The study of an energy efficient cool white roof coating based on styrene acrylate copolymer and cement for waterproofing purpose—Part I: Optical properties, estimated cooling effect and relevant properties after dirt and accelerated exposures

• The addition of Altiris 800 greatly increases the NIR reflectance of the coating.
• The cool white roof coating can reduce the roof surface temperature by 30.8 °C.
• The low Tg of the binder endows the cool coating with moderate dirt resistance.
• Artificial accelerated weathering reduces the solar reflectance of the coating.
• The inferior weather resistance is due to the presence of CC in the polymer chains.

The composition and the preparation process of a bi-functional cool white roof coating based on styrene acrylate copolymer and cement that integrates both a good cooling effect and good mechanical properties and water impermeability are introduced. Its optical properties, cooling effect and relevant properties after dirt and accelerated exposures are systematically explored. Compared with the conventional polymer-modified cement-based waterproof coating, the cool white roof coating based on styrene acrylate copolymer and cement has a much higher solar reflectance due to the presence of the titanium dioxide rutile and Altiris 800, and it can significantly reduce the coating surface temperature. The sticky nature of the high elastic styrene acrylate copolymer emulsion makes it easy for the cool white roof coating based on styrene acrylate copolymer and cement to collect pollutants and thus endows the coating with moderate dirt resistance. Four hundred hours of artificial accelerated weathering decreases the solar reflectance of the cool white roof coating based on styrene acrylate copolymer and cement and the cooling effect of the coating. The artificial accelerated weather resistance of the cool white roof coating based on styrene acrylate copolymer and cement is qualitatively good.