overview
Common Name: Tween 61 / Polyoxyethylene (4) sorbitan monostearate
CAS Number: 9005-67-8
EINECS Number: 500-020-4 (EC No) :contentReference[oaicite:0]{index=0}
Molecular Formula: C₃₂H₆₂O₁₀
Molecular Weight: ~606 g/mol :contentReference[oaicite:1]{index=1}
Polysorbate 61 (Tween 61) is a nonionic surfactant derived from the ethoxylation of sorbitan monostearate. As a hydrophilic emulsifier (O/W type), it helps stabilize oil-in-water systems and improve dispersibility of oily components. It exhibits good solubility in ethanol and ethyl acetate, and can be dispersed in warm water. Polysorbate 61 finds use in cosmetics, personal care, and industrial formulations where moderate emulsifying strength, mildness, and compatibility with fatty ingredients are required.
Molecular structure description
Hydrophilic part: Polyoxyethylene (20) sorbitan head group
HLB value: ~10.5 (balanced emulsifier, can stabilize both oil-in-water and water-in-oil systems)
Specifications
It is a nonionic surfactant composed of polyoxyethylene (4) sorbitan esterified with stearic acid, resulting in a moderately lipophilic molecule that can act as a primary or co-emulsifier.
It is dispersible in warm water and ethanol; slightly soluble in vegetable oils; and insoluble in mineral oil.
When dispersed in water, it forms milky emulsions. Its lower hydrophilicity compared to other polysorbates makes it suitable for water-in-oil or multiple emulsion systems.
| Test Indicator | Unit | Min Value | Max Value |
|---|---|---|---|
| Saponification Value | mgKOH/g | 88 | 98 |
| Hydroxyl Value | mgKOH/g | 44 | 60 |
| Acid Value | mgKOH/g | - | 2 |
| Moisture | % | - | 3 |
Applications
It is suitable for both oil-in-water and water-in-oil systems, particularly in products requiring a more lipophilic emulsifier.
Its compatibility with other surfactants allows flexible formulation design.
Emulsification Efficiency – Stable W/O Emulsions
Sorbitan esters are highly effective in forming stable water-in-oil emulsions. Ideal for margarine, creams, and ointments, they help maintain consistency and prevent separation over time.
Mild & Skin-Friendly – Ideal for Cosmetics
Widely used in lotions, creams, and makeup products, sorbitan esters are non-irritating and suitable for sensitive skin. They provide smooth textures and enhance product stability.
Food Grade & Safe – Emulsifiers for Processing
Approved for food use, they act as emulsifiers in sauces, dairy products, and spreads. Improve mouthfeel, extend shelf life, and maintain homogeneity of processed foods.
Pharmaceutical Use – Enhances Drug Stability
Used in medicinal creams, gels, and suspensions, sorbitan esters help deliver oil-soluble actives effectively. They improve bioavailability and ensure long-term formulation stability.
storage & package
Storage:
Store in a cool, dry, and well-ventilated area, away from direct sunlight and sources of heat.
Avoid contact with harmful or incompatible substances. Handle with care during transportation to prevent leakage or contamination.
Transportation:
Transport as a general chemical product, following standard safety and handling procedures.
Package:
Polysorbate 61 is packed in high-quality PE drums with double-seal lids.
Standard packaging sizes include 25kg/drum, 200kg/drum, and 1000kg IBC tote to meet different usage needs.
25 Kg /drum
200kg/drum
