Low-gloss UV-curable coatings: Light mechanisms, formulations and processes — A review

UV-curable coatings are in constant development due to the increasing environmental regulations and norms. UV-curable coatings have several advantages such as low environmental impact (from limited use of volatile organic compounds, VOCs), rapid polymerization rates and increased production rate. To meet the demand for low-gloss aesthetics, which have the ability to embellish textures and surfaces, UV-curable coating industries and researchers have need to adapt. While many processes and technologies have been identified to produce effective coatings, achieving an optimal combination of high mechanical performance and low-gloss aesthetics is still an ongoing challenge. This paper focuses on light theory and its relationship to surface texture, which are essential to understand the matting mechanism of applied coatings. Formulation strategies to induce matting, including the use of physical matting agents and dispersants as well as modifying the composition of a coating formulation, are summarized. Furthermore, the different processes that lead to surface structuring and enable facile manipulation of gloss are reviewed. Last but not least, new emerging technologies, such as self-matting coatings, which are promising for UV curing applications, are discussed.