Surfactants are a class of fine chemicals with various functions. Surfactants have various functions such as wetting, dispersing, emulsifying, solubilizing, foaming, defoaming and washing and decontaminating.
When a liquid comes into contact with a solid surface, the gas is repelled and the original solid-gas interface disappears and is replaced by a solid-liquid interface, a phenomenon known as wetting. In a general sense, wetting is a fluid is replaced by another fluid from the surface of the process.
Usually the process of dispersing particles or droplets of one substance and tiny forms into another medium is called dispersion. The resulting homogeneous, stable system is called a dispersion.
Mineral oil defoamer
Mineral oil defoamers usually consist of three types of substances: carrier, oxidized polyethylene wax which accounts for 75% to 80% of the entire system; hydrophobic particles 10% to 15%; emulsifier or spreading agent 5% to 10%; some formulas also contain There is a small amount of stabilizers or preservatives.
The carrier takes the main defoaming material into the foam system and helps to diffuse to the foam film, playing the role of bearing and dilution. It has a greater impact on the defoaming performance and durability of the defoaming agent. For the foam system, it is characterized by selectivity. The carrier should be a material with low surface tension, which must have suitable incompatibility with the foam system and easily rise to the surface of the foam system. Commonly used carriers are hydrocarbon oils or water, and others such as fatty alcohols, fatty acid esters or solvents. It occupies most of the formula and often plays a role in reducing the price of defoamers. Polycyclic aromatic hydrocarbons are rarely used because they may be harmful to the physiology.
The hydrophobic component plays the main active role in the antifoam formulation. It can be in liquid or solid form. If it is in liquid form, it exists as emulsion droplets; if it exists as solid particles, its particle size should be a hydrophobic material between 0.1 and 20 pm. If the particles are too small, the effectiveness is significantly reduced; if the particles are too large, they cannot enter the foam film layer, and the aggregation of microbubbles into large bubbles will not occur. They are neither soluble in the system of this formula nor in the foam system. The choice of which hydrophobic component depends to a large extent on the nature of the foam medium. It must not only eliminate the foam, but also leave the paint It is extremely important to have a flat and smooth film underneath. There are many hydrophobic materials to choose from, they are wax, silicone oil, hydrophobic silica, aliphatic amide, fatty acid ester, metal soap, polyurethane, high molecular weight polyethylene glycol, saturated fatty acid and unsaturated fatty acid, polyurea, etc.
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