Application of Polyether-Based Powder Defoamers
Polyether-based powder defoamers are a mixture of polyether surfactants and dry powder carriers, appearing as white to light gray powder. They function to inhibit bubble formation, rapidly expel air bubbles introduced into building materials through mechanical mixing or chemical reactions, and provide long-lasting suppression of foam generation. Their core mission is to make materials denser and stronger. In the construction industry, they are a key additive for enhancing both the “intrinsic quality” and “aesthetic appeal” of building materials.
- Primary Application Scenarios
Flooring & Leveling Materials: Cement-based self-leveling compounds, gypsum-based self-leveling compounds. This is the largest volume application area. Defoamers prevent surface defects like pinholes and blowholes on floors, ensuring a smooth and level finish.
Structural Reinforcement & Repair: Non-shrink grouts, equipment base grouting, concrete repair mortars. Here, defoamers ensure grouts fully fill gaps, improve bonding strength with rebars/substrates, and safeguard structural integrity.
Walls & Finishes: Interior/exterior wall putties, plastering mortars, tile adhesives, grouts. They prevent bubble formation and hollowing on walls, resulting in a smoother surface for painting or tiling.
Special Components: Ultra-high performance concrete (UHPC), artificial stone, decorative renders.
- Core Performance Advantages
In construction applications, polyether powder defoamers primarily address the following pain points:
Eliminates Surface Defects (Prevents Pinholes & Pitted Surfaces): During mixing with water and application (troweling, spraying), building materials can trap air, forming bubbles. Polyether powder defoamers weaken the bubble film, causing bubbles to burst quickly, thus avoiding unsightly “pinholes” or “blowholes” on the hardened surface.
Enhances Mechanical Strength: Bubbles are weak points in materials. By reducing internal porosity, defoamers increase the density of mortars or concrete, thereby improving strength.
Improves Workability (Increases Fluidity): Excessive foam increases the viscosity of the mix, making it “thicker” and harder to work with. After defoaming, the fluidity improves, making the material easier to spread and level, which is particularly beneficial for self-leveling products.
Weather Resistance & Durability: Bubbles create channels for water and harmful substances to penetrate the material. Reducing bubbles lowers permeability, thereby enhancing resistance to freeze-thaw cycles, abrasion, and overall durability.
- 3. Application & Usage Guidelines
Dosage: Typically very low, ranging from 0.05% to 0.3% of the total dry powder weight ( 0.5 kg to 3 kg per ton of material). The exact amount should be determined through testing based on the specific formulation and ambient temperature.
Mixing Method:
Dry Mixing (Common method, ensures most uniform dispersion): Directly mix the powder defoamer with other dry ingredients (cement, sand, fillers) in a mixer until homogeneous.
Wet Mixing (For liquid polyether defoamers): Slowly add the liquid defoamer to the mixing water during the stirring process.
Important Notes: Although it is a “defoamer,” more is not always better. Excessive addition may lead to issues like bleeding, segregation, or reduced bonding strength in the mortar.
Summary
On construction sites, polyether-based powder defoamers are the preferred solution for tackling the “foaming” challenges in cement and gypsum products. They not only improve the visual appearance of building surfaces but, more importantly, enhance the strength and longevity of structures from within their micro-structure.