For industrial protective coating applications, a two-component, epoxy-based coating has many advantages over other chemistry-based systems like acrylics or polyurethanes. Bisphenol A type epoxy coatings have an excellent adhesion to various substrates, superior chemical resistance, and improved thermal and mechanical properties. However, due to its aromatic ring structure, it results in poor UV resistance, and their amine curing agent causes increased yellowness in the system.
Driven by end-user demand, there is a strong desire to reduce the yellowness of clear epoxy coatings for many cosmetic applications. However, compromises in coating performance are unacceptable for the sake of less yellowing; epoxies are an important class of coatings, utilized in several demanding applications and environments, that are expected to provide high-performance aesthetic properties. Using a cycloaliphatic type amine, such as an IPDA or PACM-based amine, is one common route to lower yellowness for epoxy coatings.