Redispersible Polymer Powder for Waterproof Mortar System: Product Grades, Core Functions and Application Performance

Redispersible polymer powder (RDP) is commonly used in cement-based waterproof mortar to modify key properties

such as bonding strength, flexibility, and water-related performance.For formulators and buyers, the main challenge is 

not simply adding RDP, but selecting a grade that matches the performance requirements of the waterproof mortar system.

What Does RDP Do in Waterproof Mortar?

In a cement-based mortar, RDP is mainly used to improve the balance of adhesion and flexibility after polymer modification.

Depending on the selected grade, the key performance requirements may include:

1) Bonding strength to cementitious substrates

2) Flexibility

3) Waterproofing or water-related performance

4) Workability during mixing and application

The importance of each property depends on the intended waterproof mortar application.

How to Select RDP for Waterproof Mortar

A practical selection process is:

Application requirement → Required performance → RDP grade → Formulation testing

1. General waterproof mortar

If the formulation requires basic bonding strength and flexibility without a specific waterproofing function from the RDP, 

a universal-grade product can be considered as a starting point.

JINT™-503 is a universal-grade RDP for dry mix mortars. Its listed functions are bonding strength and flexibility. It can be 

evaluated in waterproof mortar formulations where these are the primary polymer-related requirements.

2. Waterproof mortar requiring higher bonding strength

When stronger adhesion is an important formulation target, a high-bonding-strength RDP can be considered.

JINT™-502 and JINT™-740 are listed as high-bonding-strength RDP grades, with bonding strength and flexibility as their stated functions.

The two grades should be compared through the customer's actual formulation rather than assuming that one is universally better than the other.

3. Waterproof mortar requiring waterproofing as an additional performance target

When waterproofing is a specific requirement of the formulation, the RDP should be selected accordingly.

JINT™-745 is a flexible-grade RDP whose listed functions include bonding strength, flexibility, and waterproofing. It can therefore

be considered when all three performance requirements are relevant to the waterproof mortar system.

Test the RDP in the Finished Mortar

Product specifications alone are not enough to determine the best RDP for a waterproof mortar formulation.

For an initial laboratory comparison, keep the cement, filler, cellulose ether, water level, and RDP dosage consistent, 

and compare candidate grades under the same curing conditions.

Depending on the application, useful evaluation items include:

1) Bonding strength

2) Flexibility

3) Water-related performance

4) Workability and application behavior

The final RDP selection should be based on the performance of the complete mortar formulation, not the polymer powder alone.

Conclusion

Selecting RDP for waterproof mortar should start with the application requirement and the performance target.

For a general formulation, JINT™-503 can be considered as a universal-grade option. When higher bonding strength is required, 

JINT™-502 or JINT™-740 can be evaluated. When bonding strength, flexibility, and waterproofing are all required, 

JINT™-745 is the most directly aligned option based on its listed product functions.

Laboratory testing in the final mortar formulation remains the key step before production use.

Name: Molly.Wang

E-Mail:molly.wang@jtdf-rdp.

Mobile:+86 156 5045 0156（Whatsapp）