Anti-foam additives in the world of coating

One of the main components that goes into the composition of all paints and is listed among the adjuvant additives is the defoamer additive. Not to be confused with biocides to prevent the formation of mold on facades for example, they are also called "anti-foaming". These are chemicals whose main property is to reduce the formation of foam in mixtures, paints, varnishes, liquids. When shaking or stirring a liquid mixture, a lot of bubbles and foam are formed, especially in water-based mixtures, which can make it difficult to use.

The suppression as well as the prevention of the foaming effect are therefore an essential point for all preparations in the world of coating. Whatever the particular field of application, whether in building painting with a roller or when applying by spraying (airless or by paint gun in the automobile), but just as much in the world of printing and flexography and rotogravure, or even for more special application techniques, by water curtain, dipping or dipping.

The defoaming additive for use only in manufacturing

These are additives specific to the world of paint. They are concentrated and incorporate according to a calculation on the total formulation, with doses as low as 0.1 to 1.0% in the pure version. Concentrated defoamers are normally compatible with waterborne or solventborne mixtures. They contain hydrophobic particles, are often composed of organic polymers and contain no silicones or mineral oils.

Many of the defoamers are used in the food industry and are produced from renewable components. Regarding their implementation, they are incorporated pure or diluted to facilitate the dosage, during the phase of dispersion or grinding of the pigments. Each formulation is tested to validate the anti-foaming power and also the effectiveness over a long period.

Innovative defoamers

Some recent anti-foam additives offer very high and very reliable performance over time, especially with the new hyper-branched polymers, with their three-dimensional structure that takes on the shape of a star and their properties that are both hydrophilic and hydrophobic.
These innovative products make it possible to dispense with conventional defoaming additives based on mineral oil or silicone. The action of the defoamer always takes place at the molecular level, in particular at the level of surface tension at the microscopic scale.

Foam in body paint

Is it really a problem to have foam in your varnish mixture ? Should we avoid shaking a clearcoat + hardener mixture so as not to have bubbles ? No, this is a false belief that some painters have. It is also useless to add defoaming additives in its paints, this could only bring risks of defects. It should be known that when a mixture is in a bucket of guns, the foams remain in the top of the bucket. And in any case, the liquid passes through a nozzle, projected by pressurized air, to be atomized there: the foam cannot create air bubbles.

Dispersant additive
Additive and wetting agent