Despite their good mechanical and thermal properties, as well as chemical resistance to solvents, epoxy resins are sensitive to ultraviolet (UV) light, which restricts their applications. In order to overcome this drawback, UV absorbers are usually used to decrease the rate of UV degradation. In this work, a water-based epoxy was prepared using a simple method at a low cost and the effects of the commercially available organic and inorganic UV absorbers on improving the UV resistance of the water-based epoxy coating were investigated. Tinuvin 1130 and zinc oxide (ZnO) were used as organic and inorganic UV absorbers, respectively. Optimization of the parameters (preparation and photodegradation) was done using Response Surface Methodology (RSM). Optimum formulation, minimum particle size, and the highest stability were found at 1.7 g anionic surfactant, 3.1 g nonionic surfactant, and stirring speed of 860 rpm. The optimum UV protection and the lowest yellowing were found at 2.5 g ZnO and 2.3 g Tinuvin 1130 after 1000 h of UV radiation. It was revealed that the use of Tinuvin 1130 in the water-based epoxy coating was very effective in reducing the negative impacts of photodegradation.

Water-based epoxy, photodegradation, UV absorbers, response surface methodology