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Tips for making Coating Formula and defoamer in coating How many factors would affect defoamer performance in the paint&coating?


Tips for making Coating Formula and defoamer in coating

How many factors would affect defoamer performance in the paint&coating?

Ⅰ.Surface Tension
The surface tension of the paint has a greater impact on the defoamer. The surface tension of the defoamer must be lower than the surface tension of the paint, otherwise the defoaming and antifoaming effects cannot be achieved. The surface tension of the coating is a variable factor, so when selecting a defoamer, a constant surface tension must be taken into account, and the surface tension change factor must be taken into account.
Ⅱ.Effects of other additives
The surfactants used in coatings are mostly incompatible with the tendency of defoamers to function. In particular, emulsifiers, wetting and dispersing agents, leveling agents, thickeners, etc. can affect the effectiveness of defoamers. Therefore, we must pay attention to the relationship between different auxiliaries when selecting various auxiliaries, and choose the best balance point.
Ⅲ.Baking temperature
The coating enters high-temperature baking at normal temperature, and the viscosity drops back instantly, and the air bubbles can move to the surface. However, due to the volatilization of the solvent, the curing of the coating, and the increase of the surface viscosity, the foam will become more stable, trapped on the surface, and shrink. Holes and pinholes, so baking temperature, fixed-line speed, and solvent evaporation rate also affect the effectiveness of the defoamer.
Ⅳ.Coating solid content, viscosity, elasticity
High-solid coatings, high-viscosity, and high-elastic coatings are very difficult to defoam. In these coatings, the defoamer is difficult to diffuse, the microbubbles become larger, the foaming speed is slow, the foam's ability to migrate to the surface is reduced, and the foam has high viscoelasticity. There are many adverse defoaming factors. Foam in these coatings is quite difficult to eliminate. It is best to choose a defoamer and a defoamer together.
Ⅴ.Painting method and application temperature
There are many coating construction methods, such as brush coating, roller coating, shower coating, doctor blade coating, spray coating, screen printing and so on. Different coating methods have different levels of foaming. Brushing and roller coating have more foam than spray coating and doctor blade coating. The temperature is higher than that when the temperature is low, but the foam is easy to eliminate when the temperature is high.

How to do when using defoamers

  •           Stir well before use and mix well;
  •          Add when the coating is stirred;
  •          Before use, generally do not add water for dilution;
  •          Appropriate amount, too much amount will cause shrinkage, shrinkage, poor brushing and other problems; too little amount, poor defoaming effect;
  •          It is best to add it in two, that is, add it in the grinding stage and the paint adjusting stage, usually half of the total amount. Use a defoamer with a good foam suppression effect in the grinding stage, and use a foam breaking effect in the paint adjusting stage. Ok.



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