Tween T-81 (Polyoxyethylene (5) Sorbitan Monooleate) is a classic nonionic surfactant produced by Guoli Chemical, with the molecular formula C34H64O11 and a molecular weight of approximately 690. At room temperature, this product appears as a light yellow to amber oily liquid, characterized by low foaming and slight hygroscopicity. It is readily soluble in oils and organic solvents and can be dispersed in water. As a balanced performance emulsifier, Tween T-81, when used in combination with the Span series (sorbitan fatty acid esters), can flexibly adjust the hydrophilic-lipophilic balance value of the system, achieving more precise emulsification effects.
With excellent chemical stability, Tween T-81 can maintain its activity in mild acid, alkali, and hard water environments, making it widely applicable in industries such as cosmetics, food, pharmaceuticals, pesticides, coatings, and metalworking fluids. The following physicochemical technical parameters are sourced from the Guoli Chemical product database, providing an accurate basis for user formulation design and quality control.
| Parameter Item | Technical Indicator |
|---|---|
| Product Name | Tween T-81 |
| Chemical Name | Polyoxyethylene (5) Sorbitan Monooleate |
| CAS No. | 9005-65-6 |
| Aliases | Polysorbate 81, PEG-5 Sorbitan Monooleate, Tween 81 |
| Molecular Formula | C34H64O11 |
| Molecular Weight | Approx. 690 |
| Product Type | Nonionic Surfactant |
| Appearance | Light yellow to amber oily liquid |
| Active Content | ≥97% |
| HLB Value | 10 |
| Cloud Point (1% Aqueous Solution) | 50-60°C |
| pH Value (1% Solution) | 5.0-7.0 |
| pH Value (5% Solution) | 5.0-7.0 |
| Density | 1.00-1.05 g\/cm³ |
| Kinematic Viscosity (25°C) | 200-500 mm²\/s |
| Refractive Index (20°C) | 1.470-1.480 |
| Surface Tension | Approx. 30-35 mN\/m |
| Critical Micelle Concentration (CMC) | 0.01-0.1 g\/L |
| Acid Value | ≤2 mgKOH\/g |
| Saponification Value | 45-55 mgKOH\/g |
| Hydroxyl Value | 65-85 mgKOH\/g |
| Iodine Value | 18-25 gI2\/100g |
| Moisture Content | ≤3.0% |
| Flash Point | >150°C |
| Hygroscopicity | Slightly hygroscopic |
| Foam Performance | Low foaming |
| Chemical Stability | Stable at room temperature; stable under mild acid and alkali conditions |
| Solubility | Readily soluble in oils and organic solvents, dispersible in water |
| Heavy Metals | ≤10 mg\/kg |
| Arsenic | ≤2 mg\/kg |
| Packaging Specification | 50kg\/200kg plastic drum |
Tween T-81 has an HLB value of 10, making it suitable as a transitional emulsifier for O\/W and W\/O emulsions, especially performing well in cosmetic creams, lotions, and makeup removers. It is recommended to be used in combination with the Span series (e.g., Span 80). By adjusting the ratio of the two, a composite emulsifying system with an HLB value ranging from 4 to 10 can be achieved, enabling more precise emulsification and stabilization effects. In pesticide emulsifiable concentrates and microemulsion formulations, the recommended dosage is typically 2% to 8% of the total formulation. In metalworking fluids, a recommended addition amount of 3% to 10% can significantly enhance emulsification stability and boundary lubrication performance.