Steel, a time-honoured and unyielding substance, has played an essential role in shaping modern infrastructure and construction for generations. However, with the innovation of its colour-coated variant, steel’s versatility reached new heights. By marrying the strength of conventional steel with a spectrum of colours, the innovation of pre-painted steel/colour-coated steel, has opened up a world of possibilities in paint systems. Each system boasts unique advantages, catering to specific requirements.

Some of the most popular paint systems used for colour-coated steel products are: Regular Modified Polyester (RMP), Silicone Modified Polyester (SMP), Super Durable Polyester (SDP), and Poly Vinylidene Fluoride (PVDF). In this article, we delve into the traits, diverse varieties, and extensive applications of different coatings in colour-coated steel.


Types of colour-coated steel

1. Regular Modified Polyester (RMP) coated steel:
Regular Modified Polyester (RMP) is a type of polyester coating used in the pre-painted steel industry. It is a popular choice for various applications due to its favourable characteristics and cost-effectiveness.

Applications:

• Roofing: RMP-coated steel is commonly used for roofing applications in residential, commercial, and industrial buildings. Its weather resistance and aesthetic options make it a popular choice for roofing sheets and panels.

• Wall Cladding: RMP-coated steel is also used for wall cladding in buildings. It provides an attractive and durable finish, protecting the building's exterior from weather elements and enhancing its visual appeal.

• Interior Decoration: Polyester-coated steel is frequently used in interior applications such as ceiling tiles, wall panels, and partitions in commercial and residential buildings.

• Indoor Furniture: It manufactures indoor furniture components and fixtures, adding an aesthetic touch to household items.
  

2. Polyvinylidene fluoride (PVDF) coated steel:
PVDF is a high-performance coating known for its exceptional weather resistance and ability to retain colour vibrancy over an extended period. It is made from fluoropolymer resin, which offers outstanding resistance to UV radiation, chemicals, and atmospheric pollutants. The coating can be used in the temperature range of -60 degrees celsius to 150 degrees celsius for a long time. Usually the thickness is 40-60 microns and can be customised for special requirements.

Applications:

• Roofing and cladding: PVDF-coated steel is extensively used in roofing and wall cladding for commercial, industrial, and residential buildings due to its ability to withstand harsh weather conditions.

• Architectural façades: It is employed in creating visually stunning architectural façades that remain vibrant and attractive for years.

• Outdoor signage: PVDF-coated steel is ideal for outdoor signage due to its exceptional colour retention and resistance to fading.
  

3. Polyurethane (PU) coated steel:
Polyurethane coatings are highly durable and offer resistance to various elements such as ultraviolet light, moisture, and temperature. They are especially useful in applications that require added protection against wear and tear. PU-coated steel is available in different finishes, including smooth, textured, and embossed, providing a variety of aesthetic choices. Usually, this coating is 1.5 mm (1500 microns) as it is applied in multiple layers.

Applications:

• Industrial equipment: PU-coated steel is used for manufacturing industrial equipment and machinery that requires excellent resistance to chemicals and wear. PVDF piping has a service temperature up to 248°F (120°C).

• Garage doors: It finds application in manufacturing garage doors that can withstand frequent use and harsh weather conditions.

• Transportation: PU-coated steel is used in the transportation industry to create durable and visually appealing road signs, billboards, and railings.

4. Plastisol-coated steel:
Plastisol coatings consist of PVC (polyvinyl chloride) with plasticisers, resulting in a textured and highly durable finish. This type of colour-coated steel is known for its exceptional resistance to physical damage and abrasion.

Applications:

• Roofing and wall cladding: Plastisol-coated steel, usually 200 microns in thickness, is a popular choice for roofing and wall cladding in industrial and commercial buildings due to its robustness and longevity.

• Agricultural buildings: It is used in agriculture for barns and storage facilities, where resistance to environmental elements is essential.

• Industrial doors: Plastisol-coated steel is employed in manufacturing industrial doors, automotive parts and medical devices for added durability.
  

5. Silicone Modified Polyester (SMP) coated steel:
SMP-coated steel is a popular choice for applications that require enhanced weather resistance and improved colour retention. It is a blend of polyester and silicone resins, offering superior UV protection and durability compared. Silicone coating, having a thickness of 20 microns, improves the weather resistance and gloss retention of polyester coatings.

Applications:

• Residential roofing: SMP-coated steel is commonly used in residential roofing applications, where its weather resistance ensures long-lasting protection for homes.

Conclusion
The use of colour-coated steel has revolutionised the fields of construction, architecture, and manufacturing due to its numerous benefits, a wide range of types, and versatile applications. This material has become vital for architects, engineers, and designers who prioritise aesthetic appeal and functionality. GI (Galvanised Iron) and GL (Galvalume or Aluzinc) are two distinct steel substrates that play a crucial role in the world of pre-painted steel products. GI is coated with a layer of zinc, achieved through galvanisation, which imparts excellent corrosion resistance to the steel. On the other hand, GL is a combination of zinc and aluminium. The pre-painted steel products with GI and GL substrates offer a reliable and visually appealing solution for a wide range of applications, combining corrosion resistance, durability, and design flexibility. As technology progresses, coatings for colour-coated steel are expected to continue to improve, presenting even more opportunities for diverse applications.