Stearic Acid Polyoxyethylene Ether SG-9 (CAS No.: 9004-99-3), chemically named Polyoxyethylene (9) Stearate, with molecular formula C18H35O2(OCH2CH2)nOH (where n≈9), and molecular weight about 600. The product appears as a white to light yellow flaky solid, easily soluble in water, ethanol, acetone and other organic solvents. It has excellent chemical stability, resistant to acid, alkali and hard water.
As a nonionic surfactant, SG-9 has an HLB value of about 11.6, belonging to the category of oil-in-water (O/W) emulsifiers. Its critical micelle concentration (CMC) is about 0.07 g/L, and surface tension is about 31 mN/m, demonstrating good surface activity. The product exhibits low foam and low hygroscopicity, making it suitable for industrial scenarios requiring foam control.
In terms of purity and composition, SG-9 has an active content ≥99%, with monoester content ≥80%, diester content ≤20%, and free alcohol ≤3%. The heavy metal and arsenic contents are controlled at very low levels (heavy metals ≤10 mg/kg, arsenic ≤2 mg/kg), meeting strict safety standards for cosmetic and personal care raw materials.
| Parameter | Value | Remark/Condition |
|---|---|---|
| Appearance | White to light yellow flaky solid | Room temperature |
| HLB value | About 11.6 | Theoretical value |
| Cloud point | About 85–95°C | 1% aqueous solution |
| Melting point | 28–35°C | — |
| Density | About 0.99 g/cm³ | 25°C |
| Refractive index | 1.450–1.460 | 25°C |
| Flash point | >180°C | Closed cup method |
| pH value (1%/5% aqueous solution) | 5.0–7.0 | 25°C |
| Acid value | ≤2 mg KOH/g | — |
| Saponification value | 90–100 mg KOH/g | — |
| Hydroxyl value | 70–80 mg KOH/g | — |
| Iodine value | ≤2 | — |
| Kinematic viscosity | About 30–40 mm²/s | 40°C |
| Surface tension | About 31 mN/m | 25°C, 1% aqueous solution |
| Critical micelle concentration (CMC) | About 0.07 g/L | 25°C |
| Moisture content | ≤0.5% | Karl Fischer method |
| Active content | ≥99% | Solid content |
| Monoester content | ≥80% | — |
| Diester content | ≤20% | — |
| Free alcohol | ≤3% | — |
| Unsaturation | ≤0.08 mol/kg | — |
| Heavy metals | ≤10 mg/kg | As Pb |
| Arsenic (As) | ≤2 mg/kg | — |
| Ion type | Nonionic | — |
| Chemical stability | Stable, resistant to acid, alkali, hard water | Not resistant to strong alkali |
| Foam property | Low foam | Ross-Miles method |
| Solubility | Easily soluble in water, ethanol, acetone, etc. | — |
| Packaging specification | 50kg/200kg plastic drum, IBC tote | Guoli Chemical standard packaging |
Based on the HLB value (about 11.6) and physicochemical properties of SG-9, this product is particularly suitable as a primary emulsifier or co-emulsifier in O/W emulsification systems. In cosmetic creams and lotions, the recommended dosage is 1%–5%. It can be used alone or combined with low HLB emulsifiers to broaden the emulsification range. In textile oils and metalworking fluids, the recommended dosage is 2%–8%, leveraging its excellent emulsifying, dispersing and antistatic properties.
Due to its melting point of 28–35°C, it may be solid at low temperatures. Before use, it is recommended to gently heat and melt at 30–40°C with stirring to avoid local overheating leading to degradation. When adding to formulations, it can be pre-dissolved in the oil phase, then emulsified with the water phase.