Two-part polyurea spray elastomers were brought to market in the 1990s after being invented by Bayer in Germany–the aspirin company. They are useful coatings for large surface area projects because of their fast reactivity and relative insensitivity to moisture. They can be applied at nearly any temperature, bonds easily to concrete and metal surfaces, cures to full strength in as little as a half an hour, is flexible enough to bridge small cracks and withstands high temperatures when cured. Some polyureas reach strengths of 6000psi (40MPa) tensile and over 500% elongation making it a tough coating. Due to rapid cure time, many coats can be built up quickly.
Is Polyurea Really this Good
The biggest factor that determines how well a polyurea will bond and last is preparation of the substrate. Moisture vapor emmission rate and proper solids content are also important factors in developing a proper bond. When those conditions are met, you will experience a truly professional polyurea coating system.
The reported applications range from a new way to topcoat concrete floors to sealers for concrete countertops to impermeable coatings for concrete bridge beams as well as spray on linings such as bedliners (The history of Spray Bedliners) and floor coatings. In the decorative concrete arena, the most intriguing potential applications are as a replacement for epoxy/polyurethane coatings for floors.
Is a polyspartic a polyurea?
All polyureas are two-part systems, meaning that a resin has to be mixed with a catalyst to create the curing reaction that hardens the material. Polyurea has been used very successfully for corrosion-resistant coatings and repair materials, although application is awkward since it has an extremely short pot life–about 3 seconds, so the two parts must be mixed at the spray tip, requiring lots of maintenance on expensive high-pressure equipment.