Span S-85, chemically named sorbitan trioleate, has the molecular formula C₆₀H₁₀₈O₈, a molecular weight of approximately 957 g/mol, and CAS number 26266-58-0. This product is synthesized by esterifying sorbitan with three molecules of oleic acid. The three long-chain unsaturated fatty hydrocarbon groups in its structure impart extremely strong lipophilic properties, making it one of the lowest HLB value varieties in the Span series (only 1.8). It is almost insoluble in water but readily soluble in most organic solvents and oils.
The product is liquid at room temperature (melting point below 0°C), with good low-temperature fluidity and chemical stability. Its iodine value ranges from 75 to 85 gI₂/100g, reflecting the presence of certain unsaturated double bonds in the molecular chain. Prolonged high-temperature heating or contact with strong oxidizing agents should be avoided to prevent oxidative degradation. The product is not classified as a hazardous chemical; under GHS classification, it has no hazard pictograms or hazard statements. However, it is still recommended to wear protective gloves and safety goggles during handling.
| Physicochemical Technical Parameters List | |
|---|---|
| Parameter Item | Specification/Value |
| Chemical Name | Sorbitan Trioleate (Sorbitan Trioleate) |
| CAS Number | 26266-58-0 |
| Molecular Formula | C₆₀H₁₀₈O₈ |
| Molecular Weight | ~957 g/mol |
| Appearance (25°C) | Amber to brownish-yellow viscous oily liquid |
| Ionic Type | Nonionic Surfactant |
| HLB Value | 1.8 |
| Active Content | ≥98% |
| Moisture | ≤1.5% |
| pH Value (1% Aqueous Dispersion) | 5.0 ~ 7.0 |
| pH Value (5% Aqueous Dispersion) | 5.0 ~ 7.0 |
| Acid Value | ≤15 mgKOH/g |
| Saponification Value | 165 ~ 185 mgKOH/g |
| Hydroxyl Value | 50 ~ 80 mgKOH/g |
| Iodine Value | 75 ~ 85 gI₂/100g |
| Density (25°C) | 0.95 ~ 1.00 g/cm³ |
| Kinematic Viscosity (25°C) | 200 ~ 500 mm²/s |
| Low Shear Viscosity (25°C) | 200 ~ 400 mPa·s |
| Refractive Index (20°C) | 1.470 ~ 1.480 |
| Melting Point | <0°C (Liquid at room temperature) |
| Flash Point (Open Cup) | >200°C |
| Solubility | Readily soluble in oils and organic solvents, dispersible in water |
| Cloud Point | Not applicable (Oil-soluble product, insoluble in water) |
| Foaming Property | Low foaming |
| Hygroscopicity | Low |
| Chemical Stability | Stable at room temperature; avoid strong acids and alkalis |
| Alkali Resistance | Not resistant to strong alkalis |
| Monoester Content | ≤2% |
| Diester Content | ≤2% |
| Free Alcohol | ≤2% |
| Heavy Metals (as Pb) | ≤10 mg/kg |
| Arsenic (As) | ≤2 mg/kg |
| Water Hazard Class | WGK 1 (Slightly hazardous to water) |
| Packaging Specifications | 50kg Plastic Drum / 200kg Plastic Drum / IBC Tote |
With its extremely low HLB value (1.8) and strong lipophilicity, Span S-85 is most suitable as an emulsifier for water-in-oil (W/O) systems. In the cosmetics field, it is recommended for formulations of cold creams, massage creams, sunscreens, and liquid foundations, with a suggested dosage of 1% to 5% of the oil phase total. It can be compounded with high HLB Tweens (e.g., Tween-80) to adjust the overall HLB value of the emulsion system. In metalworking fluids, as a key component of emulsifying cutting fluids and rust-preventive oils, it forms stable water-in-oil emulsion structures, providing excellent lubrication and corrosion protection. In pesticide emulsifiable concentrate (EC) formulations, it significantly enhances the compatibility of the active ingredient with organic solvents, promoting rapid spontaneous emulsification upon addition to water.
Note that this product is not resistant to strong alkaline environments; compatibility tests should be conducted when used in alkaline formulations. Due to its high iodine value (75~85), the molecular chain contains unsaturated double bonds. Prolonged exposure to air or high temperatures may cause slow oxidation. It is recommended to store sealed in a cool, dry place and use promptly after opening.