What role does redispersible latex powder play in mortar products?
Release Time:
2016-08-10
Source:
What role does redispersible latex powder play in mortar products?
Redispersible Latex Powder What role does it play in mortar products?
Redispersible latex powder is a generic term for modified, formulated latex powders—dry powdered polymers that can be redispersed in water to reform an emulsion. These powders are produced by subjecting polymer emulsions to proper spray drying, often with the addition of suitable additives. When the dry polymer powder is mixed with water, it re-forms an emulsion; during the setting and hardening of cement mortar, the water can be removed once again, allowing the polymer particles to form a polymeric network within the mortar. This process is analogous to that of polymer emulsions and imparts modifying effects to the cement mortar. The significance of redispersible latex powder lies in the fact that, compared with polymer emulsions, it eliminates the need to address issues such as emulsion formulation, stability, and dosage control. Additionally, it offers advantages such as freeze-thaw resistance, ease of packaging, light weight, convenient and economical transportation, resistance to mold growth, and long-term storage stability. It can be blended with cement, sand, and other ingredients to produce single-component pre-mixed mortars that require only the addition of water and mixing prior to use.
Redispersible Latex Powder Components:
Polymer resins: These reside at the core of the latex powder particles and are the primary components responsible for the performance of redispersible latex powders, such as polyvinyl acetate and ethylene resins.
Additives (internal): Substances added to the resin to modify its properties, such as plasticizers that lower the film-forming temperature.
Protective colloid: A hydrophilic material, predominantly polyvinyl alcohol, is coated onto the surface of redispersible latex powder particles.
Additives (external): Additional materials are incorporated to further enhance the performance of redispersible latex powder. For example, superplasticizers are added to certain flow-enhancing latex powders.
Anti-caking agent: a fine mineral filler primarily used to prevent adhesive powder from caking during storage and transportation and to facilitate its flow.
