What is the reason for the defoamer to float oil?
Defoamers may have floating oil during use. Some of these oil spots will not disperse for a long time, some will disperse after a period of time, and a thin oil film will form on the water surface, and some will even stick to the wall of the container containing the aqueous dispersion. So what is the cause? Let’s take a look together.
According to experts in the defoamer industry, defoamers are generally mixtures, generally composed of main defoamers, carriers, and additives. Depending on the type of defoamer, the main components of the defoamer are probably silicone oil, polyethers, higher alcohols, mineral oil, vegetable oil, etc. Carriers include water and solvents, such as aliphatic hydrocarbons, aromatic hydrocarbons, oxygen-containing solvents, etc. In addition, defoamers will also add some additives including thickeners, preservatives, etc.
Polydimethylsiloxane and polyether-modified polydimethylsiloxane, etc. Silicone has become a commonly used defoamer because of its high temperature resistance, low temperature resistance, stable physical properties, chemical inertness and low surface tension. It is recommended that our company’s products be solvent-based directional defoamers, which can be used in matte coatings, metallic coatings and color coatings. They have the characteristics of fast defoaming speed, small dosage and no effect on recoating.
Defoamers such as polyacrylic acid defoamers cause selective incompatibility by changing the polarity and molecular weight of the polymer. The use of such defoamers requires an evaluation of the impact on gloss. It is recommended that our company’s products be solvent-based non-silicon defoamers, which are particularly suitable for coil coatings and two-component polyurethanes, high-viscosity coatings, polyester coatings and acrylic coatings, and have excellent defoaming ability.
Generally speaking, defoamers must be substances that are insoluble in the foaming medium. They can be dispersed into the foaming medium in the form of droplets, droplets encapsulating solid particles, or solid particles. Defoamers have lower surface tension than the foaming medium and can spontaneously enter the liquid film to burst the bubbles. And water-based defoamers are one of the products with the most outstanding performance.
