Primers used in UV-curable nail varnishes

Abstract Adhesion-promoting substances (primers) play an important role in the durability of UV-curable nail varnishes on human toe and finger nail plates. The efficacy of these substances regarding the adhesion that exists between the UV nail coating and the substratum depends on the type of primer and its method of application. In the current study, we used non-acid and acid-based primers as additives in the coating composition and as individual layers applied directly onto the substrate. Adhesion tests were performed using organoleptic, dynamic and “pull-off” methods and using different substrates. The application of adhesion promoters was found to increase the level of adhesion between the varnish formulation and substrate. The best adhesion was obtained when the primer was applied as a separate layer prior to application of the coating. To the best of our knowledge, this work is the first systematic study comparing the effect of using primers with UV-curable nail varnishes on the adhesion of the polymer to the nail plate.