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Uganda What are the ink defoamer for paints(1)



Uganda Selection of antifoaming agents for different applications:

Flat coating


Action mechanism of polysiloxane defoamer
The representative defoaming mechanisms of polysiloxane mainly include "bridging spreading" mechanism, "bridging dehumidifying" mechanism, and "spreading liquid entrainment" mechanism. The "bridging spreading" mechanism mainly starts from the basic point of "polysiloxane has a relatively low tension and is easy to spread on the liquid film." It emphasizes that defoamer droplets are prone to deformation, but this theory cannot explain the defoaming differences between individual polysiloxanes and mixtures of polysiloxanes and solid ions as defoamers. The "bridging dehumidification" mechanism is mainly based on the hydrophobicity of polysiloxanes themselves, but the defoaming effect of polysiloxanes with high viscosity cannot be well explained. The "spreading liquid entrainment" mechanism cannot be confirmed because some facts indicate that polysiloxanes sometimes do not spread on the surface of the foam film, but can also break the foam.

Features: Low viscosity, low defoaming pressure


Recommendation: Mineral oils or mineral oil modified polyethers

Elastic coating

Features: High viscosity, high ink defoamer pressure

Stability factors of foam
The direct cause of foam is the presence of surfactant, which reduces the surface tension of the solution. Under the combined effect of this reason and the attenuation mechanism of foam, different foam systems show different stability properties, which are mainly related to the following factors: the surface tension of foaming solution, the surface viscosity of foam, the viscosity of solution, the self-healing effect of surface tension (i.e. Gibbs surface elasticity and Marangoni effect) "The surface double layer repulsion and entropy repulsion forces of liquid membranes, the hydrophobic end structure of surfactants, and the steric hindrance effect are not independent factors, and changes in one factor can cause other factors to also change.". The most important factors affecting the stability of foam are the elasticity of the liquid film and the liquid discharge rate. From this perspective, it can be seen that the main factors affecting the stability of foam are different in different foam systems, and sometimes several factors exist at the same time and work together.
In addition to the above factors, some other factors will also affect the stability of foam, such as the size of foam, the coordination of solute and solvent, temperature, pH value, the evaporation rate of solvent, the impact degree of foam and the adsorption rate of surfactant



Recommendation: Polyether modified silicone


Surface coating and film covering adhesive

Recommendation: Polyethers, which can effectively prevent surface defects and have a small impact on gloss

Water in Water Colorful

Defoaming mechanism of hydrophobic solid particles
Hydrophobic solid particles in the foam system will first attract the hydrophobic end of the surfactant, making the hydrophobic solid particles become hydrophilic, thus reducing the concentration of surfactant in the foam film and promoting the foam to burst. This defoaming mechanism cannot explain the action mechanism of other defoaming agents, which is too one-sided. [4] Other reasons for the bursting of foam are the impact caused by the expansion of defoamer, the solubilization of surfactant and the collapse of electrolyte, and the bursting of electric double layer on the liquid film surface. [4] It can be seen from the above defoaming mechanisms that each defoamer has different emphasis on different foam systems, but defoaming is achieved by destroying the stability factors of foam

Features: More surfactants, stable foam

Uganda Recommendation: Use polyethers or mineral oil to modify polyethers

Precautions for use of paint ink defoamer:

Before use, stir thoroughly and mix evenly; Adding the paint while stirring; Before use, it is generally not diluted with water; The dosage should be appropriate. Excessive dosage can cause shrinkage, edge shrinkage, poor brushing performance, and other problems; Too little dosage leads to poor defoaming effect; Add it in two stages, namely, add it in the grinding stage and the paint mixing stage, generally accounting for half of the total amount each time. Use defoaming agents with good foam suppression effect in the grinding stage, and use defoaming agents with good foam breaking effect in the paint mixing stage