What Is a Photocatalytic Coating Agent?
Photocatalytic coating agents are coatings applied to building exteriors and interiors that have antifouling properties to prevent these stains.
The antifouling effect is achieved by taking advantage of the properties of photocatalysts.
Uses of Photocatalytic Coating Agents
Photocatalytic coating agents are used to coat building exterior walls, interior wallpaper, and curtains that are exposed to ultraviolet light from the sun or fluorescent lamps. Photocatalytic coating agents are characterized by their high hydrophilicity and positive charge. They decompose organic matter such as pollutants, viruses, and odorants contained in water, and provide antifouling and cleaning effects.
Therefore, the antifouling effect makes it possible to maintain cleanliness. When used on building walls, when rainwater adheres to the wall surface, the rainwater spreads along the coating film, and the pollutants in the rainwater and organic matter such as dirt adhering to the wall surface are decomposed by the oxidation-reduction reaction with the photocatalyst and washed away with the rainwater.
In addition, photocatalytic coating agents do not damage fibers and can be used on fabric products such as curtains and sofas, thus reducing material deterioration and preserving the beauty of the product. Furthermore, since it decomposes organic substances, such as viruses, odor components, and dirt, it also has the deodorizing and antibacterial effects required for these products used indoors.
Principle of Photocatalytic Coating Agents
Photocatalysts, such as titanium dioxide (often called titanium dioxide) used in photocatalytic coating agents, are highly hydrophilic and positively charged when they absorb UV light.
When moisture adheres to the film created by the photocatalytic coating agent, it spreads along the film due to its high hydrophilicity. At this time, the organic matter contained in the water is decomposed by the redox reaction of the positively charged photocatalyst.
Photocatalytic coating agents are very sustainable coatings, considering the fact that the effect can be achieved repeatedly as long as the photocatalyst is exposed to light, air, and water, and that the effect is achieved without the use of energy such as electricity, and that no waste products are generated.
Other Information on Photocatalytic Coating Agents
1. Advantages and Disadvantages of Photocatalytic Coating Agents
Advantages
These include antibacterial, antiviral, and deodorizing effects when used for interior applications. Another advantage is that once used, the effects are long-lasting and require little or no maintenance.
Furthermore, there are virtually no health problems. The main ingredient of photocatalytic coating agents is titanium dioxide, which has almost no effect on the human body even if ingested orally. Another advantage is that commercially available products meet safety standards for various items, including acute toxicity tests, skin irritation tests, and mutagenicity tests for oral intake.
Disadvantages
One disadvantage related to photocatalytic coating agents is that they tend to be more expensive. This is because photocatalytic coating agents themselves are more expensive than other coating agents, resulting in higher initial costs at the time of installation.
Also, when used on walls and other surfaces, antibacterial, antiviral, and deodorizing effects can be expected on the coated surface, but little effect can be expected on substances suspended in the air. Another disadvantage is that there are various types of bacteria and viruses, so antimicrobial and antiviral effects against all types of bacteria and viruses cannot be guaranteed.
2. Photocatalytic Coating Agent Price
There are various quantities and types of photocatalytic coating agents on the market. Prices vary, with most products available for hundreds to thousands of dollars. Spray-type products have smaller volumes and are relatively inexpensive, while paint-type products for interior walls have larger volumes and are more expensive.
If photocatalytic coating agents are to be applied to the entire interior, a request must be made to a specialized contractor. In this case, the unit price per square meter of coating is several thousand yen, but it varies slightly depending on conditions, such as the location to be coated. Photocatalytic coating agents are more expensive than other paints, so the initial cost tends to be higher, and a comprehensive decision must be made based on factors such as service life and effectiveness.