Span S-20 coconut fatty acid (HLB value 8.6), as a W/O non-ionic emulsifier, has a dosage that varies significantly depending on the specific application area, typically ranging from 0.5% to 10% of the total formulation. The optimal amount should be determined through experimental optimization based on the formulation system.
Detailed Explanation
Span S-20 coconut fatty acid (sorbitan cocoate) is a non-ionic surfactant derived from renewable resources, with an HLB value of 8.6. It is a lipophilic emulsifier, particularly suitable for constructing water-in-oil (W/O) emulsion systems. When used in formulations, the product typically needs to be heated to 40~60°C (due to its high viscosity, approximately 4000 mPa·s/25°C) and fully dissolved in the oil phase before emulsification. It is soluble in oils and organic solvents and disperses as a milky emulsion in water. Its low-foaming characteristic makes it perform excellently in industrial formulations where foam suppression is required.
There is no unified standard for the specific dosage of this product, as it varies considerably depending on the application scenario and formulation requirements. When used as the primary emulsifier, the dosage is higher; as a co-emulsifier or dispersant, the dosage is relatively lower. It is recommended to start with small doses during formulation development, conduct gradient experiments, and combine with the HLB value matching principle. If necessary, blend it with high-HLB value emulsifiers (such as Tween series) to adjust the hydrophilic-lipophilic balance of the system, achieving optimal emulsion stability and product performance.
According to the Guoli Chemical product database, the product has an active content of ≥98%. The effective dosage should be calculated based on the pure content during practical use. The product is classified as practically non-toxic, with a skin irritation index (PII) of 0, making it mild and skin-friendly, and safe for use in personal care products.
Technical Parameters
| Parameter Item | Value |
|---|
| Product Name | Span S-20 Coconut Fatty Acid (Sorbitan Cocoate) |
| CAS Number | 1338-39-2 |
| Ionic Type | Non-ionic |
| HLB Value | 8.6 |
| Active Content | ≥98% |
| Appearance (25°C) | Amber viscous liquid |
| pH Value (1% Dispersion) | 5.0~7.0 |
| Density (25°C) | Approximately 1.00~1.05 g/cm³ |
| Kinematic Viscosity (25°C) | Approximately 4000 mm²/s |
| Surface Tension (0.1% Aqueous Solution) | Approximately 28 mN/m |
| Critical Micelle Concentration (CMC) | Approximately 25 mg/L |
| Acid Value | ≤7.0 mg KOH/g |
| Saponification Value | 155~175 mg KOH/g |
| Hydroxyl Value | 290~360 mg KOH/g |
| Water Content | ≤1.5% |
| Flash Point | >150°C |
| Pour Point | <10°C |
| Foam Characteristics | Low Foaming |
Usage Recommendations
Recommended reference dosages for different application areas are as follows (data source: industry common experience; specific amounts should be verified through formulation experiments):
- Personal Care Products — Skin Creams/Lotions: As the primary W/O emulsifier, the recommended dosage is 1.5%~5.0%; when compounded with Tween series, the dosage of Span S-20 can be reduced to 0.5%~2.0% to adjust HLB value and system stability.
- Sunscreen and Color Cosmetics: For dispersing inorganic sunscreens (titanium dioxide, zinc oxide) and pigments, the recommended dosage is 0.5%~3.0%, pre-dissolved in the oil phase before addition.
- Shampoo/Hair Care Products: For solubilizing silicone oils and fatty ingredients, the recommended dosage is 0.5%~2.0%.
- Agricultural Chemicals (Pesticide Emulsifiers): The recommended dosage is 3.0%~8.0%, mixing the technical material with the emulsifier uniformly and then diluting to form a stable emulsion.
- Metalworking Fluids: As an emulsifying and lubricating component, the recommended dosage is 2.0%~10.0%, suitable for cutting fluid and grinding fluid formulations.
- Coatings and Inks: For pigment wetting and dispersion, the recommended dosage is 0.2%~2.0% (based on pigment mass), effectively preventing pigment flocculation and floating.
- Industrial Cleaners: For penetrating and solubilizing heavy grease stains, the recommended dosage is 1.0%~5.0%.
- Textile Finishing Agents: As an emulsifying auxiliary component, the recommended dosage is 0.5%~3.0%.
Key Usage Points
- Preheating: The product is a viscous liquid (approximately 4000 mPa·s at 25°C). It is recommended to preheat the product to 40~60°C before use to reduce viscosity for accurate weighing and dosing.
- Oil Phase Dissolution: Add Span S-20 coconut fatty acid to the oil phase components of the formulation, stirring evenly until fully dissolved.
- Emulsification Process: Under stirring, slowly add the aqueous phase to the oil phase containing Span S-20 (or vice versa according to process requirements). Using a homogenizer or high-shear equipment can enhance emulsification effectiveness.
- Compounding Recommendations: To prepare systems with higher HLB values, blend with Tween series (e.g., Tween-20, Tween-80, etc.) in appropriate ratios, adjusting the overall HLB value through weighted calculations.
