The use of plastics continues to increase in a wide variety of applications. This growth can be attributed to several key advantages plastics have in comparison to metal, including a decrease in part weight, the ability to form complex parts using low-cost tooling and the lack of corrosion.1 These plastics are often coated to provide improved aesthetics or resistance properties. However, the choice of coatings technologies can be somewhat limited because of the low heat distortion temperature of many plastics. Due to these lower temperature requirements, two-component (2K) polyurethane coatings are often the technology of choice in applications requiring higher performance, as they are capable of curing at room temperature or below.
For some of these high-performance applications there is a desire to use one-component (1K) polyurethane coatings due to their ease of handling. The 1K coatings do not have the carefully controlled mix ratio requirement or the potlife concerns of 2K polyurethane coatings. Traditionally these requirements can be met through the use of blocked isocyanates.