Tween T-20 laurate (Polysorbate 20) is a hydrophilic nonionic surfactant with an HLB value as high as 16.7, and is highly soluble in water. In routine use, it is recommended to add it slowly directly to the aqueous phase, stirring at room temperature or slightly warm (not exceeding 40°C) until completely dissolved, forming a clear or slightly milky solution. When used as an oil-in-water (O/W) emulsifier, it is often combined with lipophilic emulsifiers (such as Span series) to obtain a more stable emulsion. Its typical critical micelle concentration (CMC) is only 0.008% (w/v), so it can exert solubilization and surface tension reduction effects at very low concentrations.
In the compounding process, Tween T-20 can be first dissolved in the water phase and then mixed and homogenized with the oil phase; or the "oil-in-agent method" can be used, where Tween T-20 is first mixed with the oil phase, and then water is added for phase inversion emulsification. Considering its chemical stability, long-term use in strongly acidic (pH less than 2) or strongly alkaline (pH greater than 12) environments should be avoided, as ester bond hydrolysis may occur, affecting product performance. Additionally, Tween T-20 has certain hygroscopicity; the packaging must be sealed immediately after use.
As a solubilizer, it is common to directly mix the oil-soluble substance to be solubilized (such as fragrances, essential oils, fat-soluble drugs) with Tween T-20 evenly, then slowly add water to dilute to the required concentration. This method effectively avoids the formation of a "gel phase." In laboratory ELISA or Western Blot experiments, the commonly used working concentration of Tween T-20 is 0.05%~0.1% (v/v) as a washing solution (PBST) or blocking buffer component.
| Parameter Item | Value |
|---|---|
| Appearance | Light yellow to amber viscous liquid |
| Ionic Type | Nonionic |
| HLB Value | 16.7 |
| Active Content | ≥97% |
| Cloud Point (1% aqueous solution) | 76~78°C |
| Critical Micelle Concentration (CMC) | 0.008% (w/v) |
| pH Value (1% aqueous solution) | 5.0~7.0 |
| Surface Tension (1% aqueous solution) | 30~32 mN/m |
| Solubility | Easily soluble in water, methanol, ethanol |
| Saponification Value | 40~50 mgKOH/g |
| Hydroxyl Value | 95~110 mgKOH/g |
Cosmetic Emulsification: As an O/W emulsifier, it is recommended to use at 1%~5% of the total formula. Water-soluble ingredients can be mixed with Tween T-20 as the water phase, heated to 70~75°C, and then homogenized with the oil phase at the same temperature to form a fine cream or lotion. At low dosages (0.5%~2%), it can serve as a solubilizer for water-soluble fragrances and essential oils.
Pharmaceutical Solubilization: For solubilizing poorly soluble oral or topical preparations, it is recommended to use 5 to 20 times the amount of active ingredient. The drug and Tween T-20 can be mixed first, then the aqueous phase is added dropwise under stirring. In injections, a grade suitable for injection (such as meeting ChP, USP standards) must be used, with dosage typically controlled at 0.1%~0.5%.
Food Emulsification: In ice cream or pastries, the recommended dosage is 0.1%~0.5% (based on the final product). It can be thoroughly mixed with the oil or water phase first, and then homogenized or whipped according to the process to improve overrun and melt resistance.
Industrial Cleaning: As a wetting and penetrating agent, the recommended dosage is 0.5%~3.0%. It can be directly added to a water-based cleaning agent and stirred evenly. Better results are achieved when used with alkaline additives, effectively removing mineral oils and animal or vegetable fats.
Pesticide and Coating Dispersion: As an emulsifying dispersant, it is recommended to use 5%~10% of the amount of active ingredient (or pigment). After premixing with oil-soluble components, high-speed shearing or sand milling in water can significantly improve dispersion stability and suspension rate.