Tuvalu What are the Free of silicone defoamers for paints(1)

Tuvalu Selection of antifoaming agents for different applications:

Flat coating

Features: Low viscosity, low defoaming pressure

Recommendation: Mineral oils or mineral oil modified polyethers

Elastic coating

varnish

dispersant

Features: High viscosity, high Free of silicone defoamers pressure

Recommendation: Polyether modified silicone

colorant

Surface coating and film covering adhesive

There is no unified understanding of the mechanism of defoaming agents. According to the mechanism of defoaming agents proposed by predecessors, there are generally the following types: [4]
General defoaming mechanism
Typical defoaming mechanisms with a broad overview are the Robinson defoaming mechanism and the Ross hypothesis. Among them, Robinson mechanism is the basis of Ross hypothesis, which mainly emphasizes the liquid drainage of defoamer destroying foam and Marangoni effect to realize defoaming; The Ross hypothesis is based on the fact that the defoamer particles are insoluble droplets, while some defoamers actually produce defoaming effects in a dissolved state, so the defoaming mechanism of the Ross hypothesis is not comprehensive

Explanation in reference book
An agent that promotes the uniform dispersion of material particles in the medium to form a stable suspension. Dispersants are generally divided into two categories: inorganic dispersants and organic dispersants. Commonly used inorganic dispersants include silicates (such as water glass) and alkali metal phosphates (such as sodium tripolyphosphate, sodium hexametaphosphate, and sodium pyrophosphate). Organic dispersants include triethylhexyl phosphoric acid, sodium dodecyl sulfate, methyl pentanol, cellulose derivatives, polyacrylamide, gum, fatty acid polyethylene glycol esters, etc.

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

Ink

Water in Water Colorful

Attenuation mechanism of foam
Under the condition of gravity and pressure difference, the liquid membrane of foam will flow and discharge liquid unevenly, and the gas in the bubble will continue to diffuse and permeate due to the different pressure difference on both sides of the bubble membrane, so the instability of foam itself is mainly reflected from the dynamics. [4]
The attenuation mechanism mainly includes the diffusion of gas through the liquid film and the discharge of liquid from the liquid film. These two properties are inherent attributes of foam itself, and have nothing to do with the existence of surfactant. However, these two attenuation mechanisms only play an obvious role in the initial stage of foam system formation. With the attenuation of foam system, these two effects gradually weaken, making the foam attenuation rate gradually slow. [

defoamer

Features: More surfactants, stable foam

Tuvalu Recommendation: Use polyethers or mineral oil to modify polyethers

Precautions for use of paint Free of silicone defoamers:

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