What are the ingredients of redispersible latex powder?

Redispersible polymer powder (RDP) is an important chemical product, widely used in building materials, coatings, adhesives and other fields. It is made by spray drying polymer emulsion and has the property of being able to redisperse in water to form a stable emulsion. The main components of redispersible latex powder include polymer resin, protective colloid, defoamer, filler, and additives.

1. Polymer resin

Polymer resin is the core component of redispersible latex powder and determines the main properties of latex powder. Common polymers include ethylene-vinyl acetate copolymer (EVA), ethylene-vinyl acetate-ethylene monomer copolymer (VAE), acrylate copolymer, styrene-acrylate copolymer, etc. Each resin has different characteristics:

EVA (ethylene-vinyl acetate copolymer): This polymer has good flexibility and adhesion, and is suitable for the preparation of flexible materials, such as exterior wall insulation materials and tile adhesives.

VAE (ethylene-vinyl acetate-ethylene monomer copolymer): VAE has the advantages of EVA and has better water resistance and weather resistance. It is widely used in building mortar.

Acrylate copolymer: This polymer is usually used to improve water resistance, alkali resistance and UV resistance. It is suitable for exterior wall coatings and products with high weather resistance requirements.

Styrene-acrylate copolymer: It is characterized by high hardness and is mainly used in coatings and floor materials that require high wear resistance and high gloss.

2. Protective colloid

The main function of the protective colloid is to stabilize the emulsion, protect the polymer particles from agglomeration during the spray drying process, and ensure that the particles can be evenly distributed during redispersion. Commonly used protective colloids include polyvinyl alcohol (PVA), hydroxypropyl methylcellulose (HPMC) and polyethylene glycol (PEG).

Polyvinyl alcohol (PVA): PVA is one of the commonly used protective colloids. It has good water solubility and film-forming properties and can effectively improve the stability of latex powder.

Hydroxypropyl methylcellulose (HPMC): HPMC not only has a protective effect, but also improves the water retention and construction properties of latex powder, and is often used in building mortar.

Polyethylene glycol (PEG): PEG is usually used as an auxiliary protective colloid to improve the stability of the emulsion and enhance the dispersion effect.

3. Defoamer

During the production and application process, the generation of foam will affect the dispersibility and application effect of latex powder. Defoamers are used to inhibit and eliminate foam. Commonly used defoamers include silicones, polyethers and mineral oils.

Silicone defoamers: They have good defoaming and antifoaming properties, high temperature resistance and good stability, and are often used in the production process of latex powder.

Polyether defoamers: Polyether defoamers have excellent performance, but the price is relatively high, and they are mostly used in occasions with high requirements for defoaming performance.

4. Fillers

The fillers mainly play the role of dilution and increment in redispersible latex powder, and can also adjust the performance of the product, such as improving crack resistance and compressive strength. Commonly used fillers include calcium carbonate, talc and silica.

Calcium carbonate: It is a common filler with low cost, which can improve the compressive strength and wear resistance of the product.

Talc: Talc has good lubricity and can enhance the flexibility and smoothness of the product.

Silica: Silica is mainly used to improve the heat resistance and chemical corrosion resistance of the product.

5. Additives

In order to improve the performance of redispersible latex powder, some additives such as preservatives, plasticizers, antifreeze agents, etc. are also added.

Preservatives: It is used to prevent latex powder from mildew or corruption during storage. Commonly used preservatives include sodium benzoate, potassium sorbate, etc.

Plasticizers: Plasticizers can improve the flexibility and ductility of latex powder. Commonly used plasticizers include phthalates and epoxy fatty acid esters.

Antifreeze: In low temperature environments, antifreeze can prevent latex powder from freezing, thereby maintaining its usability. Commonly used antifreeze agents include ethylene glycol, propylene glycol, etc.

Redispersible polymer powder is a complex multi-component material, whose main ingredients include polymer resin, protective colloid, defoamer, filler and various additives. The selection and ratio of each component will affect the performance of the final product, so the formula needs to be carefully adjusted according to the specific application requirements during the production process. Redispersible polymer powder has become an indispensable and important material in the fields of building materials and coatings due to its excellent dispersibility and adhesion.