Span S-85 (sorbitan trioleate) has an HLB value of only 1.8, making it one of the most lipophilic varieties in the Span series. It appears as an amber to brownish-yellow viscous oily liquid at room temperature, easily soluble in mineral oil, vegetable oil, silicone oil, and various ester solvents, but insoluble in water and only dispersible. This strong lipophilic property makes it an ideal primary emulsifier for preparing water-in-oil emulsions.
The core method for using Span S-85 is the "oil phase introduction method": directly add the required amount of Span S-85 to the oil phase components in the formulation, stir and heat to 60~70°C until completely dissolved and uniformly mixed; simultaneously heat the water phase to a similar temperature; then under high-speed stirring (e.g., using a homogenizer or high-shear disperser), slowly add the water phase in a thin stream to the oil phase, maintain stirring and temperature, and gradually cool to room temperature after emulsion formation to obtain a fine and stable cream or emulsion. For high-viscosity systems (such as cold creams or massage creams), the process can also involve heating the two phases separately, then adding the water phase to the oil phase followed by homogenization.
Span S-85 is often used in combination with low-HLB (3~8) Tween series (e.g., Tween-80) or other hydrophilic emulsifiers to adjust the overall HLB value of the system, thereby achieving optimal emulsification effect and long-term stability. In addition, its excellent pigment wetting and dispersing ability makes it widely used in non-emulsification scenarios such as pigment paste grinding and paint dispersion. When used, it can be directly added to the grinding base material and mixed with pigments before grinding.
| Parameter | Value | Data Source |
|---|---|---|
| Appearance | Amber to brownish-yellow viscous oily liquid | Guoli Chemical Database |
| HLB Value | 1.8 | Guoli Chemical Database |
| Active Content | ≥98% | Guoli Chemical Database |
| Solubility | Easily soluble in oil, dispersible in water | Guoli Chemical Database |
| Density (25°C) | 0.95~1.00 g/cm³ | Guoli Chemical Database |
| Kinematic Viscosity (25°C) | 200~500 mm²/s | Guoli Chemical Database |
| Flash Point (Open Cup) | ＞200°C | Guoli Chemical Database |
| Acid Value | ≤15 mgKOH/g | Guoli Chemical Database |
| Hydroxyl Value | 50~80 mgKOH/g | Guoli Chemical Database |
| Saponification Value | 165~185 mgKOH/g | Guoli Chemical Database |
| Water Content | ≤1.5% | Guoli Chemical Database |
| Iodine Value | 75~85 gI₂/100g | Guoli Chemical Database |
Cosmetics and Skincare: In W/O products such as cold cream, massage cream, sunscreen, and liquid foundation, the recommended dosage is 1%~5% of the total formulation weight. When compounded with Tween series, the total HLB value of the W/O system should be controlled at 3~6. For high-oil-phase formulations (oil content >60%), it can be used alone at an addition level of 3%~8%.
Pharmaceutical Preparations: As a W/O emulsifier in topical ointments and cream bases, the recommended dosage is 2%~6%. For adjusting suppository bases, the addition amount is typically 1%~3% of the base total weight, which can adjust melting characteristics and hardness.
Metalworking and Petroleum Extraction: In emulsified cutting fluids and rust-proof oils, the recommended dosage as the primary emulsifier is 3%~10%; when used as an emulsifier in drilling fluids, the recommended dosage is 1%~5% (based on oil phase weight). For high-temperature and high-salinity conditions, other salt-tolerant emulsifiers should be combined.
Coatings and Inks: When used as a pigment wetting and dispersing agent, it is recommended to add 1%~5% of the pigment weight during the grinding stage, which can effectively shorten dispersion time and prevent floating and flooding. In pesticide emulsifiable concentrates (EC), the recommended dosage is 5%~8%, compounded with hydrophilic emulsifiers to ensure full emulsification upon water addition.
General Emulsification Process Temperature Recommendations: Control at 50~80°C, avoid prolonged heating above 100°C to prevent oxidative decomposition of unsaturated bonds. After emulsification, slowly cool and stir at low speed to room temperature; rapid cooling may cause emulsion breakdown or rough cream texture.