Selection of Coating Materials for Color Steel Rolls

At present, the types of coatings used for color coated steel plates include polyester coatings/fluorocarbon coatings/silicon modified coatings/high weather resistant coatings/acrylic coatings/polyurethane coatings/plastisol coatings, etc.

1、 Polyester coatings have good adhesion to materials, and color coated steel plates are easy to process and shape, with low prices, a wide range of products, and a wide range of color choices. In general environments, direct exposure can result in a corrosion resistance life of up to 7-8 years. However, in industrial environments or heavily polluted areas, its service life will be relatively shortened. However, the UV resistance and film crushing resistance of polyester coatings are not ideal. Therefore, the use of PE coating still needs to be restricted. It is usually used in areas with less air pollution or for products that require multiple molding and processing.

2、 Due to the presence of active groups - OH/- COOH in polyester, it is easy to react with other macromolecules and polymers. In order to improve the light resistance and pulverization of PE, silicone resin with excellent color retention and heat resistance is used for denaturation reaction, and the denaturation rate with PE can be between 5% and 50%. SMP provides better durability for steel plates, with a corrosion resistance life of up to 10-12 years. Of course, its price is also higher than PE, but due to the poor adhesion and processing formability of silicone resin to materials, SMP color coated steel plates are not suitable for occasions that require multiple molding processes, and are mostly used for building roofs and exterior walls.

3、 High weather resistance polyester coatings are superior to ordinary silicon modified polyester coatings, with an outdoor weather resistance of up to 15 years. In the process of synthesizing high weather resistant polyester resin, monomers containing cyclohexane structure are used to achieve a balance between resin flexibility, weather resistance, and cost. Aromatic polyols and polyacids are used to reduce resin absorption of ultraviolet radiation and achieve high weather resistance of coatings. Add UV absorbers and space blocking amines (HALS) to the coating formula to improve the weather resistance of the paint film.

4、 Plastic sol has good water resistance and chemical resistance. Generally, it is a high solid content coating with a coating thickness of 100-300 μ M, which can provide a smooth PVC coating or a light embossing treatment as an embossed coating; Due to PVC coating being a thermoplastic resin with high film thickness, it can provide good protection for steel plates. But PVC has poor heat resistance.

5、 Due to the strong bond energy between PVDF chemical bonds, the coating has excellent corrosion resistance and color retention. It is a more advanced product in Baosteel's color steel coil coating for construction, with high molecular weight and direct bonding structure. Therefore, in addition to chemical resistance, its mechanical properties, UV resistance, and heat resistance are also very outstanding. In general, the anti-corrosion service life can be as long as 20-25 years. In recent years, fluororesins co polymerized with trifluorochloroethylene and vinyl ester monomers have been widely used in China and have been widely applied in building exterior walls and metal panels. Due to the use of easily hydrolyzed vinyl ester monomers, the fluorine content is about 30% lower than PVDF, and its weather resistance has a certain gap compared to PVDF.

6、 Acrylic resin has good comprehensive performance and high price, and is only used in specific fields such as containers.