Solving Defoaming Challenges in High-Viscosity Coatings: Technical Strategies

High-viscosity coatings (e.g., epoxy floor paints, conductive silver pastes) face significant defoaming challenges due to poor fluidity and slow bubble migration. 

Entrapped bubbles cause:

Performance Failure: Insulating air pockets reduce conductivity in silver pastes;

Surface Defects: Bumps or craters compromise smoothness and gloss;

Weak Adhesion: Bubbles block coating-substrate contact, diminishing effective bonding area.

Chemi Tech Defoaming Strategy for High-Viscosity Systems

Deaerator-Defoamer Synergy

Deaerators: Contain hydrophobic silica and polymer carriers to merge micro-bubbles into larger ones, accelerating ascent. Ideal for viscosities >5000cP to shorten migration paths.

Defoamers: Modified silicone oils rapidly rupture surface bubbles. Recommended ratio: 2:1 (deaerator:defoamer) for comprehensive bubble removal.

Process Optimization

Vacuum Mixing: Apply vacuum (-0.08MPa~-0.1MPa) during production to extract dissolved gases;

Temperature Control: Pre-heat coatings to 40℃±5℃ before application, reducing viscosity to 2000~3000cP for faster bubble escape.

Technical Advantages of Chemi Tech

High-Penetration Formula

Defoamer particle size ≤5μm prevents agglomeration; polar groups in molecular chains ensure >98% resin compatibility without craters.

Dynamic Foam Suppression

Components adsorb onto nascent bubbles during high-shear processes (e.g., blade coating), inhibiting foam regeneration.

Case Study

A conductive silver paste client resolved microbubbles causing resistance fluctuations in flexible circuits by:

Adding 0.4% deaerator (KM-120) under vacuum (-0.09MPa, 20min);

Incorporating 0.2% defoamer (KM-190) during dilution;

Reducing bubbles by 90% and resistance fluctuation from ±15% to ±3%.

Conclusion

Defoaming high-viscosity coatings requires enhancing bubble mobility and rupture efficiency. Chemi Tech’s deaerator-defoamer synergy and process integration deliver reliable solutions for high-solids, viscous systems.