Silicone waterproofing agents can be divided into three categories: water-soluble, emulsion type, and bulk solvent type.
Water-soluble silicone waterproofing agents are mainly sodium methyl silicate and Potassium Methyl Siliconate, which are the first generation of silicone waterproofing agents. Its advantages are good water solubility, low price, easy use, and safety. The disadvantage is that it is strong in alkalinity and needs to absorb carbon dioxide in the air to be cross-linked and cured. It is easy to be washed away by rain before curing and loses water resistance.
Emulsion-type silicone waterproofing agent uses polysiloxane containing active groups, such as hydroxy silicone oil, hydrogen-containing silicone oil, epoxy silicone oil, an alkylsilane, to be dispersed into an oil-in-water emulsion under the action of an emulsifier, and then diluted with water to a certain concentration After the emulsion is sprayed, it is sprayed onto the substrate by a roller, penetrates into the pores of the substrate, and cross-links to form a waterproof and breathable film under alkaline conditions. The advantage of emulsion-type water repellent is that it does not use solvents, is environmentally friendly and safe. The disadvantage is that it contains hydrophilic emulsifiers, and its water-repellent and waterproof effect is not as good as that of solvent-based waterproofing agents. Furthermore, its penetration depth into cement components is less than that of solvent-based waterproofing agents. Especially the high molecular weight silicone oil is not easy to penetrate into the substrate, so it is waterproof. Poor durability.
Solvent or bulk water repellent is polysiloxane or alkylsilane with active groups, with or without organic solvents, spray, brush, or roll on the surface of the substrate, and then penetrate into the capillary pores. Under conditions or catalysts, it is cross-linked into a network structure. The advantage is that the water repellency is excellent, the penetration depth is greater than that of the emulsion type waterproof agent, and it is waterproof and durable, up to more than ten years. The disadvantage is that organic solvents have an impact on the environment, so pay attention to fire prevention.