Span S-60 (CAS No.: 1338-41-6), also known as Span 60 or sorbitan monostearate, is a white to pale yellow waxy solid provided by Guoli Chemical. As a nonionic surfactant, its HLB value is approximately 4.7, making it inherently lipophilic, efficiently dispersing water in oil to form stable W/O emulsions. The molecular structure of its sorbitan backbone and long-chain stearic acid imparts good oil solubility and chemical stability, maintaining reliable performance over a wide pH range and in hard water conditions, with minimal impact from acidic or alkaline environments.
The active ingredient content of this product is as high as ≥98%, with an acid value ≤10 mgKOH/g, saponification value between 145 and 160, and hydroxyl value between 230 and 270. These parameters ensure the emulsification efficiency and batch-to-batch stability of Span S-60. It is soluble in hot oils and organic solvents, with a melting point range of 52~57°C, so it must be pre-melted in cold blending processes. Its low-foaming characteristic is also very suitable for industrial operations requiring defoaming or low-foam environments.
Due to its excellent emulsifying, dispersing, and stabilizing functions, Span S-60 plays an irreplaceable role in multiple industries. It can be used alone or often compounded with hydrophilic Tween series surfactants (such as Tween 60 and Tween 80) to adjust the ratio to achieve the target HLB value, thus precisely designing product formulations.
| Application Field | Specific Function | Application Examples |
|---|---|---|
| Cosmetics | Primary emulsifier/Co-emulsifier | Used in creams, lotions, sunscreens to form a fine texture and moisturizing film |
| Food Industry | Emulsifier, stabilizer | Used in margarine, chocolate, pastries to prevent oil separation and extend shelf life |
| Pharmaceutical Preparations | Suppository base, drug carrier | Used in vaginal and rectal suppositories to ensure uniform drug dispersion and sustained release |
| Textile Industry | Fiber oil agent, softener | Used in synthetic fiber spinning to provide smoothness, antistatic properties, and a soft feel |
| Plastics Industry | Anti-fog agent, antistatic agent | Used in agricultural films to eliminate fog inside the greenhouse and reduce dust adsorption |
| Agrochemical Formulations | Pesticide emulsifier | Used in pesticide emulsifiable concentrates to help the active ingredient self-emulsify when diluted to form a stable emulsion |
| Coatings and Inks | Pigment wetting and dispersing agent | Prevents pigment agglomeration, floating, and flooding, improving coating gloss and color uniformity |
When using Span S-60, it is recommended to compound it with a high HLB emulsifier (such as Tween series) based on the target HLB requirement of the system. When preparing W/O emulsions, first dissolve Span S-60 in the oil phase, heat to above 55°C to completely melt it and stir evenly. Then, while stirring, slowly add the water phase to the oil phase to form a stable emulsion. When used as an internal anti-fog additive in plastic films, the recommended dosage is 0.5%~1.5% of the total resin weight, and it should be mixed with the resin base material and granulated before use.
Although the oral LD₅₀ of Span S-60 in rats is > 15,000 mg/kg, classifying it as a low-toxicity substance, precautions should still be taken during handling: its dust or vapor generated by heating may cause mild irritation to the skin, eyes, and respiratory tract. It is recommended to wear chemical safety goggles and nitrile/neoprene gloves during operation and work in a well-ventilated area. The product should be stored in a cool, dry place with an ambient temperature below 35°C, avoiding direct sunlight and contact with strong oxidizers.