Surface Treatment of Color Coated Aluminum Roofing Sheet

Color coated aluminum roofing sheet can be divided into 10 series, among which 3xxx serves as the main material for building construction: roofing, ceiling, wall cladding etc. The alloys include 3003, 3003 and 3005. Generally there are two relative surface treatment methods for aluminum roofing sheet: plain treatment and paint coating.

Plain treatment refers to the fact that no coating process is applied to a piece of sheet. In other words, It is not color coated aluminum roofing sheet at all. This kind of roofing sheets require little about outlook and cost less than painted ones. Normal surface treatment methods for such sheets are embossing (irregular or regular patterns) and advance passivating (oxidized protective film). Paint coating, on the other hand, means to coat paintings onto the surface of an aluminium sheet and make it a real piece of color coated aluminum sheet. There are two basic types of coating processes available: spray coating and coil coating. Up to now seven kinds of paintings have been applied: polyester, polyurethane, polyamide, modified silicone, epoxy resin, polythene and fluorocarbon, yet only the last two are frequently adopted. Fluorocarbon, better known as PVDF in the industry, shows the strongest aging resistance. It is regarded as the organic composite with the strongest anti-UV property in accordance to knowledge of humankind. It’s usually coated by processes of automatic horizontal coil coating, including 2-coaing&2-baking, 3-coaing&3-baking and 4-coaing&4-baking. The resin content of PVDF ranges between 70% and 80%. The final coating layer will not form until advance chemical treatment of the aluminum sheet’s surface, primary coating and precise coating have all been applied. The coating thickness for the front side is normally 25um, and the back side is coated with corrosion resistant paintings. Haomei supplies color coated aluminum roofing sheets of competitive price, welcome to contact us for more information!