Q: Why does my UV coating keep developing foam and pinholes?

Foam can enter a UV coating during high-speed mixing, pumping, circulation, or application. If the bubbles cannot escape before UV curing, they may become trapped in the cured film and cause pinholes, craters, uneven gloss, or other surface defects.

The problem is especially noticeable in UV-curable systems because curing can occur quickly once the coating is exposed to UV or LED light. This leaves limited time for entrapped air to escape.

Q: Should I simply choose the strongest defoamer?

Not necessarily. A defoamer needs to remove foam without creating new problems in the coating. A product with strong foam-breaking ability may not be the best choice if it causes compatibility issues or affects gloss, transparency, adhesion, leveling, or recoating.

The first step is to identify the actual problem. Is the foam generated mainly during mixing? Does it appear during application? Is the coating clear or matte? What resin, monomers, wetting agents, and other additives are already present?

These factors can change which defoamer works best.

Q: What is more important: compatibility or defoaming efficiency?

Both matter, but the priority depends on the formulation.

For UV systems where compatibility and preservation of film appearance are important, Lencolo 2108, a UV high-efficient defoamer with good compatibility, can be considered as a starting point. It is supplied as a raw material for incorporation into UV coating formulations.

When stronger foam elimination is the main requirement, Lencolo 2190, a silicone defoamer with strong defoaming ability, provides another option. It can be evaluated when foam generation is more aggressive during production or application.

The two products therefore represent different formulation considerations rather than one being universally better than the other.

Q: Can the defoamer affect other coating properties?

Yes. This is why foam reduction should not be evaluated separately from the finished coating.

After adding a defoamer, formulators should check surface appearance, gloss, transparency, leveling, adhesion, and recoatability. In some systems, interactions with wetting or leveling additives can also change the final surface.

A defoamer that removes bubbles effectively but creates craters or reduces adhesion may not provide a practical solution.

Q: How should I test a UV coating defoamer?

It is better to screen several dosage levels rather than test only one concentration. Compare foam generation during mixing, observe bubble release after the coating rests, and then apply the formulation using the actual production method.

After curing, check pinholes, craters, gloss, transparency, leveling, adhesion, and other application-specific properties. Storage stability should also be evaluated if the coating will be stored before use.

The optimum dosage depends on the complete formulation and processing conditions, so laboratory results should be confirmed under realistic production conditions.

Q: Does choosing a defoamer solve every surface problem?

No. Foam, poor leveling, pigment wetting, and surface defects can have different causes. A defoamer primarily addresses foam and entrapped-air problems; it should not be used as a substitute for a suitable leveling agent or dispersing system.

For example, if the main issue is poor pigment wetting, changing the defoamer is unlikely to solve it. If the problem is orange peel or uneven flow, the resin, viscosity, application conditions, or leveling additive may require investigation instead.

Q: What is the practical approach for UV coating development?

Treat defoamer selection as part of the complete formulation rather than as an isolated additive choice. Identify when and where foam is generated, examine the resin and additive system, compare compatibility and defoaming efficiency, and then validate the result through controlled application and curing tests.

Lencolo provides UV functional additives including Lencolo 2108 and Lencolo 2190, giving formulators different starting points depending on their foam-control requirements. Final product selection and dosage should always be confirmed through testing with the specific UV coating system.

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Guangdong Lencolo New Material Co., Ltd.