Tween 60 (Polyoxyethylene (20) sorbitan monostearate, CAS No.: 9005-67-8) is a polyol-type nonionic surfactant with an HLB value of approximately 14.9, making it a typical oil-in-water (O/W) emulsifier. Its molecular structure contains hydrophilic polyoxyethylene chains and lipophilic fatty acid ester chains. This amphiphilic structure allows it to form a stable interfacial film at the oil-water interface, significantly reducing interfacial tension, thereby playing an irreplaceable role in multiple industrial fields.
With excellent acid-alkali stability and hard water tolerance, Tween 60 maintains functional stability over a wide pH range and can be well compounded with anionic, cationic, and other nonionic surfactants, laying a solid foundation for its cross-industry applications. Additionally, its low toxicity and good biocompatibility have earned it widespread recognition in products that come into contact with the human body, such as food, pharmaceuticals, and cosmetics.
1. Food Industry — As an emulsifier and stabilizer, Tween 60 promotes uniform mixing of oil and water in baking fats, preventing oil separation; in ice cream and frozen desserts, it controls ice crystal growth, improving overrun and smoothness; in coffee creamers (non-dairy creamer), it evenly disperses oil droplets, providing good whiteness and solubility; in dairy products and beverages, it prevents oil-water separation and protein precipitation, extending product shelf life. Typical addition levels range from 0.1% to 0.5% (based on oil weight).
2. Cosmetics and Personal Care Products — In creams and lotion formulations, Tween 60 is compounded with the Span series (e.g., Span 60) to build a stable O/W emulsion system, resulting in fine texture and a refreshing skin feel; in shampoos and shower gels, it acts as a solubilizer, uniformly dispersing fragrances, essential oils, and lipophilic active ingredients (e.g., vitamin E, plant extracts) into the aqueous system, enhancing product transparency and efficacy; in color cosmetics, it aids in pigment dispersion, improving spreadability and skin adherence. Recommended usage is 1% to 5% of the total formulation weight.
3. Pharmaceutical Preparations — Tween 60 serves as a solubilizer in oral solutions and injections, encapsulating poorly soluble drugs (e.g., fat-soluble vitamins, hormone drugs) in micelles, significantly improving drug solubility and bioavailability; in topical ointments and creams, it acts as an emulsifier, ensuring uniform drug distribution in the base, promoting transdermal absorption, and maintaining the physical stability of the preparation. Its oral LD50 is greater than 5000 mg/kg, indicating practically non-toxic levels, meeting pharmacopoeia standards.
4. Textile Industry — During spinning, it is used as an antistatic agent and lubricant coated on fiber surfaces to reduce friction and static electricity buildup between fibers and metal parts, decreasing breakage rates; in weaving and finishing, it acts as a leveling agent and wetting agent, promoting uniform dye uptake, reducing color spots and shading, while imparting a soft and fluffy hand feel to the fabric. Typical usage is 0.5 to 2 g/L of the working solution.
5. Pesticide Formulations — In formulations such as emulsifiable concentrates (EC), microemulsions (ME), and oil-in-water emulsions (EW), it acts as an emulsifier, allowing hydrophobic pesticide active ingredients to spontaneously form stable emulsions upon dilution, ensuring good wetting, spreading, and penetration of the spray liquid on crop surfaces, thereby improving pesticide efficacy. It is typically used in combination with other nonionic or anionic emulsifiers, with total emulsifier content ranging from 5% to 15% of the formulation weight.
6. Plastics and Polymer Industry — As an internally added antistatic agent, it is incorporated into plastic films, injection-molded parts, and sheets. It migrates to the product surface to form a conductive layer, effectively dissipating surface static charges, preventing dust attraction and electrostatic discharge; it also acts as an internal lubricant during processing, reducing melt viscosity, improving mold flow, and facilitating demolding. Recommended dosage is 0.1% to 1.0% of the resin weight.
Emulsion System Construction: Tween 60 (HLB ≈ 14.9) is suitable for preparing O/W emulsions. To adjust the hydrophilic-lipophilic balance of the emulsion system, it is recommended to use it in combination with low-HLB Span series (e.g., Span 60, HLB ≈ 4.7). By adjusting the ratio of the two, the target HLB value can be achieved to match the emulsification requirements of different oil phases.
Solubilization Process: When solubilizing fragrances or lipophilic active ingredients, it is advisable to first mix Tween 60 thoroughly with the substance to be solubilized, then slowly add water phase while stirring. This helps form a clear and stable microemulsion system. A solubilization temperature of 40 to 60°C yields better results.