{"id":18982,"date":"2014-06-17T22:40:04","date_gmt":"2014-06-17T22:40:04","guid":{"rendered":"https:\/\/www.uniqchem.com\/tecnologia-antiespumante\/"},"modified":"2025-07-15T15:20:40","modified_gmt":"2025-07-15T15:20:40","slug":"tecnologia-antiespumante","status":"publish","type":"page","link":"https:\/\/www.uniqchem.com\/es\/tecnologia-antiespumante\/","title":{"rendered":"Tecnolog\u00eda antiespumante"},"content":{"rendered":"\t\t
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In many stages of production, handling and application, air can be incorporated and then finely dispersed into resins, lacquers, and paints. Introduced air or gas will form spherical bubbles in the liquid phase. In pure liquids, foam is not stable. Foam is only stable in systems containing surfactant-like substances such as wetting agents, or certain surface control additives needed to improve important properties of the paint. All these surfactants have in common the fact they can migrate to the air\/liquid interface of the paint, thereby reducing the surface tension.<\/p>

CAUSES OF FOAM<\/strong><\/p>

Foam is a stable dispersion of a gas in a liquid medium that results when a surfactant layer forms around air bubbles and entrains them within it. Air can be incorporated into a coating by:
\u25cf Mixing during the polymer\/pigment grinding and let-down steps.
\u25cf Pumping during package filling.
\u25cf Shear or spraying during application.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t

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\n\t\t\t\t\t\t\t\t\tMarangoni effects\uff1a<\/strong>\n
\nThe bubbles come closer together as a result of the gravitational forces allowing the liquid to flow out of the foam and the lamella to become thinner and thinner.\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t
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\n\t\t\t\t\t\t\t\t\tElectrostatic repulsion\uff1a<\/strong>
\n\nThe presence of ionic surfactant molecules at the surface creates electrostatic repulsion.The bubbles come closer together as a result of the gravitational forces allowing the liquid to flow out of the foam and the lamella to become thinner and thinner.\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t
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\n\t\t\t\t\t\t\t\t\tGibbs elasticity<\/strong>\n
\nThe foam lamella exhibits a higher elasticity due to a stretching effect caused by the presence of surfactant molecules.The bubbles come closer together as a result of the gravitational forces allowing the liquid to flow out of the foam and the lamella to become thinner and thinner.\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t
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DEFOAMING MECHANISM<\/strong><\/p>

The principle of inhibiting or destroying foam (defoaming) is generally based on an overcoming of the stabilizing mechanisms. Foam control additives (DEFOAMER) possess properties which are opposite to those needed for foam stabilisation.
Foam control additives function by a variety of mechanisms to prevent or rupture foam.
Their individual efficiency is determined by 3 key factors:<\/p>