In the complex world of emulsion technology, achieving the ideal balance between oil and water phases often requires more than a single emulsifier. The synergistic combination of different types of surfactants is a common strategy to fine-tune product performance, stability, and sensory attributes. Among the most effective pairings is the combination of Sorbitan Monostearate (Span 60) and its ethoxylated counterpart, Polysorbate 60 (Tween 60).

Span 60, with its low HLB value of approximately 4.7, is a lipophilic emulsifier. It excels at forming stable water-in-oil (W/O) emulsions and acts as an effective co-emulsifier or stabilizer in oil-in-water (O/W) systems. Its primary function is to reduce interfacial tension and provide a barrier around oil droplets dispersed in water, preventing them from merging.

Tween 60, on the other hand, is a hydrophilic emulsifier with a much higher HLB value, typically around 14.9. It is formed by the ethoxylation of Span 60, meaning ethylene oxide units are added to the Span molecule. This addition of hydrophilic polyoxyethylene chains makes Tween 60 highly soluble in water and excellent at stabilizing oil-in-water (O/W) emulsions. It effectively encapsulates oil droplets dispersed in a water phase, preventing them from coalescing.

When used together, Span 60 and Tween 60 create what is known as an emulsifier system. The combination allows formulators to achieve a desired HLB value for specific applications by adjusting the ratio of the two emulsifiers. This tailoring of the HLB is critical for creating stable emulsions with specific characteristics, whether it’s a light lotion (O/W) or a rich cream (W/O). The synergy between Span 60 and Tween 60 allows for the creation of fine, stable emulsions that are resistant to phase separation under various conditions, including temperature fluctuations.

In food applications, this pairing is commonly found in baked goods, ice cream, and confectionery. For instance, in cakes, the Span 60/Tween 60 system can improve dough aeration, crumb structure, and shelf-life. In ice cream, it ensures a smooth texture and prevents ice crystal growth. In chocolate coatings, it helps maintain gloss and prevents bloom.

In the cosmetic industry, this emulsifier pair is used to create stable creams, lotions, and makeup products with desirable textures and application properties. The ability to control emulsion type and stability is key to product efficacy and consumer appeal.

NINGBO INNO PHARMCHEM CO.,LTD. offers both Span 60 and Tween 60, providing formulators with the essential components to build high-performance emulsifier systems. By understanding the complementary properties of these two surfactants, manufacturers can unlock new levels of product stability and performance in their formulations.