. Polyester became popular because of its high resistance to weathering, aesthetics, good color fastness, ductility, durability, a huge selection of colors, all at reasonable prices. This material is widely used in Russia for the manufacture of roofing and wall structures, both in the private and in high-rise and industrial construction. Wide range of PE-coated steel applications is caused primarily by the fact that the coating is suitable for all climatic conditions. Products made of PE-coated galvanized steel are a guarantee of durability and high corrosion resistance, wide range of colors, multi-purpose area of application, reasonable price.

2.1) MATTE POLYESTER is polyester-based coating. This coating is chosen by people who do not like shining roofs. Matte polyester seems velvet when you run your hand over it. The reason is that the surface is not smooth as in the other coatings, it is covered with microscopic irregularities. Sunlight diffuses when reflecting from such coating. Therefore, the coating is matte. Since it is impossible to determine exactly the thickness of such coating, it is in any case applied in a thick layer, as a reserve. Therefore, its lifetime is longer than that of polyester coating, though they have similar chemical composition. Lifetime - 40 years. Warranty period - 15 years. The material has a high color fastness and mechanical resistance, retains its quality in any climate. Due to the velvety surface, the original polyester-based coating is very closely imitates natural materials. Matte polyester has an attractive texture. Due to its matte surface, rather than shiny surface of conventional polyester, imitation of natural materials is achieved. Improved chemical resistance and good mechanical properties of matte polyester is achieved by coating thickness - 35 microns.

3) PLASTISOL (PVC) is a polymer consisting of polyvinyl chloride and plasticizers. Due to the large thickness (0.2 mm), this coating is the most resistant to mechanical damage, has high corrosion resistance, which creates additional protection in polluted environments or on the coast, but it has a relatively low thermal resistance and quickly fades in the sun. It is recommended to use light colors of plastisol that fade or heat up less and reflect light better. The coating has a relief surface - embossing simulating leather or line scratching, which does not allow for sun glints.

4) POLYURETHANE (PU) is coating made of polyamide- and acryl-modified polyurethane. Polyamide gives it excellent resistance to UV and acryl provides high strength. It has a silky matte surface. The durability of the material is made up of high corrosion resistance, resistance to adverse effects of ultraviolet radiation and unmatched resistance to mechanical damage. Nominal coating thickness is 50 microns. Moreover, polyurethane has an extremely high resistance to many acids, ie chemicals specific for industrial atmosphere. Results of salt spray resistance testing confirm that the durability of polyurethane-coated materials holds firm in a marine environment. When processing and bending at low temperatures, the material does not form microcracks in bend sites. This coating is more durable than polyester. Lifespan - 30-50 years. Warranty period - 15 years. Polyurethane coating is widespread in Russia thanks to its English counterpart. Colorcoat Prisma is made in England, by Corus - one of the world’s largest steel concerns. Prisma-coated steel has a Galvalloy protective layer consisting of 95% zinc and 5% aluminum, providing unrivaled corrosion protection. Prisma-coated products have superior resistance to UV and mechanical effects.

Whenever top coating is applied to a strip, it is recommended to apply backside coating. If this coating is absent, there is a great risk of damage to the top coat by an uncoated side when rolling. Backside coating is usually applied in a layer of 5-7 m thickness (dry layer). It is usually applied in conjunction with top coating and dries out simultaneously. Such coating may be of any type, but for economic reasons alkyd resin- or polyester-based coatings are most commonly used. Aluminum strip coating is typically a layer of colored lacquer.