Defoamers and deaerators are indispensable additives for formulators of waterborne coatings. Coatings with low VOC, very high viscosity and that use airless spray application equipment are a challenge to formulators. Reflow of pinholes is indirectly proportional to the dynamic viscosity of the coating. VOC-containing materials, such as solvents, are used to help in foam mobility. However, reduced levels of solvent may increase surface tension.
Further, the use of airless spray equipment improves coating efficiency and reduces waste, but at the same time increases the incorporation of air due to the shear forces that are inherently part of the application process. Defoamer technology has advanced over the years, along with coating technology, VOC reduction and application equipment.
Mineral oil defoamers are economical and effective, but often contain a large level of VOCs. Siloxane and silicone defoamers provide improved effectiveness at low dosage, but they lose defoaming properties during coating storage, can increase defects like cratering and poor recoatability, and are sometimes difficult to incorporate during the coating production process.
Cytec has developed a new class of polymeric defoamer/deaerator based on patented technology that outperforms traditional defoamers. It is nearly 100% active and provides powerful defoaming and deaerating activity, while maintaining effectiveness during the coating’s shelf life. Further, it provides the benefit of improved flow and leveling properties and can be used in both coatings as well as pigment paste concentrates.