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    Home > Coatings News > Paints and Coatings Market > Infrared reflective slurry is used in cold coatings

    Infrared reflective slurry is used in cold coatings

    • Last Update: 2020-12-30
    • Source: Internet
    • Author: User
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    With the attention paid to the heat island effect in big cities and the need to reduce energy consumption, people are paying more and more attention to the slurry that reflects infrared light to reduce heat accumulation materials. In addition, many countries have begun to enact regulations requiring the use of "cold" coatings to reduce energy consumption. To meet these new requirements, coating formulating designers are looking for raw materials to support their research and development.
    we know that sunlight is the main source of infrared energy. When these light waves are absorbed by any outdoor surface, the surface becomes hotter and hotter. On a black surface, it's hot enough to burn the skin. During the summer's scorching peak temperatures, the black tarradra is hot because dark surfaces do not reflect energy from the sun's infrared light. In addition, this effect can cause the room temperature of dark roof buildings to rise. In buildings without air conditioning, excessive indoor temperatures can be hazardous. Using air conditioning to lower the room temperature increases costs.
    the use of infrared reflective pigments in coatings is a way to reflect infrared energy from the coating surface into the atmosphere. This reduces the surface temperature. Although roof coatings are where these slurry is used, in fact, the application of infrared reflective slurry to other fields will also benefit humans and the environment. This paper outlines the techniques and uses of infrared reflective slurry.
    total solar radiation
    solar radiation energy includes about 3% ultraviolet (UV), 44% visible light and 53% infrared. Most of the energy from ultraviolet light is absorbed by the atmosphere. In addition, the atmosphere scatters blue light waves from a large amount of visible light, which is why the sky is blue. However, most of the energy of infrared light reaches the Earth's surface, and infrared light generates heat. Near-infrared light (about 700-2500 nanometers) contains most of the heat generated by sunlight. Figure 1 shows a spectral map of solar radiation, including solar radiation from the upper atmosphere, as well as the distribution of ultraviolet, visible and infrared energy in solar radiation on the Earth's surface.
    earth usually absorbs solar radiation during the day and transmits it back into space at night. About 23% of the solar radiation energy that reaches the Earth's atmosphere is absorbed by the atmosphere, 31% is sent back into space, and 46% is absorbed by the Earth's surface. The Earth's surface radiates the absorbed solar radiation back into space through heat exchanges such as long-wave radiation, latent heat and heat. Figure 2 describes the process.
    the overall temperature of the Earth's surface does not change when the radiation from the input and output is in equilibrium. However, the radiation energy balance of the inputs and outputs may change as the Earth's surface is covered by heat-absorbing materials such as black roofs, coated concrete, asphalt, or other dark surfaces.
    to offset the infrared radiation absorbed
    to offset the effects of the absorbed infrared radiation, the coating reflects infrared light back into the atmosphere from the coated surface. Infrared reflective coatings can be made of a variety of pigments, metals (e.g. aluminum) or other raw materials to form an infrared reflection barrier layer. These raw materials reflect the near-infrared region spectrum that produces the most heat. Because these infrared rays are reflected, the surface coated with the infrared reflective coating has a lower temperature than the surface that uses the traditional coating.
    way to understand how this concept works is to consider why white appears in the visible light region. Because white reflects all wavelengths in the visible spectrum, the color appears white in the human eye. In fact, titanium dioxide, a raw material used in most white coatings, reflects infrared and visible radiation. Instead, materials that do not reflect visible light appear black. Carbon black also absorbs most of the infrared wavelength of light, making it hotter than most other colors. If we can see the color of the material in the infrared wavelength range, the coating that reflects all infrared wavelengths will also appear white. Figure 3 describes this phenomenon by showing the gray in the visible and infrared light regions, which are made with non-infrared reflective pigments such as carbon black and infrared reflective pigments, respectively.
    when it comes to coloring surfaces, there is a desire for more choices, and white coatings are not suitable for many uses. There are now a number of coloring materials that offer a wide range of colors as well as reflected infrared wavelengths. These materials have been made into liquid dispersions by Chromeflo Technologies, making them easy to use by paint formulator designers.
    use the color selection of the infrared light reflection slurry
    when determining the color option and the infrared reflection coefficient, the total solar reflectivity (TSR) of the material needs to be taken into account. TSR is solar radiation energy reflected from the surface of the material, expressed as a percentage. At higher TSR values, the surface absorbs less solar radiation, resulting in lower surface temperatures. Temperature changes are measured in degrees and are called Heat Builds (heat build-up). The TSR value of white paint is about 75%. The reason for this is that titanium dioxide reflects more than 90% of the infrared between about 700-1300 nanometers and about 30% of the wavelength of about 2,500 nanometers. The TSR value of the carbon black coating is about 5-10%. The TSR values of the coloring materials used in coatings range from about 25% to 70%. Mixing any infrared reflective slurry changes the TSR value of the solid slurry. Therefore, for the target TSR value that ultimately determines the color, the correct selection of the slurry is important for a specific color space.
    the technology has been used in roof coatings, building exterior coatings, wood (doors and windows) coatings. The purpose of these applications is often to reduce the heat absorbed by the building surface in an effort to reduce the energy cost of cooling the interior space of the building and protecting the substrate from high temperatures. These technologies will also apply to other surface coatings, such as outdoor tanks, playground equipment, pool decks, concrete surfaces, automotive interiors and theme parks. In summary, any outdoor surface coating that can benefit from lower surface temperature will become an application for infrared reflective coatings.
    solvent-based and water-based
    are specifically designed for solvent-based and water-based infrared reflective slurry with a wide range of compatible coatings. An example of solvent-based infrared reflective slurry is the Partacryl PM
    ®
    series, which can be formulated for the general purpose color paste system provided by coating formulators for coloring and complete coloring of most solvent-based industrial coatings. There is also a Chrome-CHEM
    ®
    -based low VOC slurry with a temperature of 846. These pigments provide wide color space, excellent durability, light resistance and chemical resistance and are dispersed in a unique and proprietary acrylic substate that provides excellent wetting and dispersion. The solvents used are a variable mixture of proprietary esters and propylene glycol monomethyl ether acetate.
    examples of water-wide infrared reflective slurry are the Chrome-Chem50-990 series and the 897 series. The former is a low VOC pigment dispersion, which is composed of finely ground pigments scattered in water, additives and a unique low VOC paint base. The resulting combination of slurry and water-based products has a wide range of compatibility. To better meet the requirements of current VOC regulations, these slurryes do not contain any added volatile organic compounds and do not contain glycol. The 897 product is a low VOC slurry with high coloring strength and is designed for use in a variety of water-based industrial coatings. These pigments provide excellent durability, light resistance, chemical resistance and ACE-free.
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