Foam build-up can lead to a number of problems during various industrial products and processes, including coating defects, machine damage, poor product quality, bacterial growth, and more. Defoaming agents are crucial in controlling foam and preventing the issues associated with it. By stopping the bubbles from stabilizing, defoamers eliminate existing foam to prevent damage to products and equipment.
In order to work, a defoamer must have entry and spreading coefficients that are greater than zero. This allows it to enter the interface between the air and bubble wall (or lamella) and then enter the lamella through a process referred to as “bridging the film.” As the defoamer spreads, the lamella thins and ultimately ruptures.
Defoamers are often separated into two broad categories: silicone-based and non-silicone, each of which contains several subgroups which offer their own unique advantages and disadvantages. It’s important to understand the differences between each type to ensure the best product is selected for your application.
Non-Silicone Defoamers Vs. Silicone-Based Defoamers
Non-silicone defoamers differ from silicone-based defoamers in a variety of ways. Understanding their benefits will guide you in making the ideal selection for your needs.
Silicone-based defoamers offer an efficient means of preventing and controlling foam in various processes. The primary functional component of this class of defoamers consists of polymers with alternating silicon and oxygen backbones with various organic groups attached. Often, they are further compounded to increase performance and formulated into emulsions or dispersions for easier handling and application. Because silicone has a low surface tension, it can spread quickly and evenly over the foam film, causing it to thin and collapse. Silicone-based defoamers are very effective at knocking down surface foam and releasing air bubbles.
To meet the requirements of specific applications, silicone defoamers can be broken into subgroups including 100% active compounds, emulsions, dispersions, organo-modified silicones, food-grade and industrial grade defoamers.
Some benefits of silicone-based defoamers include:
- Enhanced properties. Silicone-based defoamers are often preferred for their beneficial characteristics, including low surface tension, temperature and pH resistance, and chemical inertness.
- Suitable for non-aqueous systems. 100% active silicone compound defoamers are highly effective in non-aqueous applications such as oil refining, paints, inks, and coatings.
- Reduced Consumption. Compared to many non-silicone defoamers, silicone defoamers are often effective at a much lower active concentration.
At Crucible Chemical, we carry a wide range of silicone-based defoaming agents to meet your specific needs.
Non-silicone defoamers provide effective foam control in nonaqueous and water-based systems. Like silicone defoamers, non-silicone defoamers have a low surface tension, allowing them to spread well over the surface. However, non-silicone defoamers are often preferred in certain applications due to concerns about silicone contributing to deposition or surface defects.
When formulators require the utmost quality in adhesion, recoatability, and defect-free films, non-silicone defoamers generally hold the advantage over silicone-based defoamers. Other key benefits include:
- Versatility. Organic defoamers range from low to high compatibility, balancing ease of incorporation and dispersibility with moderate to powerful foam control. This allows formulators considerable flexibility concerning defoamer longevity, recoatability, surface defects, and foam control.
- Preferable handling properties. Specific non-silicone defoamers offer desirable handling characteristics such as low viscosity and extended product stability.
- Availability and price. Silicone derivatives have occasionally been prone to shortages, most recently in 2022. As a broadly general class, non-silicone defoamers and their base components are typically more readily available in the marketplace and not as prone to major price fluctuations based on availability.
- Safe and long-lasting. Many silicone-free defoamers are eco-friendly and have a balanced composition and long shelf life.
Crucible Chemical Company supplies a broad selection of silicone-free defoamers in the Foamkill™ product line.
Common Types of Non-Silicone Defoamers
The most common types of non-silicone defoamers are oil-based, and water-based, water-extended and synthetic.
Oil-based defoamers are commonly based on mineral oils, white oils or vegetable oils. They are 100% active products and typically consist of an oil base and hydrophobic particles, often with emulsifiers and additional functional components to attain desired products attributes or performance. They are cost efficient and chemically stable, making them beneficial for use in a wide range of applications.
Oil-based defoamers offer strong foam control performance in a wide variety of applications that include:
- Paints & Coatings
- Pulp & Paper
Water-based and Water-extended Defoamers
Water-based defoamers use water as the carrier at a level greater than 50%. Water-based defoamers are oil-in-water emulsions, meaning they contain some form of hydrophobe such as a wax, fatty alcohol ,or oil. By presenting these active elements in an emulsified state, water-based defoamers easily disperse into water-based media to effectively control foam and entrained air. Alternatively, water-extended defoamers are water-in-oil emulsions that perform similarly to oil-based products, but contribute less oil to a system than their 100% active oil-based counterparts.
Water-based and water-extended defoamers offer an efficient and effective foam control solution. Many water-based defoamers contain little to no VOCs and are biodegradable, making them ideal for applications that demand an eco-friendly solution for suppressing foam.
Water-based and extended defoamers offer the following advantages:
- Lower cost
- Ease of application
- Broad compatibility
- Environmental friendliness
Industrial applications for water-based and water-extended defoamers include pulp and paper, water & wastewater treatment, agriculture, fiberglass mat, and coatings.
Synthetic defoamers use esters, polyols and synthetic polymers as carrier fluids. As a class, they are very
effective de-aerators and their silicone and mineral-oil free composition allows them to be used in
paints and coatings without the gloss reduction attributed to most defoamers. Additionally, the lack of
mineral oils does not induce swelling of rubber rollers, making them favorable additives in ink, graphic
arts & printing applications. Synthetic defoamers are also effective deaerators and defoamers in
wastewater treatment, adhesives, construction chemicals, and more.
Work with Crucible Chemical for All Your Defoamer Needs
Non-silicone defoaming agents offer a safe and effective way to eliminate foam in various industrial processes. Crucible Chemical Company offers a wide variety of non-silicone based defoamers to conform to specific application requirements and suit the foam control needs of industrial operations. Our non-silicone defoamers will prevent maintenance, safety and product quality issues caused by foam, ultimately saving you time and money.
With more than 50 years of experience, we offer a complete line of foam control products to meet the demands of any industry that processes fluids. The experts at Crucible Chemical have the skills, experience, and resources to solve your unique process challenges. Regardless of the application, we can troubleshoot your current foaming issues and provide an effective foam control solution.
For more information about our range of non-silicone defoamers, or to get started on your customized defoaming solution, contact Crucible Chemical today.