Overcoming Oxygen Inhibition in UV Curable Protective Coatings

Overcoming Oxygen Inhibition in UV Curable Protective Coatings

Neil Cramer
Colorado Photopolymer Solutions

Many different UV curable formulations and curing techniques are utilized to achieve a wide range of materials and coatings applications.  UV cured coatings are desirable in many applications as they typically contain no VOCs, exhibit extremely good hardness and durability, and are chemically resistant to salt water, acids, bases, solvents, alcohols, etc.  A ubiquitous challenge in these applications is the necessity to overcome oxygen inhibition and achieve complete curing as efficiently as possible. Recently, the advent of UV-LED lights has enabled lights with increased operating lifetimes and improved energy efficiency. The narrow wavelength emission spectrum of UV-LED lights strongly affects both curing rates and oxygen inhibition. Here, different chemical compositions, monomer and oligomer functionality, and photoinitiator packages are evaluated and compared for their ability to rapidly form cured coatings. Additionally, both UV broadband and UV-LED curing lights are compared by examining their effect on oxygen inhibition, cure speed, and material properties.