What is Polyurea coating and Polyurethane Coatings
Polyurea coating is basically a two-component system based on Amine terminated prepolymer crosslinked with Isocyanate which forms the urea linkages. The crosslinking between reactive polymers take place at a rapid speed at ambient temperature. Normally this reaction does not require any catalyst. Since the Pot-life of such coating is within seconds; special type of Plural Component spray gun is require to carry out the application.
The coatings can build up to 500 to 1000 microns of thickness in a single appllication. Because of such high thickness it gives excellent chemical and abrasion resistance. However, the desired property largely depends on the surface preparation of the object to be coated. It is recommended to sand blast or grit blast the surface as per standard method [e.g., Sa 2½, SSPC-SP10/NACE No.2] to near white metal. Despite of such a high thickness it still imparts excellent flexibility; elongation [around 300%] and low permeability. Typical application includes on concrete mainly in water tunnel where high water is passed with high velocity and pressure, tank lining, industrial flooring and various metal structure.
Polyurethane coating provides a thin film, high gloss finish with exceptional weathering performance characteristics. This coating is used in virtually all industrial markets to provide a smooth durable finish that has superior resistance to corrosion, abrasion, and chemical exposure. Polyurethanes are normally used to topcoat high build epoxy and inorganic zinc.