What is re-dispersible latex powder?

Re-dispersible latex powder, also known as redispersible polymer powder (RDP), is a free-flowing white powder obtained by spray drying an aqueous vinyl acetate-ethylene copolymer dispersion. It is a key additive used in construction materials such as mortars, tile adhesives, self-leveling compounds, and exterior insulation and finish systems (EIFS).

Here are some key characteristics and properties of re-dispersible latex powder:

1. Polymer Composition: Redispersible latex powder is primarily composed of vinyl acetate-ethylene copolymers, although other polymers may also be present depending on the specific formulation. These copolymers provide the powder with its adhesive, cohesive, and film-forming properties.
2. Water Redispersibility: One of the most important characteristics of redispersible latex powder is its ability to redisperse in water after drying. When mixed with water, the powder particles disperse to form a stable emulsion, similar to the original polymer dispersion. This property allows for easy handling, storage, and application of dry mortar and adhesive formulations.
3. Adhesion and Cohesion: Redispersible latex powder improves the adhesion and cohesion of cementitious materials, such as mortars and tile adhesives. It forms a flexible and durable polymer film upon drying, which enhances the bond strength between the substrate and the applied material.
4. Flexibility and Crack Resistance: The incorporation of redispersible latex powder into cement-based formulations imparts flexibility and crack resistance to the final product. This helps to reduce the risk of shrinkage cracking and improves the long-term durability of the construction material.
5. Water Retention: Redispersible latex powder can enhance the water retention properties of cementitious materials, allowing for extended working time and improved workability. This is particularly beneficial in hot and dry conditions where rapid drying of the mortar or adhesive may occur.
6. Improvement of Mechanical Properties: Redispersible latex powder contributes to the improvement of various mechanical properties of cement-based materials, including compressive strength, tensile strength, and impact resistance. It helps to create more robust and durable construction products.

redispersible latex powder plays a crucial role in enhancing the performance, workability, and durability of cement-based materials used in construction applications. Its water redispersibility, adhesive properties, flexibility, and crack resistance make it a valuable additive in a wide range of building products.