The magical principle of defoamer
Defoaming agent is used to prevent bubbles from forming in lubricating oil. Its working principle is to change the surface tension of the foam so that small bubbles gather into large bubbles, and then burst the bubbles to achieve the defoaming effect. Properties: colorless oily liquid, insoluble in polar solvents such as DMF and water, physiologically stable, odorless, tasteless, non-toxic, non-irritating, and non-allergic to the skin. Uses and applications are as follows: 1. Defoaming: especially to remove raised fabrics. Air in the polyurethane impregnation liquid is brought into the non-woven fabric to reduce pinholes, bubbles, etc. 2. Enhance the dispersibility of pigments. 3. Increase the wettability between polyurethane and fibers. 4. Improve the surface finish and feel of finished leather. 5. The usage amount is 0.05~0.1% of the total weight of the polyurethane slurry.
The magical principle of defoamer: 1. The local surface tension of the foam is reduced, resulting in the collapse of the foam. The origin of this mechanism is that after the higher alcohol or vegetable oil is sprinkled on the foam, when it dissolves into the foam liquid, it will significantly reduce the surface tension of the place. Because these substances generally have low solubility in water, the reduction of surface tension is limited to the local part of the foam, and the surface tension around the foam has almost no change. The part with reduced surface tension is strongly pulled and extended to the surroundings, and finally bursts. 2. Defoamer can destroy the elasticity of the membrane and cause the bubble to collapse. When the defoamer is added to the foam system, it will diffuse to the gas-liquid interface, making it difficult for the surfactant with foam stabilization to restore the membrane elasticity. 3. Defoamer can promote the drainage of the liquid film, thus causing the bubble to collapse. The rate of bubble film drainage can reflect the stability of the foam. Adding a substance that accelerates the drainage of the foam can also play a defoaming role. 4. Adding hydrophobic solid particles can cause bubbles to burst. The hydrophobic solid particles on the bubble surface will attract the hydrophobic end of the surfactant, making the hydrophobic particles hydrophilic and entering the water phase, thereby playing a defoaming role. 5. Solubilizing and foaming surfactants can cause bubbles to burst. Certain low-molecular substances that can be fully mixed with the solution can solubilize the foaming surfactant and reduce its effective concentration. Low-molecular substances with this effect, such as octanol, ethanol, propanol and other alcohols, can not only reduce the surfactant concentration in the surface layer, but also dissolve into the surfactant adsorption layer, reducing the tightness between the surfactant molecules, thereby weakening the stability of the foam. 6. Electrolytes break down the double electrical layer of the surfactant and cause bubbles to burst.
