Defoamers: the critical missing element of your aqueous paint
Why are defoamers needed?
The foam that appears in paints can be formed when air is trapped at the production and application stage, or by the use of processing surfactants which can trap gas bubbles. For instance, aqueous paint, has an inherent tendency to aerate and foam due to the presence of emulsifiers in resin binders.
This foam can lead to poor adhesion, less than desirable surface finishes with surface defects including pinholes.
The defoamer works to prevent these defects by essentially bursting the bubbles and removing the foam buildup. However, when selecting a defoamer consideration must be given to more than just its ability to remove foam.
The chemical additive must be sufficiently stable to shear, dyes, chemicals, temperature and pH to prevent adverse effects such as scum formation, silicone spotting or other surface defects.
As leading speciality chemicals manufacturer, with 40 years’ experience of providing technical support and working with industry we have developed our own comprehensive portfolio of silicone-free defoamers for aqueous systems – many of which are suitable for use at elevated temperatures.
Get to know our 5000 series of defoamers
Our defoamers have been designed to release bubbles and control any generated foam, effectively combatting air entrainment and foam by promoting bubble coalescence in the bulk, as well as bubble breaking at the surface.
DeCAL 5032 is a blend of non-ionic surfactants and hydrophobes in a highly refined mineral oil with a low level of silicone oil.
It has been designed for successful application in:
- Matt and sheen paints
- PV acetate-based adhesives and grouts
And it is highly recommended for treating foam generated during sludge separation through centrifuge or belt presses.
DeCAL 5045, white emulsion in appearance, is a solvent free foam control agent for aqueous systems. Effective over a wide range of pH levels and temperatures, this universal product can have varying addition levels and as such this should be determined by the end user. However, typical addition levels are in the range of 0.1-0.5% in total as supplied.
It can effectively be used in:
- Emulsion paints
- Paper coatings
- Adhesives
DeCAL 5052 is mineral oil-free and VOC-free and can also be used for foam control in numerous aqueous based systems. It remains highly effective at low concentration and is supplied as a pale-yellow liquid in 200Kg drums or 1000Kg IBCs.
It is highly effective in:
- Coatings
- Adhesives
DeCAL 5155 is a highly stable, efficient and long-lasting silicone defoamers over a wide temperature range. The reacted polysiloxane defoamer disperses readily in water with a good stability to dilute acids and alkalis.
It is resistant to emulsification by processing surfactants and is effective in a number of applications including agrochemicals, textiles, paints, coatings and adhesives where excellent compatibility is preferred.
And, unlike many other silicone defoamers, DeCAL 5155 is stable in the presence of high concentrations of electrolytes from a variety of sources including:
- pH modifiers
- Water (hardness ions and trace metals)
- Dyes
- Chemicals (cationic and anionic)
- Salts (e.g. sodium chloride, sodium sulphate)
If you’re ready to increase the stability of your product and reduce the risks of surface defects, make an enquiry or request a free sample of any of our products.
