UV-curing sealers for short cycling times of thermal sprayed parts

The advantages of UV-curing polymers are well-known and used in various coating and adhesive applications. Curing times of a few seconds and long application windows allowing an increased throughput in series production. The use of UV-curing polymers in sealers is beneficial, but so far insufficient due to only surface-curing. With a newly developed dual-cure mechanism in sealers it is now possible to combine deep penetration curing and surface curing. The hybrid sealers combine radical polymerization with subsequent polyaddition or polycondensation. The development of sealers for thermal spray coatings involves an extensive requirement profile. This includes properties such as corrosion protection, penetration depth and processing times. High penetration depths of the sealant into the coating system are important to ensure a protection over the full live time of the TS-coating. The depth of penetration of the developed sealers into various TS-coatings was determined by measuring the gas permeability in a specially developed test procedure. The corrosion protection effect in combination with TS-coatings was determined by measuring the galvanic potential. Resulting, two UV dual-cure sealers have been developed to seal TS-coatings with deep penetration and long-term corrosion protection.