Commercial and residential rooftops in Latin America increasingly are taking on a cooler white visage as users of acrylic emulsions recognize both the economic and environmental value in reflecting more of the sun's rays. "This technology works best in tropical areas, which includes most of Latin America, where it has great potential for growth," said Cesar Soto, the marketing manager of industrial, construction, and aquaset paints and coatings for Rohm & Haas in Mexico.
As a supplier of acrylic resin to paint and coatings formulators in Latin America, including General Paint and Henkel, Rohm & Hass is currently producing enough acrylic base product in Latin America-including the company's new plant in Mexico's Queretaro state-to supply regional demand. "The use of acrylic resins for cool roofs will increase much as the demand for architectural paints increases in Latin America," said Soto. "The demand in the Caribbean is already very strong, especially on islands like Puerto Rico. In Central America and the Andes, where the technology is less well known, the demand is growing more slowly."
A primary product in the company's elastomeric coating or Cool Roof line is Roplex EC 9791, which is 100% acrylic, and offers characteristics of strong adhesion, durability, UV reflectivity, substrate degradation resistance and fungal resistance. One high-profile application of the product was made in 2007 in Mexico by General Paint, which covered the rooftop of Mexico City's Central de Abastos, or produce market. However the technology is applicable in a broad range of situations, ranging from homes to commercial offices to industry.
"The air conditioning market in Latin America is mature, but there are varying levels, with some very sophisticated, like offices, and others at a low level use, as in houses. Cool roof technology can help save energy at all levels and anyone can apply it," said Soto.
The white acrylic coatings has been shown to have a stronger albedo-the fraction of light that is reflected from a surface-at 0.87 than aluminum asphalt emulsions at 0.60, and more than ten times the reflectance of black asphalt, which is about 0.06, according to Rohm & Haas' technical service specifications.
Other proposed applications for the white acrylic technology includes roads, where the goal of use is to reduce surface heat and thus reduce the greenhouse effect aggravated by carbon emissions. The Public Works Research Institute in Japan has experimented with coating roadways white, and researchers at Lawrence Berkeley Laboratory are advocating widespread coating of both rooftops and roads in California.
The cool roof application works well because it reflects far more than visible light. Total solar reflectance is the sum of ultraviolet, visible and near infrared (IR) reflectance. Ultraviolet makes up five percent of the electromagnetic spectrum, visible 43%, and IR 52%, according to Plasticolors, of Ashtabula, OH, which also produces IR reflective coatings.
Rohm & Haas cools off rooftops in Latin America
Cool roof technology continues to grow in popularity as industry seeks energy efficient solutions.
By Charles W. Thurston
Published February 2, 2009
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