Hydrated lime coatings or paints are well known as disinfectants, biocidal, and biostatic agents. In order to retain their biocidal activity after application to a desired surface, a hydrated lime coating must retain (1) the ability to pull in and substantially encapsulate a microorganism, and (2) the alkalinity necessary to kill microorganisms. In order to kill microorganisms, the lime must have a pH between about 11-13. In order to retain the alkalinity necessary to kill microorganisms, the coating, or paint, must be protected from attack by carbon dioxide.
Unfortunately, hydrated lime is highly susceptible to environmental attack, primarily by carbon dioxide. Carbon dioxide converts the hydrated lime to calcium carbonate, which does not have the alkalinity required to kill microorganisms. As a result, conventional coatings or paints containing hydrated lime are not effective as long term disinfectants, biocides, or biostatic agents.
A means is needed to prolong the biocidal activity of a hydrated lime coating.