Metalworking Fluid Defoamer Selection

In aqueous metalworking fluids, foaming is often caused by the use of epoxidized emulsifiers and other surfactants. Generally, there are three types of antifoams added to metalworking fluids:
Organic oil defoamer
Silicone oil defoamer
Organic Modified Siloxane Defoamer
Organic oil defoamers are known for their high compatibility with the corresponding organic particles in the dispersion system. However, due to their high surface tension, the efficiency of these products is only moderate. In contrast, silicon-based defoamers are highly efficient due to their low surface energy, but their disadvantage is their incompatibility with organics in polymer dispersions. Defoamers based on organo-modified siloxane have special advantages due to their organic structural units. The alkane backbone enables high defoaming efficiency.