Steareth-40 (SG-40) (also known as PEG-40 stearate, polyoxyethylene (40) stearate, CAS No.: 9004-99-3) is a high-purity nonionic surfactant produced by Guoli Chemical. The polyoxyethylene chain in its molecule imparts excellent hydrophilicity to the product. It is a white to slightly yellowish waxy solid at room temperature, disperses well in water and various organic solvents, and has a melting point of approximately 30-40°C.
Its most prominent feature is its ability as a highly efficient O/W (oil-in-water) emulsifier, capable of forming stable, fine emulsions over a wide temperature and pH range, significantly reducing oil-water interfacial tension. Moreover, its molecular structure exhibits excellent chemical stability, maintaining outstanding surface activity even in acidic, alkaline, and high-concentration salt solutions, an advantage that is difficult for many ionic surfactants to match.
From a safety and environmental perspective, this product is classified as non-hazardous, with extremely low acute oral toxicity (rat LD50 > 5000 mg/kg), no skin or eye irritation, low toxicity to aquatic organisms, and excellent biodegradability (meeting OECD 301 standards), aligning with ecological principles of sustainable development.
| Characteristic Dimension | Specific Performance |
|---|---|
| Emulsifying Ability | Highly efficient O/W emulsification; forms stable, fine emulsions over a wide temperature and pH range; significantly reduces interfacial tension |
| Electrolyte Resistance | Maintains excellent surface activity in acidic, alkaline, and high-concentration salt solutions; suitable for complex formulation systems |
| Compatibility | Nonionic nature allows compound use with anionic, cationic, and amphoteric surfactants, achieving synergistic effects |
| Wetting and Dispersing | Possesses excellent wetting, spreading ability, and solid particle dispersibility, enhancing system uniformity and stability |
| Physical Form | White to slightly yellowish waxy solid; melting point approx. 30-40°C; good dispersibility in water |
| Toxicological Safety | Extremely low acute oral toxicity (LD50 > 5000 mg/kg); no skin/eye irritation; non-sensitizing |
| Environmental Performance | Readily biodegradable; low aquatic toxicity (fish LC50 > 100 mg/L); non-hazardous |
Based on its core characteristics, Steareth-40 (SG-40) is mainly recommended for the following applications: