BYK-3480 and BYK-3481: new defoamer surfactants

BYK-3480 and BYK-3481: new defoamer surfactants

Wednesday, 14 October, 2020

Authors: Jaume Figueras (jaume.figueras@altana.com; +34 629 789 267) and Pilar Casas (pilar.casas@altana.com; +34 699 659 491) both from BYK-Chemie GmbH – BYK Marketing & Technical Service.

With aqueous paints the current challenge involves reducing surface tension sufficiently in order to prevent cratering without foam stabilising during manufacture and application (particularly with spray application). This is the only way to achieve excellent film appearance in terms of spread and levelling.

The Byk-3480 and Byk-3481 products – exclusively distributed by Comindex for more than 60 years – are silicone surfactants characterised by having a slightly higher molecular weight compared to other aqueous wetting additives and a more non-polar organic modification. These characteristics mean that they are lightly incompatible in the system and, accordingly, they do not stabilise the foam and have a degree of anti-cratering strength. They are 100% additives that work in doses of between 0.1 and 0.5%, recommended in systems with a volume of co-solvent higher than 3%, such as 2K epoxy and polyurethane, styrene-acrylic emulsions, kiln systems or solvent free UV systems. Byk-3480 is more polar than Byk-3481 and works better in pigmented systems, while Byk-3481 works better in varnishes. The additive must be incorporated into the finished product and may be used post-addition in order to resolve issues.

Figure 1: excellent levelling on 2K polyurethane varnish with spray application

Formulation of a 2K polyurethane varnish with spray application on a PMMA material. Additive dose = 0.1% in the whole formulation. With 3.4% co-solvent in component A and 12.1% in the whole formulation.

EThe table shows that both Byk-3480 and Byk-3481 heavily reduce surface tension, providing excellent material wetting and levelling. Moreover, as mentioned, they are two additives which, owing to a higher molecular weight, do not stabilise the foam (the measurement for foam formulation has been made by stirring 50g of paint using a sprocket at 2,000 rpm for 1 minute).

Figure 2: excellent levelling on 1K polyurethane varnish with spray application

Formulation of a 1K polyurethane varnish. Additive dose = 0.1% in the whole formulation. with 8% co-solvent. Spray application on a PMMA material.

Figure 3: working method of silicone additives in aqueous systems

The graph shows how three kinds of silicone additives work in aqueous systems. We use the “Y” axis to depict the surface tension while the “X” axis illustrates the change in the recently-finished film (0% butyl glycol) once part of the water has evaporated (30% in butyl glycol). We see that Byk-333 works well using a substantial volume of co-solvent and essentially provides anti-cratering strength and glide. On the other hand, Byk-348 works highly efficiently with little co-solvent, thus providing paint spread and wetting. Lastly, we can see how Byk-3480 and Byk-3481 lower surface tension upon application of the paint, and, furthermore, once the water has evaporated. This phenomenon is due to the afore-stated incompatibility of the additive (larger molecular weight and more non-polar modification).

Figure 4: anti-cratering and problem-solving effect

Formulation of a melamine-acrylic aqueous kiln curing and spray application system with 15% co-solvent.

Figure 4 shows the effect described in figure 3. In this case, Byk-3480 remains on the interface upon evaporation of the water and can provide anti-cratering effect and glide..

In short, the new Byk-3480 and Byk-3481 defoamer surfactants are ideal in systems with at least 3% co-solvent which require excellent wetting strength, in addition to anti-cratering strength and/or glide.

For further information about these products, please contact our technical advisory team.

URL: www.byk.com

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