What Are Redispersible Polymer Powders (RDP)

Redispersible polymer powders are free-flowing, white powders manufactured by spray-drying polymer dispersions. When added to water, these polymer powders can disintegrate and form individual polymer dispersions again, with identical properties as the original dispersion.

Redispersible polymer powders are added to mortar to increase the flexibility and cohesiveness of mortar. This forms a continuous polymer film that helps improve water retention, enhance the bond strength of mortar, and improve the workability of dry mix mortar.

RDP Production Process

The redispersible polymer powder is a latex emulsion created by spray-drying macromolecular dispersions under particular conditions. During production, polyvinyl alcohol is added to stop the latex particles bonding together. These polymer powders are usually manufactured based on acrylic polymers, polyvinyl acetate, copolymers of vinyl acetate with vinyl versatate or with ethylene.
RDPs comprise of polymer resin, the crucial ingredient of dispersion particles and an important player for redispersible powders to function. As an additive, polymer powders act as modified resin and polymer resin.

Properties of Redispersible Polymer Powders

When water is added to the dry mix mortar, the polymer powder becomes a dispersion and forms a film upon drying. This film promotes elasticity and adhesion. Redispersible polymer powders are classified into highly elastic with low adhesion, rigid with high adhesion, and medium elastic with standard adhesion. Water is added to some powders to impart hydrophobic characteristics to the material.

• Vinyl Acetate-Ethylene Polymers (VAE) – These powders blend the flexibility of ethylene and the adhesion of vinyl acetate, leading to many economic and ecological benefits without affecting performance.
  They offer several benefits, including excellent cohesion, flexibility, good low-temperature film and variable glass transition temperature. They also show great adhesion to certain substrates like plastics and wood.
• Vinyl Chloride Copolymers and Terpolymers – These polymer powders show great water resistance, high hydrophobicity, and excellent tensile adhesion.
• Terpolymers based on VEOVA and VAcE – These polymer powders have extremely low transition temperatures. The benefits of using polymer powders based on VEOVA and VAcE include good workability, non-slump behaviour, good tensile adhesion strength, excellent crack-bridging properties, and low stickiness.

Applications

Redispersible polymer powders have numerous applications across various industries. They are widely used in:

• Construction adhesives
• Tile adhesives
• Joint mortars
• External wall putty
• Building binders
• Filling compositions like concrete repair joints, crack isolation membranes, and waterproofing membrane applications.

Interested in RDP Powders Products? Contact Bisley & Company

Bisley offers a variety of RDP polymer products that can help improve abrasion resistance, flexural strength, gas migration, and workability properties of the mixed mortar. These polymer powders are easily dissolved in water and develop stable emulsions.

Please send us a message online to learn more about the available specifications, grades, packaging, and applications of polymer powders. Our team will help you find an RDP powder product that suits your application.