Acrylic polyurethane coatings are widely used due to the advantages of both the excellent corrosion resistance of polyurethane and the weather resistance of acrylic resins. However, strong solar radiation in the western plateau is prone to rapid aging. "Ultraviolet Aging Behavior of Acrylic Polyurethane Coatings" is mainly based on the problem that acrylic polyurethane coatings are prone to rapid aging under strong solar radiation in the western plateau area, and studies the influence of strong ultraviolet rays on the aging laws of acrylic polyurethane coatings.
In this paper, the UV accelerated aging cycle experiment method is used to carry out the aging experiment on the acrylic polyurethane coating, and the UV/condensation aging mode is set to simulate the climate characteristics of the western plateau. The UV aging behavior of acrylic polyurethane coatings was studied by using gloss and color difference detection, SEM, EDS, FTIR, contact angle and other technical analysis, combined with AC impedance spectroscopy (EIS).
The conclusions show that:
(1) The degradation law of acrylic polyurethane in the ultraviolet accelerated experiment presents the characteristics of three stages: in the early stage (slow photoaging), performance evaluation indicators such as contact angle and color difference show slight changes; in the middle stage (rapid photoaging) , due to the accumulation of photo-oxidation products in the previous stage on the surface of the coating, resulting in the strong absorption of ultraviolet light by the coating, the photodegradation of the coating is rapid, the above-mentioned performance indicators change drastically, and the protective performance of the coating declines rapidly; Aging), the base material has been seriously lost, there is very little degradable resin on the surface, the photooxidation reaction is very weak, and the changes of various indicators are gentle.
(2) Gloss changes can more sensitively reflect the UV aging process of acrylic polyurethane coatings.
(3) The comparative analysis of the EIS test results and other test results shows that the protective performance of the acrylic polyurethane coating has declined significantly before the apparent performance of the acrylic polyurethane coating changes significantly.
