Лако-красочные материалы — производство

Dry films are also subject to microbiological attack by fungi and algae, which impairs the aesthetic appearance of the film by discolo­ration or patching. In certain situations, this also affects film integrity and hence performance of the coatings. Dry-film preservatives are aimed at preventing the growth of bacteria, fungi, and algae on the paint film surface. As opposed to in-can preservatives, the solubility in water and volatility of dry film preservatives should be as low as possible in order to prevent leaching from the film and to ensure long­term film protection.

Some important examples of dry film preservatives include benzi­midazoles such as carbendazim, octylisothiazolinone, carbamates and dithiocarbamates such as thiram, zinc pyrithione and chlorotha — lonil. Representative examples are shown in Figure 5.23. As with in-can preservatives, the optimum use levels should be determined by experiments.