Span S-80, chemically named Sorbitan Monooleate, is a non-ionic surfactant with CAS number 1338-43-8, appearing as a yellow to amber viscous liquid. Its molecular structure imparts strong oil affinity, making it sparingly soluble in water but soluble in various oils and organic solvents, typical of an oil-soluble surfactant. With an active content ≥98% and monoester content ≥80%, it ensures high purity and efficient performance, achieving stable water-in-oil emulsification even at low dosage.
As a water-in-oil emulsifier, Span S-80 forms a stable interfacial film at the oil-water interface, dispersing the water phase finely and uniformly into the oil phase. It maintains stable surface activity under acidic, alkaline, and hard water conditions, with good chemical stability, but note that its ester bond may be hydrolyzed under strong alkaline conditions. Additionally, Span S-80 features low foaming and excellent lubricating properties, making it outstanding in diverse industrial formulations, especially irreplaceable in scenarios requiring strong lipophilic emulsification capability.
| Parameter | Specification | Description |
|---|---|---|
| Ionic Type | Non-ionic | Insensitive to electrolytes and pH |
| HLB Value | 4.3 | Strong lipophilicity, suitable for W/O systems |
| Appearance (25°C) | Yellow to amber viscous liquid | — |
| Active Content | ≥98% | High purity of active ingredient |
| Monoester Content | ≥80% | Diester content ≤15% |
| Acid Value | ≤10 mgKOH/g | Low free acid content |
| Saponification Value | 145~160 mgKOH/g | — |
| Hydroxyl Value | 200~240 mgKOH/g | — |
| Iodine Value | 65~85 gI₂/100g | Reflects unsaturation degree |
| Moisture Content | ≤1.5% | — |
| Density (25°C) | 0.98~1.05 g/cm³ | — |
| Viscosity (25°C) | 1000~2000 mm²/s | Viscous flowable liquid |
| Flash Point (Closed Cup) | >150°C | Relatively safe |
| Solubility | Soluble in oils and organic solvents, sparingly soluble in water | Typical oil-soluble characteristic |
| Surface Tension | Approx. 30 mN/m (1% solution in liquid paraffin) | Effectively reduces oil phase interfacial tension |
| Foaming Property | Low foaming | Suitable for foam-sensitive systems |
| Alkali Resistance | Poor | Ester bond can be hydrolyzed by strong alkali |
Span S-80 is widely used in cosmetic creams and lotions, food bakery fats and non-dairy creamers, pharmaceutical ointments and suppository bases, pesticide emulsifiable concentrates, petroleum-based lubricants and rust-proof oils, textile fiber oils, and internal lubrication and antistatic agents in plastic processing. It is recommended to be compounded with high-HLB emulsifiers (such as Tween series) to adjust the system HLB value for optimal emulsification stability. Typical dosage is 1%~5% of the total formulation, with specific amount determined through experimental optimization based on the oil-water ratio and target emulsion type.