Waxes are used in a wide range of applications in different industries of which the best known application is candle making where paraffin is melted and poured into a mould. However, many applications demand the wax to be incorporated in a system in a liquid form at ambient temperatures. If this system is solvent based, the wax can be added either direct or via a solvent based solution or dispersion. In the case of aqueous systems, the wax needs to be emulsified in water first and that is where wax emulsions come into place.
Waxes can be emulsified in water by using emulsifiers or surfactants. Some waxes are easier to emulsify than others and, depending on the application and final properties, tailor made formulations are needed. Wax emulsions are often a well balanced mixture of wax(es), surfactant(s) and small amounts of additives, and are produced via a clever and thought-through production process.
A wax emulsion formulation depends strongly on the end-use. Very small particle size emulsions are for example used where high gloss levels are needed, whereas coarser emulsions work better to create a matting effect. Emulsions based on very hard waxes improve the scratch and abrasion resistance in inks, coatings and lacquers, while softer waxes are beneficial for anti-slip effects or haptic finishes on textiles. In systems where a high level of hydrophobicity is demanded, emulsions with very low surfactant content are essential.