Peru What are the No Foam for paints(1)

UV

Organosilicon type
silicone oil
The commonly used silicone oils include polydimethylsiloxane and polymethylphenylsiloxane. Polydimethylsiloxane is used in paints and inks. Although polymethylphenylsiloxane has good compatibility, it does not have the ability to control surface state, so it is basically not used in leveling agents, and is mostly used for high-temperature resistance

Peru Selection of antifoaming agents for different applications:

Additives

A substance that can reduce the surface tension of water, solution, suspension, etc., prevent the formation of foam, or reduce or eliminate the original foam. [1]
Defoaming agents should have the following properties: ① strong defoaming power and low dosage; ② Adding to the foaming system does not affect the basic properties of the system, i.e. does not react with the defoaming system; ③ Low surface tension; ④ Good balance with the surface; ⑤ Good heat resistance; ⑥ Good diffusion and permeability, high positive spreading coefficient; ⑦ Chemical stability, strong oxidation resistance; ⑧ Good gas solubility and permeability; ⑨ Low solubility in foaming solutions; ⑩ No physiological activity, high safety

non-silicon

Flat coating

Features: Low viscosity, low defoaming pressure

Recommendation: Mineral oils or mineral oil modified polyethers

Elastic coating

viscosity-reducing

Features: High viscosity, high No Foam pressure

Recommendation: Polyether modified silicone

foam

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

The study of foam can be traced back to Plato's time, but for hundreds of years, people have not formed a unified understanding of the definition of foam. American colloid chemist L · I · Osipow and Dow Corning's R · F · Smith defined foam from the density of foam; Japan's Koichi Ito defined foam from the perspective of foam structure, but ignored the correlation between bubbles; Professor Zhao Guoxi, a famous surface physicist in China, defined foam as: foam is a dispersion system in which gas is dispersed in liquid, gas is a dispersed phase (discontinuous phase), and liquid is a dispersion medium (continuous phase). Bubbles in liquid rise to the liquid surface, forming a bubble aggregate composed of a small amount of liquid that separates gas with liquid film. Scholars at home and abroad agree that foam itself is a thermodynamic unstable system. When the gas enters the solution containing surfactant, it will form a long-term stable foam system.

Features: More surfactants, stable foam

Peru Recommendation: Use polyethers or mineral oil to modify polyethers

Precautions for use of paint No Foam:

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