Span S-20 coconut acid (sorbitan monolaurate, CAS: 1338-39-2) is a classic nonionic surfactant produced by Guoli Chemical. Its appearance is typically a pale yellow to amber viscous liquid with low foaming properties. The molecular structure endows it with excellent water-in-oil (W/O) emulsifying ability, and it is soluble in oils and organic solvents, dispersing in water to form an emulsion, making it an ideal choice for formulating creams, lotions, and more.
In terms of physicochemical stability, this product is stable at room temperature and under normal pH conditions, with a flash point above 150°C and no flammability risk. However, note that under strong acidic or alkaline conditions, its ester bonds may undergo hydrolysis. The product has low hygroscopicity and can be effectively preserved by sealed storage at 5–40°C.
From a hygiene and safety perspective, this product is classified as practically non-toxic in acute oral toxicity (rat LD50 > 5 g/kg), non-irritating to skin and eyes, and shows no sensitization reactions. The content of heavy metals (≤ 10 mg/kg) and arsenic (≤ 2 mg/kg) is strictly controlled at very low levels.
| Parameter Category | Parameter Item | Technical Indicator / Typical Value |
|---|---|---|
| Basic Physical Properties | Appearance (25°C) | Pale yellow to amber viscous liquid |
| Density (25°C) | Approx. 1.00–1.05 g/cm³ | |
| Kinematic Viscosity (25°C) | Approx. 4000 mm²/s | |
| Refractive Index (25°C) | 1.470–1.480 | |
| Melting Point | < 10°C | |
| Structure & Composition | Molecular Formula | C18H34O6 |
| Molecular Weight | 346.46 g/mol | |
| CAS Number | 1338-39-2 | |
| Chemical & Functional Indicators | Ionic Type | Nonionic |
| HLB Value | 8.6 | |
| Active Content | ≥ 98% | |
| pH Value (1% Dispersion) | 5.0–7.0 | |
| Surface Tension (0.1% Aqueous Solution) | Approx. 28 mN/m | |
| Critical Micelle Concentration (CMC) | Approx. 25 mg/L | |
| Cloud Point | None | |
| Foaming Characteristics | Low foaming | |
| Purity & Hygiene Safety | Moisture | ≤ 1.5% |
| Heavy Metals (as Pb) | ≤ 10 mg/kg | |
| Arsenic (As) | ≤ 2 mg/kg | |
| Free Alcohol | ≤ 2% | |
| Characteristic Values | Acid Value | ≤ 7.0 mgKOH/g |
| Saponification Value | 155–175 mgKOH/g | |
| Hydroxyl Value | 290–360 mgKOH/g | |
| Iodine Value | ≤ 5 gI2/100g | |
| Monoester Content | Approx. 30–40% | |
| Diester Content | Approx. 20–30% | |
| Stability & Safety | Flash Point | > 150°C |
| Chemical Stability | Stable at room temperature and normal pH, may hydrolyze under strong acid or alkali |
Note: The above parameters are sourced from Guoli Chemical's product database and represent typical values or specification ranges. For specific batches, please refer to the factory inspection report.
Based on its HLB value (8.6) and W/O emulsifying characteristics, Span S-20 coconut acid is particularly suitable for: