Preparation and Properties of Epoxy Resin and Polyurethane Blend Resin-Based Low-Infrared-Emissivity Coatings

A low-infrared-emissivity composite coating with outstanding mechanical properties and low glossiness was prepared by using an epoxy resin and polyurethane blend modified resin, flake brass powder, the silane coupling agent KH560, and a dispersant as an adhesive, a functional pigment, and interface modifiers, respectively. The effects of the mass ratios of epoxy resin and polyurethane, the addition amount of flake brass powder, the addition amount of KH560, and the addition amount of dispersant on the coating performance were systematically discussed. The results show that the coating has lower emissivity (0.424) and glossiness (28.8) when the mass ratio of epoxy resin to polyurethane is 6:4 and the addition amount of brass powder is 50 wt%. Using KH560 to modify the interface structure of the coating, KH560 can form chemical bond with the resin matrix and flake brass powder so as to obviously improve the impact strength and flexibility of the coating. The addition of the dispersant can obviously enhance the dispersion state of the flake brass powder in the coating and thus enhance the reflection intensity of infrared light for the coating, such that the emissivity of the coating is obviously reduced. When the addition amount of KH560 is 7 wt% and the addition amount of the dispersant is 9 wt%, the coating has the optimal emissivity (0.332), glossiness (9.0), adhesion strength (grade 1), impact strength (50 kg·cm), and flexibility (1 mm) at the same time. The above mentioned low-infrared-emissivity coating has an important application prospect in the field of infrared stealth for various aircraft.