Coating additive defoamer
Originality: Old Paint Workers
The use of emulsion, wetting agent, dispersant, rheological thickener and other components in latex paint promotes the formation and stability of foam in latex paint, and increases the difficulty of eliminating foam, which makes the use of defoamers very important in the formulation and production of latex paints. On the other hand, the use of defoamers is related to many factors, which will affect the properties of coatings such as gloss, water resistance and "oil shrinkage", making the use of defoamers complicated. Following is an introduction to the classification, action principle, effect of defoamer on paint performance and main points of application from the point of view of practical use.
Types and main components of defoamers
Depending on the composition, defoamers include low molecular alcohols (e.g. octanol), phosphate esters (e.g. tributyl phosphate), mineral oils, silicone oils and compounds. However, at present, the composite commercial defoamer used in waterborne coatings is seldom a single substance in composition, mostly a combination of two or more components.
According to the different defoaming functions, defoamers can be divided into three types: defoamers, antifoamers and defoamers. The foaming agent can quickly destroy the bubbles; the antifoaming agent is used to prevent the foaming agent of the paint, and can inhibit the generation of the foam; the defoaming agent can reduce the air bubbles to make the paint easy to grind, and add in the modulated slurry. Defoamers and defoamers generally have many functions, such as foam breaking, anti-foaming and defoaming. Sometimes it is very difficult to distinguish them clearly.