How RDP Enhances Adhesion and Flexibility in Tile Adhesives and Wall Putty

Redispersible Polymer Powder (RDP) is widely used in cement-based dry mix mortars, including

tile adhesives and wall putty. In these applications, the main reason for adding RDP is to improve

the balance of bonding strength and flexibility required by the finished mortar.

For formulators and buyers, however, choosing an RDP should not be based only on the general

benefits of polymer modification. The better approach is to match the application requirements 

with the required performance and then evaluate suitable RDP grades in the complete formulation.

What Does RDP Do in Tile Adhesive?

In a cement-based tile adhesive, RDP is mainly used to modify the bonding and deformation 

behavior of the mortar.

After mixing with water and curing, the polymer contributes to the formation of a polymer phase 

within the hardened mortar. This helps the formulation achieve the bonding and flexibility required

for tile installation.

The key performance areas to evaluate include:

- Bonding strength: Important for maintaining adhesion between the tile adhesive and substrate.

- Flexibility: Helps the mortar accommodate certain deformation within the system.

- Water-related performance: Relevant when the tile adhesive is used in applications where moisture

   resistance is an important formulation requirement.

- Workability: Should be evaluated as part of the complete mortar formulation rather than attributed 

   to RDP alone.

The required balance depends on the tile adhesive formulation, substrate, tile type and project condi-

tions.

Why Are Bonding Strength and Flexibility Important?

Tile adhesive must maintain a reliable bond while the substrate and tile system experience changes 

during service.

If the formulation requires stronger adhesion, the RDP should be selected according to the required

bonding performance. If the system also needs flexibility, the RDP should be evaluated for its contri-

bution to both bonding strength and flexibility.

This means that RDP selection should start with a simple question:

What is the main performance requirement of the tile adhesive?

For example:

- If bonding strength is a major requirement, evaluate an RDP grade specified for high bonding

  strength.

- If a general-purpose balance of bonding strength and flexibility is required, a universal-grade

  RDP can be considered.

- If the formulation requires bonding strength and flexibility together with waterproofing, a

  grade with waterproofing listed as a product function should be evaluated.

How to Select RDP for Tile Adhesive

RDP should be selected according to the application requirement rather than simply choosing the 

highest-performance grade.

1. Identify the Main Application Requirement

First define what the tile adhesive needs to achieve.

Typical priorities may include:

- Higher bonding strength

- A balance of bonding strength and flexibility

- Flexibility for the intended application

- Additional waterproofing performance

The required performance should be considered together with the cement, aggregate, cellulose ether

 and other formulation components.

2. Match the Requirement with the RDP Grade

JINTEDIFU offers several RDP grades that can be evaluated for tile adhesive formulations.

JINT-502 is a high-bonding-strength RDP for dry mix mortars and is listed for tile adhesive, with bonding

strength and flexibility as its stated functions.

JINT-503 is a universal-grade RDP for dry mix mortars. It is listed for tile adhesive and provides bonding

strength and flexibility.

JINT-740 is a high-bonding-strength RDP for dry mix mortars and is also listed for tile adhesive, with 

bonding strength and flexibility as its stated functions.

JINT-745 is a flexible-grade RDP listed for tile adhesive. Its stated functions include bonding strength, 

flexibility and waterproofing, making it relevant when waterproofing is an additional formulation 

requirement.

The choice should therefore follow:

Application requirement → Required performance → Suitable RDP grade → Laboratory validation

Practical RDP Testing in Tile Adhesive

When comparing RDP samples, it is better to evaluate the polymer in the actual tile adhesive formulation

rather than judging the powder by itself.

For an initial laboratory comparison:

- Keep the cement, aggregate, cellulose ether and other additives unchanged.

- Use the same RDP dosage for the first comparison.

- Keep mixing procedure, water addition and curing conditions consistent.

- Compare the finished mortar according to the project's key requirements.

Depending on the formulation, useful evaluation items may include:

- Tensile adhesion strength

- Adhesion after water exposure, where relevant

- Flexibility or deformation-related performance

- Fresh-mortar workability

- Overall mortar stability

If one RDP performs better in one test but creates an unacceptable change in another property, the formulation

should be optimized before making the final grade selection.

RDP for Wall Putty

RDP is also used in wall putty, where adhesion and flexibility are important formulation considerations.

The same selection principle applies: define the required performance first, then evaluate an RDP grade that 

matches those requirements.

For wall putty applications where bonding strength and flexibility are the main requirements, RDP grades such 

as JINT-502 and JINT-503 can be evaluated according to their stated applications and functions.

Choosing the Right RDP for Your Formulation

There is no need to select an RDP simply because it offers more functions. The more practical approach is to 

choose the grade that matches the actual requirements of the mortar.

For tile adhesive:

- High bonding strength + flexibility: Evaluate JINT-502 or JINT-740.

- General-purpose bonding strength + flexibility: Evaluate JINT-503.

- Bonding strength + flexibility + waterproofing: Evaluate JINT-745.

The final selection should always be confirmed through testing in the complete formulation.

If you are developing a tile adhesive or wall putty formulation and need to compare RDP grades, contact 

JINTEDIFU for product information and sample evaluation.

Name: Zane.Liu

E-Mail:Zane.Liu@jtdf-rdp.com

Mobile:+86 166 5317 6310（Whatsapp）