How to choose the most suitable aqueous defoamer?

How to choose the most suitable aqueous defoamer?

Monday, 16 November, 2015

When selecting a defoamer for a particular system we must take into account several characteristics of the various available options. In the following table we summarize our most modern choices and the most important features.

We have introduced in the table BYK-038 as a representative of mineral oils chemistry, but in general, these products have become obsolete because of their lack of stability, volatility (SVOCs) and the inability to chemically modification to improve them. For these reasons they are rarely recommended products.

The following are the main aspects to consider when selecting a defoamer:

1. When we have to find a defoamer for highly viscous systems (putties or matt and semi-matt with high PVC paints) we can choose defoamers located on the right, BYK-1615 is the first recommendation of this area and the best option according to efficiency / cost relationship.

We will consider products derived from vegetable oils chemistry when we want our system characterized by the sustainable chemistry of its components: the first recommendation is BYK-1740.

2. In situations where we incorporate the defoamer in processes which apply very high shear (such as grinding with microelements) we will choose additives from the top, these additives are the only ones that will not be consumed during the process and maintain its effectiveness at the end. BYK-017 and BYK-044 are two examples of these products.

3. If we have to incorporate a defoamer with very low shear and low viscosity system (as aqueous varnish) we recommend defoamers with easy incorporation: products at the bottom of the table as BYK-025.

4. The typical defoamer to incorporate into a dispersion process in "Cowles" (enamels or low viscosity systems applied with spray) we will use defoamers from the middle / left side. The classic product in this area is BYK-022.

5. If we look for products giving very low emissions, the only valid is the chemistry of acrylic polymers. This chemistry offers other advantages such as peroxides resistance, high temperature and pH extremes, and makes them the best option for the polymerization of resins. BYK-1640 is the best product and the most modern among the additives of this chemical. General characteristics of this additive make the best candidate for a universal defoamer in aqueous systems, from the polymerization of the resin to any aqueous architectural paint, by way of the formulation of aqueous pigment concentrates.

For more information on these products contact our Technical Advisory team.

URL:

http://www.byk.com

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