Alkyd coatings are a major type of organic coating. The alkyds and modified glyptals are used as protective & decorative coatings for consumer products. These coatings are also used as corrosion protective coatings for metals. Alkyd coatings may be either air-drying or baking types. The air drying types are modified chemically by incorporating unsaturated fatty-acid groups into the polymer structure. These are used for such diverse applications as air-drying water emulsion wall paints and baked enamels for automobiles and appliances. The properties of oil-modified alkyd coatings depend on the specific oil used as well as percentage of oil in the composition.