Tactile Friction of UV-Curable Coatings and Its Relation to Surface Hardness

This contribution examines the relationships between surface hardness, perceived friction and tactile friction of selected UV-curable coatings. For this purpose, the chemical composition of the investigated coatings was varied on the basis of curing agent and binder resin, as well as selected fillers were added. This allowed the adjustment of various surface parameters such as hardness, surface free energy and roughness over a wider range. Tribological tests were carried out in which the coefficient of friction between the finger pad and the respective coating was measured using a specially developed measurement setup that enabled reproducible results. The surface hardness of the coatings was investigated via nanoindentation measurements. In addition, the coatings were evaluated with regard to perceived friction. The results showed a good correlation between the perceived friction, the coefficient of friction and the surface hardness in terms of the indentation modulus. Thereof, particularly important is the surface hardness in terms of indentation modulus.