The demand for paints that repel microorganisms - for instance in a sterile environment or in areas where strict hygiene standards are required - is on the increase. The medical profession has already been using various antimicrobially equipped materials for many years. In addition to conventional antimicrobial additives, purely organic substances, such as triclosan, for example, are also used in a pure form, i.e. metallic silver products.1
The effectiveness of such silver products is based on the slow and continuous leaching of superfine silver ions that interact with the metabolism of the microorganisms in various ways.1 For example, silver ions can inhibit enzyme activity, especially those containing sulfur. In doing so, they have a major influence on the energy metabolism of these microorganisms. Products containing silver demonstrate a broad level of antimicrobial effectiveness, however, significantly less activity is observed for attack with fungus when compared to bacteria.2,3 Examples of these antimicrobials are products where silver is embedded into base materials, such as special zeolites or glass. Furthermore, combinations of Ag (silver) and Zn (zinc) are used in zeolites, sometimes leading to synergistic effects.4