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Antifoams are chemical agents which, as the name would suggest, are designed to control the formation of foam. They come in two types: silicone based and non-silicone based.
A wasteful build-up of foam can pose a number of serious issues during industrial processes and operations. This could include defects on surface coatings, affecting the efficiency of filling lines; it could also result in bacterial growth.
An overflow of foam can also be a slip hazard, with the associated clean-up work incurring a time and cost penalty. The benefits of antifoams, therefore, include increased manufacturing productivity, throughput and even safety.
Antifoam products are emulsion additives that are used to control the formation of this foam, with products suitable for water-based, solvent-based and even solventless industrial systems. Relevant settings include, but aren’t limited to:
Finding the right product for you is ultimately determined by the application needed.
You may often see antifoams referred to as ‘defoamers’ — the two terms are sometimes used interchangeably. However, antifoams are designed to prevent foams, whereas defoamers eliminate existing foam. As such, defoamers are used when needed, whereas antifoams are added up front.
The antifoam market is dominated by silicone-based products. This is due to their enhanced properties — low surface tension, chemical inertness, thermal stability and complete insolubility in water.
Within this silicone group, there are subgroups — this includes technical-grade and food-approved antifoams. In another blog post, we’ve explored the precise differences between these sub-groups of silicone-based antifoams.
Silicone-based antifoams are polymers with silicon backbones that are either oil or water based. They hold low surface tension, allowing them to spread through foam quickly. These types of antifoams float easily over the foam wall, occupying openings that cause the foam wall to thin and collapse.
The silicone compound consists of a hydrophobic silica dispersed in a silicone oil. Emulsifiers are added to ensure that the silicone spreads fast and well within the foam.
Silicone-based antifoams are good at knocking down surface foam and releasing entrained air. Some products are also suitable for non-aqueous systems like crude oil and oil refining.
Antifoams also come in other forms, including mineral and organic-based products.
The use of these types of antifoams has reduced in certain applications due to the effectiveness of silicone-based products. However, they are still used in effluent treatments and process waters where silicone products are prohibited.
Generally speaking, these organic-based antifoams require higher dosages to work effectively, which in turn increases the cost. This usually makes silicone-based solutions more desirable.
If you’re in an industrial environment where food processing considerations apply, you’ll likely need an food-approved silicone antifoam. In other water-based technical industrial areas, a technical-grade antifoam will most likely be suitable.
We’re a UK distributor of the leading Akasil® antifoams range.
Akasil’s TG antifoam range is the technical grade. These products (10%, 20% and 30% activity) are most effective in water-based technical processes, where undesirable levels of foaming are present due to biological, chemical or physical effects. These products work effectively in hot and cold aqueous wastewater systems, achieving complete dispersion with minimal agitation.
These antifoaming agents hold low surface tension, allowing them to spread through foam quickly, occupying openings that cause the foam wall to collapse, keeping pipelines, pumps and process routes clear and free-flowing.
The other Akasil® antifoam range is FD, food grade antifoam. These are also silicone-based, but are specially developed for use in food processing environments.
These FD antifoam products comprise siloxane emulsions at 10%, 20%, and 30% activity, formulated for use in any environment where food processing considerations apply.
Examples include fruit and vegetable washing, meat processing, fermentation, beverages, dairy products and in-line cleaning practice.
As discussed, non-silicone (or ‘organic’) antifoams have fallen out of favour due to the excellent effectiveness of silicone solutions. That said, they still have their place in certain environments — Airfoam NSA Antifoam, for example, is suited to defoaming within textile and dye processes.
The Akasil® antifoam range is the product of over 35 years of development in siloxane-based technology.