{"id":5058,"date":"2021-10-29T06:05:19","date_gmt":"2021-10-29T12:05:19","guid":{"rendered":"https:\/\/www.ulprospector.com\/knowledge\/?p=5058"},"modified":"2022-04-06T09:39:25","modified_gmt":"2022-04-06T15:39:25","slug":"pc-defoamers-an-introduction","status":"publish","type":"post","link":"https:\/\/ulprospector.ul.com\/5058\/pc-defoamers-an-introduction\/","title":{"rendered":"Defoamers: An Introduction"},"content":{"rendered":"

\"\"Original article date: Aug. 19, 2016<\/em>
\nUpdated Oct. 29, 2021<\/em><\/p>\n

Originally, this article was written about five years ago, and with most things, there have been advancements in new technologies for the use of defoamers and antifoams<\/a>, as well as the composition of the additives due to greater regulatory restrictions and the need for different technology for different uses. There is some essential information below and more can be found in the endnotes.<\/p>\n

Both antifoams and defoamers are used for foam control. Given their similarities in function, they often have similar chemistries. The main difference between them is the timing of application. In order to prevent it, antifoams are designed to be applied before the formation of foam, while defoamers are designed to be applied after foam formation in order to destroy it. Below, we provide a closer look at antifoam and defoamer chemistry.<\/p>\n

For this article, defoamers and antifoam agents are focused on use in paints, inks, adhesives and even construction products. Defoamers are very important in the growing market of oil recovery applications but fall outside of the scope of this paper. There are food-grade defoamers and even ones designated as kosher or halal, but they are mentioned but not discussed here.I<\/sup><\/a><\/p>\n

\"FoamDependent upon the application and performance requirements, defoamers consist of polydimethylsiloxanes and other silicones, insoluble oils, waxes, stearates and glycols, as well as inorganics, such as silicates and talc. The regulatory requirements of zero VOC, or close to it, have changed the landscape of defoamers. The further development of bio-based products has also resulted in variations which might include the use of a soy-based oil instead of a non-vegetable oil.<\/p>\n

There are many types of antifoams available, and they are often lumped into two broad categories:<\/p>\n

Silicone antifoams<\/a> are normally composed of hydrophobized silica that is finely dispersed within a silicone fluid. The resulting compound is then stabilized into a water-based or oil-based emulsion. These antifoams are highly effective due to their general chemical inertness, potency even in low concentrations, and ability to spread over a foam film. If needed, they can be combined with other hydrophobic solids and liquids to improve their defoaming properties.<\/p>\n

Non-silicone antifoams<\/a> generally contain surfactants, which enhance their dispersal capabilities and effectiveness in foaming water. They can be water-based, oil-based, or surfactant-based. These antifoams can be used for a wide range of industries. Compared to silicone antifoams, they are sometimes more readily biodegradable and less prone to causing certain problems such as discoloration, spotting, and negative membrane effects.<\/p>\n

As far as new technologies, examples are:<\/p>\n

\"\"FOAMSTAR\u00ae ST 2400<\/a> is a series of\u00a0defoamers\u00a0based on\u00a0new\u00a0defoamer chemistry developed and patented by BASF. It is the first\u00a0new defoamer chemistry in over 30 years. It is based on a hyper-branched polymer with a 3-dimensional star-shaped structure containing hydrophilic as well as hydrophobic elements. FoamStar\u00ae technology breaks down foam on a molecular level. It acts as a unique surfactant interacting with the foam-related surfactants and destabilizes the foam bubbles.<\/p>\n

Soy-based defoamers are the preferred choice for biobased defoamers but can also be made from other vegetable sources instead of petroleum. Besides providing bio preferred labeling, there is a push for low or no VOC products.<\/p>\n

Processing with defoamers<\/h3>\n

In industrial processes, foams pose serious problems. They cause defects on surface coatings. They prevent the efficient filling of containers. Some of the sources of foam formation include:<\/p>\n