Redispersible powder is a polymer-modifying additive, primarily used in cementitious/gypsum-based mortar systems. By forming a continuous polymer film within the system, it significantly improves the bonding strength, flexibility, crack resistance and water resistance of the material, while optimizing workability, enhancing the adhesion of the mortar to the substrate and improving its durability. It is widely applied in building materials such as tile adhesives, putties, external wall insulation systems and waterproof mortars.