In the process of manufacturing and construction of building materials, the production of foam often becomes an invisible killer that affects the quality. For example, mixing air into concrete during mixing can lead to a decrease in structural strength, and residual bubbles during coating can form surface defects. As a functional additive, defoamers have become a key factor in improving the efficiency and quality of the construction industry by disrupting the stability of bubbles.

The essence of foam is a heterogeneous system in which liquid is wrapped with gas. During the mixing, pumping, or spraying process of building materials, air is introduced to form stable bubbles due to the presence of surfactants or mechanical shear. If these bubbles are not eliminated, they will reduce the compressive strength of concrete, increase porosity, and accelerate carbonation corrosion. Pinholes and fish eyes are easy to appear on the surface of the coating mortar, affecting the beauty and waterproof. Affects the fluidity and compactness of grouting materials, leading to potential safety hazards in the project.

Defoamers mainly penetrate the bubble liquid film through defoamer molecules, reduce surface tension, cause bubble rupture, form a hydrophobic layer on the liquid surface, and prevent the generation of new bubbles. The commonly used types of defoamers in the construction industry include organosilicon defoamers, which have high temperature resistance and chemical stability, and are suitable for concrete and grouting materials. Mineral oil defoamers have low cost and are commonly used in water-based coatings and mortars. Polyether modified defoamer with both foam inhibition and compatibility, suitable for high shear construction environments.

The selection of defoamers should take into account the compatibility of the system and avoid reactions with building materials. Consider construction conditions such as temperature, pH value, and mechanical strength. Compliant with environmental standards, VOC limits, and non-toxic requirements.