Common Coatings Used in Color Coated Steel

Color coated steel coil, including PPGI and PPGL, wins wide popularity due to its great strength and beautiful appearance. Generally, it is a product that combined galvanized zinc sheet with organic coatings. For one thing, the galvanizing process provides good coating adhesion and weldability; For another, the organic coating on the surface acts as protective insulation from rust, which extends its service life. So what are these organic paints? Let’s have a look.

1. Polyester (PE)

Polyester is a category of polymers that contain the ester functional group in every repeat unit of their main chains. As a thermoplastic elastomer, it is widely used in various industries since it was discovered. It owes good adhesion and is not strict in formability and outdoor durability. At the same time, some certain degree of chemical resistance can be seen. So it is commonly employed in PPGI products at a low cost.

2. Silicon Modified Polyester (SMP)

Silicon Modified Polyester is a silicon resin-modified Polyester paint coated and heat dried. It guarantees good hardness, wear resistance, heat resistance, chalking resistance, as well as good external durability. But its luster retention and flexibility is not very high. And it costs a little higher than PE. In general, SMP products are coated and baked with paint containing silicon resin, which is suitable for coastal areas. So this kind of pre painted galvanized steel coil can be more applied to seaside environments.

3. High Durable Polyester (HDP)

It is a weather proof resin developed with hydrogenated monomer & neo structure monomer. Similar durability to PVDF, but it offers a more competitive price and advantages of various colors & gloss. In a word, it is much better than PE but a little lower than PVDF. What’s more, it inherits SMP’s good points and adds some new benefits like UV resistance and higher adhesive force. It can be obtained in a cost-effective way. And more color options make it appreciated by more and more people. 

4. Polyvinylidene Fluoride (PVDF)

This coating, made by fluorine carbon resin, pigment and ester solvent, is solidified to dry film with super weather resistance after high-temperature roasting and baking. It assures high weatherproofing against acids and heat, and has high durability and machinability. Also, the hydrophillic surface treatment will enable dust to be removed easily and always keep clean. PVDF is especially opposed to solvents, abrasion, UV, chalk, and has low density compared to similar fluoropolymers. It is much superior to other three coatings, accompanied by high cost.

In a word, above are four main common coatings used in color coated steel coils. Believe you have grasped a detailed understanding of it. Hope you can choose the one you like when buying. In addition to the coating pattern we introduced today, it also has other patterns like embossing and printing, which gives you a variety of aesthetic needs. If you want to know more, pls consult Wanzhi Steel for further understanding.