The silica sol particles are fine, and the silica during gel separation has high activity. It can form new silicate inorganic polymer compounds with certain inorganic salts and metal oxides to form a very hard film; Strong penetrating power, fine particles can penetrate into the inside of the substrate through capillary action, and can react with the alkaline substance Ca(OH)z in the substrate to form calcium silicate, so that the coating has strong adhesion.
The enhancement of adhesion is the comprehensive effect of silica sol penetration and hardening and bonding, and is the comprehensive result of mechanical occlusion and chemical bonding, so it has a bonding force superior to the surface adhesion of general coatings. Silica sol is miscible with organic high molecular polymers, so that the organic high molecules are evenly distributed in the gaps of the silicon-oxygen-silicon inorganic coating, shielding the remaining hydrophilic groups in the inorganic coating, and the coating film undergoes alternating cold and heat. The shrinkage of the coating is buffered, and the coating has a certain degree of elasticity. The formed coating has the characteristics of both inorganic and organic coatings, making up for the shortcomings of both.
After the silica sol film is formed, the silica body is a network structure, which is not afraid of acid and alkali, and improves the performance of the coating film. The composite wall coating prepared with silica sol as the main film-forming material, synthetic emulsion (such as styrene-acrylic emulsion, vinyl acetate resin emulsion, etc.) as the auxiliary film-forming material, plus pigments, fillers, and adding JJH~J, has a unique Water resistance, fire resistance, washing resistance and pollution resistance performance. The casting coating prepared by mixing silica sol and refractory powder can better prevent molten steel from melting and plate abrasion when casting steel ingots. Most high-end latex paints such as "Nippon Paint" contain silica sol.
In addition, silica sol is widely used in the preparation of thermal conductive coatings for metal surface layers, water-resistant enamel coatings, wall bead steel coatings, energy-saving and anticorrosive high-temperature ceramic coatings, metal-type thermal insulation coatings, and foamed fire-retardant coatings.