Span S-20 (CAS No.: 1338-39-2) is a water-in-oil nonionic emulsifier with an HLB value of approximately 8.6. Common issues during use can be self-checked according to the following directions:
1. Poor emulsification effect, emulsion stratification or instability
This is the most common problem. Possible causes include: ① HLB value mismatch - Span S-20 has strong lipophilicity. If used alone in an oil-in-water system, it needs to be compounded with high HLB hydrophilic emulsifiers (such as Tween series) to adjust to the required HLB value of the target oil phase; ② Insufficient dosage - It is recommended to start from 2% to 5% of the weight of the oil phase and gradually optimize; ③ Improper process - Excessive temperature difference between the oil phase and water phase or insufficient homogenization speed can affect the emulsification effect. It is recommended to heat both the oil phase and water phase to 40-50°C before mixing, and use a homogenizer for thorough shearing emulsification.
2. Product stratification, discoloration or precipitation
First, check whether the storage conditions meet requirements. The recommended storage temperature for Span S-20 is 5°C to 35°C. Solidification or crystallization may occur below the melting point, which is a physical change and does not affect product quality. It can be restored by warming to room temperature and stirring evenly. If the product color significantly darkens or irreversible precipitation occurs, it may be due to storage temperature exceeding 35°C or exceeding the 24-month shelf life. A new batch should be replaced.
3. Turbidity, gel formation or incompatibility with other components in the formulation
Span S-20 is nonionic and has good compatibility with anionic, cationic and nonionic surfactants, but caution is needed in strong acid, strong alkali or systems containing high concentrations of electrolytes. It is recommended to check the pH of the system (suitable range 5~7) and avoid simultaneous use with strong oxidizers. If the formulation contains multiple surfactants or additives, it is advisable to conduct small-scale compounding tests first, using the surface area incremental method to test compatibility.
| Parameter | Value |
|---|---|
| Appearance | Amber to light yellow viscous liquid or waxy solid |
| HLB value | Approximately 8.6 |
| Active content | ≥99% |
| pH of 1% aqueous solution | 5.0-7.0 |
| Acid value (mgKOH\/g) | ≤7.0 |
| Saponification value (mgKOH\/g) | 155~170 |
| Hydroxyl value (mgKOH\/g) | 330~360 |
| Critical micelle concentration CMC | Approximately 2.5×10⁻⁵ mol\/L |
| Kinematic viscosity (mPa·s) | Approximately 4000-6000 |
| Flash point (°C) | ＞150 |
For different industries using Span S-20, the following dosage ranges are recommended:
Hai'an County Guoli Chemical Co., Ltd. provides professional technical application support services to every customer. You can contact us through the following methods:
It is recommended to prepare the following information before contacting us, so that technical engineers can locate the problem faster:
The Guoli Chemical technical team will provide professional solutions from the perspectives of formulation design, process optimization, product quality review, etc., based on the information you provide. If on-site technical guidance or sample re-inspection is required, we can also arrange technical services.
If personnel safety is involved (e.g., eye splash, extensive skin contact, ingestion), immediately follow the emergency response measures in the product Safety Data Sheet and seek medical attention as soon as possible. Do not delay first aid while waiting for technical support.
→ Skin contact: Immediately remove contaminated clothing and rinse with plenty of running water and soap for at least 15 minutes. If irritation persists, seek medical attention.
→ Eye contact: Immediately open eyelids and rinse thoroughly with plenty of water or saline for at least 15 minutes, and seek medical attention as soon as possible.
→ Ingestion: Rinse mouth thoroughly with water, do not induce vomiting. Drink 1-2 glasses of water to dilute, seek medical attention immediately and show the product label.