| abstract |
A protective coating composition with early water resistance is prepared, according to principles of this invention, by combining in the presence of water and in their proper proportions: (1) zinc dust; (2) a Group IA metal silicate; (3) a colloidal silica ingredient that is modified with a Group IA metal silicate; and (4) a carbonate-containing internal hardener. Optional ingredients such as a stabilizing agent, external hardener, pigments and fillers, and other additives can be used to achieve certain coating properties depending on the final intended coating application. The Group IA metal silicate and colloidal silica ingredient that is modified with a Group IA metal silicate react, in the presence of the other ingredients, to form a silicate network having early water resistance, i.e., water insolubility, improved high-temperature resistance, improved corrosion resistance, and zero volatile organic content. Coating compositions prepared according to principles of this invention are formulated to cure at ambient temperature to form a water insoluble protective coating, for use in such applications as a full primer or preconstruction primer, within three hours. |