Mechanism of Action of Defoamers

A defoamer or an anti-foaming agent is a chemical additive that reduces and hinders the formation of foam in industrial process liquids. The terms anti-foam agent and defoamer are often used interchangeably. Defoamers eliminate existing foam and anti-foamers prevent the formation of further foam. Commonly used agents are insoluble oils, polydimethylsiloxanes and other silicones, certain alcohols, stearates and glycols. The additive is used to prevent formation of foam or is added to break a foam already formed.

In industrial processes, foams pose serious problems. They cause defects on surface coatings and prevent the efficient filling of containers. A variety of chemical formulae are available to prevent formation of foams.

Generally, a defoamer is insoluble in the foaming medium and has surface active properties. An essential feature of a defoamer product is a low viscosity and a facility to spread rapidly on foamy surfaces. It has affinity to the air-liquid surface where it destabilizes the foam lamellas. This causes rupture of the air bubbles and breakdown of surface foam. Entrained air bubbles are agglomerated, and the larger bubbles rise to the surface of the bulk liquid more quickly.

Classification of Defoamers

1.Oil-based defoamers

Oil-based defoamers have an oil carrier. The oil might be mineral oil, vegetable oil, white oil or any other oil that is insoluble in the foaming medium, except silicone oil. An oil-based defoamer also contains a wax and/or hydrophobic silica to boost the performance. Typical waxes are ethylene bis stearamide (EBS), paraffin waxes, ester waxes and fatty alcohol waxes. These products might also have surfactants to improve emulsification and spreading in the foaming medium.

These are heavy duty defoamers and are normally best at knocking down surface foam.

2.Powder defoamers

Powder defoamers are in principle oil-based defoamers on a particulate carrier like silica. These are added to powdered products like cement, plaster and detergents.

3.Water-based defoamers

Water-based defoamers are different types of oils and waxes dispersed in a water base. The oils are often mineral oil or vegetable oils and the waxes are long chain fatty alcohol, fatty acid soaps or esters. These are normally best as deaerators, which means they are best at releasing entrained air.

Silicone-based defoamers

Silicone-based defoamers are polymers with silicon backbones. These might be delivered as an oil or a water-based emulsion. The silicone compound consists of a hydrophobic silica dispersed in a silicone oil. Emulsifiers are added to ensure that the silicone spreads fast and well in the foaming medium. The silicone compound might also contain silicone glycols and other modified silicone fluids. These are also heavy duty defoamers and are good at both knocking down surface foam and releasing entrained air.

Silicone-based defoamers are also suitable in non-aqueous foaming systems like crude oil and oil refining. For very demanding applications fluorosilicones may be suitable.

We Associated Rubber Chemicals (Kochi) Pvt Ltd, manufacturing ACPL Defoamer , which is super in the class of defoamers and works both as defoamer and an antifoam compound. It can be used in paint, textiles,paper, water treatment and similar chemical processes.

Acpl defoamer is highly efficient and broadly effective in a wide variety of applications. This product is based on silicone oil. Silicone oils have a very low surface tension, which contributes to rapid spreading at the gas-liquid interface and facilitating the weakening of the foam films and penetration of the bubble wall.

Characteristics of ACPL Defoamer:

• Excellent dispersion in aqueous systems
• Chemicaly inert and non-toxic

Check out the best ACPL Defoamer Manufacturer in Kerala

Technical Specification:

Appearance : White free flowing uniform liquid

Solid content : 50±5%

PH :8±0.5

Bulk density :0.850- 0.950 g/ml

Miscibility : Easily miscible with cold water

Silicone Free Defoamers : We have a speciality defoamer, which is silicone & protein free for dipped goods made from natural and synthetic latex. It is also used in coagulant and variety of aqueous system for controlling the macro foams and also have dewebbing action.

Depending upon the viscosity of latex and compounding ingredients recommended dosage is 0.05- 0.10% w/w. Additional increase can be made as needed. These concentrates should be used after emulsify 1:1 with water.