Redispersible Polymer Powder

Unveiling Redispersible Polymer Powder: The Professional Guide

Redispersible Polymer Powder (RDP) is a polymer emulsion. It is created through a series of different treating processes. These include high pressures and high temperatures, surface treatment, and spray drying, and even adding powdered thermoplastic resin materials.

When RDP is mixed with water the powdered organic binders get diffused into a new emulsion. The redispersed solution basically has identical properties to the original polymer compound.

What Are Redispersible Polymer Powders?

RD Powder is a white-colored, free-flowing powder. It is manufactured by spray-drying a liquid-dispersed polymer. Once it gets dry, the powder is carefully removed, processed and packed as a ready-to-use product.

When water is added to the RDP, it immediately diffuses and forms individual polymer particles again. The dispersed compound retains the mechanical and chemical properties of the original dispersion, such as adhesiveness, bonding properties, etc.

RDP is added to mortar to increase the cohesiveness and flexibility of mortar. This produces a uniform layer of polymer that enhances certain properties of the mortar. For instance, RDP provides mortars with improved water retention, stronger bonding power, and better functionality to the dry mix mortar.

Composition And Manufacturing Process

RD Powder is a form of polymer powder which is mostly used as a stable emulsion after being redispersed in water. It is highly useful in the construction industry as an additive. RDP helps to improve the overall performance of different cement-based materials.

RDP is obtained after a specific process called Spray-Drying. This process helps to atomize a polymer solution into a fine powdered form. This powder is then dried and processed to get the desired size of polymer particles.

These are the steps involved in the manufacturing of RDP –

  1. Selecting polymer
  2. Preparing solution
  3. Atomizing
  4. Drying
  5. Milling

The quality and workability of any RD powder depends on the standard of raw materials used, and the processing parameters applied during the manufacturing process.

Now let’s take a closer look at how redispersible polymer powder is manufactured –

1 – Selecting Polymer

The first step in manufacturing RDP is selecting the right type of polymer. The type of polymer used in producing RDP is mainly selected according to the properties desired in the final product. Different types of polymer tend to give different properties to the RDP.

For instance, some polymers can help enhance flexibility, adhesion and water resistance in the mortar. Most commonly, manufacturers of high quality RDP use acrylic polymers, ethylene copolymers, and styrene-butadiene copolymer for best results.

2 – Preparing Solution

After selecting the polymer, it is dissolved in a specific solvent to form a solution. Most commonly used solvents to manufacture RDP are organic and water solvents, such as isopropanol, and ethanol. Usually, the concentration of polymer in the solvent is around 10% to 20%.

3 – Atomization

Atomization is the next step in manufacturing high quality redispersible polymer powder. This process involves breaking the dispersed polymer solution into smaller particles. To do this, the manufacturer normally use a rotary atomizer or a high-pressure nozzle.

After the smaller particles are formed, they are then dried in a hot air stream. This step turns the dispersed solution into a fine powder form.

4 – Drying

The drying process in manufacturing redispersible polymer powder involves using a stream of hot air to remove the solvent. The process for drying is normally performed at a temperature ranging between 80-120° C.

The duration required to dry the solution completely varies. It depends on the type of polymer used, the desired particle size, and the concentration of the solution.

5 – Milling

The final stage in manufacturing redispersible polymer powder is the milling process. This process involves physically grinding the powder obtained from spray-drying into smaller-sized particles.

To grind the powder particles into smaller size, manufacturers use either a ball mill or a hammer mill to achieve the desired size of solution particles. Normally, the particle size of RDP is between 5-50 microns.

Properties Of Redispersible Polymer Powder

RDP develop several properties that have significant affect on the mortar mix. RDP modifies the cement in several ways. For instance, RDP improves the brittleness of conventional cement mortar. It also enhances the tensile bond strength along with its flexibility. It also decreases the risk of developing cracks on cemented surfaces.

The polymer and cement mortar form a strong matrix and creates a uniform film over the pores. It helps to strengthen the tensile bond between aggregates and can block some pores within the mortar. Once it gets hard, the RDP-mixed mortar is superior in quality to conventional cement mortar.

Here are the distinct properties that mortar or cement develop when they are made by mixing redispersible polymer powder –

1 – Strength

Redispersible polymer powders give incredible bonding power to the mortar. The bonding strength of mortar grows directly in proportion when you add a greater amount of RDP. However, this can inversely affect the mortar’s compressive strength. This is why there is a specific amount of RDP that you can mix to improve the bonding strength of mortar mix, without compromising compressive strength.

In addition, RDP is quite expensive, and adding more of it into the mortar mix can cause the cost of construction to rise. Apart from this, a higher bond strength can have a restrictive effect on the contraction. Though the stress generated by deformation can be dispersed it is important to have greater bond strength to prevent cracks from developing.

2 – Flexibility

The elastic modulus of redispersible polymer powder is lower than that of cement mortar. Hence, the elastic modulus of cement mortar gets reduced when you add extra RDP.

However, the dosage and type of polymer powder also affects the elastic modulus. In general, the risk of deformation increases in a mortar mix when the elastic modulus gets reduced and the cement-polymer ratio increases.

3 – Permeability

Redispersible polymer powder also has excellent water and alkali resistance. This provides the finished surface protection against impact and abrasion.

The polymer particles in RDP form a thin film that blocks the cracks and holes in cement mortar. This helps to reduce the porosity of hardened surfaces. In turn, this effectively improves the impermeability, making the mortar mix resistant to frost and water damage. This property can be enhanced by increasing the cement-polymer ratio in the mortar mix.

Abrasion-resistant property in the mortar is directly related to the type of polymer used in the polymer powder. Generally, abrasion resistance improves as the polymer-cement ratio increases.

4 – Water retention

The polymer mix formed after the redispersible polymer powder is mixed with water creates a continuous film of the mortar once it solidifies. This thin cover of RDP prevents migration of water. This way, RDP effectively reduces water loss from the mortar, and essentially enhances its water retention properties.

5 – Crack resistance

The toughness of polymer-induced cement mortar is significantly higher than that of ordinary cement mortar. Fracture-resistance power of RDP-mixed mortar cement is twice that of conventional cement mortar. Besides this, increasing the polymer-cement ratio also enhances the mortar’s toughness and ability to resist impact.

By increasing the amount of polymer powder, you can ensure good stress dispersion, and restrict the risk of developing cracks.

Applications In Construction

Redispersible Polymer Powders are multifunctional and useful in a wide variety of applications. Let’s look at some of the major applications of RDP in construction –

Mortar and cement based products

Redispersible polymer powder is most widely used in mortar and cement based products. By integrating RDP while developing mortar or cement, you can successfully increase its flexibility, improve adhesion, and enhance its water resistance.

When water evaporates and the cement/mortar dries, the polymer forms a thin film on the surface. This creates a strong adhesive bond between the cement/mortar and the underlying substrate. This prevents cracks from developing on the surface. It also enhances the overall durability of the concrete structure.

Besides, RDP is also known for its ability to prevent cracks and water damage to cement and mortar. This makes RDP ideal for use on exterior walls, especially where the surface is subject to harsh weather conditions. Thanks to this property, RDP prolongs the life of concrete structures, reduces maintenance costs and ensures long-term integrity of the structure.

Tile Adhesives and Grouts

Redispersible polymer powder is also used as additive for tile adhesive and tile grout. For instance, mixing RDP in tile cement enhances its strength and flexibility. With this, it is possible to reduce the risk of tile detachment and cracking. This is highly useful for tiles installed in heavy-traffic areas, and even in places that are exposed to extreme temperature changes.

In addition, RDP-mixed tile grouts also have extensive resistance to water damage and staining. This ensures that the tiles last longer, without loosing their aesthetic and practical integrity.

Insulation and Finishing

Redispersible polymer powder also has extensive use in EIFS (Exterior Insulation and Finish Systems). RDP has excellent crack-bridging and thermal insulation properties. By strengthening EIFS base layer, RDP increases the surface’s ability to bear remarkable thermal stress as well as structural movements. Hence, RDP reduces cracks, and ensures optimal energy efficiency at the same time.

Surface preparation

RDP is also widely used for seamless surface preparation of self-leveling compounds. This is extremely helpful for leveling uneven substrates. The RDP polymer solution forms a thin but consistent film on the surface once it dries. This gives the covered surface a seamless and smooth texture, which is suitable for installing floor coverings, such as carpeting, tiles, and even hardwood.

Besides this, redispersible polymer powder also gives better fluid properties to self-leveling compounds, which makes it ideal to get consistently smooth surfaces.

Advantages And Benefits Of Redispersible Polymer Powder

Here are several distinct advantages and benefits of redispersible polymer powder –

Improves mortar strength

The thin polymer film formed when RDP dries on the cement/mortar mix is quite flexible. The film effectively covers any cracks or gaps formed on the surface of the cement or mortar. It also essentially makes brittle and heavy cement mortar more elastic. In fact, RDP is added to mortar to enhance its flexural and tensile strength.

Enhances compound cohesion

RDP is designed to create higher tensile attachment and stronger bond with different substrate surfaces. It is essential to bond mortar with organic surfaces and smooth-faced substrates. The RDP essentially gets dispersed uniformly throughout the mortar and reinforces the cement’s overall cohesion properties.

Better damage resistanc

Redispersible polymer powder has tiny rubber particles that fill the cavity of the mortar and increase its overall density. This, in turn, improves the mortar’s resistance to wear-and-tear. With this, the mortar structure can flex and bear the action of external forces without sustaining damage.

Besides this, RDP-mixed mortar has thermoplastic properties and good flexibility. This makes the mortar capable to bear the harsh environment of outdoors with significant ease.

Improves workability

RDP particles also have a lubricating effect on the polymer powder particles, which allows the mortar to flow independently. Simultaneously, the polymer powder also has an inductive effect which provides the mortar with significant compressible properties. This, in turn, helps improve the workability of the mortar.

Factors Influencing Redispersible Polymer Powder Price

The worldwide redispersible polymer powder (RDP) market was valued at USD 2.0 billion in 2020, and is expected to grow to USD 2.8 billion by 2025, with a growth of 6.8% CAGR.

According to market experts, the biggest factor influencing redispersible polymer powder pricing worldwide is the growing demand in the Asia Pacific region. Increasing demand from the construction industries in India, Japan, and China are the major factors that are influencing the current price of RDP.


Redispersible polymer powder (RDP) is a highly versatile and widely used additive in the construction industry. It has remarkable advantageous properties, which give it a wide variety of applications across several industries. RDP works to not just enhance the strength of the cement surface, but also to improve its durability, performance and life of the structure. It has excellent resistance to water-damage, stress of structural movement, and risk of cracking. In addition, RDP can be even more useful once you understand its property, purpose and benefits.