The self-cleaning technology powered by light energy has become one of the most promising approaches in developing self-cleaning coatings today. This method utilizes ultraviolet light from sunlight to trigger a decomposition process and create a superhydrophilic surface, which effectively breaks down and removes dirt, oils, and pollutants. Such innovative solutions have already found successful applications in various fields, including automotive finishes, glass, ceramics, and lighting systems. Fuzhou Minggu Nanotechnology Co., Ltd., in collaboration with institutions like the Chinese Academy of Sciences, has applied this technology to exterior wall coatings, achieving significant progress in self-cleaning protection. They have also developed a comprehensive performance evaluation system and established practical construction methods.
Exterior wall coatings are widely favored for their vibrant colors, diverse design options, and ability to enhance architectural aesthetics. They are easy to apply, lightweight, and safe, making them ideal for modern construction. With the growing emphasis on energy efficiency and thermal insulation, these coatings have become a dominant choice for exterior building decoration in China.
However, one of the major challenges facing exterior wall coatings is their poor resistance to stains. This issue not only limits their long-term performance but also hinders broader adoption. As urbanization accelerates, air pollution worsens, and the problem of dirt accumulation becomes more severe. Traditional coatings, such as elastic paints, real stone paints, and textured coatings, often struggle with maintaining cleanliness due to their limited anti-fouling properties.
Most manufacturers attempt to address this issue by introducing hydrophobic properties—commonly referred to as the "Lotus effect." However, this approach has shown limitations in practice. The reason lies in the fact that hydrophobic materials tend to be lipophilic, meaning they attract organic pollutants like NOx and SOx present in the air. These substances can easily settle on surfaces, especially during hot weather or on low-elasticity coatings, making them hard to clean. Additionally, using nanomaterials to modify existing emulsions is costly and technically challenging, raising concerns about both economic feasibility and product design.
Minggu’s self-cleaning coating material offers an effective solution. Laboratory tests conducted according to national standards have shown that the stain resistance of elastic and textured coatings can be reduced from 25% to around 10%, improving performance by over 60%. For pure acrylic and real stone paints, the improvement rate is approximately 40%. Field exposure tests lasting 3 to 9 months confirmed that high-grade silicone-acrylic coatings achieved a stain resistance index of 9, with an improvement exceeding 60%.
Beyond stain resistance, the product also provides UV absorption, color retention, antibacterial and anti-algae properties, and even air purification. It remains colorless, transparent, and filmless, preserving the original structure and appearance of the coated surface. Being water-based, non-toxic, and environmentally friendly, it ensures safety and ease of application at a reasonable cost.
This technology has been recognized as a leading innovation in the country and was selected as a key project under the 2007 corporate technological innovation fund. Major domestic paint and exterior coating companies have already adopted its products, receiving positive feedback. With its wide range of functions and strong market potential, this self-cleaning coating technology is poised to revolutionize the industry and offer a sustainable solution to the long-standing problem of staining and maintenance in exterior coatings.
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