Defoaming agents can eliminate foam and are the most widely used additives in production in various industries. However, even for such commonly used defoaming agents, some customers still have certain misunderstandings during the addition process.
Defoaming mechanism
To eliminate foam, usually static, heating or pressure reduction methods are used, but this is time-consuming. In various production processes and product use processes, foam needs to be eliminated quickly, so defoamers must be used. For this reason, it is necessary to understand the mechanism of action of defoamers.
Theoretically, the purpose of defoaming can be achieved by eliminating the factors that stabilize the foam. Since the factor that affects the stability of the foam is mainly the strength of the liquid film, after the defoamer is added to the working fluid, it becomes a solution, emulsion or dispersion, and adsorbs on the foam surface. Since it has a lower surface tension than the foam, it can attract surfactants or foaming substances, reduce the viscosity of the foam liquid film surface, and locally thin it and break it. Therefore, the main reason for the destruction of the foam is the thinning of the liquid film and the diffusion of the gas in the bubble. At the same time, in order to prevent the regeneration of foam, the surface elasticity must be reduced or eliminated, that is, the brittle surface film is used instead of the elastic surface film to produce unstable foam.
Types and characteristics of defoamers
For defoamers, we hope that they have both defoaming and antifoaming effects, have low solubility in water, and are not easily emulsified and solubilized by the working fluid. There are many types of defoamers, but according to the category, they can generally be divided into two categories: silicon-containing and silicon-free.
Silicone-containing defoamers have low surface tension, low solubility, good dispersion, long-lasting effect, and low dosage, which means they have strong ability to break and suppress foam. In addition, such defoamers are chemically inactive, non-toxic, and environmentally friendly. They mainly include silicone oil, silicone oil emulsion, silicone oil solution (silicone oil dissolved in organic solvents), and silicone oil plus other fillers (such as SiO2, Al2O3).
Silicon-free defoamers are mainly divided into the following categories according to their components:
1) Phosphate defoamers
2) Alcohols, ethers, fatty acids and their esters, animal and vegetable oils or mineral oils, and polyethylene glycol propylene glycol and other substances.
3) Polyether defoamers
Highly transparent acrylic defoamer
The highly transparent defoamer Elite 770 developed by Shenzhen U-Sunny Technology Co., Ltd. is different from other competing products. It has high compatibility, does not produce shrinkage holes, does not affect interlayer adhesion, has high transparency, and does not produce the whitening and fogging phenomenon of conventional defoamers. It can be added at any stage, and has rapid and long-lasting defoaming. It can be used in many industries, especially for polyester and polyurethane systems. It has a significant inhibitory effect on the generation of reactive bubbles, and is recommended for transparent coating applications such as glass, acrylic, and PC.