What is Polyaspartic Coating Technology?
The chemistry of polyaspartic coatings was first introduced in the early 1990s. It is based on the reaction of an aliphatic polyisocyanate and a polyaspartic ester, which is an aliphatic diamine. This technology was initially used in conventional two-component polyurethane solvent-borne coating formulations because the polyaspartic esters are excellent reactive diluents for high solids polyurethane coatings.
More recent developments in polyaspartic coating technology have concentrated on achieving low or near-zero VOC coatings where the polyaspartic ester is the main component of the co-reactant for reaction with a polyisocyanate. The unique and adjustable reactivity of the polyaspartic esters allows for the design of fast-curing coatings tailored to the needs of the application. The fast curing feature of these coatings can provide significant, money-saving productivity improvements, along with high-build, low-temperature curing, and abrasion and corrosion resistance.
The name polyaspartics has recently become popular among formulators in the industry due to the need to differentiate it from polyureas and polyurethanes. By definition, a polyaspartic is an aliphatic polyurea because it is the reaction of an aliphatic polyisocyanate with a polyaspartic ester – which is an aliphatic diamine. However, polyaspartic coatings are very different in both application and coating performance properties from conventional polyureas. For example, polyaspartics allow the formulator to control the rate of reaction and cure, thus, potlife of the two-component mixture can range from five minutes to two hours. While spray application techniques include the use of plural component spray equipment, many applications can be applied with conventional sprayers, making application much less complicated and less prone to error.
Polyaspartic technology is closer in its applications and performance characteristics to 2-component aliphatic polyurethane coatings. It is often used as a topcoat due to its non-yellowing nature. But, here too, there are noteworthy differences. The polyaspartic coatings, for example, can be formulated to very high solids (70-100% solids) and applied at higher film builds (up to 15 mils WFT in a single coat) than typical two-component aliphatic polyurethanes. Because polyaspartics are much faster drying than typical aliphatic polyurethanes, they are often used in applications where fast cure means improved productivity in the painting operation.
Article courtesy of: Bayer Material Science