Understanding the Types of Defoamers
Defoamers in general must be low surface tension surface active agents which are insoluble in the foaming medium. Their functionality depends on their carrier fluid, hydrophobic particles, dispersing agents, and preservative package. Different lines of chemistry have different functions and surface activity. In all cases, the goal is to destabilize foam lamellas and rupture air bubbles.
Silicone Based Defoamers
Silicone based emulsions and concentrates are the dominating chemistry in the antifoam and defoamer market. The low surface tension of silicone fluids, polymer flexibility, and modification capability make them prime candidates for most applications.
Fatty Alcohols
Fatty alcohols which are emulsified in a water base are top performers in water based systems at medium to lower temperatures. Their biodegradability, organic nature, and ability to deaerate make them the choice of most paper machine application and water treatment facilities.
Mineral and Natural oil defoamers
Oil based defoamers are more traditional in chemical make-up, but span a wide range of applications and are preferred to silicones in coating applications. Mineral and natural oil defoamers are concentrated and temperature resistant products.
Polyether Defoamer
Polyethers are water dispersible concentrates that are stable at high temperatures where fatty alcohol emulsions degrade. The nature of the chemistry is to promote deaeration, as well as defoaming and antifoaming. Their versatile application range includes paper machines, coatings, and fermentation.
Polymer defoamers
Polymeric defoamers have a limited but important range of application. Pulp processing which is subject to intense requirements of minute silicone carryover and deposits require these functional chemistry. In addition to pulp, oil/gas processing applications have benefited from the concentrated polymer defoamer products without silicone contamination.