The entrapment of gas in a liquid material such as paint is very common and occurs under specific conditions:
• By mechanical introduction of air when stirring, applying, rolling and sparing printing.
• By air displacement when applying on porous substrates.
• By physicochemical processes like reactions, rapid evaporation of a solvent.
The formed foam has then been stabilized by surfactants that are already present in the paint as pigment wetting– dispersing agents and emulsifiers.
Surfactants are compounds that lower the surface tension of a liquid, the interfacial tension between two liquids, or the interfacial tension between a liquid and a solid.
On the contrary, the defoamers are compounds acting as surface tension regulators breaking the stability or preventing the formation of the foam lamella.
There are several groups of hydrophobic substances used as defomers and commercially categorized into the following general products:
- Oil based (Mineral oils vegetable oils, esters, waxes, fatty alcohols)
- Powder – defoaming particles ( hydrophobic silica, stearate derivatives)
- Water based (emulsion of foam destroying substances in water)
- Polymer based (modified silicone oils, polyacrylates, EO/PO copolymers)
Our company has combine all the known substances and categories in the following products.
Anfoam Emulsion of esters and hydrophobic particles. Green defoamer
Anfoam S Mineral oil based defoamer with dispersed hydrophobic particles.
Anfoam EM Emulsion of mineral oil, silicon oil and hydrophobic particles.
Anfoam W Emulsion of waxes and hydrophobic particles