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Colour coated steel coil has a wide range of uses across industries. It is mainly used in buildings, automobiles, home appliances, solar energy devices, furniture, etc. In home appliances, the sheets made from these steel coils are mainly used as the side door plate for refrigerators, freezers, air conditioners, and washing machines.
What is a colour-coated steel coil?
A steel coil that is coated with decorative paint on both sides is known as a colour-coated steel coil. Steel coils commonly feature polymer coating in various colours and matte, lustre or decorative natural finish. The colour coating protects it from atmospheric corrosion while giving it more strength and durability. Also known as pre-painted steel, colour coated steel is made by putting a steel sheet through surface pre-treatment, then coating for one or more layers, and finally baking and cooling.
How are colour-coated steel coils made?
Most times galvanised coils are used to produce colour coated steel coils. Usually, paint is applied after giving the hot-rolled and cold-rolled steel coils a metallic coating. Given below are the steps used to produce colour coated steel coils:
Step 1: Unwinding/paying of the steel coil into sheets
Step 2: Pre-cleaning the surface of the sheet
Step 3: Levelling the sheet
Step 4: Treating the sheet with chemicals and de-oiling
Step 5: Applying primer
Step 6: Curing/drying the primer in an oven
Step 7: Applying the paint coat (on one or both sides, dipping into a bath or using a roll method)
Step 8: Curing/drying the coat in an oven
Step 9: Cooling the sheet
Step 10: Recoiling into colour-coated steel coil
Sometimes color coated steel coil manufacturers apply a protective film to avoid mechanical damage to the colour coat.
Types of colour-coating
There are multiple chemical compounds used to colour coat steel. Depending on the type of resin used in colour coating, given below are some key types of colour-coating:
- Polyester (PE)
Based on polyether, steel coils with this coating are resistant to high air temperature and corrosion. They feature colour stability, plasticity and longevity and therefore are used in roofing and wall structures, particularly for industrial buildings. These are available in different colours. Wide range of colours and brightness make it perfect for applications like interior and exterior construction materials, assembling metals, and partitions.
- Polyester matt (PEMA)
PEMA has a smooth and matte surface with micro-roughness and is based on polyether. It has a longer life than PE and sports excellent colour stability with mechanical resistance. This steel can keep its property in any climate and can copy natural materials.
PVDF is a blend of polyvinyl fluoride (80%) and acryl (20%). It shows the highest resistance to non-mechanical environmental exposure. The compound is used for wall cladding and roofing as it features excellent resistance to water, snow, acids and alkali.
- Plastisol (PVC)
This polymer is made of polyvinyl chloride and plasticisers. It possesses a rather thick coating (0.2 mm) which contributes to good mechanical and weather resistance. However, it has relatively poor heat resistance and colour stability.
- Polyurethane (PU)
This coating is made of polyurethane modified with polyamide and acryl. It has improved resistance to ultraviolet radiation and weather exposure, high strength and longevity. Polyurethane is highly resistant to many acids and chemicals typical in an industrial environment.
- SMP, or silicone modified polyester
SMP paint systems are a combination of polyester and silicon intermediates. Silicon contributes to improving the gloss retention and weather resistance of the polyester coating. SMP-coated material is more difficult to scratch and resistant to chalk and fade.
Applications of color coated steel coil
Colour coated steel uses are many. The colour-coated steel is used in construction, home appliances, furniture, consumer goods and automotive industries. Colour coated steel coil is used for making:
- Roofs, roof structures, rolling shutters, kiosks, shutters, guard doors, street waiting rooms, ventilation ducts, etc.
- Electrical appliances including refrigerator, air conditioner, electronic stove, washing machine shell, oil stove, etc.
- Parts of automobiles including car ceilings, backboards, hoardings, car shells, tractors, ship bulkheads, dashboards, windscreen wipers etc.
There are many colour coated steel coil suppliers that offer the best quality pre-painted steel coils. To find the best colour coated steel coil manufacturers in India visit Tata nexarc’s Procurement where you can get connected with the trusted steel coil suppliers.