When selecting surfactants for your cleaning formulations or processing applications, foam is an important attribute. For example, in manual hard-surface cleaning applications—such as vehicle care products or hand-washed dishwashing—high foam levels are often a desirable characteristic. This is because the presence of highly stable foam indicates that the surfactant is activated and performing its cleaning function. Conversely, for many industrial cleaning and processing applications, foam can interfere with certain mechanical cleaning actions and inhibit overall performance. In these cases, formulators need to use low-foam surfactants to deliver the desired cleaning performance while controlling foam concentration. This article aims to introduce low-foam surfactants, providing a starting point for surfactant selection in low-foam cleaning applications.
Low-Foam Applications
Foam is generated by agitation at the air-surface interface. Therefore, cleaning actions involving high agitation, high shear mixing, or mechanical spraying often require surfactants with appropriate foam control. Examples include: parts washing, CIP (clean-in-place) cleaning, mechanical floor scrubbing, industrial and commercial laundry, metalworking fluids, dishwasher dishwashing, food and beverage cleaning, and more.
Evaluation of Low-Foam Surfactants
The selection of surfactants—or combinations of surfactants—for foam control begins with analyzing foam measurements. Foam measurements are provided by surfactant manufacturers in their technical product literature. For reliable foam measurement, datasets should be based on recognized foam test standards.
The two most common and reliable foam tests are the Ross-Miles foam test and the high-shear foam test.
•Ross-Miles Foam Test ，evaluates the initial foam generation (flash foam) and foam stability under low agitation in water. The test may include readings of the initial foam level, followed by the foam level after 2 minutes. It can also be conducted at different surfactant concentrations (e.g., 0.1% and 1%) and pH levels. Most formulators seeking low-foam control focus on the initial foam measurement.
•High-Shear Test (see ASTM D3519-88).
This test compares foam measurements under soiled and unsoiled conditions. The high-shear test also compares the initial foam height with the foam height after 5 minutes.
Based on any of the above test methods, several surfactants on the market meet the criteria for low-foaming ingredients. However, regardless of the foam test method chosen, low-foam surfactants must also possess other important physical and performance properties. Depending on the application and cleaning environment, other critical characteristics for surfactant selection may include:
•Cleaning performance
•Environmental, health, and safety (EHS) attributes
•Soil release properties
•Wide temperature range (i.e., some low-foam surfactants are only effective at very high temperatures)
•Ease of formulation and compatibility with other ingredients
•Peroxide stability
For formulators, balancing these properties with the required degree of foam control in the application is crucial. To achieve this balance, it is often necessary to combine different surfactants to address both foam and performance needs—or to select low- to medium-foam surfactants with broad functionality.
Post time: Sep-11-2025