Can ensuring the longevity of decorative exterior coatings be as difficult a task as Goethe wrote Faust? The answer is probably not. Fortunately, more and more advanced auxiliaries and binders come to our aid. Moreover, the durability of coatings is significantly influenced by the pigments themselves and their compositions used during formulation. The key assumption of this project is to assess the probability of selecting raw materials and modifying topcoats subjected to aging tests under cyclically changing conditions (temperature, humidity and radiation) in order to maximally extend their usability, by maintaining, among others, colour and gloss. Thus, colour compositions based on two polyurethane binders dedicated to topcoats and pigments in shades of yellow, red and blue were tested. The change in colour, gloss, water contact angles, chemical structure (FTIR) and morphology (SEM) of coatings placed in climatic chambers and exposed to xenon lamps and/or UV were determined. It was shown that the factor with the greatest influence on the change in the performance parameters of coatings is UV radiation. The preservation of the decorative values ​​of coatings also depended on the qualitative composition of the pigments used in each colour group. Changes in humidity and temperature had a slightly smaller effect. In all tests, the surface free energy value and the structure and topography of the coatings did not differ significantly. Based on the obtained results, cycles with a full spectrum of impact on the coatings were selected and ranked, from those causing the least degree of degradation to those showing the most negative impact on the usability of the coatings.

Acknowledgments: The research work was carried out under the project ColourTune CORNET/31/20/2022 entitled "Tuning the colour of topcoats – method for selection of pigments and safeguarding colour stability" funded by the National Centre for Research and Development.