The effects of manufacturing processes and artificial accelerated weathering on the solar reflectance and cooling effect of cool roof coatings

• Surface roughness of cool coatings decreases with grinding speed and grinding time.
• Dispersion effect of cool coatings becomes better with increased grinding.
• Reflectances and cooling effects of cool coatings increase with dispersion effect.
• 400 h of weatherometer exposure decreases the solar reflectance by less than 0.03.

The effects of manufacturing processes and artificial accelerated weathering on the solar reflectance and cooling effect of cool roof coatings were investigated using UV/vis/NIR spectrophotometry, laser diffraction spectrometry, optical microscopy and scanning electron microscopy. The solar reflectance and the cooling effect of the coatings were found to correlate positively with the grinding speed (over a constant grinding time) and grinding time (at a constant grinding speed) due to an improved dispersion effect of TiO2 particles. Artificial accelerated weathering slightly reduces the solar reflectance of cool roof coatings, and its influences on the cooling effect of cool roof coatings are negligible within the experimental error.