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Why use defoamer for waterproof paint and how to use defoamer correctly?


Why use defoamer for waterproof paint and how to use defoamercorrectly?

What is waterproof paint?

Waterproof paint is a kind of paint that can prevent rain or groundwater from leaking.
Acrylic waterproof coating is a one-component water-emulsion waterproof coating made by using acrylic polymer emulsion as the base material and adding other auxiliary additives. The waterproof film formed after the waterproof coating is cured has certain extensibility, elastoplasticity, crack resistance, impermeability and weather resistance, and can play the role of waterproof, impermeability and protection. The waterproof coating has good temperature adaptability, easy operation and easy repair and maintenance.

The performance indicators of waterproof coatings are as follows:

Solid content

Solid content refers to the proportion of solids contained in a waterproof coating. Because the coating is formed by the solid components in the coating after brushing, the solid content is closely related to the thickness of the film and the quality of the coating.

Heat resistance

Heat resistance refers to the fact that the waterproof film after the waterproof coating is formed does not soften and deform at high temperatures. Non-flowing performance, ie high temperature resistance.

Flexibility

Flexible refers to the ability of the film layer of the waterproof coating to maintain flexibility at low temperatures. It reflects the application and performance of waterproof coatings at low temperatures.

Impermeable

Impermeability refers to the performance of waterproof coatings under a certain water pressure (hydrostatic pressure or dynamic water pressure) and no leakage in a certain period of time. It is the main quality index of waterproof coatings to meet the requirements of waterproof function.

Extensibility

The ability of the stretch-type waterproof coating to adapt to the deformation of the base layer. After the waterproof coating is formed, it must have a certain extensibility to adapt to the deformation of the base layer caused by factors such as temperature difference, dryness and humidity, and ensure the waterproof effect.
The basic process of acrylic waterproof coating: clean up the base layer → the bottom waterproof layer → the detail additional layer → paint the intermediate waterproof layer → apply the reinforcing layer → paint the intermediate layer waterproof layer → paint the surface waterproof layer → the waterproof layer first water storage Test → Protective layer and finish construction → Second water storage test → Engineering quality acceptance.

Why there are air bubbles in waterproof coatings?

*  Acrylate emulsion contains or has the characteristics of surfactant, and it is easy to generate bubbles.
*  During the construction process, stir the paint evenly and leave it for a short time. Generally, it is used immediately. The air bubbles generated during the stirring process have no chance to escape from the paint and remain in the coating film. Even if the bubbles burst, the coating will lose its fluidity, leaving cracks and pores on the surface of the coating film.
*  In order to ensure that the construction of the waterproof coating is easy and the thickness is not flowing, an appropriate amount of thickener needs to be added to increase the viscosity, which makes it difficult for bubbles to escape to the liquid surface and rupture.
The generation of air bubbles will affect the appearance and waterproof effect of the waterproof coating film. Regardless of brushing or roller coating during the construction process, if the bubbles cannot be eliminated in time, pores and cells of different sizes will be formed inside the coating film. The existence of these cells not only greatly reduces the effective cross-sectional area of ​​the coating film against the action of water pressure, but also generates stress concentration around the cells, causing the cracks to expand, making the waterproof coating film lose the waterproof effect, affecting the waterproof effect of the entire project. Reduce the durability of construction projects.
It is practically impossible to avoid foaming. A more practical and effective method is to add a defoamer to eliminate air bubbles.
Customers must choose defoamer depend on their experiments to evaluate the effects of different types of defoamers. It is known from practice that different combinations of emulsifying systems and auxiliaries will give different results.

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