Stearic Acid Polyoxyethylene Ether SG-40, CAS No. 9004-99-3, chemical full name Polyoxyethylene (40) Stearate, also known as PEG-40 Stearate, Polyethylene Glycol (40) Stearate, Emulsifier SG-40. Its molecular formula is RO(CH₂CH₂O)ₙH (R=C16-18, n=40), molecular weight approximately 2045, produced by Haian Guoli Chemical Co., Ltd. This product uses stearic acid as the hydrophobic group and 40 oxyethylene units as the hydrophilic segment, belonging to the nonionic polyoxyethylene ether surfactant class.
SG-40 is renowned for its excellent hydrophilicity and chemical stability—it is easily soluble in water and various organic solvents, resistant to acids, alkalis, and hard water, maintaining superior surface activity even in complex electrolyte systems. As an efficient O/W emulsifier with an HLB value of 16-17, it can form stable and fine emulsions over a wide temperature and pH range. It also features low foam characteristics, with a critical micelle concentration of approximately 0.005%, and a surface tension of about 42 mN/m (25°C) for a 1% aqueous solution. The product has an active content ≥99%, monoester content ≥90%, high purity, good compatibility, and can be used synergistically with anionic, cationic, and amphoteric surfactants.
In terms of safety performance, SG-40 is classified as a non-hazardous substance, with an acute oral toxicity LD50 >5000 mg/kg (rat), no irritation to skin and eyes (OECD 404/405), no skin sensitization, no mutagenicity, and no reproductive toxicity. It has good ecological compatibility, with a fish LC50 >100 mg/L, is readily biodegradable (meeting OECD 301 standards), and does not readily accumulate in the environment.
| Parameter Item | Specification | Remarks |
|---|---|---|
| Appearance | White to light yellow waxy solid | Room temperature state |
| Ionic Type | Nonionic | Polyoxyethylene ether class |
| CAS No. | 9004-99-3 | — |
| Molecular Weight | Approx. 2045 | — |
| HLB Value | 16-17 | O/W type emulsifier |
| Cloud Point | >100°C | — |
| Melting Point | 48-52°C | — |
| Active Content | ≥99% | High purity |
| Monoester Content | ≥90% | — |
| Diester Content | ≤5% | — |
| pH (1% aqueous solution) | 5.0-7.0 | 25°C |
| Hydroxyl Value | Approx. 28 mg KOH/g | — |
| Saponification Value | 25-35 mg KOH/g | — |
| Acid Value | ≤2 mg KOH/g | — |
| Iodine Value | ≤1 g I₂/100g | Low unsaturation |
| Moisture | ≤1.0% | — |
| Surface Tension (1% aqueous solution) | Approx. 42 mN/m | 25°C |
| Critical Micelle Concentration (CMC) | Approx. 0.005% | — |
| Foam Characteristics | Low foam | — |
| Density | Approx. 1.05 g/cm³ | — |
| Flash Point | >150°C | Non-flammable |
| Heavy Metals | ≤10 mg/kg | — |
| Arsenic | ≤2 mg/kg | — |
| Chemical Resistance | Acid-resistant, alkali-resistant, hard water-resistant | Chemically stable |
| Packaging | 20kg/woven bag | Guoli Chemical standard packaging |
Textile Industry: Used as an efficient emulsifier, softener, antistatic agent, and leveling agent, significantly improving fiber hand feel, reducing static accumulation, and enhancing dyeing uniformity. The recommended dosage depends on the process, typically 0.5%-3% of the working solution.
Cosmetics and Personal Care: As an O/W emulsifier and solubilizer, suitable for formulations such as creams, lotions, shampoos, and body washes, providing fine foam and a refreshing skin feel. Recommended dosage 1%-5%, high HLB value, suitable for preparing oil-in-water emulsion systems.
Metalworking Fluids: Provides both lubrication and emulsification functions, used in formulating emulsified cutting fluids and grinding fluids, helping to remove heat, reduce friction, and provide auxiliary rust prevention. Recommended dosage 3%-8%, as an emulsifying base component.
Pesticide Formulations: Acts as an emulsifier and dispersant, stably emulsifying or suspending pesticide active ingredients in water, improving spray liquid spreadability and absorption efficiency. Recommended dosage 2%-10%, adjusted according to formulation type.
Papermaking Industry: Used as a deinking agent for waste paper and a paper softener, promoting ink separation and improving paper softness, especially suitable for the production of high-end household paper such as toilet paper and facial tissue.