Isocyanate free polyurethane coatings - fundamental chemistry and performance attributes

 
Two component polyurethanes are used in a variety of industrial coating applications due to their excellent weatherability, toughness, and chemical resistance. When formulated as ambient cured systems, traditional two component polyurethanes typically must balance cure speed for pot life. This paper describes the chemistry and performance attributes of a novel ambient cure, two component isocyanate free polyurethane coating technology based on the reaction of polycarbamates with polyaldehydes. One significant benefit is the ability to decouple pot life from cure speed, which allows for the development of formulations with longer pot life that provide coatings which dry fast and develop hardness very quickly. For the applicator, these attributes provide faster return to service, higher production throughput and less material waste. Additional coating benefits, including good weatherability, chemical resistance and mechanical properties, will be described for applications over metal substrates.