Span S-20 (sorbitan monolaurate, CAS No.: 1338-39-2) is a nonionic surfactant with an HLB value of approximately 8.6. It appears as a light yellow to amber viscous liquid. The hydrophilic sorbitan group and the hydrophobic lauric acid chain in its molecular structure naturally favor the formation of water-in-oil (W/O) emulsion systems, building a stable interfacial film at the oil-water interface, making it an irreplaceable functional additive in multiple industries.
In various industries, Span S-20 is often used in combination with hydrophilic surfactants (such as Tween series) to achieve a wider range of HLB values and more flexible emulsifying performance. Its nonionic nature gives it good compatibility with anionic, cationic, and amphoteric surfactants, and it remains stable and active in acidic, alkaline, and hard water media.
| Industry | Application Process/Product | Function |
|---|---|---|
| Cosmetics and Personal Care | Creams, lotions, sunscreens, cosmetic base materials | W/O emulsifier, providing delicate skin feel and system stability |
| Food Industry | Baking fats, non-dairy creamer, chocolate coatings, beverage emulsions | Food-grade emulsification, preventing oil-water separation, improving texture and shelf life |
| Pharmaceutical Preparations | Topical creams, ointments, suppository bases | Emulsification and solubilization, enhancing drug dispersion uniformity and transdermal absorption |
| Textile Auxiliaries | Softening agents, antistatic agents | Dispersing silicone oil/wax substances, giving fabrics a smooth feel |
| Pesticide Formulations | Emulsifiable concentrates (EC), emulsion in water (EW) | Emulsifying monomers, ensuring spontaneous formation of stable emulsions upon dilution |
| Coatings and Inks | Pigment dispersion, wetting processes | Reducing pigment agglomeration, enhancing color development and storage stability |
| Metalworking Fluids | Cutting fluids, grinding fluids, rust preventive oils | Emulsifying base oils, forming protective films, reducing friction and corrosion |
It is recommended to combine with hydrophilic surfactants (such as Tween T-20) to achieve the target HLB value. The general dosage is 1% to 5% (w/w) of the total formulation, specifically determined by HLB value calculations based on oil phase ratio and emulsification requirements. Applications in food and pharmaceutical grades must comply with relevant pharmacopeia or food safety standards.