An area of particular commercial interest in the art is ceramic articles and ceramic coatings. Ceramic coatings are commonly used in products that store, treat, or transport water and liquid waste. Ceramic toilets, urinals, bidets, bathroom basins (collectively known as sanitary ware), flooring tiles and other bathroom fixtures are probably the most common example of such products.
When used to collect, contain and/or transport water, ceramic products often become stained by scum and films of biologic origin (e.g., bacteria, fungus, mold, mildew). To date, the primary method of removing biological scum and film from these ceramic products has been to abrade the ceramic surface in the presence of a topical cleaning agent.
There is a need for a ceramic coating that has built-in protection against the growth and proliferation of microbes. However, existing technologies are somewhat limited in this regard. For example, the high temperatures used in ceramic firing processes typically preclude the use of organic antimicrobial agents.
Conventional inorganic silver-based antibacterial compounds (e.g., zeolite, amorphous glass, sol-gel) generally are too expensive for commercial use. Moreover, incorporation of silver-based antimicrobial agents into ceramic glazes routinely presents issues of clouding, crazing, discoloration, and other undesirable consequences to the glaze aesthetics.
Zinc oxide is known as having antimicrobial characteristics and has been used in the preparation of ceramic glazing compositions. However, known ceramic glazing compositions that rely solely upon zinc oxide as an antimicrobial agent have not shown antimicrobial efficacy sufficient for control of microbial growth and proliferation on ceramic surfaces.
Accordingly, there is a need for a low-cost ceramic coating that offers persistent built-in antimicrobial protection.