Polyurea Coating and Lining Technology

Polyurea is generally used as an industrial coating in severe environments with good chemical resistance to hydrocarbons and hydrogen sulfide gas and immersed sewage applications.Polyurea is a type of elastomer that is derived from the reaction product of an isocyanate component and a synthetic resin blend component through step-growth polymerization. The isocyanate can be aromatic or aliphatic in nature. It can be monomer, polymer, or any variant reaction of isocyanates, quasi-prepolymer or a prepolymer. The prepolymer, or quasi-prepolymer, can be made of an amine-terminated polymer resin, or a hydroxyl-terminated polymer resin.
The resin blend may be made up of amine-terminated polymer resins, and/or amine-terminated chain extenders. The amine-terminated polymer resins will not have any intentional hydroxyl moieties. Any hydroxyls are the result of incomplete conversion to the amine-terminated polymer resins. The resin blend may also contain additives, or non-primary components. These additives may contain hydroxyls, such as pre-dispersed pigments in a polyol carrier. Normally, the resin blend will not contain a catalyst(s).
Uses .Polyurea and polyurethane are copolymers used in the manufacture of spandex, which was invented in 1959.Development of two-component polyurethane and polyurea spray elastomers took place in the 1990s. Their fast reactivity and relative insensitivity to moisture make them useful coatings for large surface area projects, such as secondary containment, manhole and tunnel coatings, tank liners, and truck bed liners. Excellent adhesion to concrete and steel is obtained with the proper primer and surface treatment. They can also be used for spray molding and armor.[1] Some polyureas reach strengths of 6000psi (40MPa) tensile and over 500% elongation making it a tough coating. The quick cure time allows many coats to be built up quickly.
Polyurea is truly a remarkable coatings, linings and joint sealant technology. It is being used successfully for so many different applications today. Polyurea coatings and linings are more commonly applied over concrete and steel for corrosion protection and abrasion resistance. They also have tremendous advantages over conventional materials for joint fill and caulk applications due to their fast set nature, high elongation and durability/abrasion characteristics. Polyurea can be molded and shaped by spraying it into molds. Similarly, polyurea is also used as hard coat protective shell over expanded polystyrene (EPS) for architectural molded fascia applications
Polyurea coatings combine extreme application properties such as rapid cure, even at temperatures well below 0°C, and insensitivity to humidity, to exceptional physical properties such as high hardness, flexibility, tear strength, tensile strength, chemical and water resistance. The result is good weathering and abrasion resistance. The systems are 100 percent-solids, making them compliant with the strictest VOC regulations. Due to its specific curing profile and exceptional film properties, the polyurea spray coating technique developed into various areas, including corrosion protection, containment, membranes, linings and caulks.
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