Performance Prediction of Antiaging Aliphatic Polyurethane Topcoat

Polyurethane coatings are widely used due to their excellent flexibility, abrasion resistance, Ultraviolet stability, and chemical durability. However, quantitative evaluation of their aging behavior remains a challenge. In this study, two aliphatic acrylic polyurethane topcoats were subjected to accelerated cyclic aging tests, and their degradation processes were characterized by infrared spectroscopy and glossiness measurements. The ratio values of C═O/C–H band area with time for two aliphatic acrylic polyurethane topcoats were found to reflect the increasing of carbonyl content, which governs the transformation of surface microstructure and glossiness. A significant negative correlation between glossiness and the semiquantitative analysis of carbonyl groups was confirmed by Spearman correlation coefficients of −0.772 and −0.782, respectively. Furthermore, the relationship between glossiness and aging time was described by an exponential function, indicating that glossiness decreases progressively with extended exposure. These results provide a quantitative framework for assessing the aging performance of polyurethane coatings and offer a basis for predicting their long-term durability under ultraviolet exposure.