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The use of elastomeric cool roof coatings with high solar reflecting properties is becoming more and more popular to reduce the need for air conditioning and to keep energy consumption down. To maintain cooling power, the coating must stay clean; this is where silane-modified colloidal silica that enhances the anti-soiling properties play a key role.
Air conditioning accounts for up to 70 percent of the energy consumption in warm, sunny areas of the world. One way to reduce the buildup of heat in buildings is to apply cool roof coatings, which have high solar reflecting properties. They are designed to reflect a significant part of the energy from the sun, often aided by a reflecting pigment like titanium dioxide (Ti02).
A proven concept to improve solar reflecting properties is to use hollow, ultra-low-density thermoplastic microspheres, such as Expancel® microspheres. They are used as a filler in elastic waterproof, cool roof and wall coatings to improve several important coating properties. The micron-sized hollow microspheres have a surprisingly strong effect on reflecting solar radiation and reducing the temperature of cool roof coatings. Results from solar reflectance measurements show that the coating system filled with hollow microspheres reflect solar radiation of all incoming wavelengths (Figure 1). To further improve the concept, tests were carried out on dirt pick-up resistance by adding silane-modified colloidal silica, Levasil® CC301, to the...