NEWS

This article is based on glazed tiles and aims to achieve antibacterial properties by adding a certain proportion of antibacterial materials to the glaze of full-glazed ceramic tile products (i.e., the outermost layer of glaze). The production process involves selecting pressed raw tiles on the production line, applying glaze on top, followed by inkjet printing on the glaze surface. Then, the glaze containing antibacterial materials is applied to the surface and dried before being placed in a roller kiln for firing. Finally, the edges are polished to produce finished products that maintain their original physical and chemical properties and surface effects while also possessing antibacterial properties.

3.1 Implementation of Antimicrobial Function

In current technology, there are two mainstream methods for achieving antimicrobial function in ceramic materials:

(1) Spraying a layer of antimicrobial material on the ceramic surface and fixing the material on the glaze surface of the ceramic through methods such as low-temperature firing or room temperature curing.

(2) Mixing antimicrobial materials into the ceramic glaze to make an antimicrobial glaze, which is then fired to produce antimicrobial ceramic tiles.

The first method involves two types of sprayed antimicrobial materials:

One type is photo catalytic antimicrobial materials, such as the earliest antimicrobial ceramic technology developed by TOTO, which involves spraying a layer of photo-catalytic antimicrobial material on the ceramic tile glaze surface. This type of product was also introduced by the Guangdong Fotao Saina Company in China.

The other type is spraying metallic silver paste on the surface of the ceramic glaze, or using materials containing antimicrobial ions to directly coat the ceramic glaze surface. INAX Corporation in Japan uses a metal vapor deposition technology to generate an antimicrobial layer on the ceramic surface. However, this technology only sprays the surface layer, and the coating is thin and easily washed away by external forces, which can reduce the antimicrobial performance.

The second method involves directly preparing an antimicrobial glaze. INAX Corporation in Japan previously used this technology, and the Guangdong Foshan Garden Building Ceramic Tile Factory and many other domestic ceramic factories mainly use this technology for producing antimicrobial ceramic tiles. The fatal weakness of this method is that the antimicrobial agent is easily lost during high-temperature firing, the effective components may not be uniformly distributed, and the antimicrobial activity may be weakened.

The main types of existing ceramic antimicrobial glazes include: 1. silver ion-doped antimicrobial ceramic glaze, 2. far infrared antimicrobial ceramic glaze, and 3. rare earth element-activated antimicrobial ceramic glaze.

Photo-catalytic antimicrobial materials traditionally require ultraviolet light irradiation to be effective, which imposes certain conditions on their application. However, new types of photo-catalytic antimicrobial agents have overcome the limitations of ultraviolet light and can produce antimicrobial effects under visible light. Therefore, this study does not select photo-catalytic antimicrobial materials for use.

3.2 Process Technology Optimization for Applying Antimicrobial Agents to Product Glazes

Combining common processes in the ceramic industry, this study attempts to achieve antimicrobial function through two experimental schemes: coating the glaze with an antimicrobial agent using the Ultra Clean and Bright surface coating method, and preparing an antimicrobial glaze. Specific experimental data and testing results are presented below.

As shown in the table data above, it is more suitable to add antimicrobial agents to the topmost glaze layer of ceramics without any other materials blocking it. This can allow for full contact with microorganisms and achieve a more effective antibacterial effect.