Re-dispersible polymer powder (RDP) is a dry powder form of a synthetic polymer that can be easily mixed with water to form a polymer dispersion. RDP is commonly used as an additive in various construction materials, including dry-mixed mortar, tile adhesives, and exterior insulation and finishing systems (EIFS), due to its excellent properties, such as improved workability, adhesion, and flexibility.
RDP is made from a variety of synthetic polymers, such as vinyl acetate-ethylene (VAE), vinyl acetate-versatile monomer (VeoVa), and acrylics. These polymers are polymerized in an aqueous medium to form a latex, which is then dried and ground into a fine powder. The powder can then be easily dispersed in water to form a stable polymer dispersion.
The properties of RDP depend on the type of polymer used, the degree of polymerization, the particle size distribution, and the presence of other additives. Generally, RDP has good water resistance, flexibility, adhesion, and compatibility with other construction materials. The powder form of RDP also allows for easy storage, transportation, and handling.
In dry-mixed mortar, RDP is used to improve the workability, adhesion, and flexibility of the mortar. RDP can enhance the water retention of the mortar, which allows for better workability and increased open time. The improved adhesion provided by RDP can also increase the bond strength between the mortar and the substrate, resulting in a more durable and long-lasting finish.
In tile adhesives, RDP is used to improve the bond strength and flexibility of the adhesive. The improved bond strength provided by RDP can increase the resistance to shear and peel forces, resulting in a stronger and more durable bond between the tile and the substrate. The increased flexibility provided by RDP can also help to absorb stresses caused by changes in temperature and humidity, reducing the risk of cracking or delamination.
In EIFS, RDP is used to improve the adhesion, flexibility, and weather resistance of the system. The improved adhesion provided by RDP can increase the bond strength between the insulation board and the substrate, while the increased flexibility can help to absorb stresses caused by thermal expansion and contraction. The water resistance provided by RDP can also help to prevent water penetration and reduce the risk of damage caused by freeze-thaw cycles.
The use of RDP in construction materials has several advantages. First, RDP can improve the performance of the materials, resulting in a more durable and long-lasting finish. Second, RDP can improve the workability and handling of the materials, reducing the risk of errors and improving productivity. Finally, RDP can also improve the environmental performance of the materials, such as reducing the amount of volatile organic compounds (VOCs) emitted during application.
In conclusion, re-dispersible polymer powder (RDP) is a versatile and widely used additive in construction materials. RDP can improve the workability, adhesion, and flexibility of dry-mixed mortar, tile adhesives, and EIFS, resulting in a more durable and long-lasting finish. The use of RDP in construction materials has several advantages, including improved performance, workability, and environmental performance.