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What Is SMP Coating?

2025-05-22

SMP coating, silicone modified polyester coating, is one of the most commonly used top paints in pre-painted steel. It combines the features of polyester resin and silicone resin, which is of excellent durability and color retention, high wear resistance, and great corrosion-weather resistance. In the general environment, its service life is more than 10 years. Therefore, the SMP color Coated Steel is widely used as roofing and wall panels of buildings in light industrial areas, commercial areas, residential areas, as well as areas with heavy sandstorms, steel mills, and other fields.

Since polyester contains active groups -OH/-COOH, it is easy to react with other polymer compounds. But silicon is a relatively stable chemical element, which can improve the light resistance and chalk resistance of polyester. The denaturation ratio with PE can be 5%-50%. The hardness, wear and heat resistance of the modified polyester coating are improved, so that the SMP color coated steel has excellent durability and chalking resistance.

SMP Coated Steel Coil
RAL9003 SMP Painted Steel

Features of SMP Coating

1. Great outdoor durability;

2. Excellent pollution resistance, weather resistance, and chalking resistance;

3. High coating hardness, great wear and scratch resistance, and heat resistance;

4. Good color and gloss retention.

Applications:

Due to its great outdoor durability and scratch resistance, SMP color-coated steel is mainly used in areas with heavy wind and sand, as well as in mines, steel mills, and other fields. It is mainly used as roofing or wall panels of buildings or garages, warehouses in light industrial areas, commercial areas, residential areas, suburbs, and rural areas.

However, due to the poor adhesion and processability of silicone resin, SMP color-coated steel is not suitable for occasions requiring multiple forming processes.

Steel Roofing & Siding
Use in Warehouse

Common Paint Types

The most commonly used paints include PE (polyester), SMP (silicone modified polyester), HDP (high durability polyester), and PVDF (polyvinylidene fluoride) coatings.

PE coating features good adhesion and low cost, and rich colors. However, its UV resistance and chalk resistance are poor. Therefore, PE coatings are generally used in areas with less air pollution or products that need to be processed multiple times. Its service life can reach 7-8 years.

SMP paint has good hardness, scratch resistance, and heat resistance; as well as good durability and chalk resistance. But its softness is poor and its cost is medium. Its service life can be as long as 10-12 years. But SMP coated steel is not suitable for use in forming and processing, and most of them are used as roofing and exterior walls.

HDP paint has excellent color retention and UV resistance, excellent outdoor durability and chalk resistance, good film adhesion, rich colors, and excellent cost performance. It promises a 15-year warranty. Hence, HDP painted steel is ideal for light steel structure buildings with high requirements for UV resistance.

PVDF coating has superior corrosion resistance, excellent color retention, and UV resistance. It also has excellent outdoor durability and chalk resistance, excellent solvent resistance, and dirt resistance. Its service life is more than 20 years in a normal environment. But it has limited color and its cost is high. They are mainly used in chemical plants, power plants, steel plants, commercial and public buildings, such as high-speed railway stations, etc.

Below is a table for your reference.

Paint Types	Hardness	Bending performance	Corrosion resistance	Weather resistance	Cost
PE	Excellent	Good	Good	Great	Low
SMP	Good	Medium	Great	Excellent	Medium
HDP	Good	Excellent	Great	Excellent	Medium
PVDF	Medium	Excellent	Excellent	Excellent	High

How to Choose Paints for Different Applications?

Steel plants and power plants: PE color-coated steel is not recommended.

Smelting plant has strong corrosion resistance, and it is better to choose PVDF color-coated coils.

Cement plants are seriously polluted by dust, so HDP or PVDF coated steel or color coated steel with self-cleaning effects is more suitable.

Machinery factories/Warehouses: In general, PE coated steel is widely used. If there are boilers or other corrosive substances, choose SMP, HDP, and PVDF coatings.

Animal husbandry: HDP coating is recommended.

Public buildings: It is recommended to choose HDP and PVDF paints with high-strength and high-zinc layer base metal.

Civil buildings: Just choose according to economic conditions and personal preferences.

Home appliances: The color coated steel for home appliances mainly uses VCM and PCM coated steel sheets.

Office furniture: Pay more attention to the processing performance of the material and the cut area.

Automotive industry: has more and more demands for galvanized sheets, and the requirements for complete vehicles and accessories are quite different. Choose appropriate galvanized products according to design requirements.

Conclusion

At XINYONGYUAN Steel, the coatings, PE, SMP, HDP, and PVDF, are all available. Besides, we also offer color coated steel with special uses purposes, such as antistatic color coated sheets, nano coated steel, antibacterial steel, etc. More than that, we can offer different coating thicknesses, coating methods, colors, patterns, base metals, etc. Welcome to contact us for more details!

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