What are the main industries and processes where Stearic Acid Polyoxyethylene Ether SG-40 is applied?

Stearic Acid Polyoxyethylene Ether SG-40 is widely used in five major industries: textiles, daily chemicals, metalworking, pesticide formulations, and papermaking, playing a core role as an efficient nonionic O/W emulsifier and multifunctional additive.

Detailed Description

Stearic Acid Polyoxyethylene Ether SG-40 (CAS: 9004-99-3) is a high-purity nonionic surfactant, appearing as a white to slightly yellowish waxy solid at room temperature. With its excellent emulsifying ability, strong electrolyte resistance, and superior compatibility, this product can form stable and fine emulsions over a wide temperature and pH range, and can be compounded with anionic, cationic, and amphoteric surfactants to produce synergistic effects.

In industrial applications, SG-40 is widely adopted for its multifunctionality: it can serve as both a primary O/W emulsifier and a wetting agent, dispersant, softener, and antistatic agent. With a high HLB value (approximately 16-18), it exhibits strong hydrophilicity and good dispersibility in water and various organic solvents, making it especially suitable for formulating water-based systems. Additionally, this product has extremely low acute oral toxicity (LD50 > 5000 mg/kg), is non-irritating to skin and eyes, readily biodegradable, and offers both safety and environmental benefits.

The following sections detail the specific application processes and functional roles of SG-40 by industry.

Industry Applications and Process Details

1. Textile Industry

SG-40 plays multiple roles in textiles, including emulsification, softening, antistatic, and leveling:

• Softening finishing process: As a component of softeners, it adsorbs onto fiber surfaces, imparting a soft and smooth feel to the fabric, reducing inter-fiber friction, and enhancing wearing comfort.
• Antistatic treatment: Its hydrophilic groups form a conductive film on the fiber surface, effectively dissipating static charge accumulation, suitable for spinning oils and finishes for synthetic fibers (polyester, acrylic, etc.).
• Leveling process: In dye baths, it acts as a leveling agent, slowing the dye uptake rate, preventing uneven dyeing and color spots, thereby improving dyeing uniformity and finished product quality.
• Synthetic fiber oils: As a component of oil formulations, it provides lubrication and cohesion, ensuring processing performance during spinning and drawing steps.

2. Cosmetics and Personal Care Products

In this industry, SG-40 is widely used as an oil-in-water (O/W) emulsifier, solubilizer, and emollient:

• Creams and lotions: It builds stable O/W emulsion systems, imparting a light feel to products, promoting uniform penetration of active ingredients without greasiness.
• Shampoos and body washes: It provides a fine and rich foam structure, enhancing the cleansing sensation and user experience, while also offering some emollient effects.
• Solubilization applications: It solubilizes oil-soluble components such as fragrances and essential oils, allowing transparent dispersion in water-based formulations.

3. Metalworking Fluids

In metalworking, SG-40 plays a dual role of lubrication and emulsification:

• Emulsifiable cutting fluids: As an emulsifier, it stably disperses base oil in water, forming a uniform emulsion that removes cutting heat and reduces tool wear.
• Grinding fluid formulation: It enhances the cooling and lubrication effects of grinding fluids, reducing grinding burns and improving workpiece surface finish.
• Auxiliary anti-rust function: It synergizes with rust inhibitors in formulations to reduce the risk of corrosion on metal workpieces after processing.

4. Pesticide Formulations

SG-40 plays a key role as an emulsifier and dispersant in pesticide processing:

• Emulsifiable concentrate (EC) formulations: It enables the pesticide active ingredient solution to auto-emulsify in water, forming a stable milky emulsion, ensuring uniformity during field dilution and application.
• Suspension concentrate (SC) additives: As a dispersant, it prevents flocculation and sedimentation of pesticide particles, improving storage stability of the formulation.
• Enhancing spray liquid spreading: It reduces the surface tension of spray liquid, enhancing its spreading and penetration on plant leaf surfaces, thereby improving pesticide utilization and control efficacy.

5. Paper Industry

In papermaking processes, SG-40 provides deinking and softening functions:

• Waste paper deinking process: As a component of deinking agents, it facilitates the detachment and separation of ink from waste paper fibers, improving the whiteness and cleanliness of recycled pulp.
• Paper softening treatment: Used as a paper softener, it enhances the softness and hand feel of paper sheets, particularly suitable for high-end tissue products such as toilet paper, facial tissue, and kitchen paper towels.

Technical Parameters

Application Recommendations

• Recommended dosage: When used as the primary emulsifier, the typical addition amount is 1%-5% of the total formulation weight; optimization should be based on the oil phase content of the system and the desired emulsion viscosity.
• Operating temperature: This product is a waxy solid; it is recommended to gently heat to 30-40°C to melt it before use for accurate metering and uniform dispersion.
• Compounding suggestions: It can be used in combination with low HLB emulsifiers (e.g., S-60, S-80) to adjust the target HLB value, achieving better emulsion stability and a broader range of applications.
• pH adaptability: It maintains good surface activity in acidic, neutral, and alkaline systems, adapting to complex process conditions.

Precautions

• Store in a cool, dry, well-ventilated warehouse; recommended storage temperature 5°C~35°C; avoid melting and caking at high temperatures.