How To Choose A Defoamer For Powder Coatings

When choosing a defoamer for powder coatings, you need to consider multiple factors to ensure that it is suitable for a specific coating system and achieves the desired defoaming effect. Here are some key selection points:
1. Understand the characteristics of the coating
Coating ingredients: Observe whether the coating contains foam-stabilizing ingredients, such as dispersants, thickeners, leveling agents, etc. These ingredients may increase the stability of the foam and thus affect the defoaming effect.
Coating system: Different coating systems (such as acrylic emulsions, polyurethane dispersions, water-soluble resins, etc.) may require different types of defoamers. Therefore, understanding the specific system of the coating is an important prerequisite for selecting a defoamer.
Volatility: The volatility of the coating will also affect the defoaming effect. Coatings with fast volatility may dry before the bubbles float to the surface, making it difficult to eliminate the foam.

2. Evaluate the performance of the defoamer
Defoaming ability: Select a defoamer with strong defoaming ability to ensure that the foam can be effectively eliminated during the mixing and construction of the coating.
Stability: The defoamer should have good stability to ensure that the defoaming effect continues to be exerted over a long period of time.
Effect on coating gloss: Some defoamers may have a negative impact on the gloss of the coating. Therefore, it is necessary to consider its effect on the appearance of the coating when selecting.
Recoatability: For coating systems that need to be applied multiple times, the defoamer should have good recoatability to avoid affecting the subsequent coating effect.
Another role of wax in powder coatings is degassing or defoaming. It is often used as a coating defoamer to solve the pinhole and dent problems of porous substrates. Tianshi powder coating defoaming wax products have excellent pollution resistance, extremely low addition amount, and little effect on gloss.

3. Choose the right type of defoamer
According to the characteristics of the coating and the performance requirements of the defoamer, the following types of defoamers can be selected:
Mineral oil or mineral oil modified polyether: suitable for coating systems with low viscosity and low defoaming pressure.
Polyether modified silicone: suitable for coating systems with high viscosity and high defoaming pressure, such as elastic coatings.
Polyether: can effectively prevent surface defects and has little effect on gloss, suitable for coating systems such as topcoat and laminating adhesive.
Powdered defoamer: It is polymerized by polysiloxane, special emulsifier, and highly active polyether defoamer through a special process. It does not contain water and is suitable for powder coating systems without water. Its characteristics are strong defoaming ability, small dosage, long-lasting foam suppression, good thermal stability, good fluidity, no side effects, and convenient transportation.

IV. Precautions for use
Mix evenly: Stir the defoamer thoroughly before use to ensure that it is evenly mixed with the paint.
Add appropriate amount: The amount of defoamer should be appropriate. Too much or too little may affect the defoaming effect. It is generally recommended to add it in two times, in the grinding stage and the paint mixing stage respectively.