Stearic Acid Polyoxyethylene Ether SG-9, with the chemical name Polyoxyethylene (9) Stearate (CAS No.: 9004-99-3), has a molecular formula of C₁₈H₃₅O₂(OCH₂CH₂)nOH (n≈9) and a molecular weight of approximately 600. Industry aliases include: Polyethylene Glycol Monostearate, PEG-9 Stearate, Polyethylene Glycol Monostearate (9 EO). The product appears as a white to light yellow flaky solid with a melting point of 28–35°C, making it easy to handle and use.
As a non-ionic surfactant, SG-9 exhibits excellent compatibility and can be used in combination with anionic, cationic, and other non-ionic surfactants. It is chemically stable, maintaining its performance over a wide pH range, resistant to acids, alkalis, and hard water, and not easily affected by calcium and magnesium ions in water. The product has an HLB value of about 11.6, belonging to the category of O/W emulsifiers, and can effectively reduce the surface tension of liquids (approximately 31 mN/m), with a critical micelle concentration of about 0.07 g/L, allowing it to exhibit good interfacial activity at low concentrations.
The product has a monoester content of ≥80%, diester content of ≤20%, active substance content of ≥99%, and free alcohol of ≤3%. It is readily soluble in water, ethanol, acetone, and other organic solvents. The pH value of its aqueous solution (1% and 5%) is within the range of 5.0–7.0, making it a mild surfactant. The cloud point is approximately 85–95°C, and its low-foaming characteristics make it suitable for industrial scenarios where excessive foam is undesirable.
| Parameter Name | Value (Source: Guoli Chemical Product Database) |
|---|---|
| CAS No. | 9004-99-3 |
| Chemical Name | Polyoxyethylene (9) Stearate |
| Ionic Type | Non-ionic |
| Appearance | White to light yellow flaky solid |
| Molecular Weight | Approx. 600 |
| HLB Value | Approx. 11.6 |
| Cloud Point (1% aqueous solution) | Approx. 85–95°C |
| Melting Point | 28–35°C |
| Active Content | ≥99% |
| pH Value (1% aqueous solution) | 5.0–7.0 |
| Moisture | ≤0.5% |
| Acid Value | ≤2 mg KOH/g |
| Saponification Value | 90–100 mg KOH/g |
| Hydroxyl Value | 70–80 mg KOH/g |
| Iodine Value | ≤2 g I₂/100g |
| Surface Tension | Approx. 31 mN/m |
| CMC (Critical Micelle Concentration) | Approx. 0.07 g/L |
| Density | Approx. 0.99 g/cm³ |
| Kinematic Viscosity (40°C) | Approx. 30–40 mm²/s |
| Refractive Index | 1.450–1.460 |
| Flash Point | >180°C |
| Foam Characteristics | Low foaming |
| Monoester Content | ≥80% |
| Chemical Stability | Stable, resistant to acids, alkalis, and hard water |
| Biodegradability | Readily biodegradable (>60%, OECD 301B) |
| Heavy Metals (as Pb) | ≤10 mg/kg |
| Arsenic (As) | ≤2 mg/kg |
Stearic Acid Polyoxyethylene Ether SG-9 has a wide range of applications. The following are the main areas and suggested uses: