Polyurethane is formed from the chemical reaction between the composition containing the hydroxyl group (polyol) and the composition containing the isocyanate group. Polyisocyanates and polyols are very diverse; they differ in terms of chemical structure, reactivity, and number of functional groups. Coatings with aliphatic and cycloaliphatic polyisocyanates are highly resistant to atmospheric conditions, which are recommended for extreme environmental conditions. Aromatic polyisocyanates are not suitable for outdoor applications, unlike aliphatic. Drying and curing of polyurethane coatings is affected by the degree of reactivity of polyisocyanate, so the type of polyisocyanate can determine the application of the coating. Polyester polyol, acrylic copolymers containing a hydroxyl group and a polyether polyurethane are considered to be the most important polyols that are branched or linear. The structure and amount of active groups affect the properties of polyurethane. The higher the hydroxyl groups and the greater the degree of branching of the polyol, the higher the hardness and chemical resistance and the solvent of the polyurethane. High mechanical strength, remarkable chemical resistance, optical stability and atmospheric resistance are four main advantages of polyurethane, the latter being highlighted in aliphatic polyurethanes. Polyurethane has wide application in many areas due to its diverse characteristics, including: transportation industry (car paint, aviation, train wagon, ship, heavy vehicles), civil engineering, industrial staining (equipment, machinery Machinery, furniture), hydraulic structures for steel, oil and gas pipes, water and sewage.