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Defoamers Selection for Industrial Coatings

Review factors that are vital while selecting anti-foaming agents for your industrial coatings formulation. Find out more about various classes of defoamers, their functioning and uses in industrial coatings. Also, get a quick brief on risks and benefits linked with each category.

And, to further help you select defoamers/anti-foaming agents for your industrial coatings formulations, check out factors which need to be considered according to your substrate, application technology, function of your coating or the film formation chemistry.

Defoamers Used in Industrial Coatings


Defoamers Selection for Industrial CoatingsIndustrial coatings is majorly segmented by:

  • Waterborne (WB) coatings
  • Solvent borne (SB) coatings, and 
  • Solvent-free (SF) coatings

And, defoamers are needed in waterborne (WB) as well as solvent borne (SB) industrial paints.

  • In case of waterborne, defoamers play major role during manufacturing as well as application
  • For solvent borne, they are primarily used to avoid foaming during application as well as craters & foamy appearance in the dried film

Let’s have a quick overview on various types of defoamers used in industrial coatings, highlighting their risks and benefits:

Defoamer Families Key Benefits Risks
Oil-based (Non-dispersible) High defoaming efficacy
  • Needing good incorporation
  • Some risk for intercoat adhesion
  • Breaking flow curtain
Silicone-based Defoamers
(Easy Dispersible, Oil-free)
  • Easy incorporation
  • Good film properties
  • Meeting oil-free regulation
  • Low risk for intercoat adhesion failure
  • Low risk for haziness
High Si Content (Oil-free) Excellent binder compatibility for best film appearance
Wax- & Silicone-based Defoamers
(Oil-free, Dispersible)
  • Best adhesion
  • Film appearance
  • Modest defoaming efficiency
Risk for loosing efficacy during storage
Polyolefins Compound
  • Excellent film surface characteristics
  • Recoatability
Limited efficacy against micro foaming
Polysiloxane
  • Excellent de-aeration, also usually also vs microfoam
  • Best balance between compatibility and incompatibility (=defoaming activity)
May give some risk of adhesion failure and/ or recoatibility
Compounded Defoamers Often compounds of polyacrylates, with siloxanes, and/ or fluor-derivatives for lowest surface tension


» View All Commercially Available Defoaming Agents Grades & Suppliers in Coatings Database

This coatings database is available to all, free of charge. You can filter down your options by suitable resin, system or application (coatings, inks...), supplier and regional availability.

Now, let’s discuss the how to select defoamers/anti-foaming agents according to:



Select Defoamers According to Coatings Function



Primers - Adhesion onto substrate is the key factor to be considered in order to avoid foam formation when formulating primers for waterborne, solvent borne or solvent-free coatings. Especially, microfoam formation can occur in case of corrosion protection.

Defoamer Families Millbase Let-down
Oil-based (Non-dispersible) good good good good good good good
Silicone-based Defoamers
(Easy Dispersible, Oil-free)
good good good good good good
High Si Content (Oil-free) good good good good good good good good good
Wax- & Si-based Defoamers
(Oil-free, Dispersible)
good good good good good good
Polyolefins Compound good good good good good good
Polysiloxane good good good good good good good good good good
Compounded Defoamers good good good good good good good


Protective Coatings - Like for Primers, the selection of the most appropriate defoamer for protective coatings applications will mainly depend on how the defoamer affects adhesion onto substrate and how it can help overcome microfoaming formation.

Defoamer Families Millbase Let-down
Oil-based (Non-dispersible) good good good good good good good
Silicone-based Defoamers
(Easy Dispersible, Oil-free)
good good good good good good good
High Si Content (Oil-free) good good good good good good good good good good
Wax- & Si-based Defoamers
(Oil-free, Dispersible)
good good good good good good
Polyolefins Compound good good good good good good
Polysiloxane good good good good good good good good good good
Compounded Defoamers good good good good good good good


Repair Coatings - In repair finishes coatings, various binder systems can be used. They are mainly applied by spray application leading to air inclusion risks and microfoaming formation. Hence, the need for persistant defoamer is critical.

Defoamer Families Millbase Let-down
Oil-based (Non-dispersible) good good good good
Silicone-based Defoamers
(Easy Dispersible, Oil-free)
good good good good good good good
High Si Content (Oil-free) good good good good good good good good good
Wax- & Si-based Defoamers
(Oil-free, Dispersible)
good good good good good good
Polyolefins Compound good good good good good good
Polysiloxane good good good good good good good good good good
Compounded Defoamers good good good good good good good


Topcoats - Topcoat applications is one of the largest group in industrial coatings, with wide options for resin selection. Critical factors for defoamers selection are include their effect on:
  • Film properties
  • Cratering
  • Pinholes
  • Levelling

Defoamer Families Millbase Let-down
Oil-based (Non-dispersible) good good good good good
Silicone-based Defoamers
(Easy Dispersible, Oil-free)
good good good good good good good good
High Si Content (Oil-free) good good good good good good good good good
Wax- & Si-based Defoamers
(Oil-free, Dispersible)
good good good good good good good
Polyolefins Compound good good good good good good good
Polysiloxane good good good good good good good good good
Compounded Defoamers good good good good good good good


Solving Foam Issues with Optimal Defoamers Selection


Select Defoamers According to Your Coatings System



2 Component Coatings - In case of two component industrial coatings applications (2K) presence of reactive groups, such as OH could reduce mechanical film properties. The main procedure of application for this segment is brush / roller, notably with rolling high risk of air inclusion. The choice of the right defoamer must take these challenges into consideration.

Defoamer Families Millbase Let-down
Oil-based (Non-dispersible) good good
Silicone-based Defoamers
(Easy Dispersible, Oil-free)
good good good good good good
High Si Content (Oil-free) good good good good good good good good good
Wax- & Si-based Defoamers
(Oil-free, Dispersible)
good good good good good good
Polyolefins Compound good good good good good good
Polysiloxane good good good good good good good good good
Compounded Defoamers good good good good good good good


Baking Finishes Industrial Coatings - For these coatings, temperature stability is key criterium. Polyethersiloxanes are more critical for this than polyestersiloxanes. The most recommended defoamers are Wax-, Si-, and oil free, dispersible for low risk of adhesion failure.

Defoamer Families Millbase Let-down
Oil-based (Non-dispersible) good good good good good good good
Silicone-based Defoamers
(Easy Dispersible, Oil-free)
good good good good good good good
High Si Content (Oil-free) good good good good good good good good good
Wax- & Si-based Defoamers
(Oil-free, Dispersible)
good good good good good good
Polyolefins Compound good good good good good good
Polysiloxane good good good good good good good good good good
Compounded Defoamers good good good good good good good


UV Curable Coatings - In UV curable coatings, the main binders used are based on Acrylates and PE. One of the characteristics of UV Curable paints and coatings is that they contain low or no solvents. Selecting the right defoamer will be mainly a question of:

  • Compatibility with the binder system
  • Overcoming the risk linked to de-aeration effect

Defoamer Families Millbase Let-down
Oil-based (Non-dispersible) good good
Silicone-based Defoamers
(Easy Dispersible, Oil-free)
good good good
High Si Content (Oil-free) good good good good good good good good
Wax- & Si-based Defoamers
(Oil-free, Dispersible)
good good good good good good good
Polyolefins Compound good good good
Polysiloxane good good good good good good good good good good
Compounded Defoamers good good good good good good good


» Find Suitable Defoaming Agent for Your UV Curable Coatings System


Select Defoamers According to Your Substrate



Wood Coatings - Wood coatings refer to a large variation in term of binders systems. The risk of foam formation is mainly linked to inclusion of (micro) bubbles due to slow substrate wetting. Critical factors for selection would be to avoid microfoaming formation.

Defoamer Families Millbase Let-down
Oil-based (Non-dispersible) good good good good good good good
Silicone-based Defoamers
(Easy Dispersible, Oil-free)
good good good good good good good
High Si Content (Oil-free) good good good good good good good good
Wax- & Si-based Defoamers
(Oil-free, Dispersible)
good good good good good good
Polyolefins Compound good good good good good good
Polysiloxane good good good good good good good good good good
Compounded Defoamers good good good good good good


» Select Right Defoamer for Wood & Furniture Coatings

Floor Finishes - Main examples of flooring coatings are Epoxy (EP) and Polyurethane (PUR) floorings, which can be solvent borne, waterborne or solvent-free.

Roller application being the main procedure of application, there is a strong risk of air inclusion, affecting appearance of final flooring coating. Another risk is microfoam formation issue due to film thickness.

Defoamer Families Millbase Let-down
Oil-based (Non-dispersible) good good good good good
Silicone-based Defoamers
(Easy Dispersible, Oil-free)
good good good good good good good
High Si Content (Oil-free) good good good good good good good good good
Wax- & Si-based Defoamers
(Oil-free, Dispersible)
good good good good good good good
Polyolefins Compound good good good good good
Polysiloxane good good good good good good good good good
Compounded Defoamers good good good good good good good


OEM Coatings – They can be base coat or clear coat, with a high risk of microfoaming, whatever the binder system is (various binders systems can be used in OEM Coatings applications). Selecting the right defoamer system will avoid unwanted side effects.

Defoamer Families Millbase Let-down
Oil-based (Non-dispersible) good good good good good
Silicone-based Defoamers
(Easy Dispersible, Oil-free)
good good good good good good good
High Si Content (Oil-free) good good good good good good good good good
Wax- & Si-based Defoamers
(Oil-free, Dispersible)
good good good good good good good
Polyolefins Compound good good good good good
Polysiloxane good good good good good good good good good
Compounded Defoamers good good good good good good good


Can Coatings - In can coatings, EP and PE systems are the most used binders. In case of direct food contact, the required approval defoamer must be selected.

Defoamer Families Millbase Let-down
Oil-based (Non-dispersible) good good
Silicone-based Defoamers
(Easy Dispersible, Oil-free)
good good good
High Si Content (Oil-free) good good good good good good good good good
Wax- & Si-based Defoamers
(Oil-free, Dispersible)
good good good good good good good good good
Polyolefins Compound good good good
Polysiloxane good good good good good good good good good
Compounded Defoamers good good good good good good good good


Coil Coatings - Coil coatings are generally cured at high temperature. Critical criteria of defoamer selection are:
  • Effect on MEK resistance
  • Effect on adhesion
  • Temperature stability

Defoamer Families Millbase Let-down
Oil-based (Non-dispersible) good good
Silicone-based Defoamers
(Easy Dispersible, Oil-free)
good good good
High Si Content (Oil-free) good good good good good good good good good
Wax- & Si-based Defoamers
(Oil-free, Dispersible)
good good good good good good
Polyolefins Compound good good good
Polysiloxane good good good good good good good good good good
Compounded Defoamers good good good good good good good good


» Check Out Commercially Available Defoamers for Coil Coatings

Select Defoamers According to Your Application



Dipping Bath Coatings - A wide variation of binder systems can be used in dipping bath industrial coatings. Though they are systems that commonly exhibit low viscosity, leading to risks for creaming and separation. As a result, there is a continuous air incorporation issue: chosing the right defoamer is a key factor of success overcome these issues.

Defoamer Families Millbase Let-down
Oil-based (Non-dispersible) good good good
Silicone-based Defoamers
(Easy Dispersible, Oil-free)
good good good good good good good
High Si Content (Oil-free) good good good good good good
Wax- & Si-based Defoamers
(Oil-free, Dispersible)
good good good good good good good
Polyolefins Compound good good good good good
Polysiloxane good good good good good good good good good
Compounded Defoamers good good good good good good good


Curtain Coatings - Various binders systems are used in curtain coatings applications. Curtain break is the main concern why using defoamers in this application.

Defoamer Families Millbase Let-down
Oil-based (Non-dispersible) good good good good good good
Silicone-based Defoamers
(Easy Dispersible, Oil-free)
good good good good good good good
High Si Content (Oil-free) good good good good good good
Wax- & Si-based Defoamers
(Oil-free, Dispersible)
good good good good good good good good good
Polyolefins Compound good good good good good
Polysiloxane good good good good good good good good
Compounded Defoamers good good good good good good good


Powder Coatings - In powder coatings, there is a vast choice for binder systems. The highest risk of foam formation is linked to air entrapment in the liquid film via powder during melting and / or polymerization stage. Criteria for defoamers selection are mainly:

  • Good temperature stability
  • Compatibility with the binder
  • Ease of incorporation

Defoamer Families Millbase Let-down
Compounded Defoamers good good good good good good




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