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

2023-04-19

wear-resistant

Oman Selection of antifoaming agents for different applications:

Flat coating

agent

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

Features: Low viscosity, low defoaming pressure

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

Recommendation: Mineral oils or mineral oil modified polyethers

Elastic coating

Features: High viscosity, high Free of silicone defoamers pressure

Recommendation: Polyether modified silicone

Surface coating and film covering adhesive

UV

dispersant

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

Water in Water Colorful

Features: More surfactants, stable foam

The chemical methods to eliminate foam mainly include chemical reaction method and adding defoamer. The chemical reaction method refers to the chemical reaction between the foaming agent and the foaming agent by adding some reagents to generate water insoluble substances, thus reducing the concentration of surfactant in the liquid film and promoting the rupture of foam. However, this method has some shortcomings, such as the uncertainty of foaming agent composition and the harm of insoluble substances to system equipment. Nowadays, the most widely used defoaming method in various industries is the method of adding defoaming agents. The greatest advantages of this method are high foam breaking efficiency and convenient use, but finding suitable and efficient defoaming agents is the key.

Oman 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