A defoamer is an additive that eliminates foam when making, applying, or storing paint. Foam is a difficult problem for formulators that can cause unsightly defects and expensive manufacturing processes. Defects can impact surface appearance, gloss, and adhesion. Entrained air can contribute to foam formation that negatively impacts efficiency in applications like industrial operations.
Modified polydimethylsiloxane (PDMS) and non-silicone solutions from Borchers act as foam control agents for coatings. They help prevent the formation of foam or eliminate existing foam during the production and application of coatings.
Foam forms from entrapped gas in a liquid or solid medium. Macrofoam forms at the surface of a coating while microfoam consists of small air bubbles entrapped within a coating. When a liquid is pure, such as pure water or any liquid without surfactants, it does not generate foam. However, paints are not pure liquids as they contain surface-active substances.
Foam generation is more stable in surfactant-containing systems like coatings
Many essential processes throughout the formulation of a coating can result in foam generation. Defoamers for coatings can help avoid foam-related defects caused by the following processes:
Foaming can occur at any time and cause less-than-ideal results. Uneven surfaces, reduced gloss, and poor adhesion between the coating and a surface can all result from foam formation. Pinholes, craters, and poor leveling are a few examples of foam-related surface defects.
Defoaming agents work to reduce surface tension in coatings, making foam unstable. This causes the bubble wall in a coating to thin out and eventually burst, releasing air. As a result, foam-related defects are prevented.
The mechanism of foam destruction with foam control paint additives
Borchers AF foam control agent prevented pinholes in a solvent-free urethane modified medium oil alkyd emulsion formulation by controlling foam formation
Additive manufacturers typically offer mineral oil, silicone-based (PDMS), and silicone-free foam prevention solutions.
Mineral oil solutions are popular cost-effective additives that may contain wax or silica to boost performance.
Examples include:
Silicone (or PDMS) additives provide excellent long-term defoaming efficiency, broader application, and lower surface tension. They have good chemical inertness and thermal stability and have no impact on gloss or color acceptance.
Examples include:
Silicone-free additives contain polymers with very low surface tension. They are easy to incorporate, result in defect-free films, and do not cause color-related issues. These solutions are also low in VOCs and are efficient for use at low surface levels.
Examples include:
Selecting the right foam prevention additive requires considering a coating's criteria and conducting tests.
Finding the best defoaming additive first involves making note of the content within a formulation.
Certain defoamers will work better in solventborne formulations and others will work better in waterborne formulations. Some may work well in both.
Understanding the stage of production in which foam-related defects occur also helps narrow down selections. Manufacturers create some additives for the mill base stage, some for the letdown stage, and some for use in various stages.
Only certain defoamers will be compatible with the resin used in a coating formulation. Options are available for a wide range of resins, including alkyd, acrylic, epoxy, and polyurethane.
Whether or not a coating is high gloss, semi-gloss, matte, or high solids can all have an effect. Determining if a formulation is silicone-free or already contains a defoamer is also important. The fillers used in a coating are also essential to consider.
Yourun Synthetic Material are exported all over the world and different industries with quality first. Our belief is to provide our customers with more and better high value-added products. Let's create a better future together.
Foam generation can occur during the brushing, rolling, or spraying of a coating on a substrate. Knowing under which application method foam typically forms in a coating is important.
The particular issues taking place in a coating will have a strong impact on the type of defoamer to select.
'
A comprehensive foam control offering includes a range of custom defoaming solutions and foam control products to meet the needs of various industries. Borchers' defoamer selection guide helps narrow down options by specific formulation criteria. Our technical service team can also recommend certain additives based on your formulation content.
Popular Borchers brand defoamers are listed below:
The Borchers' team can test defoamer performance in your systems after defining criteria and narrowing down options. These include tests for compatibility, reciprocal of density, and application.
Borchers' technical service team has conducted these tests in a variety of formulations, including:
To check out these case studies, download our short defoamer webinar.
Other foam control products include deaerators, which allow air bubbles to escape more easily before application. Deaerators also improve substrate wetting and are ideal for coatings used on thin layers and porous surfaces. Anti-foaming agents work to prevent foam formation.
Borchers offers a wide range of deaerators, defoamers, and antifoam agents.
Foam can form in various stages throughout the coating formulation process, which can result in defects. Borchers has many defoamers for coating systems that you can test for compatibility.
In the field of industrial adhesives, polyurethane glue is favored for its superior adhesive properties and weather resistance. However, during its production and use, foam problems often plague manufacturers and users. At this time, defoamers for polyurethane glue have become the key to solving this problem.
During the glue dripping process, foaming may also occur due to improper operation or the influence of ambient temperature. In addition, in order to give full play to the characteristics of polyurethane glue, a large number of chemical additives are added during the production process, among which the surfactant is high and foam is also easy to produce.
Foam will increase the surface tension of the glue, affect the contact area and wettability between the glue and the adherend, and thus reduce the bonding strength and firmness. A large amount of foam will make the surface of the glue uneven, and after curing, bubbles, shrinkage holes and other defects will be formed, affecting the transparency and aesthetics of the glue.
The main function of the defoamer for polyurethane glue is to destroy and control the formation of foam, ensuring that the glue remains uniform and bubble-free during the curing process. Specifically, it works in the following ways:
1. Reduce the surface tension of the liquid: Defoamers can significantly reduce the surface tension of the liquid, thin the foam wall, and accelerate the rupture of the foam.
2. Destroy the foam film: Through physical or chemical effects, defoamers can destroy the stability of the foam film and cause the foam to disappear.
During the glue dripping process, foaming may also occur due to improper operation or the influence of the ambient temperature. In addition, in order to give full play to the characteristics of polyurethane glue, a large amount of chemical additives will be added during the production process, among which the surfactant is high and it is also easy to produce foam.
Foam will increase the surface tension of the glue, affect the contact area and wettability between the glue and the adherend, and thus reduce the bonding strength and firmness. A large amount of foam will make the surface of the glue uneven, and after curing, bubbles, shrinkage holes and other defects will be formed, which will affect the transparency and aesthetics of the glue.
The main function of the defoamer for polyurethane glue is to destroy and control the formation of foam, ensuring that the glue remains uniform and bubble-free during the curing process. Specifically, it works in the following ways:
1. Reduce the surface tension of the liquid: Defoamers can significantly reduce the surface tension of the liquid, thin the foam wall, and accelerate the collapse of the foam.
Contact us to discuss your requirements of Polyurethane Defoamer. Our experienced sales team can help you identify the options that best suit your needs.