PPGL stands for pre-painted galvalume steel, which is a kind of color-coated steel with GL as substrate. It combines the strength of steel with excellent anti-corrosion of Zn-Al coating. The galvalume coating is made of 55% aluminum, 43.4% zinc, and 1.6% silicon. Except for their excellent corrosion resistance, PPGL sheets also have high thermal reflectivity, which makes them heat-resisting.