BYK Logo


Mineral Oil Defoamers

BYK-03X is the name for the family of BYK mineral oil defoamers. Mineral oil defoamers are primarily intended for matt and semi-gloss emulsion paints and emulsion plasters. They are not suitable for high-quality aqueous industrial coatings as they may cause surface defects (oil separation, gloss reduction). Furthermore, they should not be used in solvent-borne systems as a result of their inadequate leveling properties.

Mineral oil defoamers consist of approximately 85–95 % mineral oil and 1–3 % hydrophobic particles. They also contain emulsifiers, biocides and other performance-enhancing ingredients such as modified polysiloxanes. Aliphatic mineral oils are used as the carrier oil.

Emulsifiers are required in defoamers to ensure efficient dispersion of the particles in the mineral oil. They also make it easier to incorporate the defoamer in the coating formulation. As alkylphenol ethoxylates (APEO) are no longer permitted on grounds of health protection, modern mineral oil defoamers contain APEO-free emulsifiers.

In particular, high-quality defoamers for high-gloss emulsions frequently contain small amounts of a modified polysiloxane to improve the spontaneous defoaming effect. Mineral oil defoamers are the most cost-effective products in the defoamer range.


Mineral oil


Hydrophobic particles




Modified polysiloxanes