Redispersible Polymer Powder for Exterior Wall Putty

The Benefits of Redispersible Polymer Powder for Exterior Wall Putty

Enhancing Adhesion

- Improving bond strength with substrates: RDP significantly increases the adhesion strength between the putty and various substrates such as concrete, mortar, and gypsum board. This ensures a strong bond between the putty layer and the substrate, which is crucial for preventing delamination and cracking, especially in exterior walls that are exposed to wind pressure and temperature fluctuations.

Providing Flexibility

- Accommodating minor deformations: RDP imparts flexibility to the putty, allowing it to adapt to these deformations without cracking. This is important for extending the lifespan of exterior wall putty.

Enhancing Water Resistance

- Reducing water absorption: RDP effectively lowers the water absorption rate of the putty, enhancing its water resistance. Good water resistance prevents moisture from penetrating the putty layer and the substrate, avoiding issues such as mold, efflorescence, and delamination.

Improving Workability

- Extending working time: RDP helps extend the open time of the putty. This gives workers more time to apply, smooth, and adjust the putty, improving the efficiency and quality of the construction process.

Enhancing Weather Resistance

- Resisting UV aging: RDP has good weather resistance and can withstand exposure to ultraviolet (UV) radiation. This ensures that the exterior wall putty does not age or discolor when exposed to sunlight over long periods, maintaining its appearance and performance stability.

- Adapting to temperature changes: RDP enables the putty to perform well over a wide range of temperatures. 

I. Standard process for the production of wall putty

(i) Core wall putty formulations (water-resistant putty as an example)

Raw material Modified additivesgel materialbase material

(ii) Production line key process control

Raw material pretreatment system

Gray calcium powder needs to be filtered by 200 mesh vibrating screen (sieve residue ≤ 0.5%).

Heavy calcium powder water content control ≤ 0.3% (microwave moisture meter detection).

Raw material pre-mixing adopts double screw conical mixer (speed 28-35rpm).

Dry powder mixing process parameters

Main mixing stage: first put in 70% of the base material + all additives mixing 8-12 minutes.

Final mixing stage: add the remaining base material and continue mixing for 15-20 minutes.

Requirement of mixing uniformity: deviation of gray calcium content in any three sampling points≤0.8%.

Quality Verification Indicators

Initial setting time: 1.5-2 hours (25℃/50%RH environment)

Bonding strength: ≥0.6MPa in standard condition, ≥0.4MPa after immersion in water.

Sandability test: no obvious sticky sand with 400 mesh sandpaper after 24 hours of curing.

Ⅱ. re-dispersible polymer powder application technology points

(i) Precision Additive Control Program

Gradient addition method (for high additive level formulations):

Dividing the total addition into base (1.5%) + functional enhancement (1-2%).

Put into the mixer twice, with an interval of ≥ 5 minutes.

Temperature and humidity compensation mechanism: 

Construction environment temperature

 (ii) Early warning of contraindications 

Prohibited substances in combination:

Strongly alkaline materials (pH>12): cause early gelation of polymer powder

Sulfate-type early-strengthening agents: cause structural damage to the polymer film.

Nonionic wetting agents: Reduce interfacial bonding efficiency.

Strengthening combination recommendation:

Latex powder + starch ether (0.05-0.1%): synergistically improve the anti-sagging property.

Latex powder + hydrophobic agent (0.3-0.5%): to build a double waterproof barrier