November 17, 2015
What are IRR coatings?
Infrared reflective (IRR) or near infrared reflective (NIR) coatings reflect the wavelengths of the sun’s radiation that cause surfaces to become hot.
The major cause of heat build from the sun on exterior surfaces is energy from the wavelengths in the near infrared region (about 700 to 2,500 nm). Instead of absorbing infrared wavelengths on surfaces exposed to the sun, IRR coatings reflect them, helping to limit an increase in temperature. Reducing heat build offers a number of benefits, from cooling buildings to improving comfort, and as a result, the new paint technology appeals to architects, builders and the environmentally conscious.
Pigments are the key to achieving IRR properties in coatings. That’s because pigments used in IRR coatings contain specialized chemical compounds such as mixed metal oxides or titanium dioxide, which reflect near-IR radiation. Coatings with a higher total solar reflectance, or TSR, reflect a higher percentage of near-IR wavelengths from the surfaces of buildings or structures to which they are applied. An effective IRR pigment will have a TSR value of between 40 and 70 percent. Titanium dioxide is the pigment used to provide a white color for the majority of today’s coatings because it is a relatively safe material and it is inexpensive. It also has a high reflectance in the near-IR range. Alternatively, carbon black has a TSR value of approximately 5 percent and should be avoided in all IRR coatings, as even trace amounts can substantially reduce a coating’s TSR value.
What are IRR coatings good for?
A number of industrial coating manufacturers are already employing this new paint technology for their customers’ applications. In North America, IRR pigments are utilized in metal roof coatings to reflect heat from a building’s roof. Because more heat is reflected away from the structure’s surface, less energy (and money) must be expended on cooling the interior. In large buildings, the savings on cooling costs can be significant over time.
IRR coatings are also used for other building applications, such as in the manufacture of windows and doors, where IRR pigments help limit deformation of door and window frames. In Europe, coatings producers also utilize IRR pigments in building facade coatings such as stucco.
But that’s only the beginning of the potential impact of IRR.
Protecting substrates using IRR coatings is still a fairly new development, but the materials have been around for some time. Although the initial interest in IRR focused on buildings and energy reduction, coatings manufacturers are in a unique position to help their customers explore the range of IRR application possibilities. Any exterior surfaces or structures can benefit from an IRR coating. Examples include:
The TSR values of pigments have varying levels of reflectance, and as a result, many color spaces will be difficult to match while maintaining a specific TSR value. In addition, the price of IRR pigments can vary greatly, as some blacks are based on a high cost Perylene chemistry.
In addition, exactly matching colors that use standard pigments with colorants using IRR pigments can be difficult to achieve in all light sources. For example, in a phenomenon known as metamerism, color matched in daylight may not be an exact match in horizontal light. To develop or identify a product that meets your customers’ needs, work closely with them to understand their performance and price requirements for an IRR coating.
IRR coatings represent an emerging space that will continue growing as more customers seek out ways to keep exterior surfaces cool. The more extensive your knowledge of IRR, the more comprehensive the solutions you’ll be able to provide to help your customers meet their IRR goals.
Because pigments are the primary source for IRR technology, your colorant supplier is also a critical link in the IRR chain. Work with your supplier’s colorant experts to develop right IRR formulations to deliver optimal results to your customers.
Chromaflo Technologies is a leading supplier of IRR colorants for the industrial coatings industry. Contact us at (440) 997-5137 to discuss your energy savings goals. To learn more about IRR technology, view a short video at www.youtube.com/watch?v=Na2SLhDlxmw.