Raw Materials Of Redispersed Latex Powder

Redispersed latex powder (RDP) is a type of polymer emulsion powder that is widely used in the construction industry for applications such as cement-based tile adhesives, self-leveling compounds, and exterior insulation and finishing systems. RDPs are made by spray drying a polymer emulsion, which is a mixture of water, a monomer or mixture of monomers, a surfactant, and various additives. In this article, we will discuss the raw materials that are commonly used to produce RDPs.

1. Monomers The monomers used in the production of RDPs can vary depending on the desired properties of the final product. Commonly used monomers include styrene, butadiene, acrylic acid, methacrylic acid, and their derivatives. Styrene-butadiene rubber (SBR) is a popular choice for RDPs due to its good adhesion, water resistance, and durability.
2. Surfactants Surfactants are used in the production of RDPs to stabilize the emulsion and prevent coagulation or flocculation. Common surfactants used in RDPs include anionic, cationic, and nonionic surfactants. Anionic surfactants are the most commonly used type in RDPs, as they provide good emulsion stability and compatibility with cementitious materials.
3. Stabilizers Stabilizers are used to prevent the polymer particles in the emulsion from coalescing or aggregating during storage and transportation. Common stabilizers used in RDPs include polyvinyl alcohol (PVA), hydroxyethyl cellulose (HEC), and carboxymethyl cellulose (CMC).
4. Initiators Initiators are used to initiate the polymerization reaction between the monomers in the emulsion. Common initiators used in RDPs include redox initiators, such as potassium persulfate and sodium bisulfite, and thermal initiators, such as azobisisobutyronitrile.
5. Neutralizing agents Neutralizing agents are used to adjust the pH of the emulsion to a suitable level for polymerization and stability. Common neutralizing agents used in RDPs include ammonia, sodium hydroxide, and potassium hydroxide.
6. Crosslinking agents Crosslinking agents are used to crosslink the polymer chains in the emulsion, which can improve the mechanical properties and water resistance of the final product. Common crosslinking agents used in RDPs include formaldehyde, melamine, and urea.
7. Plasticizers Plasticizers are used to improve the flexibility and workability of the RDPs. Common plasticizers used in RDPs include polyethylene glycol (PEG) and glycerol.
8. Fillers Fillers are added to RDPs to improve their mechanical properties and reduce cost. Common fillers used in RDPs include calcium carbonate, talc, and silica.
9. Pigments Pigments are added to RDPs to provide color and improve the aesthetics of the final product. Common pigments used in RDPs include titanium dioxide and iron oxide.

In conclusion, the raw materials used in the production of RDPs can vary depending on the desired properties of the final product. Monomers, surfactants, stabilizers, initiators, neutralizing agents, crosslinking agents, plasticizers, fillers, and pigments are all commonly used in the production of RDPs.