In which industries and processes is Stearic Acid Polyoxyethylene Ether SG-9 primarily applied?

Stearic Acid Polyoxyethylene Ether SG-9 is widely used across six major industries: textiles, cosmetics, metalworking, pesticides, plastics & rubber, and coatings & inks. It plays a key role in processes such as emulsification, dispersion, antistatic treatment, and softening finishing.

Detailed Description

Stearic Acid Polyoxyethylene Ether SG-9 (PEG-9 Stearate) is a nonionic surfactant with an HLB value of approximately 11~12, produced by the addition reaction of stearic acid with ethylene oxide. Its molecular structure features both hydrophilic groups (polyoxyethylene chain) and hydrophobic groups (stearate ester segment), endowing it with excellent emulsifying, dispersing, wetting, solubilizing, and antistatic properties. Additionally, its nonionic nature provides excellent compatibility—it can be freely compounded with anionic, cationic, and other nonionic surfactants, maintaining stable performance over a wide pH range and in hard water conditions, thus offering a very broad application scope.

In practical applications, SG-9 can serve as either the primary emulsifier or co-emulsifier in O\/W (oil-in-water) emulsion systems, forming stable and fine emulsions; or, leveraging its antistatic and softening characteristics, it can be directly added as a functional additive in scenarios such as textile and plastic processing, achieving "multi-function in one agent" and simplifying formulation design.

Six Core Application Industries and Processes

1. Textile Industry—This is one of the most traditional application areas for SG-9. In synthetic fiber spinning oils, SG-9 acts as an emulsifier and antistatic agent, imparting good cohesion and smoothness to the fibers, significantly reducing friction and static buildup during high-speed spinning, and enhancing spinnability. In finishing processes, SG-9 can be used as a softener component, effectively improving fabric hand feel and drape.

2. Cosmetics and Personal Care—In creams, lotions, facial cleansers, shampoos, and body washes, SG-9 is used as an O\/W emulsifier and mild solubilizer, helping to build stable and fine cream or lotion systems while imparting a soft, non-sticky skin feel. Its nonionic nature ensures good compatibility with various active ingredients, making it a common emulsifier in personal care formulations.

3. Metalworking Fluids—In emulsified cutting fluids, grinding fluids, and hydraulic fluids, SG-9 provides dual emulsification and lubrication functions, promoting uniform dispersion of oil components in water, enhancing the thermodynamic stability of the working fluid, and helping to reduce tool wear and improve machined surface finish.

4. Pesticide Formulations—In pesticide formulations such as emulsifiable concentrates (EC), oil-in-water emulsions (EW), and microemulsions (ME), SG-9 is used as an emulsifier and dispersant, ensuring that the active ingredient of the pesticide is uniformly dispersed in water upon dilution, thereby improving thermal storage stability and emulsification performance during field dilution, ensuring full efficacy.

5. Plastics and Rubber Industry—As an internal antistatic agent and slip agent, suitable for polyolefins, PVC, and other plastic products. SG-9 migrates to the product surface to form a hydrophilic film layer, effectively reducing surface resistance and dust adsorption, while also providing some mold release aid effect, improving processing efficiency.

6. Coatings and Inks—In pigment paste preparation and emulsion polymerization processes, SG-9 can be used as a pigment wetting dispersant and emulsifier for emulsion polymerization, helping to improve the color development and storage stability of pigment pastes, and enhancing the leveling and gloss of the coating film.

Technical Parameters

Application Recommendations

• Textile oil formulation: It is recommended to be used in combination with anionic emulsifiers. SG-9 typically accounts for 20%~50% of the total emulsifier amount, balancing emulsification stability and fiber smoothness.
• Cosmetic creams\/lotions: Recommended dosage 1%~5%. It can be used alone as the primary O\/W emulsifier or compounded with low-HLB emulsifiers (e.g., glyceryl monostearate) to create a broader emulsification range.
• Metalworking fluids: As an emulsifier component, recommended addition amount 2%~8%. Better performance is achieved when compounded with anionic emulsifiers such as sodium petroleum sulfonate, significantly improving the stability and extreme pressure lubricity of the emulsion.
• Pesticide EC\/EW: Recommended dosage 3%~10%. Compounding with anionic emulsifiers (e.g., calcium dodecylbenzene sulfonate) helps improve the thermal storage stability and dilution emulsification dispersibility of the formulation.
• Plastic antistatic: As an internal antistatic agent, recommended addition amount 0.5%~2% (based on resin weight). Processing temperatures should not be too high to avoid thermal decomposition.

Precautions

• The product has mild to moderate irritancy to skin and eyes (R36\/37\/38). It is recommended to wear chemical safety goggles and chemical-resistant gloves during operation, and avoid direct contact.
• Ensure good ventilation in the workplace, and avoid inhalation of dust or mist. If it enters the eyes, rinse immediately with plenty of water for at least 15 minutes and seek medical attention.
• Store in a cool, dry, well-ventilated warehouse. The temperature is recommended to be not exceeding 35°C. Keep away from strong oxidizers and strong acids and other incompatible substances. Keep containers tightly sealed, and avoid moisture and direct sunlight.
• Although not classified as dangerous goods, avoid discharge into water bodies as it has certain toxicity to aquatic organisms (LC50 fish >10–100 mg\/L, 96h).