What are the advantages of Stearic Acid Polyoxyethylene Ether SG-6 compared to other similar products?

Stearic Acid Polyoxyethylene Ether SG-6 has an EO number of 6, providing the most balanced hydrophilic-lipophilic characteristics among its series, with an HLB value of approximately 9.7, making it a preferred choice for multifunctional universal emulsifiers.

Detailed Explanation

The Stearic Acid Polyoxyethylene Ether SG-6 (CAS: 9004-99-3) from Guoli Chemical belongs to the PEG stearate series with an EO polymerization degree of 6. As the number of ethylene oxide (EO) adducts increases in this series, hydrophilicity gradually strengthens, and the product form transitions from solid to paste-like and even waxy. SG-6 with EO=6 is at the mid-to-low end of this series. Compared to SG-40 (which is overly hydrophilic and mainly used in high-water-phase systems) or SG-20 (which is more hydrophilic), SG-6 offers a more balanced affinity for both oil and water phases. This characteristic enables it to handle formulation systems containing both substantial oils and appropriate moisture, providing superior emulsification capabilities for mineral oils and animal/vegetable fats in scenarios such as pesticide emulsifiable concentrates and metalworking oil-based cutting fluids compared to high-EO-number counterparts in the same series.

From a molecular structure perspective, the ratio of the lipophilic group (C18 stearic acid chain) to the hydrophilic group (approximately 6 EO units) in SG-6 is optimized, resulting in an extremely low critical micelle concentration (CMC of about 0.08 g/L). This means stable micelles can form and exert emulsifying efficacy at very low addition levels. Such efficiency directly translates into formulation economy—users can achieve equivalent or even better emulsification stability while reducing surfactant dosage, something that high-EO-number products find difficult to accomplish in oily systems.

Technical Parameters

Application Suggestions

Scenarios where SG-6 is preferred:

• Pesticide Emulsifiable Concentrates and Emulsions in Water: SG-6 exhibits excellent emulsification and dispersion capabilities for plant oils and organic solvent-based pesticide active ingredients. Its HLB value of 9.7 lies in the transition range between water-in-oil (W/O) and oil-in-water (O/W) emulsions, allowing flexible formulation of emulsion-in-water or emulsifiable concentrate dilution systems with co-emulsifiers.
• Metalworking Oil-Based Cutting Fluids: In mineral oil-based formulations, the low EO number of SG-6 provides superior oil solubility while offering necessary emulsification, lubrication, and extreme pressure auxiliary performance, effectively reducing tool wear.
• Cream Cosmetics: The lipophilic nature of SG-6 ensures good solubility in the oil phase, facilitating the formation of a lightweight, non-greasy skin feel. It is an ideal primary emulsifier for preparing hydrating creams.
• Industrial Degreasing Cleaning Agents: Leveraging its low CMC and ability to rapidly reduce dynamic surface tension, SG-6 achieves quick penetration and efficient emulsification and removal in heavy oil stain cleaning formulations.

If the formulation is primarily water-based (e.g., water-based cleaners, high-water-phase emulsions), it is recommended to use SG-10 or SG-40 with higher EO numbers for better water solubility and high-temperature stability.

Precautions

• The cloud point of SG-6 is only 28-32℃. In systems requiring high-temperature processing (e.g., some textile scouring processes), it is advisable to blend with high-temperature-resistant nonionic or anionic surfactants to maintain overall performance.
• The product is slightly soluble in water. When preparing aqueous systems, it is recommended to pre-disperse with a small amount of ethanol or warm water before adding to the main phase, or use phase inversion emulsification to obtain a uniform emulsion.
• During storage, keep the container sealed and store in a cool, dry place at 15-35℃, avoiding moisture absorption and caking.