Span S-85 (sorbitan trioleate, CAS No.: 26266-58-0) appears as an amber to brownish-yellow viscous oily liquid with an extremely low HLB value (hydrophilic-lipophilic balance), exhibiting strong lipophilic characteristics. This essential property makes it a key component for preparing stable water-in-oil (W/O) emulsions and microemulsions, significantly reducing oil-water interfacial tension and imparting a fine texture and long-term storage stability to various emulsion systems.
This product has excellent chemical inertness and compatibility, capable of withstanding acidic, alkaline, and hard water environments while maintaining stable activity under a wide range of process conditions. It exhibits good compatibility with various oils, waxes, and active ingredients. Additionally, Span S-85 is not classified as a hazardous chemical and can be used according to general chemical handling procedures, making it easy to operate and widely applicable.
In practical processes, Span S-85 can be used either as a single primary emulsifier or in combination with high-HLB emulsifiers (such as Tween series) to flexibly adjust the hydrophilic-lipophilic balance of the system, meeting the emulsification requirements of different formulations. Its efficient dispersing ability also effectively prevents pigment flocculation, floating color, and other issues, playing a key role in various industrial scenarios.
| Industry Field | Specific Application | Process Role |
|---|---|---|
| Cosmetics & Skincare | Cold cream, massage cream, sunscreen, foundation, mascara, eye shadow | Acts as W/O emulsifier to impart fine texture to creams; disperses and suspends UV filters to enhance water resistance; improves pigment wetting and adhesion durability |
| Pharmaceutical Preparations | Topical ointments, cream bases, suppository bases | Serves as a mild W/O emulsifier to promote uniform drug distribution and skin absorption; adjusts suppository melting characteristics and hardness to improve drug release uniformity |
| Food Industry | Whipped cream, frosting, shortening, confectionery mold release oil, defoamer | Improves aeration and structural stability; functions as an emulsifier in mold release oil and as a component of defoamers |
| Textile Industry | Synthetic fiber tow finishing oil, antistatic finishing agent | Reduces friction between fibers and metal, imparting smoothness and cohesion, reducing breakage rate; provides lasting antistatic effect |
| Metalworking | Emulsifiable cutting fluids, rust preventive oils | Prepares stable W/O or semi-synthetic cutting fluids, balancing lubrication and cooling; assists film formation and solubilization of antirust additives, improving coating uniformity |
| Petroleum Extraction | Oil-based/synthetic-based drilling fluids, fracturing fluids | Stabilizes inverse emulsions, enhances wellbore stability and cuttings carrying capacity; improves oil-water mixing uniformity, aids friction reduction and flowback efficiency, tolerates high temperature and high salinity reservoir conditions |
| Coatings & Inks | Pigment wetting and dispersion, flow leveling and adhesion promotion | Wets pigment surfaces, shortens dispersion time, prevents flocculation and floating color/ flooding; modifies coating surface tension, reduces brush marks or orange peel |
| Pesticide Formulations | Emulsifiable concentrates (EC), suspension concentrates (SC) | Improves compatibility of active ingredients with organic solvents, ensuring rapid spontaneous emulsification upon water addition; aids wetting and dispersion of solid active ingredient particles, preventing sedimentation and agglomeration |
Combination Use: Span S-85 is often used in combination with high-HLB emulsifiers (such as Tween series). By adjusting the ratio, the target HLB value can be achieved to meet emulsification requirements for different oil and water phase ratios. It is recommended to determine the optimal ratio through HLB value calculation.
Recommended Dosage: When used as the primary emulsifier, the typical addition amount is 1%-5% of the total formulation (exact dosage varies depending on the system); when used as a dispersing aid, the addition amount is usually 0.5%-3% of the weight of pigments or solid particles. It is recommended to determine the optimal dosage through small-scale experiments.
Addition Process: Generally, dissolve Span S-85 in the oil phase first, heat to 40-60°C to ensure thorough dissolution and mixing, then perform emulsification with the water phase. For systems containing solid pigments, it can be pre-ground with the pigments to achieve pre-wetting before subsequent preparation.